Author Topic: Glass fibre mould from the slender plug  (Read 1624 times)

Offline PekkaNF

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Glass fibre mould from the slender plug
« on: June 12, 2018, 09:22:50 AM »
My daughter needs a anime prop: about 1200 mm long sword that has opaque blade. Tried to mould that from PC, but it turned out pretty damn difficult.

Pretty much like on this picture:
https://www.pinterest.nz/pin/598556606695462033

Plan "B" is to use two layers 160 g/m2 glass fibre cloth and clear laminating epoxy to make two halves and then glue them together.

I'm making a practice run with another sword, that essentially is a katana blade. Plug is made from two halves, split, glued on the MDF board, finished and coated with two componenet acryllic paint. Covered it with six coats of release wax yesterday.

I was planning to make the mould with polyester resin (first gel coat brushed and then resin and glass mat), but I read that it the mould would take up two weeks to harden. Is that true?
https://www.ecfibreglasssupplies.co.uk/images/mouldmaking.pdf

"Leave the mould to cure up to two weeks at room temperature is desirable, post curing the mould is desirable but not sometimes practical, less if using low shrinkage tooling resin ( 2 – 3 days), releasing a mould too early can cause distortion to the mould."

Sounds pretty long....My mould would be about 1200 mm long (blade differently and handle separately) protrusions are small (specially with katana, it's only 3 mm for half thickness and planning to use only one thin mat and then two 400 g/m2 mats.

Tempted to use the better laminating epoxy to save least week, but I don't have compatible gel coat for that.

I keep on reading about tooling gel coat and that sort of stuf. They don't have them on the local shop and those materials are hazmat, when it comes shipping them. Aargh.

Pekka


Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #1 on: June 12, 2018, 03:30:58 PM »
Two more coats of wax. This is Katana type sword that will be for her friend. This is the practice piece and I'm considering mouldin process for this one.
« Last Edit: June 12, 2018, 04:47:25 PM by PekkaNF »

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #2 on: June 12, 2018, 04:54:48 PM »
And the somewhat transparent sword has few more tricky parts and I finally made my mind how to make it. Took three prototypes :Doh:

So the blade is symmetrical, plan is to make only one mould for blade and use it for both sides. Because that will require pretty good symmetry I made a single sided jig to use router and bearing/copy bit to make both sides of the plug symmetrical.

Now the blade plug is ready for final coats and to mount on parting board.

Drat, the pictures are on the other laptop....I'll update them when I have it back.

Basically I'm trying to find faster way of making the mold than two weeks.

Pekka

Offline Brass_Machine

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Re: Glass fibre mould from the slender plug
« Reply #3 on: June 12, 2018, 04:58:53 PM »
Have you thought about making the sword out of acrylic or some other clear plastic?

Something similar to this cosplay sword build.

http://chrixdesign.blogspot.com/2015/12/red-from-transistor-sword.html

Science is fun.

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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #4 on: June 12, 2018, 05:07:11 PM »
Yes. I tried vacuumforming 1 mm polycarbonate (for two halves) to make lightweight, strong and non offending blade. Proble is that that slender piece needs an long ifrared heater and it is hard to get even temperature distribution. Managed to make decorative twisters, they looked ok in the mold and then twisted half a round when realesd from the frame.

Three tries (and two 1 kW burnt IR heater) later I gave up. I mm polycarbonate would have been pretty good.

Pekka

Offline vtsteam

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Re: Glass fibre mould from the slender plug
« Reply #5 on: June 12, 2018, 11:44:54 PM »
Pekka, what about finishing the plug well and then doing a plaster of Paris mold over? Then varnish the plaster, wax it and mold your sword material in that?

Actually, since you seem to do really nice work in wood, what's wrong with a wooden sword? Traditional for practice and children's swords, I believe.

If you really want, you could glass the outside for some wear protection. -- it does take more finish work, but far less mold work, so they're about even.
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eskoilola

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Re: Glass fibre mould from the slender plug
« Reply #6 on: June 13, 2018, 12:09:08 AM »
Yes. I tried vacuumforming 1 mm polycarbonate (for two halves) to make <snip>
Polycarbonate is not very good material for vacuumforming. I does not get really soft and when it does, it already starts to decompose. I made a swarf shield for my tiny lathe from this material and it was an excersise with heat gun. The result is not pleasing but it does the job.

I quess acryl or ordinary PVC might be better.

eskoilola

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Re: Glass fibre mould from the slender plug
« Reply #7 on: June 13, 2018, 12:16:55 AM »
<snip>
Actually, since you seem to do really nice work in wood, what's wrong with a wooden sword? Traditional for practice and children's swords, I believe.
<snip>
Do You actually believe that a small wooden sword would have any chances of survival in the hands of a viking ?
The idea of making the thing out of polycarbonate has some appeal to it as that material is virtually indestructible.
One might consider using the vacuum to fill in the particle wood sword with polyester resin. I have used the polyester resin to repair housings of old tube radios which were broken and were made out of the particle wood. The resulting composite is actually very strong.

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #8 on: June 13, 2018, 02:21:17 AM »
I should have clarified few things:
* Both swords have to somewhat transparent, therefore something bit more opaque that wood is needed. I normally would make the core out of foam and epoxy glas fibre veil to it to give some strength and surface to finish, but that does not work on this one, because there is no transparent core material (or it is unobatanium).
* All anime props must be pretty harmles, they must have no "live" (read "real") metal and maximum strenght is "wood" or the prop is not allowed. Puts some limit on materials.

We made a halberd out of closed cell foam, plastic electrical conduit, some plywood on structurally critical parts. It's about 250 cm long and has all detachable spikes (three when assembled) and few spares. Weight very little and breaks if you poke anybody with it, but looks very menacing. That was easy.

Plaster of paris came to my mind, but the mould would be 1,2 m long, least 200 mm wide and some depth....probably shrinking would be a factor and on those dimenssions POP might need some serious inforcement. Think I'm going to go for polyester. Digged out the gelcoat, resin and noticed that the MEK bottle had leaked....what a mess. Luckily the plastic box I had all of them had contained the mess.

Pekka

Offline vtsteam

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Re: Glass fibre mould from the slender plug
« Reply #9 on: June 13, 2018, 10:55:49 AM »
Hi Pekka, I think you meant translucent in the first and last post -- not opaque, hence the confusion.

eskoilola, re. "Do You actually believe that a small wooden sword would have any chances of survival in the hands of a viking ?"

Depends on the viking (or in this case samurai, not to mix up our cultures) and the type of prop use. If for costume show primarily, wood will certainly do. But if the proposal is for actual clashing with replica-looking blades, any hard plastic will also dent pretty bad and even break. Light weight hollow soft plastic like polypropylene would be more appropriate and safer.

And btw to go along with Japanese culture, bamboo swords are quite durable, even in practice battles. Not that they are particularly safe if of scale proportions. Tubular blades are much safer.

Pekka while you may not prefer to use plaster of Paris for other reasons, it can be reinforced just like any modern plastic resin would need to be -- and you can use easily obtained or scrap wire or screen or mesh, as well as set into a wooden box for support. It cures very quickly, and no, it does not shrink, which is why it is traditional for molding. Vaseline (petroleum jelly) is a great release for it, all easily obtained and inexpensive materials.

But of course everything we do must appeal to us, and if epoxies and glass fiber are what you want to work with, that's the way to go. I'm jus throwing out possibilities to consider.
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Offline sparky961

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Re: Glass fibre mould from the slender plug
« Reply #10 on: June 13, 2018, 06:30:35 PM »
I'll bet your daughter just got tired of you bugging her and decided to give you a project to keep you busy. :P

Otherwise, your daughter has a pretty damn good dad!  Or maybe she's a little spoiled.... ;)

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #11 on: June 14, 2018, 02:46:51 AM »
She is spoiled, but there are few chores she has to do in and around he house to free my time for these projects. Most of the stuff I only show few minutes how to do and then leave her to finish the work for two hours. But glasfibre work is something I don't do routinely and I'm not sure. Last summer she helped me to pave front of the garage and booked up a hotel and drove her 300 km to convetiond and stayed there two night to see that she is safe, fed and all that parenting thing. Good deal.

Steve, I see. This has to be somewhat translucent. Like, if you hold the blade, you must see vaguely hand outline, but no need to see any details.

I might try POP later on smaller detalis, specially if I need only one-off part....I am bit sceptical on that parting off wax, I never had good results with vaseline or automotive waxes. Once I brought some aclaimed release wax from USA and transported it home on my lugage (those were the times!), and it worked ok, but needed really many layers and the can dried in the end. Karnauba fourniture wax worked well in my youth and solvent stink was bening.

Anyways, Resin rep. told me that with their resin and on my case, I need to wait one and half day and then the mould should be usable. So I layed up gelcoat, some thickened resin, chopped strand mat and finally twill to tidy up. I am rusty. Took really long to do all the stuff. Check this morning (less than 6 hrs of sleep) and it still is a litlle greenish and would have been time to cut edges off, but desided to leave un disturbed.

Now: 1) Will it release? 2) Will it have voids? Noob mistakes.....I don't feel too confident, but first on this decade (actually closer to 20 years.....) is first. :lol:

Pekka

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #12 on: June 15, 2018, 04:44:12 PM »
So....my big mistake: Went techno and tried new one can 2K paint to cover the plug.

All went initially well....mould popped open easy, but from filler. Not from separation wax layer....damnhik!

Called the wax manufacturer and they were rally helppfull, All should have been fine.

Then called paint manufacurer and explained the situation. We had a really nice chat. It perspired that in order to keep that paint from setting in the can they have mixed the acid hardener in water. Therefore the after spraying the water has to evaporate off the paint layer before it hardens and it might take 7 days and has to be open all that time....a chemist is going to call me on moday and explain it fully.


Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #13 on: June 15, 2018, 04:46:19 PM »
Anyway, because the chemical reaction did not finnish in three days, layers separated on competely wrong place and there was not end to my fustration.. I used some sanding paper to remove MDF, then acetone and wood spatula to remove the unhardened 2K paint and all started to look better.

After a little more polishing pad all started to look pretty good, found one hairline fracture and few little pores. Easy to fill with epoxy/microbaloons.

To be continued tomorow...

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #14 on: June 16, 2018, 08:23:58 AM »
Sanded down to gelcoat and then polished the mould.

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #15 on: June 16, 2018, 02:57:09 PM »
6 coats of release wax + layer of PVA release film

2 layers of 160  g/m2 twil and SP106 laminating epoxy. Hope it works, but it did not go around the corners that great. Hope it does not have exsessive amount of voids.

Pekka

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #16 on: June 18, 2018, 04:15:59 AM »
All went pretty ok, but:

1: I don't use gelcoat to keep the whole thing translucent, therefore back of blade side corner was not crisp. probably have to laminate veil and think of using a perforated separation film and pressurepad or slight pressure or vacuum on it.

2: Turns out that two layers of 160 g/m2 twill is thinner than I anticipated. Anyway, glued them together on the mould to see if can be done and keeps straight.

The release wax and PVA works, it even gives an early release....now went to other end of the extreme...look and learn I guess. Maybe just a dab of film on the nearly vertical feature of the mould (back of the blade).

Think that I'm going to put just a little mictoballoon or silica thickened resin at the very back of the blade section before veil, to keep it in shape, also very tempted to add some of that micture at the very blade edge to give more surface for gluing it. Might even need to make it two steps.

I got pictures, but they are boring and they donät actually show much....paper thin one meter katana type blade at this point.

Pekka

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #17 on: June 23, 2018, 04:50:41 PM »
Started working on another sword mold. Can't get my head around it, but think I'm going to build it in two part and need two moulds: blade/handle and cross piece.

Now the interesting part is that I am not very familiar with polyester resin. Information I read is a little confliking.

One major thing is: Some information emphasis putting a veil over gelcoat, let it dry (to various harness, often completely dry and then continue with structural layer. Some videos people seem to build pretty much (or least seemingly) the whole mould laminate on one go.

Which way it is and why? I never build that thich laminate, taht it will heat up.

I get that adding stiffeners to wet laminate will shine trough, but those I could add day later.

Any advice on mould laminiation sequence?

Pekka

Offline vtsteam

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Re: Glass fibre mould from the slender plug
« Reply #18 on: June 23, 2018, 07:58:42 PM »
Pekka, general purpose polyester resin (also sometimes called "finishing resin") generally has wax in it so that it will cure hard on the surface. Wax floats to the surface before cure, insulating it from air. Best for all-at-one-go type work, or as a final coat on a molded part IF you don't plan on attaching anything else to it, since a wax surface isn't good to adhere to. Polyester resin is a poor glue to any hard surface or material. Epoxy resin can be used to glue to polyester, if any surface wax is removed. But polyester itself will not work well with an already cured polyester surface, even after wax removal.

Laminating resin doesn't have wax in it, so that it can be added to by subsequent polyester layers or attachments in a mold. Even cured, it is still tacky on the exposed-to-air-surface, so subsequent layers of polyester WILL stick to and and cure it. Polyester without wax is an air-inhibited cure resin.

Gel coat also is air-inhibited cure, for the same reasons. subsequent layers need to adhere to it. However it does cure (harden) against the mold surface, since that side is not exposed to air.

Because laminating resin stays tacky on the surface, even when cured, you can add subsequent layers without having to rush it or build up too much thickness all at once. If too much thickness is built up all at once, all the resin will cure at the same time and get hot and cause other problems.

Is that any help?
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #19 on: June 24, 2018, 06:22:40 AM »
Thank you Steve very much!

That clear my confusion completely. Now I feel pretty stupid....I had read and "knew" all details, but could not connect the dots.

I knew the difference on gelcoat and topcoat, but never knew the fundamental difference on polyester resins. I was baffled, because when I was young I helped one motobike racer to build fairings and cowlings on my summer holiday...I remember him planning everytihing beforehand, and some stuff had to done when "green", some when hardened and some demended peel off ply. Pretty sure he always used tooling resin, because backside was always stricky and had to topcoat it in the end.  I think we were building only molds and remember him showing how different the parts were when laminated from epoxy or polyester.

This was exactly why I had this confusion, because my previous experience did not match my results.

That shop where I bought my resin had only one type of polyester resin. The plan is to use this can of that resin for next mould (will be build on one go then!) and try to find laminating resin for the next week.

Pekka

Offline sparky961

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Re: Glass fibre mould from the slender plug
« Reply #20 on: June 24, 2018, 01:40:28 PM »
I performed some significant rebuilding of the coaming on my fibreglass kayak last year.  I was going to use polyester resin because it's readily available.  But after doing some tests with it, I opted for higher quality epoxy resin.  Yes, it cost more.  But it doesn't have the nasty odour typical of polyester, and cures almost transparent - unlike most polyester I've seen.  I used MAS brand after reading through many, many reviews and unscientific test comparisons of brands.  It's less expensive than the oft-touted West Systems, but many people reported obtaining very good results with it.  Though I haven't had a lot of experience with it, I was certainly not turned away from epoxy work after using it.  It actually has such low odour that I sometimes initially forgot to don my respirator - though I tried to do so religiously.

Offline vtsteam

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Re: Glass fibre mould from the slender plug
« Reply #21 on: June 24, 2018, 10:10:39 PM »
Sparky, since you were adding to already cured resin, epoxy was the sensible choice. If you'd tried to use polyester, even with wax removal and abrasion, the bond would have been relatively weak by comparison.

There is a third choice, btw, vinylester resin, which has properties somewhere in between polyester and epoxy when laminating. However it has a very short shelf life, and is mainly used for specialty production moulding.

And just to add to the confusion, there are actually two kinds of finish resins commonly called "gelcoat" - the main and original type is sprayed into a female mould, and has an air inhibited cure. The second and more recent (and unfortunate) usage for the word applies to a color coat applied to the exterior of a male moulded part. And that must be an air hardening type, since it is the final finish exterior coat.
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #22 on: June 26, 2018, 12:21:58 PM »
Interestingly some seemingly large shops don't know or recognize that little difference on wether their resin has wax ot not. Laminating resin seems to be elusive. But found a palce to order black ot red gelcoat for moulds.

Ordered one small sheet of 2 mm acryllic sheet to have plan "B" for the almost transparent blade.

Today I have been making more plugs...need to find out what paint to used to make the MDF plugs smooth and non porous.

Pekka

Offline ddmckee54

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Re: Glass fibre mould from the slender plug
« Reply #23 on: June 26, 2018, 02:42:39 PM »
Pekka:

I stumbled across this youtube channel a couple of weeks ago. 

https://www.youtube.com/user/WJP004

Don't know if it will help or not, but he pretty much walks you through everything.  In various videos he shows all the steps, making the mold, hand laying up the part, de-molding the part, trimming the part and assembling multi-piece parts.

Hope it helps,

Don
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Offline vtsteam

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Re: Glass fibre mould from the slender plug
« Reply #24 on: June 26, 2018, 10:18:27 PM »
Interestingly some seemingly large shops don't know or recognize that little difference on wether their resin has wax ot not. Laminating resin seems to be elusive. But found a palce to order black ot red gelcoat for moulds.

Ordered one small sheet of 2 mm acryllic sheet to have plan "B" for the almost transparent blade.

Today I have been making more plugs...need to find out what paint to used to make the MDF plugs smooth and non porous.

Pekka

Yes, that's often the case -- even pro's sometimes don't understand the basic reasons for what they order for supplies day-to-day -- as long as their usual method works for them. If you understand the materials, though, you can also do something different than what you're used to day-to-day.

Pekka, re finishing MDF (or wood, as I do for patterns) try hand brushing lacquer with a few spoonfulls of baby talcum powder mixed into a pint (not the cornstarch type, but the real talc type). Uhh, I mean into a half liter. You have to keep it stirred if it sits too long.

This dries very quickly and sands beautifully with fine sandpaper. MDF is quite absorbent, so it might take 3 coats, sanding between each -- but it works very quickly. Then overspray with colored lacquer (Krylon regular in rattle-cans, here in  the US is lacquer based). Two coats, then wax, or release agent (PVA is often used.

Hope that helps.
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #25 on: June 27, 2018, 09:48:28 AM »
Thank you Don. Checcked few videos and he seems to know what he is doing....alhough I tend to wear more PPE. Got few pointers there.

Thank you Steve. I was making an order of black gelcoat, polyester resin and some perforated membrane. I added a small can of talc on the list and some microballoons. Now I only have to figure out correct laquere to mix that talcum powder...used to use some urethane varnish for boat and that sort of stuff. That brand is not anymore available, it would probably have survived most of the chemicals.

Water based products seem to be big time en vogue now....those create potenttial trouble with PVA release film, unless completely dried.

Would a thin epoxy do the trick? I would not need much, all parts are pretty small.

Pekka

Offline awemawson

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Re: Glass fibre mould from the slender plug
« Reply #26 on: June 27, 2018, 10:07:21 AM »
Years back when I used to use polyester resin for moulding, the worst clean up was when it got on your nails - seemed to have a great affinity for human nails  :bugeye:

So gloves as PPE I reckon are a GOOD THING in this case - seem to remember they were flimsy polythene things that fell apart.
Andrew Mawson
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Offline vtsteam

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Re: Glass fibre mould from the slender plug
« Reply #27 on: June 27, 2018, 12:18:18 PM »
Pekka, laquer is a specific type of fast drying evaporative finish. It's not oil based varnish or enamel, or a polyurethane.  It produces a very thin coating, high gloss, super fast drying.

This is what I use:

https://www.minwax.com/wood-products/clear-protective-finishes/lacquer/minwax-clear-brushing-lacquer.

I don't think talc would work as well in other finishes. The would seem to be too thick, and would dry slowly, as well as be difficult to sand, by comparison. Epoxy would be even harder to work with, and goes on in gloppy drips. Lacquer is very fine, and the talc is the main thing you are sanding away.

And don't use microballoons except in a filler putty, if you want a fine finish.
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #28 on: June 27, 2018, 05:01:58 PM »
Thank you, I'll need to follw that lead.

I put some pictures to enertain. I am big fan of router, even drill holes with it.

Pekka

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #29 on: June 27, 2018, 05:07:47 PM »
Cross guard plug

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #30 on: June 27, 2018, 05:14:11 PM »
Did I mention that I like router copy bits, specially bearing type. And closely followed by one that you can use to drill hole and then copy.


Offline vtsteam

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Re: Glass fibre mould from the slender plug
« Reply #31 on: June 27, 2018, 05:24:37 PM »
You do great work with a router, Pekka.  :bow: Routers and I just don't do well together.  :zap:
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #32 on: June 28, 2018, 03:15:31 AM »
Thank you Steve. Means a lot coming from you. I always admired the patterns you make for sand casting and somehow they look always more demanding than my doodlings.

Routers and mixing .... I remember when I was learning to use router (pre internet -hard way), probably made all the mistakes on the book and pretty sure I invented some of my own. I learned not to route free hand - after the router run amok, me hanging on it. I learned not to hog - after the router caught a piece of wood and splinters flying every direction and learned to follw the grain and importance of the routing direction, when I got spintters more than moulding....but now I can make jig fast and use that to make joints or symmetrical parts fairly consistently.

Put on those parts some epoxy/filler putty and will sand them on the evening. Where I were with the filler? Have to have a call to local paint shop on the evening.

Pekka

Offline vtsteam

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Re: Glass fibre mould from the slender plug
« Reply #33 on: June 28, 2018, 01:12:09 PM »
About 40 years ago as an apprentice boatbuilder I had built a 16' long skiff, Painted topsides and interior, with only the sheer clamp (rails) unvarnished. It was 3/4" x 1-1/2" Doug Fir batten run down the outside of the sheer plank. I had my shiny new Sears router, and I thought I'd just radius the upper corner a bit with it.

Well, I confidently got half way down the first side from the bow when the router found a slight change in grain, and zip, it plunged diagonally in following the grain, right through the plank and out the other side, The rail broke in half under the pressure of the bend and side suddenly had a big kink in it.

That all happened in the blink of an eye. I just stood there, unbelieving, and went huh?

Sounds like you know what I'm talking about, though, too Pekka -- and obviously have worked your way past the initial little kinks in the road!
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #34 on: June 29, 2018, 03:41:16 AM »
I feel your pain. Happy didn't bite you.

I put on my brown pants when I mount over 2" bit on 2kW hand router, even if part router is mounted. You have to have a healthy respect to these things.

Pekka

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #35 on: July 01, 2018, 05:25:41 PM »
Lately, it has been basically sanding, fitting, finishing etc.

I have some mystery old polyester putty, filler, etc, How fast tye go off? Any way to figure out if they are good to go, marginal, or useless. I know that polyester resin has best before date and mechanical spesification is valid only for a year,

But how that works out in mould or something less demanding. Doesn't the hardere expire faster?

Pekka

Offline vtsteam

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Re: Glass fibre mould from the slender plug
« Reply #36 on: July 01, 2018, 06:26:20 PM »
Just try a test sample, Pekka. I think if it hardens properly, and sands okay it's good enough to use.
I love it when a Plan B comes together!
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #37 on: July 07, 2018, 10:47:33 AM »
Testing

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #38 on: July 07, 2018, 05:25:31 PM »
6 coats of release wax and half of it coated with PVA. Then I applied top coat (all black), but it would not gel in one hour and temperature was 23C. Odd...then I check the amount of hardener. Crap, i was suposed to use 1,8% but I used 1%. Excess of the gelcoat hardened on the can, but not on the sample piece. Double crap. Put it in the garage overnight and hope gelcoat is sticky on the morning.

Noob mistake.

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Re: Glass fibre mould from the slender plug
« Reply #39 on: July 07, 2018, 10:11:59 PM »
Maybe try exposing it to sunlight, Pekka? Don't overheat it, but try a short period? Besides the warmth, the UV might catalyze the cure somewhat.

Wait -- is this gelcoat supposed to remain tacky for good bonding to the glass above?

Or is this a topcoat type gelcoat that goes over everything, and you already have done your laminations under it?
I love it when a Plan B comes together!
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #40 on: July 08, 2018, 04:26:39 AM »
It is a real gelcoat and it is sopposed to be tacky before lamination, but not mark finger when you touch it. You know the drill. I forgot that gelcoat needs somewhat more hardener than polyester resin...they all are between 1-2%, but mfg. reccomedations varies and they are suposed to give a table that has corrections on air temperature and laminate thikness etc.

Anyway, could not sleep right away and gave a last check to it at 0100....it was perfect. Laminated two chopped strand mats to it with 100g of polyester resin, tooks shower and slept really well.

This morning it was all good, cut out strands, ground edges and ripped it open. It released just normal.

I got the results I wanted.

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #41 on: July 08, 2018, 04:42:48 AM »
Bottom plate is high peressure laminate over MDF, samples are tongue presser spatulas glued with epoxy.

Different paints and different drying times.

Six layers of release wax and half of the sample plate was covered with very thin layer of PVA.

Interesting notifications:

1: yellow strip, was just normal Pelikan Nakiplast, play dough (much beeswax?), soft and stcks to laminate, but releases fine and renders the shape pretty nice. Fastest.

2: Filler paste, the type that is used indoors to cover dents and holes on the walls before painting. Sandings easy on shapes, but shrinks - needs many layers. Porous and definately benefits from PVA.

3: Blue epoxy filler is expensive but nice. Dries few hours, but shrinks very little, sands just perfect and keeps the shape well. Only filler that is not porous and does not stick to mould.

other were different paints and drying times. I found one 1k epoxy base paint that dries fast, sands well and works out fine when let dry more than 24 hours. 12 hours you need PVA, shows on one sample.

Last sample was the traditional epoxy filler, primer, 2K urethane (dried 6 hours, which 2 hours in 90C in powder coating oven curing) and it worked out perfect ocourse. Looks horible, because I spread it with brush (5 ml of paint and 1 ml of hardener, hassle with sprayer). But the mould repeats the brush strokes beatiful.

Now I have the system (1k base paint, sanded fine, two days of drying (small samples faster when dried in oven) and wax + thin PVA) if I need waster, then beeswax and if I need better results, then 2K urethane, but that adds work and time.

Happy with test results, I actually got results.

Pekka

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Re: Glass fibre mould from the slender plug
« Reply #42 on: July 08, 2018, 01:37:12 PM »
That's great Pekka! Good job testing samples and refining what your own needs are.  :smart: :dremel: :clap:
I love it when a Plan B comes together!
Steve
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Re: Glass fibre mould from the slender plug
« Reply #43 on: July 09, 2018, 05:16:13 AM »
Thank you.

I had some trouble with this laminate...gelcoat geled faster and then this new polyester resin behaved differently, it did not wet the mat and was not tacky. Made it harder to negotiate around bends and bulges. Rolled a lot but the mat did not settle down and was hard o remove air. Hope there are not too severe rat holes near gelcoat, at the top there are plent of pockets and pools.....it was getting dark and and I was getting tired. Next time I will do only one mold per evening.

Questions:

1) Can I use this normal gelcoat and laminate epoxy over it? Gelcoat seems to produce good surface, but I feel more comfortable using epoxy to laminate thin parts. Handle parts needs paint and such embelishments.

2) If I gelcoat parts of the epoxy laminate, is there any tricks to paint parts of the gelcoated parts. Like if most of the surface is white and then some needs to be painted black or blue. Normal spray can paint is good enenough for few days and does not smudge hands?

Pekka

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Re: Glass fibre mould from the slender plug
« Reply #44 on: July 09, 2018, 08:18:18 AM »
Pekka, I think you're going to have to experiment again to answer #1 with the particular gel coat and epoxy you have, since that all varies. I don't know, myself.

Painting over cured gelcoat should be fine. You'll probably want to wipe it down with acetone or MEK. A light hand sanding with extra fine paper or even Scotch-Brite pad to kill the gloss wouldn't be amiss. That's what I would do, anyway.

It always boils down to the specifics of what you have for paint, etc. But cured, hard polyester fiberglass, in general paints well if wax is removed and the surface very lightly sanded.


ps, I'm also a little surprised that you are using mat on these swords instead of cloth. Mat is not easy to conform to short curves -- it has sizing in it. It's okay for large surface curves, like boats.

I would think you'd use cloth for a sword shape. And where there are complex curves, use strips cut diagonally across the bias. These will really conform well to those areas. Tape is not as good because it has a selvedge edge. Cut your own strips out of regular cloth at a 45 degree angle to the weave for difficult areas. The only trick is not over-tooling it when laying it in place, because fibers will get picked up from the edge and make a lump.

I'm guessing that you'd want something 6 oz/yd or lighter for the swords (sorry about the non-metric number, but that's what I'm familiar with). The lighter you go, the easier it will be to conform to curves, but the harder to lay in the mold without it sticking to your tool and pulling back out. And you will want more layers with very light cloth -- it's available down to 3/4 oz/yd which is like tissue.
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #45 on: July 09, 2018, 10:25:26 AM »
Thank you Steve,

You always give me usefull information to go with.

I pated down onto gelcoat twill woven fabric 160 - 200 g/m2, that's what I had in hand ant it looks like that samed my day. No problem's on the mould part of the most laborous and ambitious mould on the mould part, but all the trouble in the world outside of the mould area,

I had then impression that the mat is used to make moulds with polyester to build the bulk, it's cheap and it's available. I never really have been using much mat to epoxy, because the bulkier ones are for polyester resin ( I think it's the emulsion binder on the mat that does not work well with epoxy).

So far I have been opening three moulds, I haven't opened the last one I laminated. I'm having some trouble I am not certain, which was my inexperience in laminating, which was wrong choice of materials and was there incompapibility issues.

I made four moulds and one came out fine, one bombed (not sure am I going to try to fix it or do parts from plywood instead), most difficult one and the one I had all the trouble with came out usable on important features, but outside of those it has all the problems I can think off (did not burn though....) and the least important mould I made last and I'm willing to write off before I even open it is not open yet.

I'll make some post, one mould at the time. Comment welcome,

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #46 on: July 09, 2018, 10:40:44 AM »
This is sword #3, katana size fantasy sword that is higly impractila in any material. I had a comics drawingis to go, so I break o pieces that can be made.

The plug was easy to make and this is the first mould I made last night, Black gelcoat (used for the next item from the same pot). When gelcoat was coldilocs tacky, I patted precut pieces of twill woven fabrics, stiipled resin with brush and added a layer of mat, rolled it down and then final layer of twill. Pretty thin mould but I need only one piece out of it.

It did work out fine, has few air inclusions and few plug under runs. Nothing too severe thoug.

The last picture of the blade tip is about 1" wide, kept the shape pretty good. Mould is washed but not sanded or finished.


Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #47 on: July 09, 2018, 10:57:12 AM »
And this is sword #2 handle that I laminated in stages (used leftovers to smaller parts).

It is rather deep and large mould. This is the mould I had most trouble with in every step on the way.

Used the gelcoat from the same batch that previous one, this is the first time the gelcoat started to gel in the mixing mug and when it happened I rejected the rest and made new batch.

I covered the critical parts of this mould with the pieces of twill woven glass cloth, patted them down and proceed with mat, which I run out of and used leftover fabrics, because I had no idea how to pause at this stage: a) leave the gelcoat to dry 6-8 hours and continue as nothing happened b) put one layer of cloth/mat, laminate it with resin and then wait 6-8 hours before shops opens. Option b is tricky, because I have not been able to get toolin/laminating polyester resin, it is all finishing resin (wax in it, has to be ground off to continue).

Anyway, I had all the trouble during lamination: gelcoat that starts to set, resin that does not wet mat well, deep structures that I had hell of the time trying to press down and remove air. It was getting dark too and my worklight was a streetlight 50 meters away.

Next time I will not rush things.

But those wrinkles on the flat part of the panel. What I did wrong?

Ugly, huh?



Offline vtsteam

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Re: Glass fibre mould from the slender plug
« Reply #48 on: July 09, 2018, 11:03:42 AM »
Okay, I see, you're using mat to bulk up the female mold after first laying on cloth.

As a suggestion, it would be easiest then if the mat is laid in as narrow strips of reinforcing after your first layers of cloth -- maybe three of the mat strips -- two for the two edges to reinforce the mold flanges and a narrow one down the center to reinforce the bottom of the mold. These three don't have to touch. In fact it would be harder to get them in place and saturated if they did. The thing you want to avoid is trying to bridge an inside corner with any mat strip. It just won't want to stay there easily, or without bubbles.

There will be spaces between the separate strips. That's okay. As long as the flange strips come in all the way to the edge of the sword without turning 90 degrees onto the blade. After the mat is in, you could lay in your backing cloth or more mat or whatever. From  that point out, voids don't matter much, you are just building thickness and stiffness in the mold.

The handle area will be different -- I'd be tempted to just build that up as cloth only.  It will be hard to make mat lay down there.

I'd still use 45 degree cut cloth strips to do the layers against the gel coat, to get the best conformity without air bubbles or voids. Actually I'd use it throughout -- even the final reinforcement over the mat. It just lays down so much easier.
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #49 on: July 09, 2018, 11:04:19 AM »
What did I do wrong here? Parts are about 2" wide and longest part is 5"? long.

Offline vtsteam

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Re: Glass fibre mould from the slender plug
« Reply #50 on: July 09, 2018, 11:21:54 AM »
Looks like you just had adhesion problems -- gel coat was bonded more strongly to the mold (release) than to the laminate. So it broke the particle board mold and also separated off of the laminate.

Maybe it just didn't cure. That would leave it adhered glue-like to the mold, and not firmly attached to the laminate -- that's just a guess. Maybe something inhibited full cure?

For separating parts, have you tried compressed air?

I have to say that I don't use particle board or MDF for patterns of any kind -- I know others do, but I don't like it. I think it's too easily damaged, and also subject to moisture attack. I like wood.

If you're going to stick with particle board or chipboard or MDF, I would guess you really need a deep coating of finish and it needs to be a very glossy and strong finish that is well cured.

Just another suggestion.... when applying glass to a mold inside corners or a small female mold, use a small stiff disposable paintbrush and push the cloth into place with the tip -- like stippling paint -- kind of tapping it in. Don't try to brush the resin in like you would paint with it. That will just move the cloth and shred fibers from edges, or pull the cloth from somewhere else and make bubbles and voids. Maybe you already know this, just adding my own experiences here.
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #51 on: July 09, 2018, 11:37:13 AM »
Thnk you,

The gelcoat held ont mould everywhere, but not on the undercuts, where it had wedged. Waxing and separation here was not issue, only on the "decoration" part that had practically undercut, not draft, or what is that taper that enables separation. The wrinkles were real....googling says that often they are product of laying too thin gelcoat...I never seen that problem before and i never had it before, but problems seem to be ofthen (but not always) on the places that had litle gel coat.

I popped open the mold #4, that was made in dark, I literally had to pat down the twill over the gelcoat to see where it was. i tried new to me special foam/fabric I got small sample here. it builds 2 mm on one layer.

This mould is all wrong but for some reason the most important parts seem to be ready for lamination. This plug was way too deep and it has unpractical features, because the whole part was designed to come out at certain "deck height" to fit all parts together. Out of 11 mm of depth only 3-4 mm is used, the yellow wax made it possible to separate mould from plug,

pretty ugly, don't you think

I'll finish moulds and leave them to dry until tomorow. I'll read the messages at night.

What a learing curve.

Thank you,
Pekka

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Re: Glass fibre mould from the slender plug
« Reply #52 on: July 09, 2018, 11:49:17 AM »
Oh, okay, undercuts. That would be a definite problem, and the more you reinforce the mold the worse the problem because you can't stretch it at all to clear the undercuts.

And I take your word for it re, the gel coat being too thin.

Yes, a learning curve for sure! But you seem willing to persevere which is the best way to become expert at anything. I'm sure you will win this battle, Pekka!  :smart:
I love it when a Plan B comes together!
Steve
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #53 on: July 09, 2018, 01:28:19 PM »
Thank you for couragement and advice.

I did sort of postmortem to the worst part (decoration):

1) no matter how much I tried to put gelcoat on top, it flow to bottom...the smallest pits were around half a inch diameter and bottom was filled thick and rim was starved. I have sometimes brushed very thin layer of gelcoat and then mix glass spheres and silica gel to gelcoat and brush that over it. Now I skipped it, thought that those don't have that sharp edge. Big mistake.

2: This was made worse by delaminated fabric, it did not adhere on thight corners. I was thinkking of this and tried to get milled glass fibre to sprinkle there.  Wonder if polyester putty would have worked here?

3: I used half an inch wide strips to laminate it, but it did not work here. I tried to push cloth into corners with stiff brush and even with finger (clove). This might have been last mistake....think that when I pushed one void down, it pulled next out?

i have been waching some videos, but sometimes one hour hands on training with a mentor might be more efficient than 100 hours of videos.

Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #54 on: July 15, 2018, 08:05:10 AM »
Turned out that that the other make gelcoat had all the problems and another had no problems, even if I pushed it on very thick on thin.

Anyways, most things I tried had a snag here and there. and delayed finsishing it to deadline, but two very late nights saw a lot of progress, last steps really transformed crude parts to fairly convinsing looking parts.

Next time all steps will be done and no very few corners are cut (on drying times etc. basic stuff).

But my dayghter had a sword she is happy


Offline awemawson

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Re: Glass fibre mould from the slender plug
« Reply #55 on: July 15, 2018, 09:12:35 AM »
That should slay a few dragons  :clap:
Andrew Mawson
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Offline PekkaNF

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Re: Glass fibre mould from the slender plug
« Reply #56 on: July 15, 2018, 04:42:44 PM »
And it was partly translucent!

That got some attention, some were thinking that it could not be "legal" but when they held it, they concluded that it was pretty light to be dangerous and most just could not get over with the glass fibre part.

It shows some wear, specially gold painted parts, but my daughter thinks that it shows some real character and looks more like weathered.

Most importantly it held 8 hours of constant handling.

Pekka

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Re: Glass fibre mould from the slender plug
« Reply #57 on: July 16, 2018, 07:24:03 AM »
Great job, Pekka ! Looks really fine.  :clap:  :clap:  :clap:

 :mmr:
I love it when a Plan B comes together!
Steve
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