Author Topic: Glass fibre mould from the slender plug  (Read 2948 times)

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!
Steve
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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.

Offline vtsteam

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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!
Steve
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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

Offline vtsteam

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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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Offline PekkaNF

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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

Offline vtsteam

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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.