Author Topic: Banjo Build (Read 154549 times)

S. Heslop · « **Reply #225 on:** June 25, 2015, 03:44:40 PM »

Spent today sorting the tablesaw out. It's always been about half a degree off square since I made it, and it's one of those things I figured i'd sort out when it became a problem. Had to remove a bit of material from one of the parts, and the new rasp came in handy for that. I also sorted out the fence, which had alot of flex. It's still got some flex but it's alot more solid than it was.

Cut some strips. There's still saw marks on them but i'm blaming the cheap blade i've always been using. Sometimes I think about getting a fancy blade, but they're so damn expensive.

The idea for the fingerboard is to make it up from strips in some sort of pattern. There's probably a good reason why people tend not to make fingerboards this way, but I guess i'll find out why when it's done. I'm mostly doing it this way since i've got no wood left that's long enough to make a fingerboard from.

The obvious problem with this is that it's gonna be a hell of a thing to glue up. The strips are coming out about +/- .1mm and that's probably enough to cause some problems. I think most likely i'll make up some sort of fixture to clamp them about two strips wide at a time, so I can joint those to glue the whole thing.

Also, I spooked myself by measuring the neck on my existing banjo (which i'm mostly copying for proportions) and finding I was off by about 40mm. The dotted line on that diagram above is where the neck should really end. I've tripple checked the measurements now and it's just puzzling me how i'd be that far off in the first place.

S. Heslop · « **Reply #226 on:** June 26, 2015, 10:45:32 AM »

This drum sander is the best thing I ever built. I'm getting alot of use out of it. Here i'm thicknessing the boards because they came out with half a millimeter's difference.

Then they were trimmed to about 100mm long.

Got just enough of them.

Then glued up in rows of two. It's a bit of a weird setup, got little wedges applying the pressure (with a thin stick in between to hopefully even the pressure out), and at the edges ive got more wedges in an attempt to force... down the columns? It's hard to see how well it worked with glue obscuring it all, but I'll find out when it's done. There's also waxed paper tacked all over to stop them from sticking to what they're not supposed to.

I think they're guaranteed to have some gaps, but hopefully nothing too bad.

S. Heslop · « **Reply #227 on:** June 27, 2015, 01:32:34 PM »

Finished gluing it up.

Ran it over the jointer a few times to partially even the surface up. The glue is still a bit damp so I didn't go all the way. Just enough to see if it worked.

Plenty of gaps but it's still alot better than i'd expected. You can see the steps aren't quite even too, since the stops I had moved a bit. But the sticks are 6mm wide so it's not as noticeable as in this photo.

RussellT · « **Reply #228 on:** June 27, 2015, 03:50:44 PM »

That looks good

Do you think it would look even better if you'd alternated the strips across the neck as well. Perhaps you could take it to bits and try gluing it up that way instead.

Russell

S. Heslop · « **Reply #229 on:** June 27, 2015, 06:40:28 PM »

Quote from: RussellT on June 27, 2015, 03:50:44 PM

That looks good

Do you think it would look even better if you'd alternated the strips across the neck as well. Perhaps you could take it to bits and try gluing it up that way instead.

Russell

I tried a few arrangements in software to see what worked, and tried that too, but it looked a bit weird. It does also seem weird to cut all these strips and not do anything too fancy with them.

But like a true artist, i've been trying to cleverly justify this arrangement after already deciding on it. And i'm going with "it helps emphasize the asymmetry inherent to the banjo".

S. Heslop · « **Reply #230 on:** June 28, 2015, 01:13:16 PM »

Tidied the fingerboard up a bit more.

And started working on the neck proper. There's alot of things to do with it to turn it into a neck, of course, but i'm fussing over what order to do it all in. It's alot to keep track of. First I need to get that angled face looking a bit better, and that's going to require getting ahold of some MDF I figure to make a thing to sand it.

I'm mostly following what the guy is doing in these videos.

micktoon · « **Reply #231 on:** June 28, 2015, 06:52:34 PM »

Hi Simon , the joins look really neat , just had a look at the sanding jig, simple but effective

Keep up the good work .
Cheers Mick

S. Heslop · « **Reply #232 on:** June 30, 2015, 05:23:40 PM »

Quote from: micktoon on June 28, 2015, 06:52:34 PM

Hi Simon , the joins look really neat , just had a look at the sanding jig, simple but effective Keep up the good work .
Cheers Mick

Thanks! The joints seemed real bad on the surface, but look alot better planed down a bit. Still some gaps though.

Haven't gotten alot done the last couple days since i've caught yet another lung infection. Just in time for the hottest damn day.

Got that thing made up though and the angle sanded.

AdeV · « **Reply #233 on:** June 30, 2015, 08:43:03 PM »

There's some really great work here, I am in awe of woodworkers, I don't know how you can cope with the damn stuff. Floppy as anything, won't hold an edge, splinters if you so much as look at it funny.... ugh, give me a nice piece of ali or steel any day of the week...

Regarding the 40mm overshoot on the fingerboard - is it too late to turn it into a banjo bass? Or maybe a tenor if bass is a bit too much of a stretch

S. Heslop · « **Reply #234 on:** July 17, 2015, 11:24:34 AM »

Quote from: AdeV on June 30, 2015, 08:43:03 PM

There's some really great work here, I am in awe of woodworkers, I don't know how you can cope with the damn stuff. Floppy as anything, won't hold an edge, splinters if you so much as look at it funny.... ugh, give me a nice piece of ali or steel any day of the week...

Regarding the 40mm overshoot on the fingerboard - is it too late to turn it into a banjo bass? Or maybe a tenor if bass is a bit too much of a stretch

I used to hate the stuff too. Plywoods and other engineered woods helped ease me in since they're much easier to work with. I guess the big boon is that it's easy to cut and fairly light. Cheap too!

A few days ago I thought i'd go nuts and spend some intense time working on this. But I tidied the garage up and then had a rough evening with the bronchitis from the dust I disturbed just moving things about. I can get in with the respirator but it's not particularly pleasant to wear for long periods of time.

Anyways I did a bit playing with shellac today. Trying a few things on filling the grain.

For this bit I used a slurry of sanding dust and shellac to try push into the grain.

And for this I just put some real thick coats on. Both were sanded after every few layers, and I've got about 12 layers in total.

Neither seemed to work ideally, but the slurry worked best. I'm not entirely fussed about how it looks, but I figure on the back of the neck the grain will need to be filled so it doesn't fill up with dead skin and grease from my disgusting hands.

I think it'd probably be easiest to just buy some paste wood filler and fill the grain that way, instead of trying to do anything clever.

awemawson · « **Reply #235 on:** July 17, 2015, 12:42:18 PM »

I'm no woodworker, but I do seem to remember 'grain filler' made up from knotting filler diluted with solvent and a bit of dye added to match the colour.

Swarfing · « **Reply #236 on:** July 17, 2015, 01:18:47 PM »

To fill the grain you would be better off putting lots of layers of your finish and sanding back between coats. Better than losing the beauty of the wood.

S. Heslop · « **Reply #237 on:** July 17, 2015, 04:08:52 PM »

Quote from: awemawson on July 17, 2015, 12:42:18 PM

I'm no woodworker, but I do seem to remember 'grain filler' made up from knotting filler diluted with solvent and a bit of dye added to match the colour.

Yeah I think that's the right way to do it, I was just wondering if I could avoid buying something.

Quote from: Swarfing on July 17, 2015, 01:18:47 PM

To fill the grain you would be better off putting lots of layers of your finish and sanding back between coats. Better than losing the beauty of the wood.

With any other varnish i'd agree, but this shellac stuff puts on absurdly thin layers. It's very thin stuff when mixed so you cant goop it on so easily. Plus I don't think this construction meranti and scrap walnut has too much by the way of beauty.

krv3000 · « **Reply #238 on:** July 17, 2015, 08:09:49 PM »

hi well get sum clear casting resin its a bit like fibre glass resin you mix it in the same way but its culler less brush on leave to harden then sand off its mutch harder than varnish and can be polish to a mirror finish

S. Heslop · « **Reply #239 on:** July 17, 2015, 08:16:10 PM »

Quote from: krv3000 on July 17, 2015, 08:09:49 PM

hi well get sum clear casting resin its a bit like fibre glass resin you mix it in the same way but its culler less brush on leave to harden then sand off its mutch harder than varnish and can be polish to a mirror finish

I made a couple of model boats when I was 12, and the second one I coated in exactly that stuff from a recommendation. Perhaps I didn't mix it properly but it took years for it to stop feeling sticky to the touch, and I never could get any paint to stick to it. It'd probably work well if I knew what I was doing, but I think it'd be too risky.

Sorry to shoot down all these suggestions. I appreciate receiving them though, since it gives me more to fall back on if something doesn't work out. Plus they might come in handy in the future.

krv3000 · « **Reply #240 on:** July 17, 2015, 08:37:45 PM »

not a problem if you used the fibre glass stuff for your boats I bet you used the pasts hardener in the clear casting kit its a liquid hardener and I ant had any problems with it the only thing you must do is ad the right amount of hardener to the resin as it gets hot in the Harding proses witch Leeds to cracking or try the clear two pack epoxy resin glue £1 a go at the £1 shop

awemawson · « **Reply #241 on:** July 18, 2015, 02:07:38 AM »

In my experience fiberglass resins set slightly tacky unless the air is excluded from the outer surface. There are special wax additives you can buy, but some cling film stolen from the kitchen works just as well

chipenter · « **Reply #242 on:** July 18, 2015, 02:35:24 AM »

Sanding sealer is just talk added to the varnish or lacker .

S. Heslop · « **Reply #243 on:** July 19, 2015, 11:23:35 AM »

It's about time I did some actual woodwork.

Rough cut the neck out.

Got some actual use out of the spindle sander getting the inside corners up to the line.

The back edge was brought down with the spokeshave to remove bulk and a sanding block to level it out. Was checking it against the template i'd made from mdf. I took some video of that but had the camera in the wrong setting, recording some seriously low resolution stuff. I'm glad I noticed before cutting the neck out proper at least.

I was planning to sand the back with the belt sander but really it's not that accurate, the 'foot' of the sander is all kinds of crooked.

Back of the headstock isn't levelled yet, I need to glue on the 'ears' that extend it sideways.

I also routed the truss rod channel and got it about 0.8mm off from the center, which isn't great. Spent ages setting the thing up too. It's also a fairly loose slot but that shouldn't be a problem.

S. Heslop · « **Reply #244 on:** July 19, 2015, 03:54:16 PM »

Glued the 'ears' on. I was planning to be fancy and match the grain direction, but I didn't have any bits long enough or tall enough to do that. So I glued some on with the grain running in another direction. It's probably gonna look like ass.

So I figure some sort of face on the headstock would help make it look a little less ass. I dug through the box of wood and found two nice bits of matching burl. I've got a few fancy bits of wood but the guy that owned them before me had intended to use them as knife handles, evident from the outline traced, and had also drilled holes for the pins.

Anyways the bits of burl weren't big enough so I split them again.

The edges weren't flat and needed 'jointing' on the tablesaw. Then it was more wedges to glue it.

Stuck to a bit of MDF to send through the drum sander. Once again, i'm getting alot of use out of this machine.

After a bit more hand sanding I got it pretty smooth. I was thinking i'd probably drill the center out and set some sort of metal emblem into it, or a coin, but I think the pattern matches up so well it'd probably be a shame to do that.

awemawson · « **Reply #245 on:** July 19, 2015, 05:16:30 PM »

Very nice work on that burl Simon. You certainly set yourself some challenges

vtsteam · « **Reply #246 on:** July 19, 2015, 06:06:18 PM »

Liking the woodwork, Simon!

A few words on polyester and epoxy resins as finishes on wood:
Polyester (what most people call "fiberglass") resin has poor adhesion on wood, it also eventually yellows and becomes opaque if not protected from sunlight with a UV resistant varnish. There are "water clear" casting resins, but they aren't designed as thin finishes -- they are for casting. I'm sure it can be used where sunlight isn't strong for some interior purposes, but i wouldn't put it on a banjo.

Polyester laminating resins do not cure on the surface in the presence of air -- they are designed that way so the next layer of glass fiber roving or mat or cloth, whatever the schedule is, will adhere to the last one in the mold. The next layer of resin and catalyst will kick it hard, though will also have a sticky surface to accept the next layer.

The final layer of resin is called "finishing resin" and it does have wax added, as Andrew said, to block air, and allow a hard surface cure on the inside of the molded item. Finishing resin can be bought that way -- you don't have to add wax -- it's pre-waxed. It's no good for laminating of course, because the wax prevents further adhesion.

Epoxies also yellow and go milky opaque very quickly on exposure to sunlight-- even more quickly than polyesters. They are a poor choice for something that is finished bright where you want to see the wood.

Talc added to lacquer makes a fine sanding sealer under paint, however it isn't very clear or even and isn't good under a bright finish.

Here's what I would try for filling the meranti grain -- spread a very small amount of carpenter glue on a small patch of the surface, and then immediately, before it dries, sand with fine sandpaper. This mixes fine sawdust with the glue and wipes it into the grain divots, while removing it from the surface. The color will fit well, just slightly darker in the grain than the meranti, as it should be, but a good tonal match.

This also works well with small cracks in glue joints. There a trick to sanding enough, but not too much to fill what you want, and to sanding in the right direction to fill, and not pull out your filler material. But a little practice on scrap will show you what to do.

Hope that helps!

S. Heslop · « **Reply #247 on:** July 19, 2015, 06:48:11 PM »

Quote from: vtsteam on July 19, 2015, 06:06:18 PM

Polyester laminating resins do not cure on the surface in the presence of air -- they are designed that way so the next layer of glass fiber roving or mat or cloth, whatever the schedule is, will adhere to the last one in the mold. The next layer of resin and catalyst will kick it hard, though will also have a sticky surface to accept the next layer.

That's cool. I never knew that. I just always assumed I didn't add enough hardener to the fiberglass resin.

As for the glue and sanding thing, it seems similar to the (what people claim to be) old method of getting pumice embedded in the cloth wad you're applying shellac with and rubbing it a whole bunch over the surface and keeping it wet with shellac. It confused me at first since I thought people were filling the grain with pumice, but that stuff would show up as white. But I figure it's just sanding the surface and clogging the pores with the sawdust/ shellac mess. It seems like a long winded way to go about it.

But the thing i'd worry about glue is how well the shellac will stick to it. I'm thinking about testing it at some point, but I ran out of the mixed shellac (from the accordion) I had about.

vtsteam · « **Reply #248 on:** July 19, 2015, 09:13:26 PM »

Simon, I use shellac a lot and also occasionally sanding to fill a problem glue line crack. There is basically no glue on the surface of the wood, it's only in the crack or grain. you use very little glue and the sandpaper removes it immediately. But, I've also never had a problem with shellac over glued joints, anyway. For that kind of work I usually use titebond 2 -- the yellow aliphatic type of glue -- seems fine with shellac.

I don't think this is similar to the rottenstone thing, which is part of getting a fine rubbed shellac finish. Not filling grain.

Do try it on some scrap. I think you'll find it's no big deal. Try it on a bad joint with scrap and see the results. They do need to be level with eachother, at least, so sand them flush first. Use very little glue, and start sanding with a piece of paper in hand -- I dunno maybe 320 grit or so. Coarser if it goes too slow.

If I remember correctly I first sand crosswise to the joint. When it fills I stop, let dry, then sand with the grain to clean up. Sanding with the joint at first tends to pull the homemade sawdust putty back out. A little practice and you'll get the hang of it.

S. Heslop · « **Reply #249 on:** July 20, 2015, 06:34:36 PM »

Routed the fingerboard out, following an mdf template. Decided it probably doesn't need edgebanding. There's one spot that's not too great but it's alot of effort by the end of the day, and I don't have the materials on hand.

Finished off the truss rod too. Kinda bungled up the first attempt to stick nuts pairs on tightened against each other. So for the second I pinned them.

It works.

I maybe could've gotten a bit more done, but i've been having alot of cramps lately and standing up for more than an hour wasn't doing me any favours. So I took a break and never got back to it. I think the cramps might be from stopping codeine since I think I remember the same thing happening in the past.

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Author Topic: Banjo Build (Read 154549 times)