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How best to make this irregular multi-line rosette?
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Author:  My Dog Bob [ Mon May 13, 2013 10:28 am ]
Post subject:  How best to make this irregular multi-line rosette?
I am a bit perplexed.. I need to make/buy a bunch of these rosettes but I am not sure of the best way to go about it.. In the past Gurian made me a batch but they were only ok and made with fiber sheets and when they tried again with wood veneers in place of fiber.. They just couldn't do it.. even after many tries. After waiting for over a year! they finally gave up (they did return my money though which was honorable - considering that they tried many times)

The Rosette is made up of 32 veneers. Iam going to use real dyed wood for all the veneer layers for authenticity sake.

This is a rosette for a early Selmer/Maccaferri guitar. I make the later Oval-hole rosettes myself by clamping wood veneers around an oval-shaped caul with band clamps - one or two at a time (there are 12 layers) It's time consuming but the rosettes turn out great and I don't mind doing those.. This rosette on the other hand is going to be a nightmare because of the sheer number of layers and the geometry (a band clamp doesn't want to compress the flatter bottom part anywhere near and hard as the tighter radiuses)..

Here are my questions.. Does anyone know ANYONE that could make these for me. Large-ish minimum order is fine. I am willing to spend good money if someone could make them for me and make them REALLY nice.

If that is not an option (I hope it is), I will make them myself - probably around a caul 3"-4" thick or so.. Do you folks have any good ideas as far as how to build up the layers with no voids or distortions? I was thinking of employing my (very powerful) vacuum pump and a thin membrane and only building the rosette one or two layers at a time to control the quality of the laminations. Any other clamping ideas? Any thoughts on glue? - I was thinking maybe using urea formaldehyde so the whole mess is really stable once glued (and I could heat the laminates up to speed the curing process)

Hell, I am open to any suggestions here..

Thanks, Peter
Author:  Michael.N. [ Mon May 13, 2013 11:36 am ]
Post subject:  Re: How best to make this irregular multi-line rosette?
I don't really see a problem making that rosette. They start to get very difficult when you have to join the two ends seamlessly. That's when you start to get voids. With that one you don't have to join the two ends, it's covered by the fretboard.
I'd start with an inner former mounted on a softwood board. There are a few ways to do it. You can glue each line individually or pre glue 3 lines together and then bend them around a hot iron. If you glue the veneers individually you won't need to pre bend. You just use map pins to hold the veneers in place until the glue dries - similar to the method shown in the Sloane book. Make the veneer strips so that you can cut 2 rosettes from each glue up, perhaps 5 mm wide strips. Any more than that and it gets difficult to end up with a neat result. If you have a few formers on the go it will speed things up, in terms of per rosette.
No need to use UF glue. In fact it's probably a bad idea. I happen to use HHG. When you build up the laminations things quickly become very rigid. HHG is water soluble, if you do end up with slight voids you can glue the whole rosette in the channel and redissolve the glue between the veneer lines. The voids then get shared out between all the lines, effectively they become invisible to the eye.
Author:  bluescreek [ Mon May 13, 2013 11:48 am ]
Post subject:  Re: How best to make this irregular multi-line rosette?
trained termites
Author:  ZekeM [ Mon May 13, 2013 12:20 pm ]
Post subject:  Re: How best to make this irregular multi-line rosette?
bluescreek wrote:
trained termites

John, where would one acquire these trained termites?
Author:  Quine [ Mon May 13, 2013 12:34 pm ]
Post subject:  Re: How best to make this irregular multi-line rosette?
I don't see a problem making that. Just time consuming for all the layers.
Just make a clamping caul for the flat side and use the band clamp like you do for the oval. One side of the caul is flat and the other is curved out so the band will squeeze the two flat surfaces together.
Heck...you could just make two D-rosette glue-up forms and clamp them together flat side to flat side. Double your production!!
Author:  RNRoberts [ Mon May 13, 2013 10:00 pm ]
Post subject:  Re: How best to make this irregular multi-line rosette?
Cut a trough in a piece of polyethylene (like a white cutting board) at the same time you cut the trough in the top wood. That way the two troughs are identical.

Then you can lay up all your individual strips dry in the polyethylene rosette, taking all the time you want to get everything just perfect. Glue it up by flooding with thin CA, and then just pop it out of the polyethylene.

It will fit the trough in the top wood perfectly, you save marring your top trying to build the rosette in it, no swelling problems, no racing drying glue, no ripples or dents from pins, no clamping to mess with, etc..

Try it and I doubt you'd go back to doing rosettes traditionally ever again.
Author:  Randolph [ Mon May 13, 2013 10:09 pm ]
Post subject:  Re: How best to make this irregular multi-line rosette?
ZekeM wrote:
bluescreek wrote:
trained termites

John, where would one acquire these trained termites?


Check the Classifieds!
Author:  Alan Carruth [ Tue May 14, 2013 1:32 pm ]
Post subject:  Re: How best to make this irregular multi-line rosette?
I build round rosettes in place, but a trick that Eugene Clark talked about in his rosette articles in the GAL should work as well for the D shape as it does for a round one.

The idea is to not glue the veneers together until they're actually in the channel. Individual strips will bend dry to very tight curves, particularly if you hold them together in a bundle. You do that with 'buckles'. Clark makes adjustable ones: two L-shaped pieces that are held together with rubber bands. These form a slot that holds the veneers tightly together. I just cut slots in little pieces of cardboard. Make them nice and tight: you'll need a half dozen or so.

Cut the strips of veneer, say about 2mm wide. Stack them up dry in the right order, and put the buckles around them to hold them in place. Fit one end of the veneer bundle into the slot and work your way around, sliding the buckles back to give just enough slack to work with. It's never a bad idea to do a dry fit, to make sure everything goes in nicely: you want it to be just slightly loose, since the glue is going to make the wood swell. Removing the bundle after the dry fit is just the reverse of fitting it in the first place. Once you know everything is going to work, put a little bit of glue in the first third or so of the slot; just enough so that you can spread it around to cover the bottom. Moving with careful expedition, fit the end of the veneer bundle in, and push it down for a little way. Put some more glue into the next part of the channel, and push in the veneer. Repeat until you run out of channel. Although it's not easy to trim off the ends to get a tight fit, you can get them pretty close without too much trouble. When I have the strips all in, I run over the rosette with a small brayer, to make sure everything is pushed down. Needless to say, this requires that all of the veneer strips be cut to the same width to begin with.

Eugene uses this technique to put all of the rings for a rosette in, in one shot. You can make channels for tiles by simply waxing some of the veneer strips, so that the glue won't stick to them, and they can be peeled out later. I find the best wood for that is straight grained maple, with little or no run out across the strips.

The biggest problem with this method is that you do have to leave a glue allowance, and it's something of a matter of judgement and feel just how much to leave. I know that when I'm building up veneer tiles outside of a rosette that each glue line amounts to about .002" (.05mm). With 32 veneer layers you're talking about 1/64", which seems like a lot. It's not, really. If you cut the channel too narrow, you'll be swearing like a sailor as the wood swells up and you can't get the last half of the rosette in (the first part usually goes easy...) If it's just a little too wide the wood will swell and soften, you can mash it down a bit with the brayer, and things will look fine. If it's just sloppy, you might be able to pull the rosette out while the glue is still wet, clean up, allow things to dry out, and try again with an extra layer of veneer. In other words; there are remedies when it's too loose, but too tight is a real problem. I'd expect that the tight corners of the D would need to be a little looser than the rest, but that's just my opinion.

One reason I've gone to using this method is that I've found it difficult to make, and darn near impossible to buy, a really round pre-made rosette that is uniform in width. I imagine the problem would only get worse with something that's not round to begin with. This method takes a little practice to get right, but once you do you should be able to cut the channels all the same and use the same number of veneers each time, rather than trying to adapt a little for each rosette.
Author:  My Dog Bob [ Wed May 15, 2013 8:25 am ]
Post subject:  Re: How best to make this irregular multi-line rosette?
Thank you.. Those are great ideas.. Thank you. I really appreciate it!

Peter
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