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Alternatives to polyurethane
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=17020		 Page 1 of 1
Author:  Alain Moisan [ Tue Apr 29, 2008 1:10 pm ]
Post subject:  Alternatives to polyurethane
Hi all.

Up to now, I've been finishing with polyurethane with success. Of course, none of the guitars I've made had any rosewood on them. Actually Honduran rosewood, but this one takes polyurethane very well. Now I need to make one with EIR back and sides and of course, polyurethane won't work.

What I liked about polyurethane is that it was easy to apply, easy to sand, easy to buff, leaving a wonderfull glowing surface (once you sanded up to 1500 grit) and is transparent (no 'yellowing' as varnish or shellac will do).

I've read on archived threads about all the problems associated to polyurethane, and even though people mentioned there are other very good alternatives off the shelf, none were specifically mentioned.

An important thing to know is that I'm not equiped for spraying, and won't be until I move. So the finish will be brushed/whiped on.

I've tried brushable lacquer, and that was not good. Lacquer is a pain to brush on.

So what other brushon/whipe on finished will give me similar results with rosewood?

Thanks in advance!
Author:  James Orr [ Tue Apr 29, 2008 2:25 pm ]
Post subject:  Re: Alternatives to polyurethane
Hi Alain

Having NOT tried it, have you considered McFadden's lacquer from LMI with their retarder?

Give the archives a search for Al Carruth's finishing schedule for Rockhard varnish, too.

True Oil gets a lot of mentions here, as well.
Author:  jhowell [ Tue Apr 29, 2008 2:47 pm ]
Post subject:  Re: Alternatives to polyurethane
Alain--

I'm a newbie at instrument finishing, so take this for what it is worth... :) I am also in a position where spraying is just not an option. I have tried several different things and have ended up coming back to FP'ed bodies and Tru-Oiled necks.

I learned something from the June 2008 issue of Fine Woodworking about creating a wiping varnish from Pratt and Lambert No 38 varnish, pure Tung oil, Japan Dryer and pure spirits of turpentine. The P&L is a bit of a PITA to find, but I now have a quart. I'm going to do a side by side comparo on a piece of mahogany veneer -- FP and the wiping varnish, both over a Z-Poxy pore filler.

I'm hoping that the finishing guru's will chime in here and let me know if I'm barking up a bad tree! Iinstrument finishing is its own world as I have come to learn from following various threads over the past two years. Most of what is applicable to furniture just doesn't cut it when applied to guitars. I'm sort of hoping that this recipe is on the right track as I would like something more durable on the body, but still be able to FP the top.
Author:  grumpy [ Tue Apr 29, 2008 3:00 pm ]
Post subject:  Re: Alternatives to polyurethane
The Pratt&Lambert #38 is a good varnish all on its own. I tried it with and without Japan drier, and liked it either way. It can be brushed-on, and it will sand and buff nicely.

I tested it over some rosewoods, and while it cured slowly compared to other woods, it did cure. Now, all rosewoods aren't the same, so before you commit to a whole guitar, test whatever you do try, on the exact off cuts of the same wood the guitar is made of.

It also helped to place the finished instrument in the driveway in full sun for a few minutes. The UV seemed to help the varnish cure. Watch to be sure you don't overheat it.
Author:  Alain Moisan [ Wed Apr 30, 2008 8:59 am ]
Post subject:  Re: Alternatives to polyurethane
Thanks for the info!

I can easily get some Pratt & Lambert near my place, so I'll give it a try.

Thanks again!
Author:  jhowell [ Wed Apr 30, 2008 4:02 pm ]
Post subject:  Re: Alternatives to polyurethane
Grumpy--

Thanks for the heads up on the rosewoods. I'm going to do a little test with the mixture on mahogany and see what happens.
Author:  grumpy [ Wed Apr 30, 2008 5:42 pm ]
Post subject:  Re: Alternatives to polyurethane
Mahogany doesn't inhibit finish curing; it'll be fine.
Author:  Todd Rose [ Wed Apr 30, 2008 8:06 pm ]
Post subject:  Re: Alternatives to polyurethane
grumpy wrote:

It also helped to place the finished instrument in the driveway in full sun for a few minutes. The UV seemed to help the varnish cure. Watch to be sure you don't overheat it.


Also watch to be sure you don't run over it!
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