Murdoch's Uralkyd 500 As a Guitar Finish

[Darryl Young]

I've been searching for finish to use on the guitars I build. I used KTM-SV (a urethane)on my last build and I like it ok but you have to seal oily woods very well else the finish won't cure properly. Also, in a discussion with another luthier using this finish, he had problems with the mfg changing the mix or ingredients and he abandoned that product for another one. Playing with the ingredients or ratios of ingredients seems to be a common problem with many water base finishes.

With the new VOC regulations in place, it seems many mfgs have either re-formulated old standby finishes.......or possibly will be reformulating. It would be disappointing to find a new finish and then it be reformulated and the search need to start yet agian. So it would be nice to find a finish that is already low VOC.

I liked the new Trial2009 product from KTM......but they haven't yet decided if they will mfg it. So it may never be available again, who knows. I am open to high quality urethane based finish.

I want something safe to use at home so nitro is out. I don't want it curing inside the house and I'm not leaving the guitar out in my shed or shop as neither is temp or humidity controlled. So nitro is out.

I don't like the water based lacquers as they are made from an acrylic resin and I don't want to deal with the potential blue cast issues. Not sure how hard this product cures either (you may know).

So in my limited finish experience, I think I'm down to a varnish. In general, I've been worried that these don't cure hard enough so might not provide enough protection. Pratt & Lambert #38 is a tung oil based varnish that is fairly hard that I've considered but I recently read about Murdoch's Uralkyd 500 (U-500) finish and it is interesting.

U-500 is a product made by Sutherland Welles and I heard about it on the OLF. You can buy it from Aaron Hix (the guy on e-bay that sells a lot of tonewood). It is a blend of polymerized tung oil, urethane based resins, and a low toxic solvent called Di-Citrusol. So it already has low VOC and has low toxicity driers and solvents. Supposedly it cures very hard......as hard as nitro lacquer (we will see). Another plus is new coats bond to old coats on a molecular level it has good adhesion and supposedly no witness lines (again, we will see). Also, they claim it has a light amber cast, clear, and will not yellow.

One downside is that it is expensive......roughly $50 for a quart which can do 3 or 4 guitars. Another downside is that it needs to be kept in a sealed container with little or no oxygen or it can go bad.

Anyhow, I need a finish to use on the 00 I've been working on for an eternity now......so I pulled the trigger and ordered some (good or bad). Hope to have it by this weekend. I discussed this product for half an hour with Aaron Hix on the phone before pulling the trigger.

Anyone have experience with this product?

[Kevin Sjostrand]

Darryl,
How did it go with this finish?

Kevin