Finish?

Hey all

I am new to the forum

More then a few years ago I made two acoustic and several electric guitars. At that time lacquer was the finish of choice by luthiers. I know there have been improvements to finishes since then. Is lacquer considered the choice finish for a ukulele?

I just bought a baritone ukulele kit from stewmac. It should be an interesting build for a jumping off point

Thank you

Finishing instruments is a witches brew. Everything from oil through to UV cured polyester.

If you are confident with lacquer then go with that. You're not going wrong using it.

The word "lacquer" is a bit of a slippery word. It can mean everything from a shellac finish to a nitrocellulose finish. I and many others use shellac which has a lot of advantages along with some disadvantages. I've done nitrocellulose finishes but didn't like the toxicities/flammability issues involved. Also remember nitrocellulose finishes were originally developed to put on cars. Ukuleles are not cars. I think the big boys use it because it can be put on fast, it is relatively cheap, it is durable and it is most of all... it is very shiny!

Definition: lacquer

1a : a spirit varnish (such as shellac)
b : any of various durable natural varnishes
especially : a varnish obtained from an Asian sumac (Rhus verniciflua)
— called also Japanese lacquer

2 : any of various clear or colored synthetic organic coatings that typically dry to form a film by evaporation of the solvent
especially : a solution of a cellulose derivative (such as nitrocellulose)

another option. https://www.youtube.com/watch?v=0ocS4F6ShNI

How Well does the Tru-Oil Finish Hold up? I have tried it before. It is nice looking but the finish was thin but I doubt I built it up to 4 coats

Thanks

Allen, you make some very beautiful instruments. Do you use nitrocellulose lacquer?

I use and really like Tru-Oil. I find it wonderfully thin (which I think contributes to the sound), durable, and easy to touch up. The name is poor, it is not really an oil, more like a catalyzed varnish. Not at all like some penetrating oils such as Danish oil or Tung oil. I achieve a very shiny finish, but I do not at all follow the instructions from Mya Moe posted above. I did a write-up for this forum, which can be found at:
https://forum.ukuleleunderground.com/showthread.php?132656-Shiny-Tru-Oil-finish

Tru oil is more like an oil varnish rather than an oil (finish). By definition an oil varnish is a resin in a drying oil carrier. Traditionally these were natural resins such as pine, amber and copal. the resin and the oil were cooked together at pretty high (and dangerous) temperatures. Sometime in the 20 th century synthetic resins were developed and these largely replaced the natural resins. I think alkyd resins were one of the first to be developed. This is where things can get a little confusing because although alkyds are classed as a resin they are made from oil - in process that I know nothing of.
Tru oil is linseed oil + a 'modified oil' according to the Birchwood MSDS. Is it a heat bodied/polymerised oil or an alkyd? I don't know for sure but Tru oil certainly acts more like a varnish than a finishing oil. Of that there is no doubt. That's why it can be built into a glossy finish relatively quickly even though out of the can it is relatively thin.
There's no doubt that it displays the grain of the wood in a very nice manner - as oil varnishes/finishes do. If you were to do a side by side comparison between that and shellac on the same piece of wood then the difference would be visible. I'm pretty sure that the vast majority of people would choose the Tru oil as being better visually.
It does not get as hard as shellac, at least in the tests that I've conducted. Is it hard enough? Well that's difficult to say. Some people expect the finish on an instrument to be bullet proof and to last decade after decade. It does have the advantage of it being easy to apply. No shame in that. I get the impression that some makers view it as a finish for amateurs. Of course that is just nonsense. As a finish it isn't that far removed from the stuff that Strad was putting on his violins. In fact if you were to replace the 'modified oil' bit with pine resin it would almost be identical. Those are the violins that are now worth X millions of £££'s.

Steve-atl said:

Allen, you make some very beautiful instruments. Do you use nitrocellulose lacquer?

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I had used a cross linked nitro based lacquer made in Australia for about 10 years. Now I use a 2K polyurethane made by the same company.

Thanks, Allen

Do you spray the 2K polyurethane?

Steve-atl said:

Thanks, Allen

Do you spray the 2K polyurethane?

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Yes, the polyurethane is sprayed and far more difficult to use than nitro lacquer. But it's advantages are that it's much more durable, and takes at least 5 weeks off of my finishing process.

Some guitar companies consider varnish an upgrade and charge extra for it. Collings and Huss & Dalton do that. Collings used to spray bar top varnish. H&D spray varnish, too, but I'm not sure what kind. I spray my ukes with Formby's varnish right from the bottle. Same with Tru Oil. Other varnishes normally need substantial thinning before spraying. I've been using Tru Oil for 50 years and wouldn't apply it any other way now. I use the cheap airbrush from StewMac and have no issues with it.

Allen R. McFarlen
Interesting from what I have read it builds very fast so you need lest coats?

Thanks

jcalkin said:

Some guitar companies consider varnish an upgrade and charge extra for it. Collings and Huss & Dalton do that. Collings used to spray bar top varnish. H&D spray varnish, too, but I'm not sure what kind. I spray my ukes with Formby's varnish right from the bottle. Same with Tru Oil. Other varnishes normally need substantial thinning before spraying. I've been using Tru Oil for 50 years and wouldn't apply it any other way now. I use the cheap airbrush from StewMac and have no issues with it.

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Thanks I will give it a try

Nitro based products dry by evaporation. In actual fact they never stop drying and have a life span of approximately 75 years before there is nothing left of what was origninaly applied. Nitro will gas off for at least a week before you'd sand back and apply more coats and have to wait at least another week befor moving on. For best results most high end builders would let it sit for 3 - 4 weeks before going to the buffer.

The 2K polyurethane I use is a catalyzed product that has much less solvent and overnight you could easily put it into service. Next day level and flow coat. 4-5 days later I've found is optimum for this product to be ready to buff.

I spray my ukes with Formby's varnish right from the bottle. Same with Tru Oil. Other varnishes normally need substantial thinning before spraying

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Just to clarify. You spray Tru Oil straight from the bottle with no thinning?
Miguel

lauburu said:

Just to clarify. You spray Tru Oil straight from the bottle with no thinning?
Miguel

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I was wondering that myself but if i remember Tru Oil is pretty thin