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I'm planning on using P&L 38 on a couple instruments I'm restoring, I think it will be a good match for the character of the instruments.

These instruments are only o.k. and the original finish was an absolute hack job so I hope to improve it a lot but there are limits. I had to resort to some wood filer in spots and the instrument itself is made from poplar so my plan is to seal with shellac and then spray heavy tinting in shellac, possibly even some opaque black on the edges in a kind of burst to hide some of the defects in this instrument.

For the varnish on top of the shellac, I want to do wipe on and I remember reading about a "hotrod varnish" in FWW, happens to be issue #198 which I can't find at the moment, which consists of the following:

10 parts Varnish (P&L38)
10 parts pure tung oil
2 parts japan drier
up to 5 parts thinner to desired viscosity.

In the article he states that the tung oil is the magic ingredient that gives the finish the flow out it needs to work so well as a wipe on but, I know that common wisdom says that oil over shellac is a big no-no.

My possible options are:

1) Use that recipe as is

2) eliminate the tung oil entirely and half the japan drier

3) something in-between.

Any thoughts or experiences anyone cares to share?

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Andy - you may have seen this already, but here's the link again just in case. It's a thread from the old kit forum about a recipe for using P&L #38 as a wiping varnish. Be sure to read to the end of the thread as the recipe changed as the thread evolved.

http://www.kitguitarsforum.com/archives ... 91_0_7_0_C

Thanks Charlie, I actually had read that a few weeks ago but forgot about it. I'm really wondering about the addition of tung oil though as according to the author of the FWW article, that's the key to good flow out.

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Adding Tung Oil, and Japan Drier is counter productive. The Tung Oil will make it cure slower, while the Japan Drier will make it cure quicker. (I think I'm right about the chemistry.) I haven't used P&L Varnish, but it shouldn't need help flowing out. Thin it to a workable viscosity with pure turpentine and it will flow out just fine. It doesn't begin curing until the thinner evaporates. You can thin with (pure) Turpentine, Mineral Spirits, or Naphtha. Of these three Turpentine evaporates the slowest. Mineral spirits is a little quicker, with Naphtha evaporating the quickest. Adding Japan Drier (or Cobalt) will quicken curing, but may hurt flow out some. I suspect too much Japan Drier could cause other problems. I don't think adding Japan Drier to a short oil Varnish is a good idea. If you need quicker cure times use a catalyzed finish. I'd suggest testing on scrap with the three thinners I've listed. Warmer temperatures also accelerate the cure time for Varnish.

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Woody, is it possible that the japan drier is added to counteract the slower drying time from the tung oil, or does it not work that way?

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I haven't used the P&L on a guitar yet but I did some testing using turpentine to thin the varnish. Worked great except that the turp smells VERY strong! My shop is just a room in my basement and the smell permeated the entire basement, including my sons' bedrooms, for days. They were not pleased. I'll use MS in the future.

That's the way I see it, and unless I'm missing, or otherwise don't understand something I'd say why bother. Instead of adding a bunch of stuff, just add reducer.
I just re read your original post. WD Lockwood Oil soluble dyes work great for tinting oil based Varnish. I'd skip the shellac and spray tinted Varnish for your color coats. For spraying Varnish I normally thin with naphtha. If it's really hot I use mineral spirits.

You can get WD Lockwood dyes here. http://www.toolsforworkingwood.com/store/dept/CLWO

_________________
I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Anyone know if Transtint works OK in varnish? I have a plethora of tints on hand is why I ask.

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Can't help with the tints, but, I've added japan drier to P&L #38. My take on it is that it helps it cure more "completely", allowing a better buff-out. Without the japan drier, it seems to remain a bit softer, more "varnish-like" and tougher to buff.

Other than that, I'm not into modifying canned varnishes. I keep reading of folks adding this oil and that oil, or acetone or whatever to this or that varnish, and methinks it harkens back to the "goodle days" when folks had to make their own varnishes from scratch. Methinks the trained chemists that formulate the stuff we buy these days know a LOT more than I do...

I'll be driving by a woodcraft tomorrow so I think I'll pick up a pint of tung oil and do a comparison between with and without over shellac. Looking on the webs, it seems that transtint is compatible with varnish so long as it isn't thinned too much with mineral spirits (what I'm planning on using).

So, I think I'll try the following:

A) P&L 38 + a touch of japan drier + MS to desired consistency
B) Same as above with the tung oil, probably half of what was recommended in the recipe.

I suspect that Mario's correct that the chemist in the lab know what they're doing but it will be interesting to try anyway.

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Just don't overdo it with the Japan driers... If you do, the finish will remain sticky forever.
Don't ask how I know this.

I planned on staying below 1:10 of Japan drier to varnish or varnish/oil mix. Not planning on counting the mineral spirits.

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How much Japan direr is appropriate?

Hopefully Grumpy will post again about the Japan Drier, but I think 10% is way too much. Wouldn't something like 2% be more appropriate? I also suspect there's no set forumlation for Japan Drier so it may take alot more of one brand than it would another. I've never used Japan Drier, but added as much as 4% cobalt to Epifanes Varnish in the past. Epifanes is a long oil Varnish so it would need more "help" than a short oil Varnish like P&L. (I think) I've never added any cobalt or drier to SW varnish.

_________________
I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Just so it's documented - I chatted with Mario earlier today and he said he uses "Not much, maybe one cc in 2-3 ounces. I don't measure stuff too often. I figure that the JD helps kick the varnish a bit, whether I use a wee bit or a lot, and I'd rather not use a lot and mess up the basic chemistry of the varnish."

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I don't measure stuff too often. I figure that the JD helps kick the varnish a bit

Yeah, that JD(Jack Daniel's) kicks all kinds of things.....

Oh, right! This was a varnish discussion! Wrong forum.. Yes, JD is Japan Drier when discussed here.....

f-in hack! the best bourbon, by far, is booker's. I've converted scotch drinkers with that stuff.

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http://banduramaker.blogspot.com

I tend to agree with Grumpy about adding things like driers and oils to modify the properties of the film. All told I'd think it would be better just to find a varnish that works right, and use that, if what you're looking for is a 'varnish'.

Lots of folks do like the 'oil' finish look, or, at least, the look of a thin, oil-like wiping varnish like Tru-Oil. You can duplicate that look with a mix of equal parts of oil varnish, drying oil, and thinner. That's a different finish, of course...

Adding reducer/thinner and acetone to an oil varnish simply thins it out, giving you something that's more like the stuff violin makers use, and less like a furniture maker's varnish. It doesn't alter the properties of the varnish film, but does change the technique of putting it on. It's particularly handy when you're using a varnish that is highly colored, or in helping to avoid 'witness lines'.