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I went to Grizzly last week to buy some Rock Hard Table Top Varnish. They discontinued stocking it. A search of the H.Behlen sight revealed that they have reformulated the Rock Hard Varnish and it is now a polyurethane. Tho old short oil formula is no longer available.

Now the Problem. I have two guitars that need a couple more coats before they are ready for buffing and I am out of old formula.The question,for you varnish guys, is what to do now? I would rather not sand back to wood and start over but will if need be. Will Pratt and Lambert or Sherwin-Williams products be compatible or is there something else more appropriate? What will most closely match the amber cast of the Rock Hard?

In short, what should I do now?

cecil

I've used TruOil over Rockhard, they're pretty similiar.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

I've used Tru Oil over Rockhard with success too. The Tru Oil is good at covering up any witness lines you might end up with when leveling the Rockhard. The last batch of Rockhard I used was a real dog--I ended up sanding it all back off. I wonder if it was some of the new poly formula...

I'm using Pratt and Lambert now, but it doesn't have the same color as Rockhard.

Dave

Thanks for the help guys. I'll give the True Oil go and see what it looks like,
.

cecil

http://www.garrettwade.com/rockhard-tab ... /99P52.01/

You might want to call to confirm.

Well crap - I just ordered some

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Steve Smith
"Music is what feelings sound like"

Tru Oil and Rockhard are not at all the same thing. Tru Oil is highly polymerized linseed oil and Rockhard is an oil varnish, meaning a resin/oil conglomeration. The original Rockhard used phenolic resin, and yielded an unpleasant orangey-yellow color in the cured film. Some folks love the color, but I am not one. I have done some preliminary work with the new Rockhard, the urethane version. It is purported to be a short oil varnish like the original and my tests have done nothing to disprove that claim. I have yet to finish a whole guitar with the new Rockhard, but so far I like everything about it better than the old version.

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Stay with the happy people.
--Reynolds Large

Ah, so there is hope. I suppose I could give it a shot anyway - I thought I might like to try it so I bought a quart the other day, should be here soon.

Any reason not to put it over Zpoxy filler?

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Steve Smith
"Music is what feelings sound like"

Definitely true. But Tru Oil as a topcoat over Rockhard works really well from my experience. After leveling the Rockhard, I've always had very faint witness lines (as is the case with all of the varnish I've used), but after topcoating with Tru Oil, they go away and everything buffs up very nicely.

Dave

I could be wrong, but I think I remember reading that TruOil is a short oil phenolic resin varnish, and Rockhard is a long oil phenolic resin varnish. Definitely not the same thing, but compatible.
Wetsanding Rockhard will produce witness lines, TruOil is a quick & easy overcoat. I don't think it's quite as hard as Rockhard, but I haven't used Rockhard as often.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

Witness lines can be a problem, but I've found they can be much reduced or even eliminated if the last two coats are applied fairly close together, like four hours. That, with acetone, seems to help the coats amalgamate to a small degree, though not like lacquer or shellac. When they have appeared, they usually disappear with buffing. A few applications of French polish does the job too. I'll have to try Tru-oil.

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

Thanks for the info, Pat. Do you find when you top the varnish with shellac that it compromises the gloss you get when you buff?

I have spoken directly with the chemist at Birchwood Casey (who make Tru Oil) and he told me the only thing in Tru Oil is linseed oil. Not even any solvents or diluents. It has been specially polymerized to get it to dry harder and faster than regular linseed oil. Rockhard has always advertised itself as a short oil varnish, one of a very few if not the only short oil varnish remaining.
Compatibility is really not an issue with mechanically adhering finishes, unless a solvent in one is too strong and attacks the film underneath. Adhesion qualities differ from formulation to formulation and based on your reports is seems that Tru Oil has very good adhesion qualities.

_________________
Stay with the happy people.
--Reynolds Large

Tom and Steve, let us know how your trials go with the new formulation.

cecil

Charlie,

I haven't buffed FP over Rockhard, but I do like the finish using the usual FP techniques when I FP over rock hard. It's different from either FP by itself or Rockhard by itself.

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

Ah, I must be showing my ignorance about FP. I assumed it was buffed but sounds like it is not. Thanks for the info, Pat.

Any updates on the new RockHard Varnish formulation? Maybe TRein has an update.

Curious how it's working out.

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Formerly known as Adaboy.......

If I understood TRein correctly, the new formulation is based on a Urethane, correct?

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Formerly known as Adaboy.......

What abt the pratt and lambert oil varnish ???, got some old rock hard from wodcraft.

A bit of discussion in this recent thread:

http://luthiersforum.com/forum/viewtopic.php?f=10101&t=39793

I got some of the new Rockhard poly, and did a trial piece with it. It seems to harden about like the old stuff, but I'm not as fond of the look of it. Also, I'm prejudiced as regards polyurethanes, having had some problems with them in the past.

I also ran trials on three other varnishes at the same time: A Sherwin-Williams furniture varnish, Pratt & Lambert's #38, and, something one of my students found, Murdoch's 'Ur-Alkyd 500' floor finish. All of them, including the new Rockhard, seem to harden in about 12 hours. The SW was too soft. P&L seems about as hard as the old Rockhard, and the Murdoch's is significantly harder. The P&L is dark, but not as dark as the old Rockhard, while the Murdoch's is almost water clear. One intertesting thing about the Murdoch's varnish is that it is thinned with a citrus based solvent.

One of my students is now trying out the Murdoch's varnish on an archtop, and so far it's looking good. He's sanding back the final coat, and there is no sign of witness lines. If it proves to be resistant to perspiration, I'll probably use it when I want something that's nearly white. Otherwise, I know other folks have had success with the P&L, and I'm disposed to go that way on most things.

I can't say whether any of these would be a good top coat over Rockhard. If I had to do it, I'd level the existing finish as best I could with about 220 paper, and be sure to build up enough of the new stuff to preclude any possibility of sanding through. I'd probably go with the P&L, as using the harder Murdoch's would seem to violate the old 'fat over lean' rule, and could lead to checking down the road.

Yeah, the Uralkyd 500 (U500) is the stuff that A.Hix sells/recommends. I'm considering it. Supposedly can be sprayed or brushed. Ken Jones is also trying it and I think will have a report soon.

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Formerly known as Adaboy.......

I'm interested in the Uralkyd 500 too. I ordered some and received it last week. I used a foam brush to apply 3 coats to some spruce and mahogany scraps and so far I like it...east to work with, levels well and seems to highlight the grain nicely. It feels harder than varnish I have played with in the past (P&L and Ace). My frame of reference with finishes is very limited though, so I'm interested in what others have to say about it. I'm going to let it cure for a week before buffing and see what kind of gloss can be achieved.