Official Luthiers Forum!

Just about to order some Behlins rock hard.
Does a guy need to buy the behlins reducer or is there a substitute?
thanks,

Peter

Turpentine, real turpentine from pine pitch, not a substitute.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Thank you

Which is sold as "Pure Gum Spirits of Turpentine." The best grades are in art stores, but that's probably not necessary. I actually don't know why you couldn't use naptha. Laurent?

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Howard is correct, hardware store pure gum spirits of turpentine Ace or Klean-Strip do nicely (the Klean-Strip smells better, it seems to have less petroleum distillates). Naptha flashes off too quickly IMHO and does not have the oils turpentine has, which seem to really help with the self-leveling process. On the other hand adding a bit of acetone to subsequent coats speed the curing process a bit, and appears to melt the new coat better onto the preceding one.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

I may add that turpentine should only be added to regain the original consistency of Rockhard once the can is opened and the varnish irremediably thickens. Bloxygen is a must have to avoid throwing out half-full cans, so is pouring the remaining varnish in smaller glass jars.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

For actual thinning, I've had best results with Behlen's own reducer. Naptha is fine for cleaning brushes.

Pat

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

Pat, just curious, what do you mean by better results?

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

I've never tried turps. When I used plain old hardware store paint thinner I got a white precipitate, and the varnish took longer and longer to harden. Since then I've been using the proprietary reducer: the trouble costs more than the small material savings.

I use marbles to keep the varnish from hardening in the can. As long as the varnish surface is right up near the top, so that there's less than 10% air in the can, it won't harden, or not fast enough to matter at any rate.

I use mine thin, so what I do is dilute each can when I get it. I have saved some pint and quart cans, which I clean out between uses. When I get a new quart I pour out 1/3 of it into a pint can, so that each is 2/3 full. I add enough reducer to get pretty close to the top, some acetone, and a few drops of kerosene. The kero is a brushing agent that flaots to the top and helps the brush slide over the surface as the acetone flashes off. The rapid evaporation of the acetone helps the varnish coat body up so that it won't run, as well as adding some 'bite' into the coat below (I sincerely believe). Cutting it allows me to pull the coat out really thin and even. Of late I've been using a 1/2" camel hair brush, which does a nice smooth job. It's slow, though; I need to get a 1" one.

As I use the varnish I add in marbles until they get to the top of the can. At this point you've got about 1/3 of a can of varnish and 2/3 of marbles. When I've used both the pint and the quart I've got about a pint of varnish. I pour that into a clean pint can, and dump the marbles out onto a few paper towels. These can be cleaned off with a little cheap thinner and reused. When the pint is full of marbles it's time to buy a new quart can, and start over. When you've got two pints you can consolidate them, and so on.

It might sound like a lot of work, but it pays off. It's not just that you get to use all of the varnish you pay for; skinning over in the can gives you gels in the varnish, and that slows drying and makes it much harder to get a level coat.

I'll note that bonding between coats is not the problam it can be with, say, polyurethane. The issue here is witness lines, caused by sanding through into previous coats. The stuff hardens from the top down, so as you remove the top coat the varnish gets softer and softer until you break through into the coat below. The harder surface makes a shiny witness line.

There are only two ways around this: don't sand through, and wait until the varnish is fully cured. I've had the best luck with thin, level coats that only need to be sanded to get rid of the dust and 'sand' (tiny varnish particles from the brush). Waiting at least a month will largely mitigate the problem, but most finishes take three months or so to really cure. Most of us are not that patient.

Filippo, there is no chemical bond with oil varnish. It needs a mechanical bond to adhere to the preceding surface. Like Alan, I believe acetone helps in this. It certainly reduces the witness lines issue and seems to speed the curing of the varnish.

I've never used Behlen's proprietary reducer, and after 25 guitars or so finished with Rockhard and turpentine as a reducer, I haven't encountered any problem… BTW I got the turps tip, and a lot of good advice with an oil varnish finish, from Bruce Sexauer.

I spray Rockhard, as it comes out of the can. When I used a brush, unlike Al, I didn't dilute Rockhard, but again brushed it as it comes out of the can. I only add turpentine to regain the same consistency. I used a 2 1/2" China brush suspended in a half turpentine/half odorless mineral spirits solution. Turpentine on the brush seems to keep the hairs soft, even improve the "feel" of the brush.

I agree that the longer the wait before leveling and buffing the better the results. The varnish definitely seems harder. It also cures/hardens faster in warmer temps.

Alan you should try Bloxygen, the marbles are brilliant though.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Laurent,

you say you spray Rockhard straight out of the can. Is that with no thinning with turpentine or adding acetone? I'm a little confused. I'm about to try Rockhard for the first time, after some practice pieces, and wanted to spray but was afraid it would be too thick out of the can. I don't want to get runs, however. Thanks for any help.

SR

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"We might not be big but we sure are slow"

Yes I spray Rockhard as it comes out of the can, I use a small HVLP touch-up gun with a 1mm tip, about 45PSI at the gun. I only add turpentine when the varnish starts to thicken after the can is open (even with Bloxygen and transferring in smaller jars).
I add acetone to the mix at the second coat. You could do it at the first coat, it depends what you use as a sealer. If shellac is used the acetone will make it curl. Make sure you scuff the shellac before spraying the varnish. I've been using Waterlox as a sealer lately, acetone is not an issue.
Edit - I also use turpentine to clean the gun, it keeps things oiled… I'll take apart and clean the gun entirely after 3 or 4 guitars with lacquer thinner.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

I've seen Al's finishes recently and I'm very impressed. I'm seriously considering using his method on one of my next guitars.

Laurent wrote:
"Filippo, there is no chemical bond with oil varnish. It needs a mechanical bond to adhere to the preceding surface. "

I believe there is a chemical bond, albeit a weak one. Sanding the surface before re-coating helps, not so much because of any mechanical 'toothing', but by raising the 'surface energy'. When you remove material you are breaking chemicl bonds, and some of these remain open for a while, looking for something to latch onto. Glue and finish adhere much better to a freshly worked surface for this reason.

The thing about 'Bloxygen' is that I'd be bound to run out just when I couldn't get more. If I've got a handful of marbles I'm all set, and I can clean them off and re-use them, unlike CO2 (or whatever) from a can.

Guys, would http://www.bhphotovideo.com/c/product/318712-REG/Kaiser_204198_Accordion_Storage_Bottle_.html work?

(sorry, I don't know how to make the URL appear as a word)

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

Sorry, my above post was pretty ambiguous. The link is to a collapsible bottle that I thought might be easier to store varnish in, as opposed to adding bloxygen or marbles. Would this work, or would it be too hard to clean?

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

Mike if you hover over the URL button you will see text in the blue box. It gives the format for using the URL option.
[u r l=http://url]URL text[/url ] is the format you want. I spaced out the url so that it wouldn't turn it into a link.

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Aoibeann

Cool. Thanks, Lillian!

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

I've found any sort of jar or bottle with a screw top to be a pain with oil varnish. If the top is loose air gets in and the varnish hardens up. If the top is tight enough for a good seal it only takes the tiniest drop of varnish on the threads to glue it down solidly. Then you end up either breaking the jar or puching a hole in the top to get at the varnish. There's a reason paint comes in paint cans.