Official Luthiers Forum!

If so, how long does it need to cure before buffing?

I've power buffed shellac with a car-type buffer and really fine grit liquid polishes many times. A week or so has been fine. I personally wouldn't try it on a big buffer with aggressive cutting compounds. It melts at a pretty low temp, and I usually have a very thin coating to begin with. In my experience it would take a very very light touch.

Dave

Yes, use my pedestal buffer with buffing compound, same as for nitro. Works great.

Yes, use my pedestal buffer with buffing compound, same as for nitro. Works great.

Awesome. Jason, how long do you leave it to cure, and how many coats do you spray
Thanks

I french polish for a month or so, then rest it for a week before buffing.

Is there a reason that you don't spray it?

Shellac sprays terribly... it doesn't atomize quite right and you really have to strain the shellac before spraying because there are always lumps inside the shellac solution. I sprayed shellac on the Stella restoration because I don't want to take forever french polishing the stuff but I would spray for quick builds, then french polish them afterwards.

I also hate cleaning shellac out of spray guns.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

shellac can be sprayed but you have to have the right tips and thinned properly.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Hard shellac, applied with a fad, wait 10 days minimum, then cut and power buff.

_________________
Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Looks nice, Trevor! What hard shellac do you use?

So exactly what is a "hard shellac"? Is it one of those U Beaut crosslinked shellac?

Since I cannot get them (because its flammable liquid) how do I make them out of shellac flake?

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

Never buffed shellac,
because I don't have a buffer ,
but I did spray it with no problems.
I used a 1 lb cut,
with an old Binks jamb gun,
35 psi,
largest tip for the gun.
It was a pleasure because it dried fast,
and the fumes were not too bad.
Took a month to cure for polishing.

Dewaxed shellac from flake was something I was able to spray nicely through the Rockler sprayer. I would like to try it as a complete finish. I can get uv poly done for a reasonable cost, and can do KTM-SV myself for a certain amount of effort, but they both seem to really change the resonance of the box audibly.

With the U-bueat, are the crazing problems gone? It also seems horrendously expensive.

Is shellac in general subject to crazing?

Thanks

I use the Shines stuff (probably not availably outside of Sydney), but Robert Rae of Shines is the guy who "invented" the stuff, which was then subsequently marketed by U-beaut. U-beaut initially removed the plasticizer but put it back in, apparently, after the crazing issues. There is also an additive that extends the wet edge time (for furniture makers) which Robert removes for me, because I'm looking for drying speed.


Sorry, I don't know. However, I suspect the hardening additives are some fairly traditional mixture, e.g. sandarac and a mastic. There is nothing new! But, I could also be completely wrong.

_________________
Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Is shellac in general subject to crazing?

Thanks[/quote]
Yes. where your forearm hangs over the top, the humidity in your skin will eventually craze it. Also if you try to put too much on in a session and dont wait long enough for it to cure between sessions it will craze. Its not particularly durable.