BYO Shellac Finish

Buco

I think everybody's good except I confused Alan that one time. I mostly decided to mention Tru Oil when @vanmalmsteen told about his project, for the sake of putting this option out there since it offers the tonal benefits of a light finish like French polish at probably less than half the time and effort. But I figured @Bones might be interested too since I found that a lot of full time luthiers love it.

Bones

Thanks guys....hmmmm, options....

Bones

Does anyone know the pros and cons of waxed versus de-waxed shellac? I can get pre-mixed shellac locally at the hardware store but I think it is NOT de-waxed. Thanks

slowlearner

De-waxed shellac is used as a sealer coat. If you are going to top coat with varnish or laquer you don't want wax in the shellac.

jared

Don't buy the premixed stuff. There is no telling what is really in there - potentially some nasty chemical dryers and "denaturing" chemicals for the alcohol. Plus you never know how long it has been on the shelf. Fresh is good. Flakes and pure ethanol is the way to go. Dewaxed flakes are normally slightly harder, but I find they don't work as smoothly in the FP process. The lighter grades are usually dewaxed and the darker (orange, garnet, button lacs) usually have more wax. Shellac flakes vary a great deal from different sources so there is some learning and experimentation involved in controlling variables. When you mix your own you can remove some wax and little bits of debris by letting the stuff settle and taking the nice clear fluid from the top. I have french polished about 60 instruments and never got too worked up about the dewaxing unless the mixture was really cloudy and nasty. If you are not going for a full FP finish and plan to put anything over top of the shellac, you should definitely use a dewaxed shellac.

Bones

Thanks guys. No I was just planning to do a FP with nothing over the top.

So pure ethanol not denatured alcohol?

Who do you get the flakes from. Yeah looks like a LOT of sources on the web.

jared

LMII, Stewmac, and Lee Valley have some if you are mail ordering. They are all good quality flakes, but a little expensive. I get my flakes from Mohawk Finishing for about half the price. Your local paint or hardware store may have them.

Denatured means they are basically putting poison in there to stop people from drinking it. No one will tell you what the poison is and there are a lot of possibilities, so you don't know what you are breathing. Methyl alcohol also works just fine, but can cause nerve damage (especially to the optic nerve) when inhaled over time. Methyl is sometimes used as a denaturing agent in ethanol, so what you are getting in denatured ethanol can actually end up to be a mix of ethanol and methanol. Everclear or similar 95% alcohol hooch works well. Way more expensive, but I like my optic nerves as they are.

Bones

Got it. Thanks. They have ethanol at Home Depot (in the cleaner aisle).

fhanshar

For the Selmer-style guitar I made this past year I used a French Polish finish which took a (very) long time but I am very happy with the outcome. I will use it on my next build. It requires very little sanding at all and can be done at your own pace. The drawback is how long it takes. I “bodied” for about three weeks before going into the “spiriting off” stage. I found some minor flaws after bodying, and had to cutback a couple spots and rebody a bit. Spirting off when well. I found the process very relaxing.

I followed all the free tutorials by Pablo Requena on YouTube https://youtube.com/user/redkitekk which where a pleasure to watch and were extremely helpful. I used Dark Auburn flakes bought dry from Lee Valley (in Canada) https://www.leevalley.com/en-ca/shop/tools/supplies/finishing/finishes/76311-shellacs and mixed with Methyl Hydrate which I bought from Home Depot. I used mineral oil as the oil for bodying. I used an old pillowcase as the wrap around cheesecloth as the rubber. I used different rubbers for bodying and spiriting off. All these details and more are in the videos I watched.

I practiced on the inside of the sides before I assembled the body to get familiar with the process and (in theory) help reduce moisture exchange.

I have never seen a French polish finish on a real guitar before in person and I think it is unparalleled now that I compare it with factory made guitars which seem to have clear coats of either lacquer, poly, nitro etc. I posted photos in a thread on my recent build if you want to see the raw wood vs finished product. It turned out more orange than I imagined so I think I am going to use more of a blonde shellac on the next guitar to let the natural wood colours speak for themselves.

Bones

I like the look of the orange shellac and the french polish. I might try it when I get back out in the shop.