Can I use Shellac over a Tru Oil finish on a stained Mahogany Body

[sammy1]

I am putting Truoil on top of a stained Mahogany body. Any one here with experience using shellac over cured Truoil.

My question is can you put lacquer or shellac over a cured Tru oil finish?

Also how many coats of tru oil should I use on a stained body and would you sand in between each Coat.

Thanks

 

[magicfingers99]

i think you might have problems with cracking and or hazing. Tru oil contains oil, shellac contains solvent, solvent can dissolve oil.

alcohol removes grease from frying pans...
alcohol softens nitrocellulose
oil and alcohol will mix until the alcohol evaporates.

give a try, I love experimental science, take lots of pictures.

you got a a 50/50 shot...

 

[jrblue]

I think magicfingers99 is raising a valid concern. The question is: what result are you trying to achieve? Sometimes, having an existing finish softened as a new one is applied is good. Sometimes, it's disaster. Are you brushing or wiping shellac? What result do you want to achieve? I hate tru-oil and would have gone with French Polish to begin with.

 

[sammy1]

I used stain on a completely stripped mahogany body. My next move is to fill the grain with multiple coats of Tru oil. (I haven't used it yet so I can still go a different direction). I guess what I am wondering is , do multiple coats of turmoil provide an appropriate seal after 10 or 12 coats, or should the cured Tru oil be finished?

Thanks for your input

 

[urbandefault]

I would forget the lacquer and just continue with Tru-Oil until you've built up a film finish. It will polish out to a high gloss, and is easy to repair. Remember, it was designed to protect gunstocks from the elements.

 

[bender66]

or should the cured Tru oil be finished?

Can you explain this?

I've done french polish shellac & nitro so yes, you can.
If you're trying to grain fill you could use the shellac & finish with either lacquer or TO (i'm doing just this).

I don't think i'd attempt anything on top of TO. It doesn't make sense to me. Someone will put me right I'm sure.

 

[Wallaby]

You can use shellac over varnish.

I don't understand using varnish *underneath* in any finish, though, because of the long cure time. My experience is with furniture and boats, though, so YMMV. I'm open to it, though, it's just not something I'm familiar with.

I wouldn't put anything on top of varnish until it's cured enough to level, which IME is 2 - 4 weeks.

 

[Silverface]

My question is can you put lacquer or shellac over a cured Tru oil finish?

Also how many coats of tru oil should I use on a stained body and would you sand in between each Coat.

As note above, Tru Oil is simply a varnish stain - a REALLY thin one. In other words - it's essentially a Danish Oil.

As far as "coats" you have to apply hundreds of coats to equal 4-5 coats of lacquer because it builds almost no surface film.

When it looks like how you want it to .look - that's enough coats, if you will be topcoating it. BUT - what you think is "dry" may not be, as oils in it may leach our of the wood for quite a long period of time if the wood is porous. That's one reason I never use varnish stains as "stains" to be top[coated.

You can apply shellac over it, but you gain almost nothing. Shellac has very poor abrasion and impact resistance and very low solvent resistance. It's a good finish for restoration of old violins and ukes that were finished with it originally, but I'd never use it as a "new" finish.

You can also apply lacquer over it, although the solvents in the lacquer attack/melt the Tru Oil resin to some degree with unpredictable results.

The ONLY advantage it has is that it touches up easily because the alcohol solvent melts the old finish (like lacquer solvents melt into each other).

You already stained the body - so why even bother with Tru Oil? It's a redundant component - simply another stain with a small amount of resin. If you plan to topcoat it's going to complicate matters more than anything else.

If you were thinking about lacquer, apply lacquer sanding sealer (it should have also been appllied BEFORE the stain but you still need it at this point), then your lacquer system. You won't have to wait weeks for Tru Oil to be absolutely dry - conventional lacquers like Mohawk, Behlens, Rust-Oleum, ReRanch, Valspar, Sherwin-Williams etc dry in 30-60 minutes per coat. There is NO cure time!

You need to practice application - apply the whole system on scrap (from prep to buffing) before continuing on the guitar. Trying to learn by working on the rel thing can get you into all sorts of trouble, so get some scrap mahogany, practice and/or test application, refine your technique, and make sure you know how to do the WHOLE job correctly before painting yourself into a corner .

But again - I'd forget the Tru Oul. It serves absolutely no purpose in your proposed system. And forget shellac as well - just go with lacquer, or if it's too much trouble use a simple urethane. You won't get the same result as lacquer, but it's a bit more "convenient" (however, ALL these require wearing of a full cartridge respirator & eye protection. Dust masks and old shirts tied around your mouth and nose are the same as using nothing at all!

Good luck!

 

[sammy1]

Silverface, Thank you so much this is very helpful. it seems that my truoil did enhance the stain to a nice color I see now where I could have accomplished that by tinting the stain to the end result I was looking for and then clear Lacquer over that. A much speedier process for sure. At this point I will let the Truoil dry for another week (3 weeks total ) and wet sand the "whiskers" and the go with clear Lacquer. I will post pics when I complete the clear coating.

Thanks again for your time and input to respond.