Prostheta Posted August 8, 2008 Report Share Posted August 8, 2008 I have a mahogany guitar which I finished in Tru-oil a while back although i've never been to happy with it. I would like to remove the finish so I can finish the instrument in solid white. Sanding the surface layers off is obviously the first step, although what potential problems will I encounter from thereonin? I presume that the oil will have penetrated the wood to a depth which is impractical to sand out, and it's presence below the surface may cause compatibility problems. Specifically, I am planning on using Plastikote super white with clearcoats over the top....at least at this stage.... Quote Link to comment Share on other sites More sharing options...
WezV Posted August 8, 2008 Report Share Posted August 8, 2008 might need to do some tests but you could try something like shellac as a sealer first Quote Link to comment Share on other sites More sharing options...
Prostheta Posted August 8, 2008 Author Report Share Posted August 8, 2008 Probably a very good idea Wez. I'll have to do some work before committing, but that was a given anyway :-\ Darn. Quote Link to comment Share on other sites More sharing options...
erikbojerik Posted August 9, 2008 Report Share Posted August 9, 2008 Tru Oil does not penetrate all that far; it is more an varnish than it is an oil. If you just sand down to wood, you'll remove everything except what's in the pores (which you'll probably have to fill anyway before your primer). Quote Link to comment Share on other sites More sharing options...
Prostheta Posted August 9, 2008 Author Report Share Posted August 9, 2008 I think i'll do some scrap tests first as Wez mentioned. It's weird to finish scrap in oil, only to sand it back and pretend i'm painting it :-\ I'll post progress as it happens - thanks Erik, Wez... Quote Link to comment Share on other sites More sharing options...
Daniel Sorbera Posted August 10, 2008 Report Share Posted August 10, 2008 I've done this a couple times and never had any problems. Just sand it back like you normally would and continue as if it were never there. As Wez mentioned tru-oil doesn't penetrate very deep. Quote Link to comment Share on other sites More sharing options...
Prostheta Posted August 10, 2008 Author Report Share Posted August 10, 2008 Awesome - thanks Daniel. I imagined that with mahogany being a moderately open-grained wood, the Tru-oil would wick into the pore structure a reasonable amount and perhaps cause compatibility issues from thereonin. Quote Link to comment Share on other sites More sharing options...
kpcrash Posted August 10, 2008 Report Share Posted August 10, 2008 Not as bad as if you had used say redwood, but agreed - tru-oil isn't that deep and as already stated, a few coats of sanding sealer would prevent any sort of undesired interactions. I wouldn't consider any other type of chemicals at all for this - Plastikote is pretty stable. Quote Link to comment Share on other sites More sharing options...
Prostheta Posted August 10, 2008 Author Report Share Posted August 10, 2008 I have a couple of tins of the "Jet" Vinyl Sanding Sealer as sold on the behlen.co.uk site. http://www.behlen.co.uk/Merchant2/merchant...gory_Code=SANDS Any reservations about this stuff? The health warnings about dying on the tin are a bit scary. Quote Link to comment Share on other sites More sharing options...
kpcrash Posted August 10, 2008 Report Share Posted August 10, 2008 I have a couple of tins of the "Jet" Vinyl Sanding Sealer as sold on the behlen.co.uk site. http://www.behlen.co.uk/Merchant2/merchant...gory_Code=SANDS Any reservations about this stuff? The health warnings about dying on the tin are a bit scary. I read the MSDS, it's not as scary as some of the 2k uros some are using. This only recommends a standard respirator and ventilation, gloves, etc. "Normal" protective gear. No worse than the plastikote. Quote Link to comment Share on other sites More sharing options...
dugg Posted August 10, 2008 Report Share Posted August 10, 2008 Oils in wood finishes are what are known as drying oils. They don't really 'dry' in the actual sense, but polymerize by absorbing oxygen from the air. Unlike urethanes, virtually anything will adhere to drying oils, so a shellac coat is not really needed. That tru-oil is no longer an oil in the strictest sense. It's a solid now, and wll not only be more solid in three hundred years, but by then you won't even be able to tell for sure that it was tru-oil to start with! Quote Link to comment Share on other sites More sharing options...
Prostheta Posted August 11, 2008 Author Report Share Posted August 11, 2008 Very useful information Dugg....I presume that on the basis of Tru-oil essentially being a good solid compatible base to work from, I should flat the instrument's finished surface instead of having to flat it right back to bare wood? Sounds good. I'll have to re-examine the degree at which the pores have been filled by the Tru-oil....does it still move or fall back into the pore structure over time? It has been roughly a year since the Tru-oil was applied. Quote Link to comment Share on other sites More sharing options...
dugg Posted August 11, 2008 Report Share Posted August 11, 2008 Prostheta, I'm not entirely sure whether it stops moving altogether, but I'm fairly certain the oil won't shrink and cause deeper pores that way. I would venture that some continued movement of an oil finish is one of it's advantages 'cuz as we know, wood is always moving a bit too. With the older spirit and oil based finishes, most everything is compatible. Laquer and urethane are newer finishes and seem to have more issues with other finishes as well as themselves. Let me know if there's any problem, I'll commit seppuku.... Quote Link to comment Share on other sites More sharing options...
Prostheta Posted August 11, 2008 Author Report Share Posted August 11, 2008 Hahahaha....! I think i'm just trying to talk myself out of spending lots of hours sanding back the entire body :-D For the sake of completeness, I should really go back to the flat wood surface so I can apply a good grain filler rather than relying on the Tru-oil. As nice as likely compatibility sounds, I really want to achieve a uniform high gloss white so I better not give into the temptation of cutting corners anywhere. Out comes the granite slab, DST and sandpaper! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.