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Hi Folks;
A friend of mine is building his first guit & has decided to finish with Tru-Oil.
I'm wondering if the oil is likely creep under the bridge masking tape & impair the bridge glue joint.
He can glue the bridge on before applying the finish, but it's much easier to get the finish on first.
Also... Tru-Oil comes in a two part kit with a small bottle of "sealer / filler". Is it recommended to use the sealer? I've never heard of any luthiers using the stuff.
I've only used tru-oil on a couple of necks & the sealer didn't *seem* to do anything different than the straight oil.
If someone can help out, we'd appreciate it... LOTS!
Thanks,   Dan

Dan,

On my early guitars I used just Tru-oil but used to do the finish after I had glued the bridge on. I don't buff my finishes up to a mirror shine and used 0000 wire wool and micromesh which worked OK. On later guitars I built up some shellac/FP coats first and then put 3-4 coats of Tru-oil on top. I did this the normal way - finish the whole top and then position the bridge and scrape back to wood for gluing. Again this worked fine. I never did the masking tape thing. Try it on some scrap - I'd be very surprised if it did creep. Because it is linseed oil based people regularly trot out the "it's bad as it sinks into the top killing tone" but I don't think it goes any further in than shellac - it's more like a wiping varnish. I say this after having sanded a top down from Tru-oil after it had been on there for a couple of years. The issues are with it's looks, wearing powers and ability to stand up to hard use rather than any tonal issue i.m h.o.

I wouldn't use the sealer/filler on the top - wash coats of shellac would be much better. I do use it on the necks though - 2 or 3 coats before applying the Tru-oil coats and a like the feel this gives much better than just using Tru-oil - can't explain why. On my latest neck though I wiped on diluted Z-poxy with a paper towel, sanded/polished back with 0000 wire wool and then Tru-oiled over this. This worked really well and I love the feel.

Hope this helps.

_________________
Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

I've finished three so far with tru-oil. Like Dave, I put a couple of shellac seal coats on, hit it with 0000wool and then tru oil. Bridge area masked off and have had zero problems. No seeping of oil at all.

Ron

_________________
OLD MAN formerly (and formally) known as:

Ron Wisdom

Somewhere in the middle of Arkansas......

Dan, dedicated sealers are usually just a thinned version of the finish that's supposed to go over it. You can make your own by thinning your finish. That's why the Tru-Oil sealer seemed to behave just like the oil. It really doesn't work as a "filler" either, so use another method for filling if you want closed pores. Now, I'm not an expert on this, but for a guitar finish I think that shellac would be a better sealer under Tru-Oil, because thinned oil would be more likely to seep into the wood before the solvent can evaporate. We don't want that. We want a surface finish only (probably not as crucial on the neck, though, within reason).

As Dave mentioned, Tru-Oil differs from straight or "boiled" linseed oil. It's a polymerized oil, which is achieved by heating it to around 500 deg. Fahrenheit in an oxygen-free environment. It thickens and becomes partially cured. Solvent is then added to make it useful for wiping or brushing. I once wrote that T-O is a varnish, but it's not, according to Bob Flexner's "Understanding Wood Finishing" (where I'm getting all of this information). Varnish is made by heating an oil with resins, which transforms it into something different from either.

According to Flexner, polymerized oil (linseed or tung) is the fastest-drying, most protective of all oil finishes, even beating out varnish. In fact, it's one of the most protective of any finish against water and solvents. This is good for instrument finishing because if you wipe it on and almost immediately wipe it off, it won't sink into the wood. It drys hard, on the surface.

Impress upon your friend that finishing with Tru-Oil may be easy, but it's not fast. Many people only put on one coat in each 24-hour period. Some do two coats in one day, with several hours of drying time between. In Bill Woods' LMI tutorial, he says that once you have a sufficient finish thickness, you should wait at least one week before doing any kind of buffing or polishing, with four weeks being ideal. Patience is the key with Tru-Oil! Woods puts three to six coats on hardwood, and up to eight coats on the top (it takes more finish to build a sheen on softwood). If you've been diligent in wiping off the excess, he says you'll end up with a finish thickness on the top of .003" to .005".

As an aside...we all know that shellac is a poor barrier against water. Flexner says that's correct, but it's very protective against water vapor. Interesting.

Wow Guys!
What a wealth of info. Many thanks for taking the time to reply so thoroughly.
I have printed out your posts & will pass them along to my buddy.
I see that I need to pick up a copy of Flexner's book... I'm off to check out amazon.com!
Thanks again,   Dan

Dave, when you z-poxied your neck before tru-oiling, did you sand all
the way back to wood, so just the pores were filled? Or was the whole
neck sealed with the z-poxy?

_________________
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

[QUOTE=SniderMike] Dave, when you z-poxied your neck before tru-oiling, did you sand all
the way back to wood, so just the pores were filled? Or was the whole
neck sealed with the z-poxy?[/QUOTE]

Mike,

No I didn't sand back to wood. I mixed a small amount of Z-poxy and using a piece of paper kitchen towel wiped a very thin coating all over the neck. Then when it had dryed the next day I rubbed it back with 0000 wire wool. This takes quite a while to do but eventually the wire wool levels out the Z poxy leaving a really smooth finish. The Tru-oil was then wiped on in thin coats as I normally do using more kitchen towel. It was a Spanish cedar neck and part of the reason for using the Z-poxy was to match the colour better to a sapele b/s that had Z-poxy on. I don't have a close up picture of the neck but this is how it looks on the guitar:

_________________
Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Beautiful, Dave! Thanks so much. I'd like to try something like that.
Seems like the z-poxy might add some durability as well.

_________________
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