Wipe-on finish for acoustic guitar

[mickeyj4j]

I have a cajon I am intending to build from an old wine box see my post DIY Cajon Drum
I am going to stain the box and apply a veneer over the tapa (front playing surface) or might vaneer the whole thing.

I also have a cheap ukulele I need to apply some sealer to it see Guitar Finish Ideas

I am liking the idea of true-oil as an easy wipe on finish. Would this be good for these projects I think so.

[kpcart]

I tried Tru-oil for the first time, on the back and sides of a flamenco guitar.

it is an interesting finish... 56% mineral spirits, 33% modified oil (whatever that is). and 11% linseed oil.

Is it a real oil finish?? NO, just look at the percentages above - some people say it works like a polymer finish... yet it doesn't apply as quick and thick and doesn't work as negatively on the sound as most polymer finishes. the result to me almost looks more like a lacquer. thin coated sprayed acrylic lacqer on a guitar (the stuff used on cars) looks similar, but can be buffed better then tru-oil, which can not be buffed at all really... it is certainly no burnishing oil.

the 56% mineral spirits content... that makes it closer to a lacquer varnish for me.. mineral spirits is used for paint, acrylic, laquer and varnish.


applying it is easy wipe on... but it takes a long time to dry between coats... 12 to 24 hours is recommended. but I think in warm weather with touch dry after a few hours you can recoat - but I am not sure if it is fine to steel wool between coats after only a couple hours. I personally waited a day between most coats as I was not in a hurry, but at the end did a couple coats a day. i had a bit of tiny bubbles form from my finish (dust particles?), in the same way i have previously got on French polish, so had to level between coats.

it takes about as long as French polish to be finished overall. I think you only need about 8-10 coats, but it depends if you are "wiping on", or if you are "wiping on and off". I experimented a bit between coats.

I aimed for a fairly shiny finish. no oil finish can look as shiny as well polished French polish, but this was OK looking . Since it doesn't really work with buffing, you want to wipe it on evenly and not wipe too much off if you want a nice shine.. steel wool will give you a nice sheen or matte. you cant really"polish" this finish unfortunantly.

one thing I like about it, is that it is a very thin finish, even after 10 coats much like French polish, so it is good for sound. it does not fill pores (like French polish), so you need to prepare the wood well, and also even very light sanding marks not going with the grain show up.

One last thing, this finish was designed for gun stocks... yet speaking to a few gun people, it doesn't seem that popular because of its long drying time, and gun guys can get a shinier coat with a wipe on poly, and a matte coat can be achieve quicker with Danish oil. It seems that the guitar world is a bit more focused on this finish at this current time then gun owners who refinish their guns.

I enjoyed the process and will use Tru-oil again.

[old_picker]

just to add my 2c worth to this info packed thread.
wiping varnish recipe:
3 turps
2 varnish
thats it
either wipe on thinly with a soft cloth and leave to go off
or use a wide very soft bristle brush again applied just enough to wet the surface
3 or 4 coats is enough - it wont fill grain

some else mentioned
1/3 varnish
1/3 boiled linseed
1/3 turps
this is a danish oil but lacks the terebine [japan driers] found in off the shelf stuff like cabots Danish oil
flood surface leave for 10 minutes wipe off till surface dry - repeat at 24 hourly intervals at least 3 times
not great for acoustic instruments

[mickeyj4j]

1/3 varnish
1/3 boiled linseed
1/3 turps
this is a danish oil but lacks the terebine [japan driers] found in off the shelf stuff like cabots Danish oil
flood surface leave for 10 minutes wipe off till surface dry - repeat at 24 hourly intervals at least 3 times
not great for acoustic instruments

This has been recomended on other sites as a good finish for acoustic instruments. Works for me.

[old_picker]

mickeyj4j
mate if you look at my quote you'll see the last line says "not great for acoustic instruments"

I wouldn't recommend it especially for the sound board - this stuff soaks right into the grain structure and would assume it to have a deadening effect. Having no experience with acoustics I am really not qualified to comment on this thread but seeing as I have been quoted I'd suggest that Truoil probably ok as it stays on the surface and wipes off with acetone easily - shellac great - a traditional acoustic finish

[pmatolcsy]

Hi,
I have used Tru-oil successfully on a few of my electric builds.
Just a warning it will not set on anything in the Dhalbergia family. Apparently the oils in the wood interfere with the polymerization process. The fix is to build up shellac until all the wood is covered and level. I used a brush, then leveled and applied the truoil.
Also available is Birchwood casey gun stock sealer and filler. It is a pore filler designed to work with truoil. Instruction seem simple. Apply with brush or cloth, level and apply truoil
phil

[pmatolcsy]

Hi,
I have used Tru-oil successfully on a few of my electric builds.
Just a warning it will not set on anything in the Dhalbergia family. Apparently the oils in the wood interfere with the polymerization process. The fix is to build up shellac until all the wood is covered and level. I used a brush, then leveled and applied the truoil.
Also available is Birchwood casey gun stock sealer and filler. It is a pore filler designed to work with truoil. Instruction seem simple. Apply with brush or cloth, level and apply truoil
phil

[routout]

This is a good point Shellac has to be one of the most versatile finishes out there most wont use it .

[pmatolcsy]

I like to think of truoil over shellac as french polish without all the work plus alcohol and water resistance.

[Jules93]

Im still deciding on finishes for my first guitar build which is based on a Gibson J-45
I have hardly any room for any sort of spray so its down to
Wipe on which is what I kinda preferred anyway

My choices
oil especially cause there’s so many types
Some sort of water based (if it exists)
shellac

Some say oil finishes effect tone (not in great terms)
And obviously shellac can be wiped, padded brushed
I’d be doing French polishing

Just need a light on the choices
Especially whether I’m wrong about oil finishes

[Mark McLean]

The view that oil finishes dampen tone may have come from use of traditional oils (like linseed or tung oil) that soak into the timber, possibly affecting weight or resonant qualities. Even then you would wonder how people determine such things. Tru Oil is a different entity, it is not really absorbed into the timber. It sits on the surface and polymerizes more like a varnish. Hard wax oils (various brands) are the latest product of this sort and they are also proving very good for instrument finishing. They were developed as a flooring and furniture finish and they are very hard wearing. Easy to apply by hand, and one of the useful features is that they are very easy to repair. For example if you need to repair a dent or crack you can sand back to bare wood, fix the defect, and then reapply the oil finish and it will seamlessly blend into the existing finish.

[yakka]

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