Learn me about wet-sanding a tru-oil finish...

[Jim Beam]

I know, I know, take it to Finely Finished. Frankly, there's just too much contradicting info there in all the past threads I've dug up. I'd like to hear what the frequent fliers here have to say about this.

I've got about 10 coats of tru oil on my first build. The padouk top is starting to look pretty good, thick and glossy, although the open grain pores are still mostly open. Not too worried about that. That mahogany back needs a lot more coats tho.

So at some point am I supposed to wet sand the finish? To make it, I don't know, flatter or something? What grits would I work through? Do I use water or mineral spirits to lubricate? Advice on technique here would be most appreciated. Lotso-lube? Or not a lot? With the grain? Or in circles?

I presume that, after wet-sanding, I should put another one or two or 19 coats of tru oil on?

Thanks to the Collective for your help!

[Tom Pettingill]

When I'm going for a flat and shiny mirror finish I generally lightly wet sand every 3 - 4 or so coats as I'm in the building the film phase. I find that 1000 grit and a few drops of mineral spirits works well for me. Once you get within the last coat or two, you can move up to 1500 - 2000 before the last glaze coat. Being that you have basically done all the leveling as you go, if you want to polish it out you can go strait to the fine polish when cured. Sand with the grain, and let the Tru Oil cure about a week before you polish.

.

[JustPlay]

Originally Posted by Tom Pettingill

When I'm going for a flat and shiny mirror finish I generally lightly wet sand every 3 - 4 or so coats as I'm in the building the film phase. I find that 1000 grit and a few drops of mineral spirits works well for me. Once you get within the last coat or two, you can move up to 1500 - 2000 before the last glaze coat. Being that you have basically done all the leveling as you go, if you want to polish it out you can go strait to the fine polish when cured. Sand with the grain, and let the Tru Oil cure about a week before you polish.

.

Wow - that's a really beautiful instrument!

[dazzaman]

Originally Posted by Tom Pettingill

When I'm going for a flat and shiny mirror finish I generally lightly wet sand every 3 - 4 or so coats as I'm in the building the film phase. I find that 1000 grit and a few drops of mineral spirits works well for me. Once you get within the last coat or two, you can move up to 1500 - 2000 before the last glaze coat. Being that you have basically done all the leveling as you go, if you want to polish it out you can go strait to the fine polish when cured. Sand with the grain, and let the Tru Oil cure about a week before you polish.

.

That is only Tru Oil? Wow, what a fantastic finish. Is your "glaze" coat thinned at all or straight from the bottle. And how are you polishing. If a finish like that is possible with Tru Oil I would be very willing to try and become a convert.

[flatfive]

Be warned: Tom Pettingill is a master at gloss Tru-Oil finishes!

Tru-Oil is not well-suited to wet sanding because the layers don't
melt together as they do with lacquer. I guess that's why Tom
sands with 1000 grit -- so that he doesn't sand through the top
level and get "boundary lines".

If you want a perfect mirror finish, it's a lot easier with lacquer.

[fretman_2]

This, as they say, is perfection!

Originally Posted by Tom Pettingill

[fretman_2]

But Tru Oil, if you do it like Tom laid out, is very well suited to wet sanding!

Here's a neck I did in Tru Oil...wet sanded then buffed. Not as smooth as Tom's finish, but you can see what you can do with a reasonable effort.

Originally Posted by flatfive

Be warned: Tom Pettingill is a master at gloss Tru-Oil finishes!

Tru-Oil is not well-suited to wet sanding because the layers don't
melt together as they do with lacquer. I guess that's why Tom
sands with 1000 grit -- so that he doesn't sand through the top
level and get "boundary lines".

If you want a perfect mirror finish, it's a lot easier with lacquer.

[4string]

Originally Posted by flatfive

Be warned: Tom Pettingill is a master at gloss Tru-Oil finishes!

Tru-Oil is not well-suited to wet sanding because the layers don't
melt together as they do with lacquer. I guess that's why Tom
sands with 1000 grit -- so that he doesn't sand through the top
level and get "boundary lines".

If you want a perfect mirror finish, it's a lot easier with lacquer.

+1. If you expect Tru-oil to look like a lacquer finish and are using Tru-oil because spraying seems like a daunting task, you have it 100% a$$-backwards....

[dazzaman]

Originally Posted by flatfive

Be warned: Tom Pettingill is a master at gloss Tru-Oil finishes!

Tru-Oil is not well-suited to wet sanding because the layers don't
melt together as they do with lacquer. I guess that's why Tom
sands with 1000 grit -- so that he doesn't sand through the top
level and get "boundary lines".

If you want a perfect mirror finish, it's a lot easier with lacquer.

Sorry, my message was unclear. I do not disagree for a second that lacquer is easier. I didn't mean the phrase "a convert" to say that I had a wish to use TO as a replacement for lacquer, but rather an alternative.
For six months of the year the humidity is too high to shoot lacquer outside, and I don't have the right extraction equipment to do so safely indoors, so either I choose not to finish during those months or I use an alternative. I have had lots of experience with French Polish and plain linseed oil (for different types of end result, obviously). I don't wish to use either of those on guitars, despite FP regularly used on classical instruments, hence looking for an alternative. If an instrument needs or should have a lacquer finish then that is what I will give it.

[Keyser Soze]

Originally Posted by flatfive

Be warned: Tom Pettingill is a master at gloss Tru-Oil finishes!

Tru-Oil is not well-suited to wet sanding because the layers don't
melt together as they do with lacquer. I guess that's why Tom
sands with 1000 grit -- so that he doesn't sand through the top
level and get "boundary lines".

If you want a perfect mirror finish, it's a lot easier with lacquer.

The only layer you cannot cut through is the top layer. As you note, cut through that and you will get witness lines that no amount of polishing will erase.

So, if you do level sand then always plan on one (or two) final coat(s) that you will only sand with the finest papers (think 2000 grit and above - if at all) or that you will only hit with compound and/or polish.

And, as always, proper surface preparation - level sanding, and level filling, make the finishing process much, much easier, adn the final results that much better.

[flatfive]

Originally Posted by fretman_2

But Tru Oil, if you do it like Tom laid out, is very well suited to wet sanding!

Here's a neck I did in Tru Oil...wet sanded then buffed. Not as smooth as Tom's finish, but you can see what you can do with a reasonable effort.

That neck looks great! And I use Tru-Oil for necks myself.

But to get a mirror finish on a flat surface with Tru-Oil is
difficult. Besides Tom Pettingill's work I think I've only seen
a few examples here.

Originally Posted by 4string

If you expect Tru-oil to look like a lacquer finish and are using Tru-oil because spraying seems like a daunting task, you have it 100% a$$-backwards....

That's a good way of putting it!

[flatfive]

Dazzaman, I know exactly where you're coming from. I spent
months learning to french polish for exactly the same reasons.
But shellac is not as durable as lacquer. Water-based lacquer
is another option, but I can't see spraying it inside. I'm thinking
of trying to brush on water-based lacquer. Some brands
are supposed to have "full burn-in" like good 'ole nitro lacquer.

Originally Posted by dazzaman

Sorry, my message was unclear. I do not disagree for a second that lacquer is easier. I didn't mean the phrase "a convert" to say that I had a wish to use TO as a replacement for lacquer, but rather an alternative.
For six months of the year the humidity is too high to shoot lacquer outside, and I don't have the right extraction equipment to do so safely indoors, so either I choose not to finish during those months or I use an alternative. I have had lots of experience with French Polish and plain linseed oil (for different types of end result, obviously). I don't wish to use either of those on guitars, despite FP regularly used on classical instruments, hence looking for an alternative. If an instrument needs or should have a lacquer finish then that is what I will give it.

[flatfive]

Originally Posted by Keyser Soze

The only layer you cannot cut through is the top layer. As you note, cut through that and you will get witness lines that no amount of polishing will erase.

So, if you do level sand then always plan on one (or two) final coat(s) that you will only sand with the finest papers (think 2000 grit and above - if at all) or that you will only hit with compound and/or polish.

And, as always, proper surface preparation - level sanding, and level filling, make the finishing process much, much easier, adn the final results that much better.

Good tips!