Suggestions for a finish on this 8 string dobro?

[Mike Shipman]

Hi, I have this part built 8 string dobro (lap style) and am not sure how to progress ref a finish i.e. colour? and varnish etc.
Any suggestions would be appreciated along with hints and tips ref applications.
Thanks....here it is

[Rodger Knox]

I'm going to assume you know very little about finishing a guitar. There are a boatload of options, none of them are quick, cheap, and easy.

Nitro lacquer has become the traditional acoustic guitar finish, and there's tons of info on the web about spraying a nitro finish. There are also builders that specialize in finishing, you could sub it out to one of them.

Prior to nitro lacquer, the traditional guitar finish was either French polish or oil varnish. French polish is a hand applied shellac finish. While it is not very durable, it is easily repaired, and is probably the thinnest, lightest finish available. I typically French polish the tops of my guitars.

There used to be a wide variety of oil varnishes available, but they have been steadily disappearing from the market, and are being replaced with various types of poly finishes. I've used TruOil for years, it's cheap and not too difficult, but it does take some time to apply. I'd recommend it for an early build, and I'll post my application schedule if you're interested.

[Mike Shipman]

Rodger, thanks for your reply and suggestions.
You are right that I know little of guitar finishes, but I do have some experience of finishes on furniture including French polishing.I will want to apply a hand finish.
I would be grateful for your application schedule, Thankyou.
I’m not sure if UK will stock the products you might refer to, Zi will need to check them out.
Thank you once again.
Mike.
Ps, ref guitar binding, do you mask off when applying finish, leave it open and scrape off? Thanks.

[charles Tauber]

As Rodger stated, there are many finishing options.

Your choice of finish depends a lot on what finished appearance you want and how much protection you want. High gloss? Low gloss? Satin? For the neck, open-pored vs. pores-filled?

If you want a higher gloss, you'll need a surface finish - varnish, lacquer, urethane, shellac... A lower gloss, typically, a penetrating finish, such as oil. (I probably wouldn't recommend an oil finish on birch or maple.) TruOil is in the middle, a thin surface finish with shallow penetration.

Generally, surface finishes offer greater protection from scrapes and minor bumps and can be easier to clean. Penetrating finishes are much easier to repair.

Some prefer the feel of a surface finish, particularly on the neck, finding it "smoother": others prefer a minimal finish on the neck.

[JonWint]

Originally Posted by Mike Shipman

….but I do have some experience of finishes on furniture including French polishing.....Ps, ref guitar binding, do you mask off when applying finish, leave it open and scrape off? Thanks.

Why not French polished shellac? My preferred finish for simplicity, touchup-ability, low cost, thinness.

I don't see any bindings. I think some people scrape finish from white plastic bindings after finishing. Platina (super blond) shellac can remain. Wood bindings are easier since they're just finished with the rest of the body.

This is my 4 bottle method. Substitute your preferred local liquid for the green bottle.

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[Rodger Knox]

TruOil Finish
As with any finish, surface preparation is key, and even more so with TruOil. I usually sand the wood to at least 600 grit, 800 to 1000 on woods that will take that much polish. The smoother surface seems to make the woodgrain more articulate, and enhances any 3D appearance. I've never had any adhesion issues going that smooth with TruOil.

The pores need to be sealed, but not necessarily completely filled before you start the TruOil, I typically brush on a couple of coats of 2# cut shellac, and sand back to wood. This does not fill the pores, but it does seal them. It also shows any faults in the surface prep that need to be corrected before starting the oil. You don't have to sand back to bare wood, but I prefer the appearance of the oil directly on the wood. You also lose most of the effect of sanding to higher grits. If you do sand, you need to get all the shellac off or it will show.

I apply by dipping a finger into the oil and spreading it around with the heel of my hand. It's strictly a "feel" thing to tell when there's enough oil to keep rubbing, and when to move on before it gets tacky and will not level out. I break the top/back into 6 areas and do them one after the other initially, and as more oil goes on I cut that down to 3, and for the final coats I do the entire surface. Heating the oil to about 120°F helps getting it to go on thinly and evenly, and is more important after the first 6 or 8 coats. Until there's some oil on the surface, it's difficult to cover the entire surface before the oil starts to get tacky. With the pores sealed, the first 6 coats of TruOil will fill them. The first couple of coats will take a bit more oil to seal the wood, unless you left the shellac. Once it starts to shine a little after it dries (usually 3 or 4 coats), you can use less oil and work larger areas. I put the TruOil on very thin, at least 4 hours between coats. Every three or four coats I'll let it dry 24 hours and level sand, starting with 400 or 600 grit, and working my way up.

Application is very similar to French Polish as far as the feel required. When I get 16 to 20 coats, and have level sanded with 1000 grit, it's almost done.
The last coat has to go on perfectly, with the entire surface getting a very thin coat and nothing getting tacky while I'm rubbing, and then I'm done. I don't sand back after building the finish as is typically done with a nitro finish. This method produces a "soft gloss" which I prefer over the appearance of nitro. I may do a little hand buffing after it cures for a while, depending on how it looks.

I've found it works better if you stretch it out, there's less shrinkage if you allow more drying time during the application. I'll frequently wait 3 or 4 days to sand back, 24 hours is a minimum. I usually take at least a month, sometimes six weeks, to do a finish. It's probably only 4 hours of actual time spent, and can be done in a week, but there will be some shrinkage, similar to nitro. Nitro is sanded back, and you can also do that with TruOil, but I wouldn't advise it. It's thinner than nitro, and getting it thick enough to sand back would take 40 or 50 coats.

Do NOT wetsand at any point after you start the oil, use dry paper on a block. Wetsanding will usually guarantee witness lines.

[charles Tauber]

A little off-topic, perhaps, but under the heading of hand-applied finishes, has anyone used Odie's Oil? https://www.odiesoil.com

It sounds like God's gift to finishing. I'm tempted to try it.