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Hello everyone

I’m working on my fourth build and I’m getting to the point where it’s almost time to apply the finish and I’m on the fence on which direction to go.

I’ve done nitrocellulose for my 3rd guitar and did an osmo oil based finish for my 2nd build and was extremely happy with both. I’ve noticed the osmo finish is very thin similar to a French polish and has a beautiful satin sheen. Nitro is absolutely beautiful but the downside is that I don’t have a proper spray booth to get rid of the overspray. I was also thinking of a poly finish but only ever did one for an electric build.

I guess what I’m trying to get at is what would are you folks currently doing when it comes to finished and what are some downsides/upsides to the finishes I mentioned. Am I overthinking it and any finish will be suitable?

Any help is much appreciated

Carlos

Lately for acoustic instruments I like French Polish. Easy to do and non toxic. If you need to learn Robbie Obrien has a modified version that is relatively easy and you can purchase his online class. Just practice on wood before you tackle doing your guitar. He also has some water base finishing classes as well.

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That is a beautiful guitar. Well done. I love the look of the light colored neck on the darker body timbers. With wood of that character I would do an oil finish because I think it keeps the texture and feel of the actual timber - rather than covering it with a pane of glass, which is how it feels to me after you fill the pores and coat it with a high gloss and perfectly smooth layer of nitro or (God forbid) polyurethane. But that is just me, and I know my opinion on these things is a bit eccentric.

I've only gotten true French polish to work a few times, but lazy shellac finish always works. Pour a puddle and slop it around with a folded cloth or paper towel, replenishing the puddle as you go until the surface is fully covered. This fills the wood micro-texture, and will raise the grain and harden it.

Lightly scrape the top to remove the raised grain and wipe on a new coat, adding a few drops to the cloth for each wipe (no puddle this time). If you like a matte finish, it's done. Otherwise sand with the first three micromesh pads (rust, green, black) and wipe with dilute shellac, which will self-level to a slightly streaky but shiny surface.

Pore fill the back, either using alcohol and pumice on a French polishing pad or alcohol on 320 grit wet/dry paper. In either case, the goal is to grind up some wood dust/shellac slurry. Then use alcohol on the pad to push it into the pores. Usually it will shrink back after the first treatment, and personally I think that is the ideal look. No sharp edges of fully open pores, but more natural than a perfectly flat surface. You may need to scrape off some excess slurry here and there, and it's much easier if you used sandpaper since having pumice mixed into it dulls the scraper quickly. As with the top, give it one more coat of shellac, sand with micromesh, and then dilute shellac to self-level.

Lacquer, French polish, and varnish are all doable in the small shop.

- If you have the skill-set to have done the woodworking in the photos, I suspect you've done rag-applied and brushed film-forming finishes, so wiping and phenolic/tung varnishes might be considered if they line up with what is an existing set of skills. My personal favorite of any small shop builders: Mr. Kim Walker's brushed varnish, Epiphanes-finished guitars are flawless in appearance and have been changing hands for $90K or more lately, so the customer base is accepting of that finish for high end custom work.

- French polish is a perennial favorite due to its reduced effect on tone with thin application, despite being faster-wearing and more delicate than other choices. A lot of very nice guitars are wearing shellac.

- Finally, instrument lacquer and spray finishing (with conversion guns or turbine HVLP) - despite a definite learning curve to get to an acceptable level of appearance if you wish to eventually sell your work - is still the default standard. Lacquer has lots of issues, but it possesses the great virtue of having been used on a huge number of guitars considered iconic by the customer base.

I would suggest playing to your strengths here based on what you have done successfully in the past for other finishing work, although the temptation to build yet another finishing skill such as French polishing is an attractive notion. That said, my shop-mates where I apprenticed both claimed to have really, REALLY learned to finish wood only after moving from more general woodworking (and airplane, boat, car building, etc.) to instrument building. Multiple paths beckon... never a bad thing for the decisive, but pure torture for those of us afflicted with a case of 'too many choices' anxiety!

Thank you for the compliments and advice! I don’t have a lot of experience with woodworking or finishing as the only woodworking I’ve done is building guitars so I have a lot to learn that’s for sure. I like the idea of a brushed on varnish and im familiar with Kim Walker guitars but have never held one in hand.

How would you folks apply the Epifanes varnish and how would it compare to the osmo polyx gloss?

Thanks a ton!

Carlos

I do 2-3 shellac wash coats than use a foam brush to apply Epifanes. Thin down the first coat by 40-50%. It's self leveling so if you're careful you can get it pretty nice. I do a total of 3 coats. be sure and give it enough time to cure. it stays soft for quite some time.

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Once you’ve done the final coat, how long do you wait before it is fully cured and do you buff or wet sand to get a high gloss?

Thanks!

I sprayed my first 3 guitars with Nitro, outside, under the deck, under a small 8X8 festival "tent". Nitro is very toxic and the tiniest exposure to the solvents make me sick (even with a well-fitting respirator and fresh 3M OV cartridge).

For #4 I used EM6000 water-based lacquer (same respirator). It has its quirks but a short learning curve. WB is super easy to clean, easy to thin and is significantly less volatile in regard to the solvents. It also pulls back from sharp edges (does not bridge small gaps or grain lines either).

I never had a problem spraying outside as the area under my deck is somewhat protected from wind, and I carefully choose the time, temperature and humidity to spray. Occasional dust nubs were easy to remove from lacquer with white Scotch-Brite or 600 grit. Both nitro and WB lacquer have the disadvantage of long shrink-back time before buffing, and the advantage of being burn-in finishes that are easy to repair.

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Karl Borum