Advice for Natural Finish

[Ben17e]

I've been researching some clear finish options for the Venture-Sonic project I have started. For those who have not seen Deed Pool's Venture Sonic, it is a beautiful piece of roasted ash:

I can't fathom painting over that so I was originally thinking an oil finish but maybe want a little more protection. I have done a Tru-Oil guitar before and it was nice but I just want to try something different. I also have some Tung Oil/Citrus Solvent 50/50 from Real Milk Paint company which is very nice but I am thinking I want a bit more protection. I am leaning towards shellac either rubbed or sprayed. I have done a shellac finish on a neck before and absolutely love it so I am considering using that here or just a satin poly. I have used just a regular Minwax satin poly spray with good results.

The part I am really looking for advice for is grain fill. I am debating
A. Do I need to fill this or should I keep the ridges?
B. Should I fill with a clear filler like crystal-lac or dye a natural filler dark?
C. Should I coat with shellac, fill, then more shellac/spray poly or filler first?

Thanks for advice in advance!

[Horsefeather]

When you say "ridges" surely you don't mean the machining ridges? If you just mean the natural texture of the wood, I'd say leave it unfilled. This wood deserves to be celebrated. What about a burst of black dye around the perimeter (maybe varying in width to match the line of the guitar) and then your shellac? I have a Les Paul Studio that was given a treatment like this and it looks great.

[oid]

Shellac is fairly close to the bottom of the durability scale, it's ease of repair and speed in dry make it acceptable for many things. Tung oil is fairly close to the top of the durability scale, linseed oil is close up there as well.

We have two types of oils, non-drying and drying, most oils in their natural state (all?) are non drying and will just condition the wood as butcher block oil does. We polymerize (boil) oils to convert some into drying oils and these can be built up just as we do any other finish, but no one does that anymore and most everyone thinks of an oil finish as a finish that leaves the wood "feeling like wood." If you keep applying coats of your tung oil/solvent mix it will start building up and you can do a high gloss thick clear coat just as one would do with nitro or poly and the tung will be harder then both, in a decade or so at least. Tung oil is VERY slow to dry and continues to harden for decades, 50/50 solvent/tung mix will generally dry to touch in a day and will be harder then poly in a few days, full strength tung generally dries to touch on the scale of weeks/months.

A simple way to get a good durable oil finish is a blend of roughly equal parts boiled linseed, polymerized tung and turps. The linseed gives us a quick building finish with sane dry times, the tung cuts the yellowish color of the linseed and adds that depth which only tung can, and the solvent makes it easy to apply and makes it hard to apply the finish so thick that dry times become excessive. Do one coat with a brush or lint free rag and wipe of the excess after 10 minutes or so, let dry, apply following coats with 320/400 grit wet dry sandpaper, repeat until you have desired finish, buff to gloss if you are that sort. Applying the finish with the sandpaper creates a slurry of sawdust/dry oil which fills your pores as you apply the finish, you just need to make sure you are actually sanding (lightly) and not just pushing the wet finish around with the paper. Using 320 grit helps if you have a large pored wood, just switch to 400 once the pores have filled and you will have a nice matte oil finish that can be buffed to gloss if you desire.

Applying shellac in the french polish method adds some oil into the mix and is slightly more durable then a straight shellac finish, it probably gives more depth to the finish then any other method.

Dry polishing is essentially french polishing without the oil and gives one of the best matte finishes there is.

Filling is for filling the pores, not for the ridges, if you want a good looking finish you need to scrape/sand those ridges away. There is nothing that says you need to fill the pores, in most schools pores are looked down upon as sloppy/ignorant finishing, but many of us like the look of those pores! Generally thick clear coats do not show off pores very well, thinner matte finishes will show them off. In the end it is a matter of taste and the particular bit of wood.

You would do well to experiment on some scraps with both pore filling techniques and finishing techniques.

[Ben17e]

Thanks for the response! I tried some of the tung oil/citrus solvent in a cavity and really liked the look so I started going that route. I am debating if I want to only do that or maybe once a few coats are down, do a wash coat of shellac. While I like the grain left open, I think a really dark fill could add to the contrast as the wood did darken quite a bit with the oil. Then I could french polish on top of that with the shellac to finish.. what do you think? or just continue with the oil after the fill and buff that a bit? I think I want a satin type finish..Not glossy, but a little bit of shine.

[oid]

Thanks for the response! I tried some of the tung oil/citrus solvent in a cavity and really liked the look so I started going that route. I am debating if I want to only do that or maybe once a few coats are down, do a wash coat of shellac. While I like the grain left open, I think a really dark fill could add to the contrast as the wood did darken quite a bit with the oil. Then I could french polish on top of that with the shellac to finish.. what do you think? or just continue with the oil after the fill and buff that a bit? I think I want a satin type finish..Not glossy, but a little bit of shine.

Stain needs to go before oil/shellac since they will effectively seal the wood from the stain. A thin wash coat of shellac or oil can be done to limit penetration of the stain, but that can be tricky since if you do not get a very even coat of the shellac/oil you will end up with a blotchy stain.

You certainly can do a coat of oil and then shellac or french polish, there is little reason to do french polish after multiple coats of oil, once the oil starts to build up on the surface it provides more protection then the polish and the polish can not build up in the wood for the visual quality it can provide. I think i would likely sand all oil off the surface before french polishing, just leaving what has soaked into the wood.

The wood will also darken with time on its own, oils and shellac provide little to no UV protection so UV exposure will darken the wood with age, the natural darkening will have more depth and warmth then any stain, but you have to be patient and let it happen, In the old days egg white was a common pre finish treatment, many say the effects this has on how the wood darkens with age is the actual cause of the rich warm tone of 100 year old wood, not the 100 years. It does little at first but seems to speed and change how the wood darkens, I have no examples old enough to say for certain, just a few experiment. An egg white wash was the only finish on lute soundboards and some guitar soundboard back in the day.

No reason to buff tung oil, just wipe on with a rag, as long as you are putting on thin even coats you can just stop when you get a nice satin finish, if you continue on applying coats you can do a gloss. Gloss would need a buff to even it out, matte and satin can often be done right from the can, perhaps a quick once over with some steel wool.

For the best everyday non-showy oil finish apply just until you get a coat that builds on the surface and call it good, perhaps a buffing between coats with fine steel wool, after that make a fresh coat of oil a part of a yearly clean of the guitar for the first decade or so. Nothing gives the nice deep finish that yearly coats of oil separated by a years worth of wear will give.

[Ben17e]

Thanks again...maybe I will try just the tung oil. It seems very nice. I expected more of a film with the shellac but you seem to be suggesting otherwise. I tried the slurry with 320 technique and so far it seems to be going well. I am wondering how much effort it would take to truly fill the ash with its rather open grain and if it is worth it. I am not going to stain the wood..I was only thinking of staining some filler but I am thinking I may not fill after all beyond the slurry. I also read about doing this with pumice as a traditional method with some even feeling that the pumice stone became a "part of the tone" of an instrument. I'm not sure I believe all that but it sounds like a cool technique. Even after one heavy coat, it looks pretty lovely right now.

[Deed_Poll]

I can't wait to see it! It does darken up a lot when you wet it with alcohol or finish.

[epizootics]

There are a few ways to fill the grain with shellac. Pumice is one of them, and it works. Here's another one, although ash might have too deep a grain to work with this technique:

https://sawmillcreek.org/showthread.php ... th-Shellac

I did get good results on mahogany-type woods with this, though. I posted these pictures in my tiny-guitar-build thread the other day:





(tru-oil was applied on top of the shellac after fifteen coats or so. Probably too glossy for your needs, but you can knock it back with steel wool in no time for a satin finish)

Just like everybody else here - can't wait to see this one finished!

[oid]

Pumice is a good grain filler, age old, it is my go to if i use a separate filler.

You should not need anything other then the slurry to fill the grain, from your photo the pores do not look all that massive and a few coats with the sandpaper should fill them. But photos can be misleading regarding pores and ash can certainly have big pores.

If the finish does not seem to be building up you may need to give abit more time between coats, I am not sure how the citrus solvent works and it may dissolve the previous coat too much if it is not dry enough. It also will not look like it is building up until the pores are filled, you just do not get that smooth film and it makes it look as though it is not building up. Ash can soak up a great deal of finish and can get frustrating at times, did an old Fender 400 a few years back, that thing took weeks to finish, it just kept sucking up the shellac.

[Ben17e]

Let's see if Google Photos wants to work today for you all.... It seems like it is when I use the link, but not embed... I'll try both.
after 2 coats with some slurry technique..Grain still not totally filled but looking great I think!
https://photos.app.goo.gl/9wheyJ2zZKjB9Bih2
https://photos.app.goo.gl/IuYT6A1R4S18HB3m1
https://photos.app.goo.gl/uKUP7iUWCplZzG923

[oid]

That is looking quite nice, was not a fan of the toasted wood before finishing, but I am a convert.

[oid]

Just realised I forgot some information in my instructions. If the oil starts building up on the surface before the pores are filled you need to knock back the finish with a light sanding when dry. If the finish builds up, you will not get the slurry since you are just sanding the finish and not wood to get that saw dust mixed in. If you find yourself in that position it means you were either sanding to lightly, using to much finish, or the finish needs to be thinned abit.

Looks like most if not all of the guitar still has wood at the surface in your photos, so you seem to be doing well. You just need to watch the slurry as you you go, if it starts to go clear it means you need to adjust your technique and possibly give a quick dry sanding before the next coat.

I will give a check later tonight when I have more time to make sure I did not forget anything else!

[Ben17e]

Yeah the slurrying seems to be going quite well and seems correct to me. The oil is thinned w/ the citrus solvent so that probably helps. My last coat really seemed to start filling well. I left some of the "filler" as it dried instead of wiping right away so I think I am going to sand that off and put one more coat. At that point I think I should be totally filled or close - I am pretty close now I believe. Then I am going to decide if I want to go the shellac route and try to shine it up a bit or if I think the tung will be enough.

[oid]

The solvent evaporates off, every time the container is opened you lose some and the more air in the container the more you lose, so sometimes you need to add some solvent to keep the consistency right.

If you go the shellac route realize future finish repairs will be considerably more difficult, you will have what is essentially a color coat with the oil and then a clear coat. It will be easier then lacquer to repair, but considerably more difficult then a single finish. The tung oil will start adding the shine once you finish filling, you can switch to 400 or 600 grit for shades of matte or satin or just switch to just wiping it on for gloss. For matte or satin you want to avoid sawdust in your slurry, just want to sand the finish, not the wood. Shellac on top will add a different sort of depth, you always get that when you put on a different top coat, the difference between the two is subtle, both nice in their own way.

If you go the shellac route you need to sand the oil finish to get it very even and smooth, the shellac with really highlight any flaw in the oil beneath it. The oil is more forgiving in that sense, you can just build up the top coat then buff or wet sand through the high grits and even using the polishing compounds if you want that high gloss coated in glass look, but if you get your final coats nice and even you can avoid most, if not all of the sanding/polishing.

Tung oil and shellac are naturally gloss finishes, the trick to getting a good gloss without lots of buffing work is many light (thin) coats. This will even out irregularities in the previous coats and make it easier to avoid that irregular dipped in plastic look without the need for all that post finishing elbow grease. Or you can always combine the oil and the shellac and do the french polish, it is more work then oil or shellac, but the result is well worth the effort.

I am somewhat embarrassed by the composition of that text, being almost 4AM gives me some excuse, but in reality, I just do not feel like dealing with it

I am getting excited to see how this turns out, it is really giving me the itch to do some building.

[j mascis]

I'm looking to get a finish like these:

https://imgur.com/a/gGSnBBP
https://www.12fret.com/sold/fender-jazz ... ignment-2/

Any idea the best oil, color, and method to tackle this? Thank you.