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Thread: Beginner staining & finishing

  1. #26

    Default Re: Beginner staining & finishing

    Well, thanks to everyone's help, I managed to nail the "rustic drunkard amateur" look! I can definitely see why some sealing can be helpful, and if I ever do this again I'll experiment with much lighter seal then maybe a little sanding. All told, I'm pretty happy with the results and I do like the rustic look. While it'll be my newest instrument, it looks like it's really old. I can't say I mind that much!

    Next step, Tru-Oil finish. Can't start that until tomorrow so it may have to wait for the weekend.

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  2. #27

    Default Re: Beginner staining & finishing

    Should I sand before my first finish coat of Tru-Oil?

  3. #28
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    Default Re: Beginner staining & finishing

    No. If you sand before you have a sufficient build of your finish, you will sand through the color, no matter what your finishing medium is.

    Your first coats are sealing coats and should be only a light wipe. Do not go over the same area twice, or you will pull the color out. Let dry thoroughly. Repeat. Let dry thoroughly. You may have to repeat several times to seal the color. After you start to see some gloss, you can apply the finish more heavily.

    Only after the color is thoroughly sealed can you start building more quickly. After you are able to put a few heavier coats on, you can sand lightly and carefully.

    Most finishing problems I see are caused by insufficient drying time between steps, and sanding too often and too heavily.

    1. Wash coat, if desired. Wait.
    2. Stain. Wait.
    3. Initial sealing coats. Wait.
    4. Build coats. Wait. Sand lightly.
    5. Final coats. Wait, wait, wait. Level sand. Wait again.
    6. Final polish with compound or rubbing powders such as rottenstone, tripoli, and pumice.

    When you start to get a good build, you can scuff sand, which means that you are smoothing, but not levelling all the imperfections. You only try to produce a "perfect" surface late in the process.

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  5. #29

    Default Re: Beginner staining & finishing

    Thanks! That's exactly what I was worried about. I really appreciate the details.

    Guys on Youtube using Tru-Oil for gunstocks also had steps where they wet-sanded. Any reason to do this or not? I'm not familiar with pros and cons of wet sanding and how it differs from dry sanding.

    Also, I assume we're talking about mostly 320 grit, until the final polish. Right?

  6. #30
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    Default Re: Beginner staining & finishing

    I can't help you with Tru-oil. I don't use it.

    Whatever your finishing medium is, it's better to start with a finer grit when you're not too sure of what's best. It's better to have to move down if the finer grit doesn't get the job done than it is to start with too coarse a grit and damage your build or go through completely.

    With nitrocellulose lacquer, I use 320 dry during the building process. I can build faster with nitro than with anything else. For the final levelling, I start with 400 or 600 with either water and a couple of drops of dish detergent, or mineral spirits. I move up to 1000, then sometimes finish up with 1500. Let sit for at least 24 hours. More than that is better. Wet sanding softens a new finish, so you have to let it cure some before final polishing. I rub out with polishing compound.

    With French polished shellac, I don't have to sand much or often. I use 400. If I have to do a final sanding, I go to 600 or 1000, sometimes with just a little bit of naphtha or mineral spirits, then recoat with very thin shellac. If I rub it out, I wait 10 - 14 days and use rottenstone and oil.

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  8. #31
    Adrian Minarovic
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    Default Re: Beginner staining & finishing

    Quote Originally Posted by JeffLearman View Post
    Guys on Youtube using Tru-Oil for gunstocks also had steps where they wet-sanded. Any reason to do this or not? I'm not familiar with pros and cons of wet sanding and how it differs from dry sanding.
    TO on gunstocks is typically used on bare unstained walnut. Wet sanding creates fine dust mixed with the finish which fills the (somewhat largish) pores of walnut. Otherwise the pores would show as holes or pits in varnish.
    Mandolin woods typically have small pores that don't need fillers. The TO will fill them in several applications. Just thinly wipe on/off the finish as suggested. (carefully with first coats, you can test on scrap how much TO tends to smear the color).
    Tru oil can be also slightly thinned and applied with brush. Even some violin makers use it like that with success instead of fancy (expensive) "real" violin varnishes.
    Adrian

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  10. #32
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    Default Re: Beginner staining & finishing

    Dry sanding clogs sandpaper quickly, especially on the finer grits. "Pellets" of finish can develop in the paper, and scratch the surface of the work. Wet sanding minimizes clogging. It also cuts more quickly, softens the finish, and slows down the curing process.

    I use 320 dry most of the time. I use 400 both ways. 600 and up I usually use wet.

    It sounds like the gunstock people are wet sanding to create the same kind of filling effect that we use when we "load" a shellac based finish with pumice in the French polishing process. Filling is usually not necessary with spruce or maple. It is essential with rosewood, mahogany, and many other dark hardwoods.

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  12. #33
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    Default Re: Beginner staining & finishing

    A few things about TruOil.
    It is an oil, perhaps an oil varnish with driers most likely added. As far as I know there is no solvent in there that will disturb dried aniline or other water/alcohol dissolved dyes, so lightly rubbing a thin coat over dyes will probably work OK, though I haven't tried it so I could easily be wrong about that.
    There are several methods of applying it, most people simply rub it on. If you want to fill pores with it it will take quite a while. When I use TO I normally use it over oil varnish. I spray and sand the varnish until the surface is level and then rub TO on the surface using the "rub it on, rub it off" method. I rub a coat onto the surface and then use a clean cotton rag (old T-shirt) to rub it off. Rubbing all of the oil off is impossible, but rub like that is the intention. Doing many coats like that can give you a good finish, if there is no dirt or other imperfections. If there is some kine of "goober" in a coat, I wait until the next day and either rub with Novus 2 or with 3000 grit Trizac followed by Novus. And no, polishing with Novus 2 does not cause problems with subsequent coats.
    Once, I sealed with shellac and started TO right on the sealer without first leveling with varnish. Took forever(!) even with the first half dozen coats simply rubbed on (and not rubbed off). TO does not build fast, it is reasonably easy to apply, it is easily repaired during the finish process, but it is quite a bit of work to achieve a really fine high gloss finish. If less than high gloss is your goal, that is a little easier.

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  14. #34

    Default Re: Beginner staining & finishing

    Quote Originally Posted by HoGo View Post
    ... carefully with first coats, you can test on scrap how much TO tends to smear the color
    Good point! I tried it on the test board, no smear at all. So I did my first coat on the mando and got the same results, no smearing at all, and my fingers had no stain on after doing it all and rubbing the oil in pretty thoroughly.

  15. #35

    Default Re: Beginner staining & finishing

    Quote Originally Posted by sunburst View Post
    Took forever(!)
    I guess I better buckle in, then. I'm not expecting it to be like glass, though.

  16. #36
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    Default Re: Beginner staining & finishing

    So, if tru-oil builds so slow, and still needs levelling and polishing, why do folks favor it over French polished shellac?

  17. #37

    Default Re: Beginner staining & finishing

    Quote Originally Posted by rcc56 View Post
    So, if tru-oil builds so slow, and still needs levelling and polishing, why do folks favor it over French polished shellac?
    Does better with spilled booze?

  18. #38
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    Default Re: Beginner staining & finishing

    I suppose it would at that.
    I remember a circa 1940 F-4 with a gorgeous quilted back that belonged to a friend of mine that had a couple of booze spots on it.

  19. #39
    Registered User sunburst's Avatar
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    Default Re: Beginner staining & finishing

    Quote Originally Posted by rcc56 View Post
    So, if tru-oil builds so slow, and still needs levelling and polishing, why do folks favor it over French polished shellac?
    FP requires quite a bit of skill (I don't expect to ever consider myself good at it), and when I have used shellac over varnish the finish crazed.

    Anyone can rub on TO and I've never seen it craze. With luck and good technique little or not leveling is needed. It can be repaired/recoated at almost any time, it has a very long shelf life (until it hardens in the bottle), does not require mixing, it's as close to foolproof and any finish I've ever encountered, and when done well gives beautiful results, a neck that feels smooth and seldom tacky, resists solvents like bug spray and adult beverages... that sort of thing.

  20. #40
    Adrian Minarovic
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    Default Re: Beginner staining & finishing

    Quote Originally Posted by sunburst View Post
    Anyone can rub on TO and I've never seen it craze. With luck and good technique little or not leveling is needed. It can be repaired/recoated at almost any time, it has a very long shelf life (until it hardens in the bottle)
    I've used TO on gunstocks years ago and it hardened in the bottle after few months. One good tip I got was not to remove the cover on the bottle but rather just do a tiny hole and after use clean and close teh hole with tape.
    For faster buildup you can thin it with naphtha or white spirits (5-10% to get good viscosity) and brush it on. I've heard of folks spraying it but never had good luck using my airbrush with oil finishes. And cleaning the airbrush from oil finish was mess :-).
    Look and read here: https://maestronet.com/forum/index.p...0557-mdarnton/
    Adrian

  21. #41

    Default Re: Beginner staining & finishing

    Quote Originally Posted by sunburst View Post
    ... resists solvents like bug spray ...
    Well heck, I think I'll refinish my guitars! I hate the bug spray issue.

  22. #42

    Default Re: Beginner staining & finishing

    Well, I think I've finished finishing. These pics are without any polishing; I just used a thicker coat of Tru-Oil on the last coat and left it horizontal so it wouldn't drip (separate passes for front and back.) Looks great from a distance of a few feet, so BIG THANKS to everyone who helped. Up close, it's a catalog of errors and lessons learned.

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    So, how long should I wait before hardware setup? I'm really anxious to be playing with it rather than fussing over it. I did get a copy of Rob Meldrum's guide. Plus I've done most of the maintenance on my guitars for decades (including an archtop with a floating bridge), so I have a few clues about what goes where and how I'll want it.

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  24. #43
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    Default Re: Beginner staining & finishing

    My rule of thumb is to let a finish cure for at least two weeks before handling it in a "normal" fashion.
    That's for lacquer and shellac. Tru-oil might need a little longer.
    Give it time to harden up really well. You don't want a marred or dented finish where the bridge sits.
    If the scent of the new finish is still strong, it ain't ready.

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  26. #44
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    Default Re: Beginner staining & finishing

    That finish came out way shinier than I thought it would. Looks good. How many coats did you put on?

  27. #45

    Default Re: Beginner staining & finishing

    Quote Originally Posted by Tracy Fleck View Post
    That finish came out way shinier than I thought it would. Looks good. How many coats did you put on?
    Hmm well, a lot, or it seemed like a lot. Most days, one in the morning and one in the evening. Not as thin as advised (funny how I forget stuff when I'm in the process.) But frankly, it could have been that shiny on ANY coat, as long as I applied it thick enough and didn't let it drip. I'm guessing I did about 8.

    If you zoom way in on the pictures, you'll see that I really didn't level it as it should be: there are still obvious grain ripples. Like I said: up close it's a catalog of errors and lessons learned. But from 2 or more feet away it really looks nice.

    I'm sure if any of you seasoned folks got it in their hands, you'd say "First one, eh? Well, keep at it. It'll get better. [sotto-voce] Can't get too much worse." ;-)

  28. #46

    Default Re: Beginner staining & finishing

    Got some time today to scrape the binding, shape the bridge, and attach the hardware. I'll wait another week to put the strings on. It's gonna be a long week.

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