Nitro over shellac?

Discussion in 'Finely Finished' started by VertigoCycles, Feb 6, 2019.

  1. VertigoCycles

    VertigoCycles TDPRI Member

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    I'm in the weeds right now in trying to finish my first build. The big issue is that the plan keeps changing...I was going to paint it myself with a 2K urethane. After receiving warnings from some bike builder/painter friends, I decided to have a pro paint it, but my wife and daughter temporarily convinced me to keep the body a natural color which then was reinforced by some horror stories I've read about pro painters in addition to the fact that one of the good ones hasn't responded yet. I realized that I wouldn't be happy with the guitar if I left it natural so I've just ordered some paints from ReRanch but...

    I may have made some mistakes while dinking around with sealers and grain fillers.

    I got a sealer from my local Ace hardware that said it was good under urethane and put a coat on. After two days, it was still tacky, so I panicked and took as much off as I could with acetone. Surely it didn't all come out as the body still felt soapy but after about ten sessions it was feeling mostly smooth and dry again so I sanded it back a little. It clogged my paper up after every few strokes so something was still clearly on there but it wasn't tacky anymore so I moved on...

    ...mixed up some shellac and put a few wash coats on. It felt like shellac and I thought all was good until I went through a couple of sessions with Behlens Por-O-Pac. I've never used it before and assumed it would setup hard, but it's really chalky. Most of the pores have been filled and for those of you familiar with rock climbing, it felt like some greasy, over-chalked rock. Again, I tried sanding it back and the paper clogged up immediately. At this point, I feel like "F-it" and put on a few more wash coats just to hold the grain fill in place.

    A few minutes ago, I read the label of the Ace sealer which says not to use it if using laquer. It wasn't the plan, but the plan changed.

    At this point, I'm planning to go over it with shellac and pumice to hopefully fill in the remainder of the small grain and then shoot the primer next week and see what happens.

    Assuming this sealer doesn't come back to haunt me (I'm sure it will) is it OK to shoot nitro over shellac?
     
  2. eallen

    eallen Tele-Afflicted Silver Supporter

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    Yes, you can put nitro over shellac without any issues.

    What kind of wood, what was the original seal coat, and what shellac are you using?

    Any photos will help.

    Sent from my SM-G892A using Tapatalk
     
    Last edited: Feb 6, 2019
  3. VertigoCycles

    VertigoCycles TDPRI Member

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    Wood: roasted ash
    seat coat: Ace hardware brand solvent based sanding sealer
    shellac: StewMac Colortone. it's about a 1lb cut
     
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  4. pedro58

    pedro58 TDPRI Member

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    Everything sticks to shellac and shellac sticks to everything. It has saved my butt more than once. You're fine.
     
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  5. fraser

    fraser Tele-Holic

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    C1F47D23-6D25-4078-905A-33513C524A33.jpeg

    This is a pine body with one spray can zinsser blond shellac as a sealer coat, then 2 cans clear nitro.
    After ten years, it’s holding up nicely.
     
  6. VertigoCycles

    VertigoCycles TDPRI Member

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    I like that you only have one pickup, yet there is a switch.
     
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  7. dan1952

    dan1952 Friend of Leo's

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    Esquire wiring?
     
  8. ndcaster

    ndcaster Poster Extraordinaire

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    shellac sticks to everything, over and under

    in my exp
     
  9. ladave

    ladave Tele-Holic

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    I know what that feels like!

    I just sprayed Nitro over Zinser Bullseye Spray Shellac for my bass build. That didn't seem to cause any problems. I did have problems applying the Nitro in a consistent manner but don't think that was because of the Shellac.
     
  10. fraser

    fraser Tele-Holic

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    Ya, three way switch.
    Vol/ tone one position, other 2 positions have caps.
    I don’t recall the cap values I went with, but I get the regular setup with the tone pot, in the middle position I get a bassier sound, and the forward position gives a screaming cocked wah tone if the amp is overdriven.
    It’s a pretty versatile setup for one pickup.

    While i love this guitar, I’ve often regretted not adding strat contours, and that mismatch in the wood, with the lighter piece on the left side always stands out to me.
    Not enough to refinish it tho lol.
     
  11. FrontPU

    FrontPU Tele-Holic

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    There is no problem between the shellac undercoat and the nitro topcoat. But there is between the undercoat by synthetic sealer and the shellac overcoat.
    Most synthetic lacquer sealers don't make good combination with shellac; don't allow us to apply shellac on them with French Polish technique and even if sprayed the shellac coat on them easily comes off. So you should remove the sealers before using shellac.
     
  12. VertigoCycles

    VertigoCycles TDPRI Member

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    How long would it take for the shellac to start coming off?

    I removed as much as I can without sanding deep into the body. There are now three wash coats, three sessions of pumice grain fill with shellac and another three coats of shellac rubbed in. It's dry, looks half decent and feels pretty good. If I were to see a problem, is it going to be after the shellac fully cures?
     
  13. jrblue

    jrblue Tele-Afflicted

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    Yeesh... sorry for the incompatibility issues you are experiencing. You won't want to hear this, but I would take it back to bare wood and start the finish sequence again. But maybe someone will be able to steer you through this problem without having to do a full restart. I can't. For me, it would be a do-over.
     
  14. VertigoCycles

    VertigoCycles TDPRI Member

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    Bummer. I think I've done about as much work on this body as I'm willing to do at this time. I'm going to watch it for the next week and then spray it with nitro. If the paint falls off, so be it.

    Thanks for the advice everyone. I'm going to learn something from this.
     
  15. FrontPU

    FrontPU Tele-Holic

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    I remember it took a couple of days that some part of sprayed shellac on the default "Thin Lacquer Sealer Coating" surface of Musikraft neck started coming off.
    Then I removed all the shellac from the surface with alcohol and tried to apply the same shellac liquid again on the same "Thin Lacquer Sealer Coating" surface by French Polish method, and I noticed the surface repels the shellac liquid.
    Since then, I have wiped off the "Thin Lacquer Sealer Coating" from Musikraft necks with acetone, no sanding, and then applied shellac. No issue has been found for more than a decade.
     
  16. mgreene

    mgreene Tele-Holic

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    I used a sanding sealer recently that didnt work like the older ones that I was used to. The old sanding sealers (minwax) would dry hard and fast and anything would go over them.

    I recently tried to seal some dresser drawers (they had that stinky wood smell). The old sanding sealer would have been enough - but the newer one took forever to dry and had solvent smell even after it dried - it felt soapy too.

    I finally had to put a top coat of shellac but it still smells of solvent - overall a real fail.

    I ended up thinking that maybe the old sealers had something in them that the manufacturers arent allowed to use any more.
     
  17. philosofriend

    philosofriend Tele-Holic

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    Well, if it is smooth now and looks OK, what I would do is:
    Cautiously try wiping it down with naptha (mineral spirits). If this doesn't react with what is left on there it will help insure that your mess is shellac compatible. Then I would give the guitar another good coat of shellac. If that shellac dries hard and stays tight for a week or so, you should be good to go to put lacquer on top.

    The biggest danger is sanding down through the shellac to the sealer and finding out why the sealer says don't use with lacquer. Keep shellac in between the sealer and the lacquer. You can always intermix shellac and lacquer. If at some point you want to sand the body really smooth, play it safe and put another thin shellac coat on before the lacquer.

    Time is always good. We do our dumbest home finishing mistakes when panicked. Time also lets the shellac and lacquer totally shrink. I've had really smooth finishes show up all kinds of sanding marks months later.
     
  18. CapnCrunch

    CapnCrunch Friend of Leo's

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    At this point, what do you have to lose? I would wipe the body with Naphtha and see if anything comes up as you wipe? I'd then spray a couple coats of shellac to seal what you have, and then go with lacquer on top of the shellac. I might wait a day or two after the shellac to see if it truly cures. Once the shellac is hard, the lacquer should be fine.

    I am wondering if your issues have to do with wiping your sealer on before the filler actually dried. I've used Pore o pac many times and never had the issues with sealing you describe. It is definitely messy, and wiping the excess off across the grain with cheese cloth or burlap definitely helps cut down on sanding which is a major pain because it clogs sand paper almost instantly. However once it is dry, I've never had issues sealing it. Just wanted you to know that clogged paper is not unusual with pore o pac that's why you want to wipe off while it is still wet as it cuts down on the sanding.
     
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