That would be great. I'm curious to see what happens.
I think I had the test piece sanded to 400, FWIW.
Last edited:
Enjoy the benefits of a premium membership!
Upgrade Account
-
TalkBass has been independent since 1998. Add your voice.
Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
Join free Log in
Want zero display ads or expanded classifieds tools? Compare plans.
There's another storm brewing!
- Thread starter pilotjones
- Start date
I think I had the test piece sanded to 400, FWIW.
Hopkins
Commercial User
I sanded the piece of walnut and wenge to 220 and laid down a couple coats of urethane. When it dries I will wet sand and buff them out. The grain isn't completely filled or anything but it will dispel any adhesion issues and will give you a good idea of how it will look
Cool.
Om the other hand, I severely typo'd my last post. Sanded to 400, not 40.Honest, my test sample was not firewood!
Hopkins
Commercial User
I kind of figured you meant 400, I will post how everything works. I was at my shop today when I sprayed them. I meant to bring them home with me but I forgot them. I won't be back at my shop until next week some time.
Rôckhewer
Commercial User
- Feb 28, 2015
- 2,922
- 9,028
- Disclosures
- Owner/Builder- RockHewer Custom Guitars LLC
@Hopkins ... Isn't 400g a bit too smooth for good adhesion?
I was under the impression that it was best not to go much higher than about 220g like you do, to leave the surface with enough "tooth" ...?
Or......(and this is just speculation)
In auto paint, you always hear (read) warnings like... "make sure your clear is compatible with the basecoat"
So... Is it possible that the clear that PJ's auto paint guy used on his test pc, could have been part of a "system" that more or less relies on its companion basecoat being the correct formulation for good adhesion? And on its own, over too smooth bare wood... just didn't have what it takes to....you know....stick??
I mean....you wouldn't think that would be the case, ....but......?
I was under the impression that it was best not to go much higher than about 220g like you do, to leave the surface with enough "tooth" ...?
Or......(and this is just speculation)
In auto paint, you always hear (read) warnings like... "make sure your clear is compatible with the basecoat"
So... Is it possible that the clear that PJ's auto paint guy used on his test pc, could have been part of a "system" that more or less relies on its companion basecoat being the correct formulation for good adhesion? And on its own, over too smooth bare wood... just didn't have what it takes to....you know....stick??
I mean....you wouldn't think that would be the case, ....but......?
Hopkins
Commercial User
No, 400 grit wouldn't be too smooth at all for adhesion. When I level sand before spraying my final coats of clear I sand up to 600 at minimum. Bare wood is also very porous so it is going to absorb a lot of finish so that alone makes not having enough tooth pretty much a non issue.
As far as base/clear compatibility, on a natural finished bass there should be no compatibility issues at all because every coat will be the same product. But even so, modern urethanes are pretty much all compatible with each other. I have used Dupont base coats with PPG clear coats with no issues. You can run into problems if you are spraying a nitro clear over a urethane base that isn't fully out gassed or vice versa, but there is no real reason anyone would really do that, especially the latter.
Rôckhewer
Commercial User
- Feb 28, 2015
- 2,922
- 9,028
- Disclosures
- Owner/Builder- RockHewer Custom Guitars LLC
Ok thanks for the insight on the grit/tooth issue.
& I realize there wouldn't be any compatability issues with other products....I was thinking maybe that certain clear coat might only adhere well to a specific basecoat (chemical reaction? )
And not so well on it's own.
All in all, kind of a half baked theory... but then, I am not a paint expert, by any stretch of the imagination
& I realize there wouldn't be any compatability issues with other products....I was thinking maybe that certain clear coat might only adhere well to a specific basecoat (chemical reaction? )
And not so well on it's own.
All in all, kind of a half baked theory... but then, I am not a paint expert, by any stretch of the imagination
Hopkins
Commercial User
Ok thanks for the insight on the grit/tooth issue.
& I realize there wouldn't be any compatability issues with other products....I was thinking maybe that certain clear coat might only adhere well to a specific basecoat (chemical reaction? )
And not so well on it's own.
All in all, kind of a half baked theory... but then, I am not a paint expert, by any stretch of the imagination
That may be the case for some products, but not for urethane clears.
Yesterday my friend with the body shop had his painter shoot two coats of a clear onto my test piece. He was going to use Dupont, but they had some of a better (and higher $$) German material that gets used on high-end German cars on hand, so they used that. The test piece is like the bass, but I intentionally left some unfilled pores and some sanded-to-the-wood areas to see what happens.
He said it looks fantastic, with the guys in the shop asking wth kind of wood it is, and that the wenge striping is pretty visible. He will probably have his guy wet sand then shoot two more layers today.
I have a pic, but it's not the best.
As far as what caused problems the first time, there's one possibility that turned out to be likely. On cars, immediately before spraying they wash with some solvent that evaporates within seconds. I told him to give this at least an hour to dry this time since wood could absorb and then release the solvent.
He said it looks fantastic, with the guys in the shop asking wth kind of wood it is, and that the wenge striping is pretty visible. He will probably have his guy wet sand then shoot two more layers today.
I have a pic, but it's not the best.
As far as what caused problems the first time, there's one possibility that turned out to be likely. On cars, immediately before spraying they wash with some solvent that evaporates within seconds. I told him to give this at least an hour to dry this time since wood could absorb and then release the solvent.
Car, painters, like me rely heavily on wax and grease remover. I would have to bet that on wood it does more harm than good. Before attempting to spray my first guitar, I called the owner of the company who makes the clear I rely on. (Southern Polyurethanes, SPI) His company sells to several (unnamed ) guitar manufactureres. He warned me that his advice would be counterintuitive to me BUT told me NO wax and grease wipe down until the project was completely sealed with clear. Sand, blow off dust with air, use tack rag, dye it then clear it. First coat heavier than a mist coat but not a fully wet coat. So far, I've had only a few issues. I was taught that there are 2 types of adhesion. 1. Mechanical-from scuffing a surface with abrasive 2. Chemical-caused by cross linking of poly chains while in the open window of recoat time. I believe that on plastics, even 800 grit scratches will hold clear. If the car painter bathed your test piece and waited for only the surface to flash, I could see a problem! With all that said, I only started spraying guitars this past October. Ive done 6 so far but am no expert! Haha
Last edited:
Hopkins
Commercial User
Funny you posted that, I just had a chance to get back to my shop and take a photo of the piece I sprayed.
Its only one heavy coat, I didn't take the time to get the grain filled, but adhesion was definitely not an issue. Sprayed a piece of walnut as well, but it seems to have vanished. I believe someone may have tossed it
Its only one heavy coat, I didn't take the time to get the grain filled, but adhesion was definitely not an issue. Sprayed a piece of walnut as well, but it seems to have vanished. I believe someone may have tossed it
Hopkins
Commercial User
LOL, if that gator starts snatching my wood scraps I may have to call my old Cajun buddy to come take care of him
Yes, here's hoping it continues to work out.
Thanks for the info, I'll mention that to my friend.
Man that's certainly more holey than than when I put on a first coat of epoxy. But if that's just one coat, it seems like it should end up being a better process what with spraying being both easier and much more consistent in thickness. The pores may not be filled, but they look sealed off. And the color looks good.
Hopkins
Commercial User
I think it would take about 3 coats to get the grain filled enough to level sand it.
After the second spraying session (and with flash this time):
THAT is some quality clear AND the guy who laid it down knows how to handle a gun! I think it looks fantastic and the grain is really nice. Excellent gloss!
Yes, the coating is dead smooth except for the places I left a few partial pores. Next action is for me do do some sanding to see what it's like to work down to those low dips.
What doesn't show there, though, is places where the uneven epoxy coat caused a problem, mostly with whitish entrapped ¿powder or air? at the edges of the epoxy areas. I think I'm going to totallsand down on one of those surfaces, to see what happens if I go to a higher grit on the epoxy to get no whitishness at all. Then I'll add some test frets on the fretboard side, and have it sprayed again.
The areas where I left some bare wood (with filled pores) but no epoxy coating blended fine with the majority areas where there was a thin skim/soak of epoxy.
What doesn't show there, though, is places where the uneven epoxy coat caused a problem, mostly with whitish entrapped ¿powder or air? at the edges of the epoxy areas. I think I'm going to totallsand down on one of those surfaces, to see what happens if I go to a higher grit on the epoxy to get no whitishness at all. Then I'll add some test frets on the fretboard side, and have it sprayed again.
The areas where I left some bare wood (with filled pores) but no epoxy coating blended fine with the majority areas where there was a thin skim/soak of epoxy.
