Hi Allen,
I was applying Zpoxy to the EIR of my guitar this morning. This was the second coat applied neet. The first coat had mostly filled the grain beautifully but after leveling with a good sharp scraper, there was a few areas where you could see it would benefit from a second application prior to doing the 50% wash coat.
Anyhow the second coat, applied with a black rubber applicator had gone on very smoothly, in fact, looking at it wet, it look nearly good enough to string up and call it done (if only it where that easy). So I take my gloves off and buggerize around for a little while cleaning up the applicator with metho etc and then I go in and turn off the overhead light.
Just befor I walk out to let things set up, I bend down and look across the surface of the back and notice some fisheye forming in the still wet Zpoxy, I go back out to the shed after about 15 to 20 minutes of self flagellation and I see that the size and amount of fisheye is a real issue.
I know this will flat back out OK, but I also know that if something as viscous as Zpoxy is going to fisheye, I am in for a hell of a time when it comes to spraying precat lac...
So where to from here? Do I seek out some fisheye killer and just go forward with that when it comes time to spray? What if anything is the downside to doing that? Is there an alternative? And WTF do you think may have happened?
Cheers and TIA for your help.
Kim
Fisheye Help! Please Allen.
Thanks Martin but for this to happen, I think it is safe to assume that a contamination has indeed taken place at the wood surface, I doubt it is the Zpoxy or a contamination in the mix. I suspect that trying to sand out the contamination will only spread the problem and also introduce the risk of going too thin on the plates.
I will wait for Allen, but I suspect he will advise leveling back as per normal and then adding fisheye eliminator to the finish.
Cheers
Kim
I will wait for Allen, but I suspect he will advise leveling back as per normal and then adding fisheye eliminator to the finish.
Cheers
Kim
Could be Martin but then it could be lots of things, something on the drum sander belt maybe, something in a rag I wiped it down with (I did use clean rag but who knows) it may have been the paper I laid out when jointing the plates or some residue in the shellite rag I used after scraping but whatever it was all them fisheyes is looking up at me now wavingkiwigeo wrote: I notice you leveled with a scraper......any chance of contamination on the scraper (I use oil or ear wax when burnishing my scarpers)?
Cheers Martin
Cheers
Kim
Sorry Kim. I just got in from a barbie for my mates parents that showed up from Canada.
I've not tried Z-poxy, so don't know the viscosity and properties of it. Just thinking out load here, but there are at least a few possibilities.
First off is oil, or silicon contaminate. Either in the wood or contamination in the epoxy or application products.
I've seen on two instruments that I've used WEST SYSTEMS on, that the second coat pimpled up then burst open, looking like fish eye, but I believe they are more akin to solvent boil. Both times it was fairly hot and a good breeze going through the shop. I think the surface skinned over and trapped some gassing off of the epoxy. I just sanded back and proceeded as normal. No problems.
I've also seen more times than I care to think, that fine dust settles on a paint finish while it's still fairly wet and causes fish eye like craters. There may be a contaminate in the dust, but more often than not it's just a wet film being repelled by a foreign object. I use to know the technical term for it, but I've imbibed too many glasses of red to remember what it is. This doesn't contaminate the primary surface, so is really just a nuisance, and not a catastrophe.
In all cases it's important to wash the surface with good clean rags and solvent that isn't going to bite into the epoxy before you start to sand back. If it's a surface contaminate, then you may work it in even deeper if you just start sanding. Then sand back. Once back to the wood, clean it again several times.
If you're going to give it a wash coat of z-poxy, then I'd cross my fingers and hope for the best after giving the surface a good cleaning with your preferred solvent. I use either naptha (shellite) or our wax and grease remover from work. We use either Sikkens or Glassurit.
I never use fish eye eliminator. It's actually pure silicon and is evil stuff to have around. Fisheye eliminator causes the paint to be one large fish eye (there are so many fish eyes that they flow into each other). It causes more problems than it ever attempts to solve.
If you find that you absolutely have no recourse but to use it, then shake the bottle very well, then put a few drops in a container that has say 50 ml of the solvent for you finish. Mix this well, then add to your sprayable material. This way you have much more control of how much you are adding, and the molecules of silicon are diffused much more thoroughly in your sprayable material.
I do not use it, and instead I isolate the surface from the finish.
You do this by over thinning out your clear. Say 80% solvent. Then drop your air pressure as this is going to come out of the gun much easier than thicker clear. It'll also run fairly easy so carefully spray the surface with a thin light coat. Watch what is happening to the finish. It might want to fish eye on you, but because there is so much solvent, it's not going to leave big craters. They will dry back virtually flat. Let flash off for say 5 - 15 minutes. Depends on the conditions, then go again.
If you do see fisheyes appearing as your spraying, then you can blow air at that area with the spray gun, and then gently dust on more clear. You're trying to get enough finish on, so that the contaminate is trapped under a clean film of clear. Patience is the key. I'd usually spray on 3 coats of this 80% thinned material. There is virtually no film build, so it's no big deal. If you now have a finish that is staying together, you can now go to a more robust mix.
You still want to go easy as the lacquer bites into what''s beneath and has a possibility of reflowing the entire film build. If this coat goes on well, then you should be in the clear, and refinish as normal.
Hope this helps. Ask for more help if you need to mate.
I've not tried Z-poxy, so don't know the viscosity and properties of it. Just thinking out load here, but there are at least a few possibilities.
First off is oil, or silicon contaminate. Either in the wood or contamination in the epoxy or application products.
I've seen on two instruments that I've used WEST SYSTEMS on, that the second coat pimpled up then burst open, looking like fish eye, but I believe they are more akin to solvent boil. Both times it was fairly hot and a good breeze going through the shop. I think the surface skinned over and trapped some gassing off of the epoxy. I just sanded back and proceeded as normal. No problems.
I've also seen more times than I care to think, that fine dust settles on a paint finish while it's still fairly wet and causes fish eye like craters. There may be a contaminate in the dust, but more often than not it's just a wet film being repelled by a foreign object. I use to know the technical term for it, but I've imbibed too many glasses of red to remember what it is. This doesn't contaminate the primary surface, so is really just a nuisance, and not a catastrophe.
In all cases it's important to wash the surface with good clean rags and solvent that isn't going to bite into the epoxy before you start to sand back. If it's a surface contaminate, then you may work it in even deeper if you just start sanding. Then sand back. Once back to the wood, clean it again several times.
If you're going to give it a wash coat of z-poxy, then I'd cross my fingers and hope for the best after giving the surface a good cleaning with your preferred solvent. I use either naptha (shellite) or our wax and grease remover from work. We use either Sikkens or Glassurit.
I never use fish eye eliminator. It's actually pure silicon and is evil stuff to have around. Fisheye eliminator causes the paint to be one large fish eye (there are so many fish eyes that they flow into each other). It causes more problems than it ever attempts to solve.
If you find that you absolutely have no recourse but to use it, then shake the bottle very well, then put a few drops in a container that has say 50 ml of the solvent for you finish. Mix this well, then add to your sprayable material. This way you have much more control of how much you are adding, and the molecules of silicon are diffused much more thoroughly in your sprayable material.
I do not use it, and instead I isolate the surface from the finish.
You do this by over thinning out your clear. Say 80% solvent. Then drop your air pressure as this is going to come out of the gun much easier than thicker clear. It'll also run fairly easy so carefully spray the surface with a thin light coat. Watch what is happening to the finish. It might want to fish eye on you, but because there is so much solvent, it's not going to leave big craters. They will dry back virtually flat. Let flash off for say 5 - 15 minutes. Depends on the conditions, then go again.
If you do see fisheyes appearing as your spraying, then you can blow air at that area with the spray gun, and then gently dust on more clear. You're trying to get enough finish on, so that the contaminate is trapped under a clean film of clear. Patience is the key. I'd usually spray on 3 coats of this 80% thinned material. There is virtually no film build, so it's no big deal. If you now have a finish that is staying together, you can now go to a more robust mix.
You still want to go easy as the lacquer bites into what''s beneath and has a possibility of reflowing the entire film build. If this coat goes on well, then you should be in the clear, and refinish as normal.
Hope this helps. Ask for more help if you need to mate.
Kim, I read in Martin's 12 string thread that you said the fish-eyes were as big as 5 cent pieces. This has got to be some form of silicon / oil, or mineral contamination, and big time. If they're a lot smaller the second time around, then you're on the way to getting rid of them. Keep us up to date with your progress
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