Z Poxy Finishing Resin and Amine Blush

Discussion in 'Finely Finished' started by slick4772, Oct 5, 2021.

  1. slick4772

    slick4772 Tele-Meister

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    Hi - I just bought some Z Poxy finishing resin to use on a guitar and I read on the back of the box that you must prime before painting. I'm fine with priming - but then I did some searches and found out that some epoxy finishes (not that this is supposed to be a finish) will leave a waxy residue upon curing and that it is referred to as amine blush. You are supposed to wash this wax off with water and an abrasive (scotch pad or something). You should never use a solvent as it will spread the wax into the pores and make it impossible to remove.

    The importance of removing this amine blush is that because of the waxy nature of it, it makes paint adhesion difficult or impossible.

    SO - my question is - has anyone used Z-Poxy finishing resin and what special steps do you take prior to painting?
     
  2. Freeman Keller

    Freeman Keller Poster Extraordinaire

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    Zpoxy is my standard pore filler and I use it to enhance grain. I have never experienced what you are talking about. I almost always finish with lacquer and have had no adhesion issues

    https://www.tdpri.com/threads/zpoxy-for-pore-fill-and-grain-enhancement.940522/

    However, like any finishing question the answer is for you to test your exact products on a piece of your wood.
     
  3. Speedy454

    Speedy454 Tele-Holic

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    I have used Z-Poxy on numerous projects as a grain/pore filler and to harden up soft or punky spalted maple.

    I always sand with #320 or #400 before applying the final finish.

    Partly to ensure that the surface is perfect, part to give the final finish (lacquer, Tru Oil, Poly) something to bite into.
     
  4. Bob J

    Bob J Tele-Holic

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    I too have used zpoxy without any special washing, light sand, vinyl sealer (I guess maybe that acts as a primer?) and then clear lacquer. I have never used an opaque finish over it though.
     
  5. Timbresmith1

    Timbresmith1 Tele-Afflicted

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    In my understanding, amine blush is more likely under humid conditions.
    Amine blush looks like a white/ bluish-white haze. I think it’s more a concern when using topcoats that require mechanical adhesion. I can’t recommend washing your guitar with water.
     
  6. StoneH

    StoneH Tele-Holic Gold Supporter

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    My experience with amine blush is from using resins in the boating world. If a resin is a "finishing resin", it has a wax added to it that rises to the surface after application that seals it from air and allows it to cure. The wax is the amine blush, and it needs to be removed before further surface work. Soap and water removes it and so does light sanding.
     
  7. Vizcaster

    Vizcaster Poster Extraordinaire

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    StoneH reminded me about the two types of fiberglass resin for repairing boats. "Building" resin does not have the wax in it, so air inhibits curing on the very surface, leaving it green for the next layer of mat or glass and resin to bite and build up. When you get to the last layer, you use "finishing" resin which has a wax that comes to the surface to keep the air away and it will cure fully. You would need to strip that wax before applying a paint (actually had a boat with a white painted bilge in the engine compartment, boy it didn't stay white for long). I'm convinced that Z-Poxy is a much more modern formulation that does not have those quirks.

    Anyway, in a few projects that I've tried Z-Poxy (with encouragement from Freeman's excellent results) I've had no problem getting a topcoat to bond to it without a primer. And I use waterborne finishes that aren't famous for adhesion or compatibility with other materials. The only tricky bit is knowing how much to sand back (and like all grain fillers that's a learning curve where I'm still going uphill...)
     
  8. eallen

    eallen Friend of Leo's

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    I always seal before I start my finish coats.

    Eric
     
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