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Zpoxy woes
http://luthiersforum.com/forum/viewtopic.php?f=10101&t=32087		 Page 1 of 1
Author:  Corky Long [ Tue May 03, 2011 12:37 pm ]
Post subject:  Zpoxy woes
Well, this feels a bit like "Groundhog Day". YOu'd think that I'd have figured this out by now - I've used Zpoxy, as pore filler, on 4 or 5 guitars so far, and am always happy with the end result, but there's got to be a better way to get from point A to point B. Here's my issue:

After applying it on the guitar, letting it dry overnight, and then carefully sanding down, I always end up with patches where the zpoxy has been sanded through (or close to it). I'm not going down to bare wood - there's still a fine layer of epoxy on the wood, but since zpoxy imparts a bit of shade to the wood, I end up with a lighter/darker "splotchy" look. I reapply, then repeat, and still can't seem to get to a uniform shade. Anyone have any challenges with this?
Author:  meddlingfool [ Tue May 03, 2011 12:57 pm ]
Post subject:  Re: Zpoxy woes
Yup yup yup. Most bothersome. I believe a solution is to do a final 'wash coat' with zpoxy thinned 50/50 with alcohol. I've only tried it once, the alcohol evaporates very quickly, so I would try making two small thinned batches instead if trying to do it all in one go.
Best of luck. There is also a tut on the stuff around here somewhere...
Author:  Gtrman13 [ Tue May 03, 2011 1:10 pm ]
Post subject:  Re: Zpoxy woes
Ditto on the 50/50 wash. I just mix up a small amount in a cup and use a clean cotton cloth (gun cleaning patches work wonderfully) to wipe it on. After this coat has cured, I give it a quick sand with 400 grit and I'm all set!
Author:  Stuart Gort [ Tue May 03, 2011 1:24 pm ]
Post subject:  Re: Zpoxy woes
Mind you....not all epoxies will ultimately cure when alcohol is mixed into them. Some do. Some don't. So don't assume that you can do this 50/50 ratio thing with other epoxies. Otherwise you may find yourself down the road with a guitar that has a thin sticky layer all over it....and you need a chemical strip to fix it. :)

Zpoxy is great, however. The 50/50 wiped on mix is the solution for your blotches. Works very nice! I used vinyl sealer and nitro over the epoxy and the bond is very good. I might worry about the bond if I shot nitro straight onto the epoxy though. I've heard that others did this with success. I don't think I'd risk it though. I'm sure shellac would work well as a good intermediate coat as well as vinyl sealer.
Author:  Tom West [ Tue May 03, 2011 1:43 pm ]
Post subject:  Re: Zpoxy woes
Corky: Todd Stock has a 3 part series about Zpoxy pore filling on Youtube. Excellant info.
Tom
Author:  Chris Pile [ Tue May 03, 2011 2:24 pm ]
Post subject:  Re: Zpoxy woes
I guess I'm not with it anymore.
I always used a couple coats of sanding sealer to fill the pores.
Also, I never liked the look of colored fillers in pores - I liked to see into the grain.
Author:  CharlieT [ Tue May 03, 2011 4:36 pm ]
Post subject:  Re: Zpoxy woes
Wouldn't using a more clear epoxy such as System 3 Clear Coat address this problem, or is it the result of more than just the amber tint of the Z-poxy?
Author:  Fred Tellier [ Tue May 03, 2011 4:42 pm ]
Post subject:  Re: Zpoxy woes
My initial problems with Z-Poxy were caused by applying way too thick of coats, which were not applied that well. After watching Todd's videos I realized how much more I was applying than was needed, which caused me to do more sanding, which caused me to sand through in the thinner spots while trying to get things level. It is shocking how little epoxy is needed for a coat. I have done 7 guitars with Z-poxy and the last 3 went real easy, the others were still not that bad just more time consuming.

In the Z-poxy world less is more.

Fred
Author:  Corky Long [ Tue May 03, 2011 5:20 pm ]
Post subject:  Re: Zpoxy woes
Thanks, all. And Todd, I'll check out your toot. Your advice on getting it dead flat prior to application certainly rings true. Will pay even more attention next time. Thanks!
Author:  Stuart Gort [ Tue May 03, 2011 7:22 pm ]
Post subject:  Re: Zpoxy woes
My technique is to pack the pores and then squeegee off as much as possible. After that application cures I sand back down to the wood. Then I wipe on two coats...scotch brite between the wipe coats.

I dunno...I don't get any blotches and it turns out pretty nice.

Using sanding sealer was easier....but it shrank back after a few months and I had to relevel it.......and then THAT shrank back after another six months or so. Not doing that again.

I just got a uv cure light and all the requisite chems. The way the application guide sounds it promises to be considerably easier method to obtain a polished, flat surface. You wipe on and wipe off the sealer, wait 15 minutes, wipe on and wipe off the pore filler, hit it with the light and then it's ready for a scuff....then the topcoats.
Author:  LarryH [ Tue May 03, 2011 8:36 pm ]
Post subject:  Re: Zpoxy woes
Not building anymore but doing a little lurking and thought I'd share a discovery with ZPoxy. Use a hair dryer or heat gun (if you can get the heat low enough) and the ZPoxy thins and flows really nicely into the pores and goes on super thin and reduces bubbling. Give it a try.
Author:  CharlieT [ Tue May 03, 2011 9:20 pm ]
Post subject:  Re: Zpoxy woes
Filippo Morelli wrote:
Charlie - I don't believe so. It's a whetting issue, best as I can tell.


Gotcha - thanks Filippo.
Author:  Chris Pile [ Tue May 03, 2011 10:45 pm ]
Post subject:  Re: Zpoxy woes
Quote:
I used to do sanding sealer, too, but it is miserable stuff that shrinks back, holds finish poorly, and is only semi-transparent due to it's high solids content (stearates...a soft, fluffy soap...essentially a sanding lubricant). I just complete a refinish job on a D-35S, and the difference between the paste wood filler and Z-Poxy is amazing...you can take a high dive down into the grain. Sanding sealer is not as bad as paste wood filler, but all the stearates and fillers do a good job of scattering the light, resulting in less apparent depth on figured woods.


Gee, I wonder how all those guitars with those gorgeous finishes were made before epoxy came along.
Anyone ever tell John D'Angelico his finishes had no depth? Were the finishes of Jimmy D'Aquisto ever poo-poohed because they scattered the light?

And let's not forget other instrument makers... Bosendorfer pianos have mile deep hand-rubbed finishes, don't they? Suppose there is an ounce of epoxy anywhere on those beauties?

There's more than one way to skin a cat, Todd. Finishes were done very well before epoxy came along. And I did some dandies with sanding sealer that you'd be proud to claim.
Author:  Brad Goodman [ Wed May 04, 2011 6:15 am ]
Post subject:  Re: Zpoxy woes
Chris Pile wrote:
I guess I'm not with it anymore.
I always used a couple coats of sanding sealer to fill the pores.
Also, I never liked the look of colored fillers in pores - I liked to see into the grain.


Hi Chris,
As you have already found out "sanding sealer" is a dirty word on this forum.

I try to stay away from epoxy as much as possible- I am sensitive to it.

That said, I have been using sanding sealer for 35 years on guitars and I would proudly say that my finishes would rival any out there and are at a very "professional" level.

I don't use a lot-a thinned coat before pore filling sanded back and another after the fill.
I am now using two coats of dyed joint compound.

I have not noticed any delamination or non clarity issues over many years of service.

Of course other peoples milage may vary.

Brad
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