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Z-Poxy - Applied to Thin?
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Author:  Joe Beaver [ Sun Oct 26, 2008 11:04 am ]
Post subject:  Z-Poxy - Applied to Thin?
I finished a guitar about six months ago and used z-poxy for the first time. I really like the stuff, went on very well. But I now have a problem. The z-poxy is coming out of the pores were my thumb rest on the neck, mostly in the 1st position. (that is were I play most of the time). The rest of the neck seems fine, even the areas around where the pores are opening up is fine.

On the neck I used z-poxy thinned with denatured alcohol over mahogany. No real formula, just mixed 50/50 epoxy and then added the alcohol until it seemed right. I then padded about 3 coats on the neck, a day between coats. I sanded back to flush and the pores were filled quite well. Then one more wash coat of z-poxy. I let it dry several days then started applying tru-oil. I put on about 12 coats over several days. The neck came out great.

After about five months of everyday playing the problem started. The rest of the guitar is finished with KTM-9 over unthinned z-poxy with no problems.

Is this usual? Caused by thinning the z-pozy? Or maybe the tru-oil/skin oils broke down the z-poxy?

How would you fix it?

Thank you for your replies, they are appreciated.
Author:  Hesh [ Sun Oct 26, 2008 12:20 pm ]
Post subject:  Re: Z-Poxy - Applied to Thin?
Joe buddy I always use 2 straight coats of Z-Poxy or what ever epoxy (System III and West are good too) applied with a gloved finger (no jokes please.....). The only time I ever use a 50/50 wash coat is exactly for that reason, a wash coat and not as a pore filler.

I suspect that the wash coat only of Z-poxy did not have what it takes to fill your pores AND stay put.

As for how to fix it the only thing that I can think of is to refinish the neck sanding back to wood and then doing 2 coats of Z-poxy straight and then the wash coat if you need it to even out the color unless you sand the Z-Poxy back to the wood.
Author:  Joe Beaver [ Sun Oct 26, 2008 1:27 pm ]
Post subject:  Re: Z-Poxy - Applied to Thin?
Thanks Hesh, I suspect you are right. Do you have experience using tru-oil over full coat z-poxy? I thinking it should do ok. What do you think?
Author:  Brook Moore [ Sun Oct 26, 2008 7:31 pm ]
Post subject:  Re: Z-Poxy - Applied to Thin?
I have not seen the Z-poxy literature nor used their product, but West Systems has published figures on thinning their epoxy that shows nearly 50% loss of compressive strength with only 5% dilution with alcohol. I bet Z-poxy is not a lot different. My guess is that if you look at the leftovers from a 50% dilution you will find a somewhat rubbery compound that will make you wonder why anyone would ever put that on a guitar. West System does not like any thinning at all, but specifically recommends not exceeding 5%. Just because a few people have been doing this for a very few years does not make it seem at all reasonable to me.

Brook
Author:  Joe Beaver [ Sun Oct 26, 2008 8:18 pm ]
Post subject:  Re: Z-Poxy - Applied to Thin?
Brook,

That is good information to have. Sounds like a wash coat is a dangerous thing to mess with.....
Author:  Joe Beaver [ Mon Oct 27, 2008 1:37 am ]
Post subject:  Re: Z-Poxy - Applied to Thin?
Thanks Chris. I think I'll give it a try filling those areas with tru-oil. It did make a nice finish.

It worked well filling the neck with a z-poxy wash coat. Filled it quickly with hardly any sanding and it harden real well, faster than a straight mix, but..... :( when it comes out....in 6 months it is not good.

I'm getting ready to finish another guitar this week. I'm thinking I'll go with sytem 3 clear coat. it is already pretty thin so I won't be tempted to use alcohol.... at least not in the finish 8-)
Author:  Hesh [ Mon Oct 27, 2008 6:56 am ]
Post subject:  Re: Z-Poxy - Applied to Thin?
Joe buddy System III is nice stuff but be sure to use a gram scale to measure it. It is much more sensitive to mix ratio than Z-Poxy.

For the sake of discussion only an epoxy wash coat is not intended to be a filler. It is only intended to be applied over full strength coats of epoxy (finishing resin or West) to even out the color if there is a sand through and for folks who leave an epoxy coat on the surface of the wood. Those that sand back leaving the epoxy only in the pores won't use a wash coat, or don't need to.

System III recommends that users use a filler mixed with the epoxy for more porous woods. I found Z-poxy to be easier to use, forgiving mix ratio, sands great, and no filler required.
Author:  Joe Beaver [ Wed Oct 29, 2008 12:35 am ]
Post subject:  Re: Z-Poxy - Applied to Thin?
Hesh,

Yes, I like z-poxy also but on this guitar I'm thinking I'll try System 3. This one has a flamed redwood top and I would like to keep it as light as I can and sytem 3 seems to be a little lighter. I think maybe the thinner consistency of system 3 may be a plus on the neck.
Author:  KiwiCraig [ Wed Oct 29, 2008 2:58 pm ]
Post subject:  Re: Z-Poxy - Applied to Thin?
Joe Beaver wrote:
I finished a guitar about six months ago and used z-poxy for the first time. I really like the stuff, went on very well. But I now have a problem. The z-poxy is coming out of the pores were my thumb rest on the neck, mostly in the 1st position. (that is were I play most of the time). The rest of the neck seems fine, even the areas around where the pores are opening up is fine.

.


Joe , I've struck the very same problem , and at the very same area. This wasn't using a wash coat of thinned down Z-poxy either !, but mixed full strength. I have also read of others getting the same annoying result.

I was also concerned at the hardness of the thinned down Z-poxy , so set up a test . I have to agree with those above . It set up rubbery ,,,, hard rubber ,, but rubbery, which put me off the idea of the thinned down stuff.

On the other hand , I had a great result with another neck , when using True Oil mixed to a slurry with the sanded mahogany.
Author:  Joe Beaver [ Thu Oct 30, 2008 5:50 pm ]
Post subject:  Re: Z-Poxy - Applied to Thin?
Craig... I'm a little late seeing your post but I think it is very important info. So oil over full strenght z-poxy has the same problem? Good to know. Sounds like it is more a oil (tru-oil and skin oil) reacting with z-poxy thing. So much for ever putting oil over epoxy.

Thanks for the info....
Author:  KiwiCraig [ Fri Oct 31, 2008 6:35 am ]
Post subject:  Re: Z-Poxy - Applied to Thin?
That's what I've figured too Joe , although Others have said my Z-poxy must have too old or I musn't have let it go off long enough , which wasn't the case. Incidently , it did settle down after a while in that area after a couple of touch ups with Abralon 4000 ( like a micro mesh thing )

Interestingly , I had no other problems with any other part of the neck , which also gives away a bit of my playing ability :D


Craig Lawrence
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Author:  Michael Dale Payne [ Fri Oct 31, 2008 9:40 am ]
Post subject:  Re: Z-Poxy - Applied to Thin?
First off, Hesh is right the wash 50% epoxy/50%alcohol is intended as a coloring agent (sotto sanding sealer) only not as a pore filler. However the real thing that is confusing me is you say the epoxy (regardless of strength) is coming out of the pores where your thumb is riding. I would have expected that the wash coat strength of Zpoxy would have shrunk into the pores not fall out. Did you not apply any other finish on this neck? While Zpoxy is pretty durable and can be polished once cured I would never consider it a top coat.

For pore filling use 1:1 ratio of Zpoxy base to Zpoxy hardener at full strength.

For wash coat use 1:1 mix of Zpoxy base to Zpoxy hardener the cut the mixed Epoxy by 50% by volume with Alcohol.

This is intended only to color any spots that may have been sanded back to wood. Most of us that use Zpoxy sand the pore fill back to the wood surface leaving the epoxy only in the pores. And use the wash coat to color the wood back to a wetted state. This is not intended to be a finish system but only full strength epoxy mix as a pore filler and then the wash coat as a sotto sanding sealer.
Author:  KiwiCraig [ Fri Oct 31, 2008 3:32 pm ]
Post subject:  Re: Z-Poxy - Applied to Thin?
G'day Michael,

Sorry for not making myself clear on this .

Yes , after applying two coats of full strength Z-Poxy , leveling back to wood and leaving to cure , I then applied the true oil on top. I also left that to cure for quite some time also ( at least a couple of weeks from memory )

It's hard to tell whether it was True Oil or Z-Poxy that came oozing to the top surface by way of tiny ( and I mean " tiny " ) blisters . So small you could feel them rather than see them. As I said , the problem has settled now , but not after giving it a couple of hits with some Abralon 4000 over an extended period .

It could be that Joe and my body chemistry are the culprits here ( although I do wash and rinse my hands thoroughly before playing ) , but after reading of others getting the same result ,,,,, it seems we're not alone. Given that this reaction only took place in an area of majority hand contact , it makes sense to blame skin oil .

As I said above , I choose not to put a thinned down version of Z-Poxy as a last Z-Poxy coating and haven't found the need ( careful sanding ,,,,,, no blotches )
After doing tests on same and finding it to cure 'rubbery ' . Just don't like the idea of not having a 'hard' surface to lay the finish on.


Craig Lawrence
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