Official Luthiers Forum!

Rats... Wish Todd was here to comment. I learned a lot from him on concerning Z-poxy application. I've been wondering if there was a better way to more deeply infuse the epoxy. Such as doing a "prewash" using highly thinned epoxy, then doing several more with the squeegee as Todd suggests.

there are some really good threads on zpoxy if you check the archives, last thing you need to do is thin the z poxy...heat does wonders..

_________________
MK5acoustics.com

Perhaps I am missing your goal or concern? But -- thinning Zpoxy filler is counter intuitive, just make sure you go a bit angular with the squeegee and pack it in the pores. I am a Zpoxy convert -- works great!

_________________
Ken Cierp

http://www.kennethmichaelguitars.com/

I have not tried it but there are several on this forum that suggest heating the zpoxy a bit to make it flow easier. I have used thinned zpoxy to first seal dark wood and light bindings and purflings before filling the pores.

_________________
http://www.Harvestmoonguitars.com

If you warm the epoxy and the work a little it will be plenty thin. There are some who have said they had trouble when they thinned it too much. I have not had that problem but I am still wary of thinning it too much. I use a hair dryer to warm it and the work.

_________________
Michael F Smith
Goat Rock Ukulele
http://goatrockukulele.com

I've never felt as if the pore fill would benefit from heating the epoxy be it West, SIII, or Z-Poxy "finishing resin" but I have used various viscosities for very difficult fills that I believe in advance may take more than 2 coats.

More specifically it's been my observation that the very first fill/coat really needs to wet the bottom of the pores. Once the pores have epoxy in them building is pretty easy, until then not so much...

So I have applied it straight up for the fist coat and thickened the mixture to the consistency of cold cream as per a Mike Doolin Toot from way back for the second and hopefully final coat. But again no heat is ever involved for me.

What Ken said about applying 45 degrees to the grain direction and from every other direction as well with the added suggestion, as per my own toot on this matter, of using the credit like card to also "mash" the epoxy downward as well into the pores.

At least for me the term "squeegee" implies a removal process when instead what I believe we want to do is pack the stuff in the pores and only remove excess. Again it's a process of wetting the bottom of the pores which will in turn encourage adhesion and build of subsequent epoxy applications. So I stayed with a credit type card not being one to do windows anyway....

I remember quite well back in the day on the OLF when a few folks first tried epoxy as a pore fill and shared impressions with us. It's the kind of thing that you just have to do and although getting some ideas and techniques from others is most certainly helpful I doubt that any of this will be very sensical to anyone without getting on the nitrile gloves, mixing up the epoxy of your choice, and getting to it. Me thinks that context is everything for this kind of a subject so why not determine your approach, get out some scrap, and see what you think? Practice makes perfect or it at least wastes materials so that you can justify purchasing more....

Last caveat there is Z-Poxy glue and Z-Poxy "finishing resin" you want the finishing resin (thinner viscosity) or West or SIII and some use what ever they can find locally.

Ditto -- make sure its the correct product which has a very nice amber tint. Evaporation and gas of the solvent and water in conventional fillers is what accounts for shrinkage the last thing you want more of in a finishing process. That is not a concern with Zpoxy -- unless you add solvent to make it thinner.

_________________
Ken Cierp

http://www.kennethmichaelguitars.com/

I've used Z-Poxy quite a bit and find it takes more coats than expected, I usually use 3-4 with 4 being more common lately with a very good level sanding between coats. The good thing about Z-Poxy is its relatively fast set time. If you start early you can get 3 sandable coats on in a single day. I also heat at least the first coat as it really thins and sinks in and pops the grain nicely.

Some folks like the West epoxies better and I'll try them after my current batch runs out but so far so good with the Zpoxy finish resin.

_________________
Thank You and Best To All

I think I said something to cause confusion. I have used Z-poxy many times. Hesh came the closest to understanding what I was getting at ... surface wetting. I was asking a theoretical question... and that was whether or not it seem reasonable that a thinned "pre-application" would "wet" into the wood (absorb).

Guess I will experiment.

I expect that z-poxy has a shelf life... How do you tell when it shouldn't be used and it's time to buy some more? I've got about a third of it left and it's a couple of years old... Can I still use it?

_________________
Steve Sollod (pronounced sorta like "Solid")
www.swiftcreekguitars.com

I did not find it easier to pore fill after I used a thinned batch of zpoxy to seal the EIR to avoid color runoff. Once thinned I used it like I do shellac when I lay down an initial sealing coat. It still took me a few coats to really fill the pores to my satisfaction.

I had always thought that the tough issue was forcing the air in the pores out through the film of epoxy while filling. After the pores are not so deep they are easier to fill. On my first pass I work an area until I first see bubbles coming up and keep at it until I stop seeing many bubbles coming up. It is really easy to leave the air in the pores and just bridge the epoxy over the bubbles. Then the pores just open again with light sanding.

_________________
http://www.Harvestmoonguitars.com

OK, so you tried to do what I was getting at. And for the reasons I am concerned about. Did you find it helped? I am not addressing pore filling...

Howdy Steve - Epoxy keeps for a very long time if properly stored. It will darken with age but this should not impact it's other qualities. If you like the additional color from older epoxy go for it.

Yes it did help, when I went to pore fill I was not slopping around a brown and purple mess. I would have used shellac, but there was discussions about adhesion issues with zpoxy on shellac. I used a pad that I dipped into the thinned zpoxy and wiped the bindings and the center strip. I let that mostly cure. I then wiped the EIR (with a new thinned batch) in streaks with the grain trying to avoid even muddying the rosewood. As it was a thinned coat wiped on there was no need to sand before I pore filled.

I have found while french polishing that rosewood can stain itself leaving a muddy look. When I french polishing I will not even overlap a wet area until after the wood is sealed and I can wipe cleanly. I was bothered on earlier instruments when I was wiping the colored (from the rosewood) zpoxy over the bare wood.

_________________
http://www.Harvestmoonguitars.com

As has been mentioned you can "more deeply infuse the epoxy" by heating it, at least I have been able to from my experieince.

_________________
Thank You and Best To All

What I like to do is warm the wood first with a dryer then apply the epoxy. That helps with two problems. First it causes any moisture in the wood to evaporate greatly reducing the chance of amine blush and it thins the epoxy somewhat and helps draw it into the wood as it cools. Then I heat the epoxy a little to help with smoothing the coat

_________________
Joe Beaver
Maker of Sawdust

If others will carefully read what John posted above about the first coat mess, they will understand the point of my question. I like zpoxy. But I really dislike how it can mesh colors on first coat given all the working required. So if a wash coat can be used with minimal action to completely seal the surface with a relatively non-reactive surface, I'm interested.

I'm also a fan of the final wash coat.

I've got a couple questions regarding filling with epoxy. Can you still do it after you've laid down vinyl sealer would be the first, and second if one were to purchase say Z-poxy, would it be better to use the five minute or the thirty minute? My instinct says thirty, but I just wanted to see what other people like to use.

You want the Pacer Z-Poxy Finishing Resin. Most advise is to put it on bare wood. The five and thirty minute zpoxy are adhesives they are not what you want. The finishing resin takes about 8 hours to cure.

_________________
http://www.Harvestmoonguitars.com

Ditto John

Zpoxy Finishing Resin. Do not use epoxy adhesive/glue that will make you sad!!

_________________
Ken Cierp

http://www.kennethmichaelguitars.com/

Okay, thanks guys. Good to know for the future. I did another search on here after I asked the question and it pretty much seemed like everyone was putting it straight on bare wood so I decided to use my old fashioned Pore-o-Pac on this one as I'd already laid down the sealer coats. A very important distinction you guys pointed out about finishing resin v. laminating epoxy. I'm sure I would have bought the wrong stuff!