Official Luthiers Forum!

There's certainly been a lot written about Z-poxy on this forum and many highly credible members have sung its praises. I'm not doubting for a second that the product has served some makers really well, but I'm not one of them. It may be me -- something about how I applied the stuff, the material I put over it, etc., etc. -- I really don't know, but what I do know is that I've found that West System products are giving me an epoxy porefill that is out performing the Z-poxy in every way.

I had no real beefs in applying Z-poxy and I've done it pretty much the way you've seen described by others. Have a window squeegee thingy cut down to about 100 mm wide, and that's what I use as an applicator. Two coats on rosewood and the pores are pretty much filled. I then spray with a precatalysed polyester lacquer -- Mirocat 3220 by Mirotone. It's pretty much what most builders in Australasia are using and the New Zealand warehouse was just 15 minutes away from my old shop. The Mirocat levels and buffs out nice and I was getting that glass-like surface we aim for.

Trouble is, it didn't stay nice. Sinking back into pores would occur within a couple of months -- some instruments worse than others, but virtually all I filled with Z-poxy are, to my mind, unsatisfactory.


I started off using it on necks as well, and learned that it doesn't react well to Tru-oil -- others have written about the "fuzzies". What really surprised me was that the first guitar I ever used it on with lacquer over Z-poxy (2009) has experienced severe finish film failure all over the mahogany neck. Now, this guitar has been well played and spent a lot of its life in a recording studio in Toronto where virtually everyone would bang away on it. Still, the neck looked pretty ugly when I saw it over Christmas.

On the recommendation of respected finisher Joe White, I got myself some West System 105 resin and Z207 "Special coating" hardener -- thank you Joe!! Living in a harbour town at the time (Wellington, NZ) finding supply was easy -- every chandler has it or can get it overnight. The mixture is 3:1, so I use glass syringes to measure out the few milliliters for a given application. Essentially everything in my methods is exactly as I was doing it with Z-poxy. Clean up with methylated spirits.


The thing I noticed immediately is that the West System was thinner than the Z-poxy and had much more working time. Whereas Z-poxy begins to set almost immediately, causing drag on your squeegee and causing you to rush. No rush at all with the West System. It does take longer before you can sand, but by next morning you're set to go and there is minimal clogging of 3M gold sandpapers.

But the real objective of making the switch was to get a stable porefill with no sink back. The guitar below was completed in September 2013. And it still looks exactly as it did when it came off the buffer.

For me, that was what I was looking for ... and why you won't find Z-poxy on my shelf anymore. Only wish I changed sooner!

If you're using Z-poxy and it's doing the job for you, then that's great -- obviously many folks are getting good results. But if any of your experience lines up with mine -- there is an alternative.

One footnote -- I still don't use epoxy for pore filling necks. It's messy to do a good job, and I've found that the LMII acrylic bead filler does a fine job on mahogany.

I use a shellac barrier between the z-poxy and Tru oil, and have not had any issues. I love the feel of tru oil on a neck as a player.

Glenn

Sorry to hear about your troubles wit Z-Poxy, Tim.

I've used System III, West Systems, and Z-Poxy and have had great results with all of them. I have instruments that have had Z-Poxy fills up to 9 years ago and they still look great with no shrink back or other issues.

As such I wanted to ask you a couple of questions if I may please becuase this kind of experience with Z-Poxy is unusual to read.

First I always am very clear that what I use at times is Z-Poxy "finishing resin..." Z-Poxy comes in regular epoxy glue which is not the same thing and the packages look a lot alike. Also the hardener like many epoxies will turn dark with age. I never used any Z-Poxy that was more than two years old.

West is likely my favorite too but again no issues here with any of the three mentioned above altough SIII is more mix seisitive than the others.

Because of your multiple locations (as per your avatar info) I have to wonder if what you had was a) finishing resin and b) old, and c) exposed to high temps, etc.

Any thoughts on the above?

I agree with you on the feel of Tru-oil. When I do an oil-finished neck now, it is on a barrier of shellac on top on LMII acrylic bead filler. It just goes so much quicker without fiddling with epoxy.

One strange observation I've made is that the first coat of Tru-oil applied on the shellac cures quickly on maple or rosewood fingerboard binding, but is very slow to cure if the binding is ebony. Don't ask me to explain that! Once you get a coat of Truoil to cure, subsequent coats are no problem.

I've purchased two Z-poxy finishing resin kits -- both from LMII. They both behaved the same way. I literally tossed the second one in the bin this past week as I porefilled a rosewood classical with West System, wondering why I shipped it from Wellington to Nairobi.


Well, it's not (a), shouldn't be (b) and I don't think (c). All of my Z-poxy applications were made in New Zealand where temps are not at all "hot" and humidity not extreme.

I'm the first to admit that it's no doubt something in my technique or the chemistry of the woods and other products I'm using. I tried -- believe me I tried -- but it just didn't work for me. Having repeated just this week the experience of using West System with its lighter viscosity and longer working time, I would give it preference over Z-poxy for that reason alone.

I switched to west systems about 6 instruments back and it is a much better product than Z-poxy for filling. I also have seen some shrinking into the pores. I find even though the West takes at least 2X as long to cure it sands easier and due to its thinner viscosity seems to be easier to apply. Also the lack of amber tint seems to make it much easier to even out a sand through.

Fred

_________________
Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

I also tried using system three epoxy thinned with alcohol and silica filler to a pore fill on a locust neck with big pores works vy well.Can/t comment on z -poxy., as I haven/t tried it and prefer more tradional methods ,famowood water base pore fill and behlens oil based pore fill, only because I/ve used it so many times. I also have some bondex white powder for making castings that looks promising.

Tim it sounds like you covered all the obvious stuff and more.

In my own experience viscosity seems to be something that can cause issues too. The best results that I can get these days are using what ever epoxy I am using as thin as it comes when mixed per instructions for the first application. Then for application two I generally mix in micro ballons and thicken it up.

What I think may be happening is that the first coat is difficult to get the epoxy down into the pores and have it stay there. So I like it thin for this application. Then once there is some epoxy in the pores the second coat seems to stick to the first coat much better than it sticks on bare wood.

Some of the pro finish guys that have shared methods with me use a foam brush for application. I've always use a credit type card personally favoring how easy it is to "mash" the stuff downward into the pores. Using a squeegy seems to me to be less efficient at this "mashing" of the epoxy into the pores and more efficient at removing the excess. I'm sure technique plays a huge role here too.

Another variable the comes to mind as I am writing this and thinking about my own process is that I suspect it's also possible to think that we have a complete fill when we may not and then start applying finsh. The finsh builds with subsequent coats until we have level. But if some of the filler in the pores is actually finish and the pores were not completely filled with epoxy it could result in what we are seeing here. The finish over time shrinks back as finish does and pores not completely filled will look as if they were not completely filled.

We all may get mad at times in the shop for various reasons.... The only time that I can remember ever getting mad in the shop while building was early attempts at pore filling. I tried everything out there and had no luck with any of it.... It was so very upsetting to me that I very nearly decided to quit Lutherie. I guess that I got pretty mad....

When I learned to use epoxy I had good luck nearly at once but also needed to do at least three applications. These days I can fill in two sessions and it seems to be effortless and predictable.

Epoxy should not shrink back much if at all. There are no VOCs to gas off, etc. like there is with some finishes that do shrink back.

Strange mystery here.

I went back to pore o paq I found too many issues and many didn't show up until finish.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I've used WEST 105/207 for many years. For me, it's the lesser of all the evil ways to pore fill. I get good results with it. If you hit it with nitro too soon after the last fill coat (basically before it has fully cured) you can get nitro thinners absorbed into the epoxy which then swells and will result in minor shrink back over a long period. I've learnt to avoid this problem by leaving the epoxy long enough to fully cure (typ 24 hours around here, 48 hrs if it's cold (<15C))

_________________
Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Is anybody filling with other than epoxy? Shellac? Base layers of the finish water borne lacquer?

_________________
Greg
http://garibaldiinstruments.com/

I've used shellac (without pumice) for pore fill under TruOil. Three to five coats and then sanded back. With TruOil, the pores don't need to be completely filled, but they do need to be completely sealed. The first few coats of TruOil completely fills the pores if they're completely sealed.

I've also used thin CA, which actually worked really well. I'll use it again on wood with large pores, like bloodwood.

_________________
A man hears what he wants to hear, and disreguards the rest. Paul Simon

I definitely had issues with oil over zpoxy. Don't do that any more.

I haven't had any other issues except the amber color, so I might give West System a try.

_________________
Joe Beaver
Maker of Sawdust

I have used every type of filler (z poxy, system 3, ca, oil based traditional, water Bourne) I can find or heard of and have found nothing to be 100% able to prevent shrink back of pores. They are all hit or miss.
If you think about it and make a note to look closely the next time you are in the high end guitar section of the music store you'll see shrink back on occasion on all makes and models. Especially over time. I have a 6000 $ Collins CJ sitting in my herd with pore shrinkage showing. I've seen pores in custom Martins, Taylors, Goodalls etc. Not on every one, but enough to know that a guitar is a musical instrument, not a shiney pore free automobile.
I spray an extra coat of finish on my back and sides to make sure I've got enough to level sand again and buff a year or two down the road when shrink back might occur.


Sent from my iPhone using Tapatalk

I'm a little confused. Tim, your first picture looks like it has a normal grain filler. Was the grain filled with something else before you applied the z-poxy?

_________________
Old growth, shmold growth!

No -- there is nothing on that surface except Z-Poxy and the Mirocat lacquer.

It may be that that picture was taken in artificial light. Below a couple of photos taken just now of two EIR dreadnoughts completed in 2009. Perhaps these show the surface more clearly?

Strange performance from any epoxy as they have no volatiles to evaporate or 'shrink back' to but your experience can't be denied.

I use Z-Poxy but can't endorse or disparage it as my experience is limited to about 10 guitars and I never really focused on getting a perfect finish, especially over a long time period. The thing I like about Z-Poxy is I can get 3 coats on a guitar in a single day but if it's going to shrink back like your examples then I'll re-think my process.

As far as the viscosity goes for those still using Z-Poxy just heat the Z-Poxy with a hair dryer or heat gun on low and it will flow like water and can be brushed quite easily with a foam brush if you like..

_________________
Thank You and Best To All

Another question Tim. Do you think the surface was completely flat and all pores completely filled after you were finished applying the Z-Poxy? If not then the shrinkage may be from the lacquer shrinking back into those pores left unfilled.

I'm not challenging your experience and am not an advocate of Z-Poxy but I have started applying a minimum of 3 and sometimes 4 coats to insure a complete fill as it makes final finishing so much easier.

_________________
Thank You and Best To All

I hope the "tossed my Z-Poxy in the bin" was a metaphor.

Please people when throwing out epoxy either take to a toxic waste dump site or mix and let harden before tossing.
You can also save and use for coating jigs, shop floors, etc.
L.

_________________
Cut to size.....Beat to fit.....Paint to match.

Honestly it looks to me like either the pores weren't filled and the polyester shrank, or the wood expanded around the filled pores.

Did you sand back to the wood after filling the pores with the z-poxy before applying the finish?

_________________
Old growth, shmold growth!

Thanks to all who shared their experience here.

Personally, I'm not really looking for an explanation of why my results with epoxy pore fill were so disappointing with Z-poxy, while WEST System 105/Z207 has been such a treat. And I'm not about to go back to Z-poxy to sort it out. The fact is my combination of epoxy pore fill under Mirocat 3220 as a finish material will not be of interest to most on this board -- only to those living in Australasia where Mirotone sells its products.

It's interesting that some of my experience had been echoed by some members here, while others are undoubtedly very happy with the results they're getting with Z-poxy. My main point was that a change in product was what finally got me to a finish on rosewood that I'm happy with.

It's been a struggle. If someone else is struggling with Z-poxy, my recommendation would be to give the WEST 105/Z207 a try.

The bigger question for me is, what am I gonna do when my supply of Mirotone lacquer in Nairobi runs out? And it will! I'm working on that one. Let's just say that guitar making in Africa faces some unique challenges.

Filling is part of the fit and finish and there is a technique involved. I , like you tried a number of fillers. In the end I am back to Pore O paq and I am pleased with the results and long term. I have guitars that are out over 10 yrs and still no shrink. The key is the pore filling in the beginning. If they are not filled the finish will shrink and expose them.
I was lucky to get training out at Martin and I use the same technique they use. Paste filler with a stain added , a touch of naphtha to help flash time and power buff it in. Takes about an hour for 2 coats and I have been having great success. Often it is more the application technique. To be honest there is no fast and easy way.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

That's fine. Since you brought the whole thing up though I'm sure a number of are curious.

I for one don't accept the premise the Z-poxy is horrible and West Systems is so great, but then again I don't use either product. they look messy and gooey to me, and it seems like pore filing with epoxy is almost as much work as applying the actual finish.


I'm wondering if you sanded back to bare wood prior to finishing after you filled with the epoxy, either one.

_________________
Old growth, shmold growth!

I have never heard of anyone using grain fillers from Hood finishing.
They have a number of different products.
I have used their nitro based water clear with good results.
2-3 coats depending on grain, brushes or sprays on,very fast drying~ 1 hour, easy sanding.
The only drawback is the nitro fumes,though they have a water based product I have not tried it.

_________________
My memory is so good, sometimes I remember things that never happened.

Thanks bri for the correction it is not hydrocote.It is famowood water base filler golden oak to be exact.. I use it with sprayed water as it sets up vy quickly 30 sec, especially in dry humidity. so I can only do abt 5in by 5in at a time and use a plant atomizer to push the filler around on open pored woods like tamarind or oak . I edited the correction in my thread.