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I tried a couple of local brand quick setting epoxies for pore filling before I tried Z-poxy for the first time. I had read somewhere that you could use any ol’ epoxy glue, thin it with alcohol until it was like thin syrup and fill with that. It worked, but the sanding was terribly labour intensive; the cured glue would gum up the paper real fast so I ended up scraping much of it off, before I sanded the remaining epoxy down to bare wood.

Z-poxy both fills and sands so much better than these epoxies, but I still sand down to bare wood as I don’t like the idea of the filler anywhere but in the pores. The Z-poxy has a slightly amber colour, and if I cut through while levelling the laqcuer in subsequent finishing stages, I don’t want to have to deal with touching up a layer of epoxy too like I would have to if there was a layer of epoxy under the finish.

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Rian Gitar og Mandolin

In my experience, heating epoxy to thin it and allow the expulsion of air bubbles works very, very well. But you must keep on the move with the heat gun, not too close and not too hot and not too long. As Dennis suggest, if you over kill you will indeed introduce bubbles back into the mix as the epoxy begins to go off so fast that it boils. It's not water, you have a chemical reaction going on there already, once you add heat it will realy kick so your open time closed quite dramatically.

I do not speak with experience as a guitar builder but fishing rod binders doing cotton art have been using this trick for many years and I have built plenty of those. So be warned, use a heat gun with moderation the kick can be very quick and if you get caught out it will leave a mess.

The big tip is to remember that the chemical reaction of the epoxy is building heat, the addition of the heat gun increases that heat, if you reach the point where you think you may have gone a bit too far as it starts to gel and then you stop, the mix will maintain it's heat because of that chemical reaction well after you had your revelation and you will have a moment of clarity just before you begin hours of back tracking work.

Don't be put off as the advantage realy is there just be cautious tis all.

Cheers

Kim

I like to do the same. Just have Z-poxy in the pores and not on the surface wood.
Usually two coats of Z-poxy and I'm good to go with nitro.

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Anderson Guitars
Clearwater,Fl. 33755

the plastic faux credit cards you get in junk mail to apply and a razor blade with rounded corners to remove excess. I find the plastic is good for working the epoxy into the pores and the razor blade is better at getting off more of the excess

I will just lightly tooth the wash coat with 400p I would not call it sanding I am just dulling any glossy spots to give my seal coat of shellac a tooth.

I've done this once and I will never do it again. I was putting on epoxy for like the third time on a guitar that refuses to be filled. I tried to stay away from the bindings so just put the epoxy on the sides and back, staying clear of them (bindings) as they were already thin adn I didn't want to risk a sand through. Huge mistake! The heated epoxy penetrated very deeply in the wood and when it came time to sand back, I had to scrape all the way back to open pores before the epoxy 'spots' dissapeared. It was blotchy as all heck.

So if you plan to heat up the epoxy (I was using System III), make sure you do all the instrument and keep in mind that it will probably be impossible to sand back to wood if you do so.

I found that epoxy thinned with DA works much better. I am now using Zpoxy and I think it's much easier to use than System III.

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I'd like to be able to prove, just for once, that money wouldn't make me happy...

Why all the angst about sanding? It's just not that big a deal if you use the right tools and the right sandpaper.

For anyone with a decent compressor, DynaOrbital sanders with the 3M Gold paper is the way to go. Otherwise a good electric RO sander like a Bosch or Festool is almost as good.

If you're not mixing the epoxy correctly or if you're just too impatient, you'll have a hard time of it, but just remember that every hour you put into proper wood prep and pore filling will save you two hours of finishing time. Sounds to me like some folks are just too eager to get coats of finish on, figuring that they can drop fill their way to a good finish. You can't unless you're finishing with polyester. Even then, more time in prep = less time in the booth.

I may be a dinosaur, but I've never minded the process and the look I get with pumice. I normally apply 3 (light) coats of shelac. Then just with alchohol and pumice start at it. You start to see a slightly dulled surface that's smooth as , well..... I can do a back in 15 minutes. I usually start applying shelac from there but I'm sure you could start at that point with any finish. For me, I would see a lighter color in the pores in a certain light whenever I try the sawdust filler.
I'm not that expierenced in guitar making,5, but I can't see how epoxy is faster(or easier) than pumice. Is it better? Clinton

This is a priceless nugget of wisdom Rick. Every newbie should read this one, and commit it to memory. Despite being told this EXACT thing, I didn't pore fill well enough on my second guitar - and I drop-filled for several weeks after I started shooting the primary nitro coats. Drop fill, wait for it to shrink. Drop fill, wait some more. Sand. Drop fill, wait, sand, etc. Heading this one piece of advice would have saved me weeks, literally.

(And yes, I'm also going the Festool route on the next one for the sanding.)

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Eagles may soar, but weasels don't get sucked into jet engines.

I use system 3 SB-112 epoxy thickened up a tad with Cabosil that I get at the plastic store. Warm things up a little this time of year with heat lamps and you can re-coat in about 3 hours. Try using a small window squegee (3" or so wide blade).
Sorry if this is a repeat of advice- I'm on a borrowed computer and don't have the time to read all the previous posts.
-C

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Freeborn Guitars
and home of BeauGuard©

A very wise old painter once told me "Finishing is 95% preparation, 5% application" and "You don't apply a finish, you build it". Had nothing to do with guitar finishing, but wise words nonetheless.

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Jimmy Caldwell
http://www.caldwellguitars.com

I used the West III (105) that Bill brought over. We also used the 206 slow hardener whcich is their low viscosity curing agent. It might be better to start with the 205 medium hardener and heat it...?

Let me echo a few of the comments in this thread. We thinned the epoxy (via heat only) which flowed VERY well into a REALLY porous woord surface. The result was that it was a thin coating and VERY easy to sand back to bare wood leaving only the pores filled. First sanding was easy (ridges and all) as was the repeat application. I can also say that using lacquer, the top coats went twice as fast (like Rick mentions) with only one spot needing to be drop filled (another improvement for me). I needed to apply fewer lacquer coats to get a level surface. I think that sanding epoxy back is faster and better than applying multiple coats of lacquer and waiting for them to harden and off gas enough for sanding. I also find it easier to burn through (sanding) lacquer than epoxy. The West III/lacquer is the ticket for me....for now

As any reader on this forum knows, finishing is definitely one of those cats that can be skinned a lot of different ways. I think most find a way that works for THEM and it's hard to sway from your experience of what does and doesn't work for you personally.

Joe

Agreed Joe and thanks. I would add that I think that ALL of us struggle with pore filling initially so when we find something that works we are reluctant to change. My real point is that for those who struggle with pore filling you will get it and when you do it will be one of those ah ha moments. Regardless of if you mash or melt the finishing resin into the pores or don't even use epoxy as frustrating as pore filling initially is you will get it at some point and then it actually becomes enjoyable. With epoxy finishing resins it is your first glimpse of what the guitar will looking like under finish.

There's nothing wrong with pumice pore filling with shellac, but it's going to shrink back, and unless you allot a good three to four weeks or more to the finish process, it's going to look like crap all too soon. Unless, that is, you are wanting an open pored finish. With epoxy done correctly and then going to polyester for the top coats, you can do a dead level finish in four days that will stay dead level for years.

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Because they make for funky finish adhesion. Epoxy pore filler actually bonds the finish to the wood.

Just because something has been used for years, that does not automatically make it the best choice given modern materials.
There are a lot of traditions that are just dumb and wrong.

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Oil based pore fillers also shrink with time, giving that slightly sunken pore look. Fine if that's what you want. I don't. I want a really tough and thin finish that can take a lot of abuse and won't sink back. And I want it in less than a week. I also don't particularly like the look oil fillers give to most wood. I prefer the transparency of the epoxy and the translucent effect it gives to wood. I think that the typical oil based pore filled look of your typical Gibson or Martin looks like you took perfectly nice wood and rubbed feces into it and onto it. Just my opinion, mind you!

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Todd, fully agreed on all your points.

The micro bubble thing is one of the reasons I often use Waterlox prior to McFadden's rosewood sealer. The Waterlox acts as a presealer and seals up those tiny pores just enough to prevent the outgassing of air trapped in the wood as the instrument warms up slightly upon being taken out of the spray booth and into the drying area.

One of the tricks is to pre-warm an instrument before shooting that first coat of whatever onto it. Then the instrument will cool down during and after that first coat of spray goes on; the air in the pores will contract and literally pull the sealer into the wood.

One size does not fit all. Some woods look better (IMO, OK?) with a contrasting pore filler. On those I use a solvent based silex filler. When done properly there is no adhesion issue whatsoever, and no noticeable shrinkage (that's the point of silex--it's ground glass and does not compress or shrink). It is harder to get a good fill with silex fillers than with epoxy. On the other hand, some epoxies look green under a finish, and seem to get more so over time.

I don't understand why people would think that a finishing resin is necessarily a better pore filler than a bonding resin (because the word 'finishing" appears?). Neither one is being used for its intended purpose, and if the finishing epoxy is thinner, well, so much the worse for its ability to fill a pore level. Problems sanding off the residue are solved by application and leveling technique, not by condemning the material. I squeegee off all the excess and then sand down to the wood. Floats my boat, anyway.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

You know, I use an actual squeegee as my squeegee. It has a five or six inch long blade and a 12" handle. It was only a few dollars at the hardware store. The leverage you get from the handle along with the rubber blade really push the Z-Poxy down into the pores and leaves a thin, even coat. I've used it a few times now on guitar and other misc. projects that needed pore filling. You don't need to use the full width of the blade; I don't and have a bit more control that way.

I squeegee off as much as I can too Howard, but no matter how thorough I try to be I cannot get it all off, and there will still be some left that has to be sanded away. I am not "condemning" other materials, but the Z-poxy sands better than any other epoxy I have tried and I find this beneficial. I have no experience with the brand you mentioned.

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Rian Gitar og Mandolin

Ya know, I was just reading The Epoxy Book(available from System Three) a few days ago , and it mentions more than once how epoxy needs to be protected from UV. Epoxy breaks down completely with exposure. I didn't know that fact... Now, most of today's finishes have UV inhibitors, but none are 100%, and all lose effectiveness wit time.

They also mention that epoxy prevents full cure of polyester resins, and perhaps even break down cured polyester(something about amines not liking peroxides) wit time. I'm not remembering exactly, but the general thought that i came away with was that none of what I was reading makes me wish to use it on an instrument that has a life expectancy of hundreds of years....

Anyone else read that?

In my career, I've used McFadden's "mahogany" paste pore filler(2 thumbs up), LMI WaterBorne paste(9 thumbs down!), Target's WB filler(more thumbs down), shellac and pumice(many thumbs up), even shellac mixed with pumice as a paste and then colored, CA glue(thumbs up, but nasty fumes), but ya know, mostly, I've used the finish itself. Even nitro would fill nicely with just a few extra coats. and today, with polyester, geeze, what a no brainer that is... shoot 3 coats on the back and sides, let it cure 5-6 hours(MEKP/cobalt cured, a few minutes if you have UV <g>), sand 80% level, then top the whole body with the final 3 coats. Rick, I do it all in the same day. 100% filled, thin(especially on the top where it counts) and a one-day finish.

I pay a lot of attention to what the boat builders do, and yes, they have to protect epoxy from UV...along with everything else. But this is talking major UV exposure...outdoors, often in the tropics, way worse case than any of our instruments should ever be exposed to.

As for poly over epoxy...well, I don't...I put a barrier layer in between the epoxy and the polyester. That's what either Isolante or McFadden's rosewood sealer is about...isolating the polyester from any chemicals that inhibit cure. They are urethanes, and boat builders have been using polyurethanes over WEST epoxy built boats for decades now.

Go over to the Smith and Co. site and read up on what Steve Smith says about using epoxy as a wood sealer in exterior applications. Very interesting...