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This will be the third guitar I`ve used Z-poxy on,And I just don`t like it.After 2 full coats and a wash coat 50/50.I can still see a few spots that aren`t filled.There has got to be something out there that works better,and it doesn`t take 24 hours to sand.Any ideas?
I`m not really interested in sawdust and shellac,because of the different woods .Has anyone tried some of the other stuff LMI sells or Behlen`s.I`m open to about anything that is faster and better.
James W B

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James W Bolan
Nashville Tennessee

James, I got to tell you I know of no filler quicker of easier than an epoxy. If working with really porous wood you might want to add micro beads to thicken some but I just do multi sessions till it filled. If you are squeegeeing it on and excess off right you will pretty well know if all the pores are filled before you sand it. On occasions you will find more after sanding and always will if sand too far into wood. Other fillers like past fillers will cure out quicker but don't have the invisibility of epoxy fills.

My guess is you may be applying too thick and without working it in properly which will cause bridging due to the surface tension of the epoxy. You need to work small areas with the grain and then remove excess at a 45 degree angle.

Michael,

What kind of squeegee do you use - one with a think blade or a thinner tapered blade?

Thanks.

I normally use a credit card to spread the zpoxy. It is just about the right size to work with and is just the right amount of flexability also. Work with small amounts of it, in small areas not larger than 1/4th of a back at a time.

by the time you get to the wash coat, there should be virtually nothing left and you wonder why you even bother with any other finish since it is so shiney and glassy. I suspect if you are having to do much sanding at all, then you are putting it on too thick and you have some bridging of the pores going on.


There is also the west systems epoxy filler, but if you are having problems with zpoxy then you would have problems with that also.

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Reguards,

Ken H

Hesh, I believe it was, made a comment about z-poxy-"mash the crap out of it". You have to really mash it down into the pores. I was having trouble with it too, until I started really mashing it down into the pores. I was about to give up on it. But it works for me now, thanks to Hesh!

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Brad Tucker

Thanks Brad - Skin buddy Brad is right-on. My tendency was to use the credit card to squeegee the epoxy off when in fact you should hold the card so that it is flexing and not only squeegee put press/mash/compact the epoxy down and into the pores. As the others have said do a small area at one time say 6" X 6" and moving in all directions at first as if you are slicing a pizza.... mash it down. On the final passes again with the credit type care bent squeegee the epoxy off moving at 45 degrees to the grain direction.

I take the excess epoxy and smear it on the next area to do and often I don't even have to add more epoxy.

System III works the same way, is clearer IMHO, but is a hassle to mix in as much as a gram scale is required and not mixing it correctly is a nightmare of a gooey mess.

West Systems would be great too I am sure, perhaps better then Z-Poxy and Rick recommends it, I just have not used it yet for pore filling but pro finishers do.

In all cases though you want to mash it into the pores from all directions before you worry about squeegeeing the excess off.

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Ann Arbor Guitars

I've only done this a few times, but I've seen it done several times by a seasoned pro. Epoxy apparently has a very low boiling temp. If after the epoxy application, you'll take a heat gun and lightly (from a 10-12 inch distance) rake across the epoxy, you'll see it begin to bubble. The bubbling will be noticeable. It is not something you'll miss. And the heat gun does NOT have to be overly close to the guitar body, and the temp of the epoxy isn't something that will loosen any glues, etc. (Move the gun, gently, like drying the hair you used to have when you were younger. ) Try it on a piece of scrap first if you're reluctant at all.

But this heat will thin the epoxy considerably, and it will run much, much easier into the pores - especially the smaller pores. Then, after it's thinned enough, you can do the "Heshtone crap mashing" step if you still feel it is needed...and then rake the excess off.

Bill

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

Wow, I'm gonna try that!

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Brad Tucker

Nice tip Bill. Thanks...

Let me add this caveat to the heated epoxy trick:

Joe Herrick and I did this with his son's Uke (an outstanding instrument, by the way), and the thinned epoxy (West) actually ran THROUGH the big pores in the koa (I "think" it was koa) back/sides and made a noticeable spot on the inside of the instrument. That's the only time I've ever heard of that happening, so I asked my friend Brad Nickerson if he'd ever had that happen to him (it's Brad's method), and he said, "Yes, but it's certainly not limited to thinned epoxy, or koa. Any glue forced into a pore that runs through the wood can certainly leach out, especially at warmer temperatures. It'll depend on the characteristics of the woods and how thin the material is at the time of application."

So do be aware that it is possible to thin the epoxy to a very watery consistency, and apparently that thinned material can leach through wood with big pores.

Bill

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

been there done that, with thinned poxy on first coat (experiment) on indian rosewood. I went back to using it full strength.

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Brad Tucker

Thanks for the good info .I still think I hate it,but will take your needed advice.
SKIN

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James W Bolan
Nashville Tennessee

The wood LOOKS a lot like Koa (but without any flame), it was actually Monkey Pod. First time I used it and it IS very much like Koa only even more porous. I think it's an excellent LOOKING (cheaper) substitute. We'll see how it sounds strung up.

The system Bill describes works great and I plan to use it from here on out. The heating will extend the time you can push the epoxy around. It will also make the epoxy cover a larger area (so apply sparingly) with a resulting thinner film? I used 2 coats since the Monkey Pod was SO porous. The sanding was certainly painless. The flow through really was only really small dark spots on the inside of the Uke. I will test on scrap first in the future.

The Uke is my first and was actually built as a father/son project, he did all the building under my instruction. I can't wait until he get's home from spring break so he can buff it out. It's really hard to keep your hands off the student's work....

I'll post a pic when he's done.

Joe

I'm just about to try the epoxy as filler for the first time. No problem as I have a credit card, squeegee, and a heat gun ready to go.

1. mix full strength and press into pores.
2. sand without sanding too much.
3. wash coat of 50/50. Question: Does this need to be sanded or is this to give a working surface for your finish?

Thanks

Philip

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aka konacat

If you think my playing is bad you should hear me sing!
Practice breeds confidence and confidence breeds competence. Unfortunately, I'm stuck in practice.

-

5-minute Devcon from the hardware store works well for me. Dulled single edge razor blade for squeegee. Yes, press on it. A wash coat of shellac before filling helps the squeegee to feel right.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Philip,

The only reason you would need to sand the surface is to remove any ridges left by the epoxy. I have tried everything I can think of, but somehow I still manage to leave some trace ridges and witness lines in the epoxy. Those will need to be leveled before any further finishing or you are asking for trouble. The one thing you DONT want to do is to sand through the epoxy and into the wood, If this happens, you have to sand EVERYTHING back to the wood or it will leave spots on your guitar.

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Reguards,

Ken H

Howard,what is 5-minute Devcon? never heard of it.Tony what paste fillers have you used?
James

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James W Bolan
Nashville Tennessee

Joe what brand of epoxy did you use?

The reason that I am asking is that System III and Z-Poxy, when we speak of these two here, we are speaking of the "finishing resin" epoxy. This is a different formulation then epoxy that is used for bonding surfaces. Finishing resin is especially formulated to be very thin, unlike typical epoxies, and sands like a dream. In fact with either SIII or Z-Poxy I have experienced no clogging of the sand paper what so ever in 12 hours of cure time.

SIII takes it a bit further with two varieties of finishing resin where one is for less porous woods and is even thinner with greater wetting properties.

I am asking this question because I know that we often use a brand name here but fail to designate that we are speaking of finishing resin formulations that are already very thin, spread very easy, and are engineered to sand to a powder with minimal effort.

Recently when I tried West Systems for gluing a fret board I also noticed that this stuff is also very thin and does not sit in thick puddles when mixed like hardware store epoxies do.

With this said, and when using a quality, thin finishing resin epoxy I don't see why one would need to add any heat to thin it further. I can however see that if using epoxies that are not formulated as finishing resins and are thicker that heat would help to thin it out.

Z-Poxy also makes 5 minute and 30 minute bonding epoxies which would not work as well for pore filling so I want to be sure that everyone is talking about the same thing here - finishing resin.

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Ann Arbor Guitars

If you want THEEE FASTEST pore filler then UV pore filler is the answer. Squeegie it on, hit it with the lamp and 20 seconds later it is ready to sand. Hope you have deep pockets though

I have used Devcon products but they always loaded up the sandpaper (for me). Z-Poxy sands as easily as sanding sealer with no loading problems.

Oil based Paste fillers will continue to shrink for days, as the solvents evaporate, so it is highly suggested to wait 3 or 4 days before applying the finish over it. Longer is better.

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tim...
http://www.mcknightguitars.com

Tim, if you're talking about UV cured polyester pore filler, you're leaving out a big and important step...isolating the wood from the poly if you're making rosewood guitars. The oils in rosewood neutralize the oxidation of the polyester whether you're using UV or a catalyst to cure the stuff. The need to isolate, pore fill, level, isolate again, etc. pretty much takes the time advantage out of UV pore filler as far as I can see.

Another big caveat on UV...well several... A company that will remain nameless just wasted 10 grand on a UV booth because someone believed someone who said you could UV cure lacquer, even though an inquiry to McFadden came back negative on that idea.

So how fast do you really need to do your finishes? I can (but usually don't) do a nice thin West epoxy porefilled polyester finish in four days from bare wood to rubout. Do you really need to go faster than that? And if so, why? Given that a decent nitro job where you're not going to see pore shrinkage is a good three weeks, water based seems to be four weeks, good French polish about the same, etc., I think a finish that can cut 80% off that time should be fine for a small shop luthier.

It was Bob Taylor, the king of UV cured guitar finishes who talked me out of it. He's no dummy, you know!

Disclaimer: I have only done one guitar (but I did it about 3 times! .)

I got many of my epoxy tips from Grant Goltz, who has used many gallons of epoxy on his world-class wooden kayaks and canoes (as well as on his guitars.) He told me to warm the guitar a bit (I put a 60 watt light bulb inside the guitar for a little while - but I did that on my own, and I know that if the heat is allowed to rise too much, the glue and or wood might be compromised), then apply the epoxy, and when the epoxy is curing/drying, that the temperature should NOT be allowed to rise, but should gradually fall. His reason was that if the wood temperature rises during curing, bubbles will form and become trapped in the epoxy.

I wanted to offer that tidbit, as I see it directly clashes with what worked for others. Maybe Z-poxy's formulation allows it to be heated after application?

Like Ken mentioned, I used a credit card, and it left ridges, no matter how I squirmed and danced. In attempting to sand the ridges back down, I did sand through the epoxy, and had to do it all over again - twice! Since that episode (I was NOT a happy camper!), I have been told to use a squeegee purchased at an auto body store (or auto parts store) meant for Bondo. It's supposed to make less ridges than a credit card, so I'll try that next time. With it's flexible edge, I'll bet it naturally packs it down like Hesh is recommending too. The other piece of missing information that made my epoxy day into my own personal 'Groundhog Day' movie plot was the proper application of the final coat: after lightly sanding all the ridges down, and making sure all the pores are filled, thin down some epoxy 50/50 with alcohol, and with a lint free 'tampon' (aw, who's kidding who - for us that means a chunk of old T-shirt), spread a very thin final coat over the guitar - excluding the Spruce top. Supposedly, (and a bunch of folks confirm it), that final wash coat of epoxy ensures that there are no bare spots, and won't leave a ridge. You might have to (or want to) lightly scuff after that dries, but not really 'sand' the surface.

Although I may try Z-poxy next time, I used the epoxy brand that Grant had settled on after trying most of the others: Raka Resin 127 - I bought the Sample Kit for $18 which includes both fast (610) and slow (606) hardener. It is a 2:1 ratio by volume mix. I used those tiny plastic condiment cups from a fast food restaurant, and with a Sharpie permanent marker propped up horizontally, spun the cup to mark a line on each of the 3 cups to the same mark. Sure sounded easier that the triple beam scale I was hearing users of other epoxies having to resort to, to get the ratio right.

Again, I'm not very experienced in how to do it right, but that made me research how to make sure it is right, the next time I do it.

Dennis

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Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

I never like to do anything that is too hard. For the last five years or so I have been using Starbond medium superglue as a filler. I do the back and then each side separately. Shellac thoroughly first and, using a blue paper towel, I spread medium superglue over the back of the guitar. Wait 20-30 minutes and sand back. Shellac again and repeat. Sand and shellac again and the back is ready for lacquer. Repeat for the sides. I can get a guitar body ready for lacquer within a few hours. Not difficult and very forgiving. No real technique to it. Just work.

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Sylvan
http://www.wellsguitars.com

That's cool Sylvan. Any fume issues? Are you still using nitro for your finishes?
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Terry -
I usually just leave the room for the 20 minutes or so. The fumes can be rough. I like the look of the superglue because it is absolutely clear in appearance-no cloudiness to the wood at all. I am still shooting nitrocellulose but would like to try to experiment with the polyesters.

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Sylvan
http://www.wellsguitars.com