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Not finish adhesion for me but the problem I had with using epoxy, aside form a nasty toxic mess, was that no matter how hard I tried I would have some ridge here or there that would not sand easily flush with the rest of it. I used credit cards as a squeegee. I'm fully willing to accept the fact that it might just be that I suck at doing it, but that was one of the negative experiences I had with it.

I get some ridges too (I use those AARP cards that come in the mail), but have found that they level nicely using a razor blade as a scraper.

I give full credit to Hesh's tutorial on using z-poxy for the good results I've had with it. I followed his toot the first time I used it and it worked.https://www.luthiersforum.com/forum/viewtopic.php?f=10117&t=20320&hilit=zpoxy

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

As mentioned, the best filler for a project depends on the application and the results desired. We use a number of pore-filling approaches, depending on the nature of the work (refinish versus new; touchups, etc.).

For vintage work, we rely on paste wood fillers colored with solvent-based stains to generate the muddy, indistinct appearance of the grain of many older guitar finishes (e.g., Martin mahogany finishes). For the more modern look which emphasizes depth of figure and finish clarity, we use System 3 Silvertip epoxy both to fill the pores and to pop the figure, and for some projects that have plain-figured, open pored wood, we use latex fillers. The choice is really more a case of matching the characteristics of the filler to the finish - we work in lacquer, waterbased General Finishes EnduroVar and Pro, shellac/French polish, and 2K polyurethanes - and surface. And for some quick-turnaround work, medium CA works well, especially where the top coat is either 2K urethane or Fill N' Finish CA.

On epoxy pore filling - there are other videos available on YouTube that cover the use of industrial windshield washing squeegees as the application tool of choice for epoxy pore filling, with the Etore Pro Grip model (Lowes Item # 305969; manufacturer Model # 60012 or #306042/#60018) cut down to 6" width sections being our favorite. The thick rubber blade allows far more pressure and control than other applicators (e.g., credit card or Bondo squeegee), and works a much wider area, which is key to avoiding ridges or other unnecessary, excessively thick collections of epoxy. After working with the Etore squeegees, I tried using the credit card approach on a home refinishing project and found out just how much more work it was to work the filler in and to remove the excess - lesson learned. $12 spent is several tenth hours saved scraping and sanding between coats.

On Z-Poxy...we've had several instances where we have had finish separation from Z-Poxy fill associated with owners with very acidic perspiration years after delivery. We believe that this was primarily an issue with some sort of post-cure amine salt formation reacting with the acidic perspiration, and may be what some users report as separation of finish over filled pores (i.e., a light-colored dot collocated with a pore). Our solution was to move to a non-blushing, non-blooming epoxy formulation (System Three Silvertip with Fast Hardener), although the water-white nature of Silvertip and the more favorable viscosity, which eliminates the need to thin for a wash coat, is a side benefit. If the distinctive tint of Z-Poxy is desired instead of water-white epoxy, metal-complex dye stains such as StewMac's rebranded TransTint product may be added in moderation without affecting cure.

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A constellation only takes shape when one maps the whole.
- Beth Brower

+1 Zpoxy

Best? For me that is UV cured materials....https://howardguitars.blogspot.com/2018/11/uv-cured-finishing-for-guitars.html

This may not be for you though. My previous favorite was epoxy. I used system 3 products.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I've used ZPoxy numerous times and find it quite easy to manage especially if heated during application with a heat gun. It flows much more readily and ridges can be leveled and eliminated much more easily.

Just threw away my Ettore window squeegee and hated it, not sure why, was just awkward for me. Came across these game changer little spreaders/squeegees which are good for so many uses.

Try heating the ZPoxy and see if it's not easier to work with.

https://www.amazon.com/gp/product/B06W9 ... UTF8&psc=1

https://www.amazon.com/gp/product/B01K4 ... UTF8&psc=1

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Thank You and Best To All

Want to try the Silver Tip epoxy, not sure why... REALLY dislike the 2:1 mixing ratio versus 1:1 of ZPoxy as I do not have small enough measuring cups to not waste a lot of material. Need to Amazon some mixing cups.

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Thank You and Best To All

I use syringes for epoxy mixing all the time - even small quantities like 2ml and 1ml are very easy to measure and dispense. Plastic ones can even be cleaned with alcohol and re-used.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Great suggestion and I think I have some around as well....

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Thank You and Best To All

Sometimes I use syringes, but more often I use a triple beam balance and mix by weight. I use epoxy pore fill for laminated work because I laminate with epoxy and it blends in with the bleed through areas. I will spread epoxy with a plastic "handle" from a cheap foam brush, but squeegee off the excess, wiping the squeegee after every stroke.

Anyone tried this stuff?

https://www.youtube.com/watch?v=405f5bAFVx0

https://www.solarez.com/product/grain-s ... t-lacquer/

I've used Solarez additive for my polyester resins and surf boards building, but not this specific product whic looks to be a different formulation with low VOC's etc.

Very fast obviously and easy to work with - out of the sun - but have no experience...

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Thank You and Best To All

Another good idea. Thanks...

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Thank You and Best To All

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Thank You and Best To All

For people who find epoxy a mess, isopropol alcohol or denatured alcohol are wonderful solvents for un-cured epoxy, making clean-up simple and effective. A decent squeegee and timely removal of the excess before it get its too viscous and epoxy presented no problems for me. With an alcohol wet pad, you might even be able to French polish the epoxy while it is viscous before it cures (not sure if that would interfere with proper curing). I use the System 3 epoxy and you can buy different formulations with different cure times...the stuff I have has an open time of around 15 minutes so you can do the entire back in one shot.

Although people develop sensitivity to epoxy, wearing your respirator prevents this, and is a thousand times less irritating than pore filling with cyanoacrylate where I would wear a full face respirator to prevent eye irritation in addition to respiratory protection!

My experience with pigment based grain fillers is that they dry so quickly that it is hard to wipe on/wipe off in time, resulting in the need for tiresome sanding to remove excess material from the surface of the wood. With these grain fillers I fill about 1/4 of the back before having to start wiping off before it starts to set.

Also, although epoxy has it's health hazards, one of the clear grain fillers I bought stated that it was a teratogen on the MSDS (so if you're looking to become a parent in the near future, it might not be a good choice).

It looks good and I know people are successful with it but this post from Hesh has me concerned:



Isn't one of the golden rules of finishing not to have a soft finish under a harder one? Or maybe it's the other way round I always do get things backwards. Of course sanding back to wood would not cause that problem.

For mixing cups, maybe these would work for you: https://www.amazon.com/gp/product/B0008G1YGA/ref=ppx_yo_dt_b_asin_title_o03__o00_s00?ie=UTF8&psc=1

The smallest gradations on each cup are 1/2 tsp, 2.5 ml, and 1/8 fl oz. Those increments have worked well for me.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

When you leave a thin layer on the surface to "pop" the grain it is very thin. really just enough to soak into the exposed wood fibers a wet them out. At least that's how I do it. I don't try to leave a thin film and then cover any areas of sand through, I sand it back then wet the wood with thinned epoxy. I don't think there is enough on the surface to cause any problems form a "fat over lean" perspective. I think of it like sealing with shellac before finishing with something harder. That said, I have only used French polish over z-poxy and that is not super hard. . .

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Thanks Jay, they are on the way.... I ordered the 2 oz version a couple minutes ago...

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Thank You and Best To All

I use a small digital scale with an accuracy to .001 of an ounce. I can accurately measure very small quantities of epoxy.

I've got a digital scale as well but be aware that not all volume and weight ratios are equal. I have some surfboard epoxy that's 2:1 by volume but not 2:1 by weight.

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Thank You and Best To All

I keep a paper towel wet with alcohol to wipe the gloves if needed as I work so mess is minimal.

I scrape the surface before sanding which quickly levels any ridges. I apply with my gloved hand/fingers on all surfaces I found that it works as well as squeegee application.

I also started with Z poxy but on the advice of several people changed over to West systems I had some shrink back into the pores with it so after 3 or 4 guitars switched.

As for bleeding with oily woods I have no problems even with Cocobolo

Fred

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

I'm curious, how does one determine that an owner has acidic perspiration? As a former biologist, I'm picturing socially awkward sample collection followed by pH measurements.

Seriously though, is there a definitive physical indicator that proves acidic perspiration in a given situation? Accelerated corrosion on metal hardware maybe?

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I guess I'm the odd man out here, but I use dyed joint compound...

Works for me.

We actually test pH at various locations on the customer's body as part of the commissioning process, as well as any person he or she believes might come in contact with the instrument over prolonged periods of time.

But seriously, we asked and were told...I assume it must have come up at some time in their lives re: consulting a medical professional. Sweat varies from a moderately acidic 4.5 to a neutral 7.0, and can vary by location on the body. Of course women glow after exercise, versus perspire, so really just a male issue.

One of the gentlemen in the shop offered this helpful answer:

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A constellation only takes shape when one maps the whole.
- Beth Brower

The slight acidity of the skin is part of the defence mechanism and is known as the acid mantle layer. Not that I'm a medic or dermatologist by any stretch.
I was just doing a bit of research on why it is that some folk seem to strip a finish in a matter of months - I've had a client who did just that, quite shocking to see. I myself can play a French polished guitar for years and there's very little effect. Mild acids (like vinegar) don't seem to have any effect on shellac but of course we know that alkaline solutions dissolve it - hence why you can wash out French polishing cloths in a strong bleach solution. I don't know if human sweat can become alkaline - in certain people. If it does that would account for the rapid wear but I need to get hold of some dermatologists to confirm that sweat can indeed be alkaline. The other thought I had was that laundry detergent and insufficient rinsing might explain it but that might be clutching at straws.