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Last month the Seattle Luthiers hosted John Greven a luthier in Portland. He described his pore fill method so I decided to try his recommended product. The epoxy he uses is System 3 SilverTip Epoxy with the fast hardener. He liked it because it was clear, it goes on easily is made to work on bare wood and wets the wood well. This is mostly a boat building epoxy. The other item he recommended was getting a box of blank credit cards to use as a scraper.
White Blank PVC Plastic Cards. I got 100 for less than $13 at amazon https://www.amazon.com/gp/product/B007M413BC.



I applied a little at a time and used the card to apply and then squeegee most of it off. With the fast hardener I will sand most of it off this afternoon and reapply. I always use the first application of epoxy to find areas that need more prep because it shows up flaws just like a finish.
I am surprised that I am really liking how the Osage Orange looks. Also I am told that it darkens with age.



Day 2

The epoxy seems fully cured in about five hours. So you can apply multiple coats in a day. The instructions say you have a 20 minute working time with the fast hardener which is plenty for me.

With this epoxy I wanted to try a new process for me where I come out of the pore fill with completely level surfaces and any required drop fills dealt with. I have gotten late into the finish process on guitars and have sanded through the finish, pore fill and\or the seal coat to wood when leveling the final finish. I am trying to avoid that.

So far the system 3 silverTip is easy to work with, it is clear not as thick as zpoxy, it does not seem to foam and I can leave on a very thin wetted coat.

This morning I leveled the finish with many sand throughs, checked for low areas. found a few places to drop fill and applied a second coat of epoxy.





About five hours later I used a sharp scraper and a razor blade to level the cured second coat. I found a couple of missed drop fills, which I fixed with gluboost this fit and finish CA and applied what I hope is my final coat of epoxy. I plan to repeat the above until I have a perfect coat as there is no harm at this point in the process of sanding through.

After I leveled th epoxy


with a fresh coat.


Day 3

Just to close this off using a utility blade and a scraper I scraped most of the epoxy off. I was close but still had a low spot in one of the sides, and there were a couple of places I sanded down on the back as I saw some scratches through the finish.

In any case I put one more very thin layer of epoxy down (I spread an amount about the size of a quarter across the entire back and use one of the plastic cards to scrap most of that off.)

About five hours later, I scraped a couple ridges and drips toward the edges off with a utility blade (it just peels off in a very even ribbon).

After I had it level to my eyes I used a 800P Wet and Dry paper with mineral spirits as a lubricant. Here were the results after wet sanding



I put on 3 or 4 wipes of diluted Seal Coat (really 1 lb shellac) and called the pore fill on the body done.



To close I could of done this in a long day (2 or 3 applications) if I had properly prepared the body for finish. I have a hard time seeing all the flaws even with a naptha wipe. They do show up after wet sanding the epoxy though.

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http://www.Harvestmoonguitars.com

I used their SB112 with fumed silica as a pore fill when I first started out.Epoxy is a great pore fill though a bit messy.

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Brian

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

https://www.howardguitarsdelaware.com/

I’ve used their Clear Coat, but it takes forever to cure and is very finicky about mix ratio. I had to use a digital scale.

How did you measure out the 2:1 by volume? Were you able to mix small batches by volume?


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I got a little scale packaged with west system pumps. I seen the same scale rebranded elsewhere. You can see it in the picture below. I mix 10 grams of epoxy and add hardener till I get 14.4 grams. By weight it is 44 parts hardener per 100 resin. I used the fast hardener and it is very hard in 5 hours and it has a 20 minute working time.

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http://www.Harvestmoonguitars.com

Great write up John, it is much appreciated.

I also like System Three. I've been leaning toward their Clear Coat of late

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Joe Beaver
Maker of Sawdust

I'm using a scale that measures to a 100th of a gram. I regularly mix 2-3 grams at a time with no problems.

With Clear Coat I have had good luck measuring and mixing in calibrated plastic measuring cups. No problems.

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Joe Beaver
Maker of Sawdust

I generally hate mix ratios that are not 1:1. The West Sys epoxy is especially challenging for me. I use a digital scale and go by weight and have never had a problem with small or large batches. I've mostly used RAKA epoxy when building boats or surfboards. And used it once for pore filling with good results. Great epoxy at a great price. No blush and you can mix the slow and fast hardeners to get the working time you like. I've heard good things about the Silvertip, but have not used it. I'm currently trying ZPoxy for the first time. Expensive! But it seems to be working as advertised.

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Tony Thatcher
Bozeman, Montana

Careful with developing sensitivity to any epoxy. I did with Zpoxy. I wish I could still use it cause I loved it.

We usually find 20 grams (about 1/3 of a stroke on each pump of the System 3 kit) is good for the initial coat on mahogany and 12 grams for subsequent. Because we never mix even a full stroke's worth of epoxy, the precision gram scale gets used (0.00g), with the pumps there simply to avoid the issues with pouring.

I'm doing a filling and finishing intensive this week with the boss and Mr. Morelli, so on my second round of fills for 6 bodies and 7 necks...getting the hang of a thin coat and no swirl marks! Lots of debate on thick versus thin coats and degree of prep...reinforcing the notion that that best way to get a half dozen different opinions on some topic is to put two luthiers in a shop and have them work on just one thing.

We are using mostly slow hardener (which still cures overnight), but one nice thing about System 3's Silvertip epoxy system is that the fast and slow hardeners may be mixed for a tailored cure time, which gives us a small batch that can still get a full coat on a body or a few necks at a time, provided the 100:44 mix-by-weight ratio of resin and hardener is observed.

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For the times they are a changin'

- Bob Dylan