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I put a seal coat on the sides and belly the other day; a very thin coat with a free AARP card. Scraped it smooth yesterday, (I changed the angle on my scraper, a plane blade, to 12 degrees the other day, and they work really well now) then sanded, and put a coat on to fill in some low spots. I want SOME grain on the belly, its supposed to be an arch top by Guadagnini in 1770 or so; but I don't want it to look like a washboard.

This morning it looks really good, finish does wonders; it has some spots that I might spot fill with the Z poxy, but it feels somewhat; very slightly sticky; not wet, just not slippery; is some thicker spots. It isn't really sticky, more like just not absolutely slippery. I'm not sure that the mix was perfect.

I weighed it out on a gram scale I got at Harbor Freight. Someone here said it was the only thing he'll buy there.

I wouldn't buy it. I guess that's why they call it horror freight. It will not always work as you are squirting resin in the container on the scale.

I squirted out one gram, then grabbed the next bottle and started another pile. About 3/4 even it said 1.7grams. Cool. I got them about even and it still said 1.7 grams. The scale does not like adding things in. I lifted the plastic I had it in, but it back down. 1.6 grams. I added some more of the resin to 1.8, then it looked like too much so I added more hardener to 2.0 grams. They looked pretty even.

Was the mix a little short on hardener? Will it still work? Can you brush on a thinned coat of properly mixed Z poxy over it, to boost it? Will it just take 24 hours or so to harden if it was a little too resin rich? I have no idea.

If the scale was accurate, I wouldn't be so unsure. It couldn't have been that far off. Could it?

I had a little scale from International Violin for years, but I broke it somehow. I'll order another. Among other things, I used to weigh out HHG and water, and it never did that to me. The description says 1000 gram, but the photo says 500g. I only use it for small things. I can even weigh a guitar on my other scale, it just doesn't have a .1g accuracy.

The horror freight one doesn't either.

https://www.internationalviolin.com/Pro ... m-capacity

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Why be normal?

I mix zpoxy by eye and have had no problem with drying at all.

I had an issue with z-poxy once where it took forever to cure and it was because my basement was on the cooler side (60-65). Once I moved it upstairs into the 70 degree heat it cured up. Is is possible its too cool?

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yah, I've noticed mine is a little sticky sometimes. It really makes sanding down a pain. I usually just wait another day or two for it to cure and it turns out ok.

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-Marcus
http://www.bailieguitars.com
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If the epoxy has cured, but has a sticky film, I believe that is amines sitting on the surface. It's a byproduct of the curing process and can wreak havoc on the finish, in my experience. It's caused by incomplete curing, old product, excess humidity, temperature too low. It can be removed with water. When left on the surface, it can contaminate the wood during sanding if you snd through, and not be a problem for months, when the pores erupt, leaving small bumps. It's happened to me on two guitars. Since switching to Devcon 5-minute, I've not seen the problem.

edit: amines, not bromines

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formerly known around here as burbank
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http://www.patfosterguitars.com

I use small syringes to measure, cheap as chips. I wash with alcohol and re-use.
Under poor conditions (humid)you can get amine blush which I believe can be washed off with soap and water.
Too cool and it won't set.

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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.

I'll bring it upstairs, or put it in the light box for some heat. My basement is never warm. I don't have air, and the upstairs is hardly ever warm! Global warming? I don't think so, Not here.

It did set hard the first time,

edit, We were out for a while, and it feels better already. Just a slower cure.

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Why be normal?

For mixing z-poxy, I use these graduated disposable medicine cups. I typically mix a total of 1 tsp at a time using the markings on the side. I mix it thoroughly by stirring and then apply as you describe using a card. https://www.amazon.com/gp/product/B0008G1YGA/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

The box that the z-poxy finishing resin comes in includes a small yellow paper insert that says to apply it only at temperatures above 69 degrees. The one time I've had a problem with z-poxy was when I applied it when the room temp was in the 60s. I sanded it all off, raised the room temp to over 70, and reapplied and it worked fine.

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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

Thanks Jay.

Who reads the instructions? My basement is never 70 degrees, and the house isn't even that from October through April. Guess it's a summertime thing. Those cups look easy enough, and will help the mix.

I think this coat will be fine, It is very thin; less than 2 grams for the sides and belly. I have it over the heat register now.

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Why be normal?

I just had this issue w zpoxy. I ended up scraping / sanding it off and reapplying. It only happened when I mixed very small batches. I think my measuring cups weren’t accurate (or are harder to read) at small batch sizes.
For the most part though it’s normally easy to do by eye... w no issues


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I've had many years' experience with z-poxy. It's a finishing resin, and I've not found any need to wash down the hardened surface to remove anything. And I've used medicine cups exclusively. Put in one component, put in the same volume of the second, and stir for a long time. The resin's a little heavier than the hardener. It's sold by volume, 6 fluid ounces each of resin and hardener. I do wind up with a lot of waste, as any time I mix some up, I want to be sure I've used equal parts. I also keep the mixing cup and inspect the (hopefully) hardened leftover. Nice check on the mix. And the box label is optimistic on set times, I wait overnight.

The stuff ain't West Systems', but it does the job I ask for.

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Peter Havriluk

We’ve never had issues with the 1:1 mix on Z-Poxy, but the blush and body chemistry issues we’ve seen led us to System 3 Silvertip for filling. 100:44 mix by volume, which is easily done with a $15 digital gram scale.

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For the times they are a changin'

- Bob Dylan

This is far different from my homemade varnish. Mine spreads nice with a card, and later with fingers or foam brush, so does the Z poxy, but you only have a few minutes with mine. More time than HHG, but not a leisurely task. It is stickier than the Z poxy, and it stays put. The Z poxy floats around and runs. Very strange.
Mine is only dependent on UV for drying. A day or two in full sun at 10 degrees, and it is hard. Overnight in a Lightbox.

I did my back and neck yesterday, so I can start on my inlay, and I warmed the components up on the heat register. Worked good. Spreads amazingly thin. I laid it on its side facing the heat register, and 3 hours later I checked it, and it was hard and dry. Success!

NOT SO FAST.

This morning I see that the resin ran, even though it was very thin, and the side on the bottom, that I didn't check, is still tacky. I see a few runs on it, and there weren't any runs before; it was really smooth. So you have to keep it level, even with very thin coats. Maybe I'll buy a heat gun, and zap it for a while to get it hot.

It's a different animal altogether. Another new technique that I have to learn. I have a hard time with anything slow!

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Why be normal?

I noticed you said you weigh the components for equal part mixing.....
I’m sure someone else can chime in on this, and I may be thinking about it wrong, but with ZPoxy you’ve got to mix according to volume and not weight. I’m not sure the 2 components actually WEIGH the same. I do know that the hardening liquid is more dense per volume than the resin because it sinks through it when you pour it on top. It seems you’d end up with not enough hardener if you go by weight, and that would cause your drying issues.
So make sure you’re measuring it out by volume and not weight.
Hopefully I’m not completely wrong here.


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That's why I stick with syringes for measuring.

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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.

Equal parts by volume per the instructions, with a fair amount of allowable error - close to 10% - having little in the way of impact on cure from what we saw while using it. Z-Poxy resin is about 15% denser than the hardener, so mix by weight would likely be outside the sort of error in volumes we see on small batch mixes. The resin density may be lower due to the lower density fillers added to bring the mix to a 1:1 volumetric ratio.

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For the times they are a changin'

- Bob Dylan

Right! I feel like if the op is using a scale like w other epoxy mixes he could be getting a bad mix this causing his issues


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I guess a person could weigh equal volumes of resin and hardener, then derive how to mix a precise ratio using weight. Or, just use mixing cups that allow you to pour one component up to a line, then add in the other component up to the 2X line. Without a weight ratio recommendation from the manufacturer, it is probably smarter to stick with volume.

I ended up going by eye. Two 1 gram drops are easy enough to judge. I wish it wasn't so runny. Other than that, it worked great.

Maybe the scale not working properly saved me some grief.

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Why be normal?

I don’t understand.
Be thinking in mills and not grams. Mixing ZPoxy is a volume thing and has nothing to do with weight


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I think he means he just poured two similar sized puddles and went for it. That's what I do these days. I also was tried to use a scale before being told it was by volume. Now I do two quarter sized lumps on a paper plate. Mix and serve.

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Like Brad said. Maybe nickel sized. Before they spread.

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Why be normal?

My experience with Zpoxy is limited, but repeated with two packs. It is mixed 1:1: volume and is supposed to be quite tolerant of imprecise measurement. That was also my experience — two puddles each the size of a quarter, applied around 20°C, easily sandable the next morning. No problems there.

My issue with Zpoxy was its pore filling efficiency and stability under top coats. After a year, pores that had been filled before top coating , sunk. Truoil (as I used to use on necks) on Zpoxy leads to a fuzzy neck unless it is very well sealed with shellac. Lacquer films direct over Zpoxy failed after 2-3 years of use.

I abandoned it and switched to West System 105/207. Slower to set and more finicky to mix, but I use glass syringes, cleaned afterwards with DNA (thanks Joe White for that recommendation). After several years, no issues with sunken pores, finishes stay where they’re put.

I’m amazed that so many have better experiences with Zpoxy, but I ain’t goin’ back to it.


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I don't use z-poxy that often these days but it seems to me it is 1:1. If you went with 1:.75 I would think it would have trouble hardening.

I use a shot glass type measuring cup. It works quite well.

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Joe Beaver
Maker of Sawdust

I used the Z-poxy as a mastic on my inlay around the edge last night. I found some little metal cans I have that hold a little over 12ml. I put two measures of water into a plastic glue syringe, and squirted it into the inlay to see if it was enough. It seemed like it was, so I dried it all off, set the box of resin and hardener on the heat register, and warmed the edge up with a heat gun I just bought. Level 3 worked good.

I mixed up one can of each, with some blue pigment mixed into the clear; mixed them together (it turned purple, the hardener is red), and poured into the syringe. It worked really well. Some run-overs in a couple of spots, but I got pretty uniform coverage. When done, I went around it for 15 minutes or so with the heat gun again.

I'll do the belly today. Then I have to scrape and sand things down (I think I'll wait at least a few days on that), fill in more spots, and then it will be ready for varnish.

It isn't perfect, but at least it's getting done!

Ken

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Why be normal?