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Etex set hard in 10 minutes
39 replies to this topic
Posted 10 July 2008 - 10:44 PM
I have been useing etex for a long time with almost no trouble. I tryed putting some polyester glitter in my final coat the other night. I may have added to much because when I did I guess it caused a chemical reaction of some kind. The cup I mixed it in became so hot I had to put it down. Then in about ten minutes it was ruined. It set hard in 30 minutes. Has anyone here had this happen before? I have used this glitter before with no problems in less amounts. I was going for a heavy glittered bait and I got a mess instead.........Oscar
Posted 11 July 2008 - 08:49 AM
I'd love to know why that happened.
Try emailing the Etex tech support people. Last time I had a question about their epoxy, the woman who replied was both knowledgeable and helpful.
Posted 11 July 2008 - 10:53 AM
i've had e-tex go off quick but on that occasion i'd warmed it up to much before mixing which seemed to accelerate the curing process so now i very rarely bother to warm it
Posted 11 July 2008 - 12:17 PM
That makes sense. It's a chemical reaction, so heat should speed it up.
Maybe a double boiler ice bath will extend it's working time in the summer.
Posted 11 July 2008 - 12:54 PM
Oscar, sounds like you found a quick cure polyester hardener for Etex. I'm guessing the Etex solvent broke down some of the glitter and did just that. Epoxy generates heat while curing. The larger the epoxy mass, the more heat is retained and the faster the cure. That's why spreading epoxy on a flat surface extends its work time - the greater surface area allows the heat to radiate off faster, slowing the cure.
Posted 11 July 2008 - 01:11 PM
Ah, so deska! Thank you, Sensei. I'll be spreading my Etex onto a flat, taped surface from now on.
Posted 12 July 2008 - 12:11 PM
If you get it too warm this will happen. Take some etex and put it in the micro for 20 seconds, pull it out and you will have a diamond! lol
Posted 12 July 2008 - 12:14 PM
Exactly the same here. Too many mins in the micro and voila rock hard.
Posted 12 July 2008 - 12:16 PM
Does this mean if I put a drying wheel in a microwave I can finish the top coat in seconds rather than 24hrs+ ???
Posted 12 July 2008 - 11:03 PM
You may have let the etex sit in your mixing cup for too long. If you let it sit still in the cup for 5 min without mixing then it will harden immediately. Etex must breathe in order to slow curing time. Not too sure if it was the glitter?
Posted 15 July 2008 - 08:40 AM
That's interesting, and not my experience.
I usually mix my Etex, and then let it sit for five minutes to be sure both components have mixed thoroughly, and that most of the air bubbles are gone. I've never had it set up in the mixing cup, but I've had to hit it with a hair dryer during the coating process, if I'm doing multiple lures, because it did start to get a little stiff.
Maybe there are other variables at work?
Posted 15 July 2008 - 12:48 PM
Maybe you are right? It may be 10 minutes before it started to sit. I left my etex in the mixing cup untouched for about 10min and it hardened immediately...didn't know why but I haven't chanced it since. Maybe it is the mixing cup I was using. I use polyester glitter too and have never had a problem. Weird deal...
Posted 15 July 2008 - 12:56 PM
I don't think I've knowingly used polyester glitter, but that may be what's in the Krylon spray glitter that I use. I've just never had a problem, at least not so far! Knock on wood.
Posted 15 July 2008 - 01:50 PM
I think now it wasn't the glitter. I have done some baits with it since and not had any trouble. When it done blew up on me I had a full cup for doing a bunch of baits. I think the amount had more to do with it. It could not breath the way it should. I think I will only mix small batchs from now on. I like to fill up my drying wheel when I coat them. I guess I should have made my wheel hold ten baits instead of twenty.
Thanks for all your opinions. I know where to go for good informed answers. :worship:You guys are great. I really appricate all the help.....Oscar
Posted 15 July 2008 - 02:10 PM
Twenty baits! Man, you are ambitious!
I only mix up enough to do four or five jointed lures at a time.
Here's something I thought of when BobP mentioned that heat sets off epoxy.
I know from personal experience that the epoxy cures more slowly in colder weather. In the winter, I use a hair dryer to make my Etex flow more easily.
You might try putting ice cubes and a little water in a larger dish, and setting the epoxy mixing cup into the ice water, to slow down the rate at which it goes off, while you're coating that many lures, to give you more working time.
If it's too stiff, you can hit it with a hair dryer once it's on the lure, to soften it up and make it more spreadable. The ice bath should keep the mixing cup stuff from going off while you're using the HD and brushing out the lures.
Try it once with a small batch to see if it works first. I've never done it myself.
Posted 16 July 2008 - 04:45 PM
I've been formulating paint and coatings for about 15 years. I can guarantee you that ployester flakes are fine. I've used automotive effect pigments cast on polyester films in 2 component epoxies and urethanes, and never seen a reaction. Theoretically and chemically, it's almost impossible.
Honestly, from your description of the heat generated, it wasn't the amount you mixed either. Though, I probably would mix less, as recommended. My theory is that the part A wasn't mixed thoroughly by the manufacturer and you got a shot with excessive accelerator in it. There's an additive we put in the part A of epoxies which controls how fast it cures/reacts. I can make it cure in 10 secomds if I want, or leave it out and it takes hours. It's used in such miniscule amounts, that if not mixed in properly, it can have the same effects you experienced. And when it's used in higher percentages, it does generat tremendous heat. I've melted polyethylene mixing cups when I made a super-fast set epoxy sealant.
Posted 16 July 2008 - 09:00 PM
Thanks for the info downriver. That may be what happened. I use polyethylene cups for mixing and it didn't melt but it was close to it. I have been using the same bottles of etex with no more problems....Oscar
Posted 17 July 2008 - 08:14 AM
Do you think the accelerator might separate out if it's stored in the heat, like my hot garage?
I now mix my Etex on flat masking tape on my work bench, so I can match the sized of the blobs of resin and catalyst before I start mixing. The more I want to mix up, the wider the tape section I lay out before I start. Masking tape is cheap and easy to peel off and throw away when I'm done, and that way I don't have any unmixed areas, like can happen in the bottom of mixing containers.
I tend to mix really thoroughly, and then let it sit for a few minutes before I start coating. I don't think mixing would make up for a bad batch with too much accelerator, but I've had spots that didn't set up before, and I think it was becuase I didn't mix it enough.
Are Envirotex and Devcon 2 Ton different kinds of epoxy? BobP posted that D2T is sold as a glue, and I know Etex is sold as a bar top coating, so I just wondered if they were different in their chemical makeup.
Posted 17 July 2008 - 12:54 PM
You said you have worked with wood all your life.
If you use masking tape to poor the 2 epoxy components on, for a perfect 50/50% mixing, that's OK, but then it is difficult to mix them on a flat surface.
I would make a kind of hole into a piece of wood, with the shape of, let's say, one third of a sphere, then after having the right quantities on the piece of masking tape, I would transfer that piece onto the hole, for a better and easier mixing.
Posted 17 July 2008 - 05:10 PM
Very, very doubtful that it would separate.
Both are what's called Bis-A epoxies. Most on the market are. Where epoxies differ is the harness, elongation %, UV resistance, and tensile strength. Devcon is "junk" epoxy, used for glues. Very hard and virtually no UV resistence. It will chalk and yellow in no time. I couldn't find technical data on the Etex, but I'd guess it's not quite as hard with some UV resistance from the resin itself. Their MSDS makes no mention of inhibitors, so it will probably yellow fairly quickly also. I'd never use the Devcon on a lure. Never tried it, but Etex looks OK. My only concern would be for balsa lures and it cracking over time, and yellowing.