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View Full Version : Need Help With West Sys Epoxy



ssmith007
08-02-2002, 08:06 AM
I'm restoring a 1972 Sidewinder. While attempting to install a new stringer, I removed the old rotted one which left a channel approx. 1/4" deep and 1&1/2" wide, I mixed about a quart of epoxy (slow catalyst) and added the thickening agent. Then I filled the channel with the epoxy mixture, grabbed the stringer and tried to put it in the channel (maybe 20 mins. from start of mixing). the stringer wouldn't go in as the epoxy had started to gel already, kinda like rubber. Of course I grabbed a putty knife really quick and scraped the epoxy out. It was really hot. I put it back in the mixing bucket and it steamed a little and hardened in about an hour. I thought I'd have at least an hour's working time. I never imagined that it would start to set up that fast. It was about 90 deg. F and I was in my garage. Luckily except for wasting some epoxy I didn't create much aditional work for myself. A friend suggested mixing 4 - 1/4 quart batches individually and applying each to the channel individually. WHAT DID I DO WRONG AND WHAT SHOULD I DO TO DO IT PROPERLY THIS TIME ? Thanks in advance. Smitty

vector mike
08-02-2002, 08:34 AM
I'm not that familar with the West Systems stuff since all I ever use is fiberglass resin . I don't know if you are familar with it but the resin will set in just a couple of minutes depending on how much hardner you use and how hot it is outside. Yes it does get very hot when curing.

pyro
08-02-2002, 03:55 PM
West epoxy resin mixes 5 parts of resin to 1 part hardener. You can't mix the stuff 1:1, sounds like that may have happened(?)
Mix it 5:1. Do not use any other ratios.

My experiences with West resin are as follows:
On one occasion, I used some resin 5:1 with slow hardener at 68-70 degrees F. It took 2 days for the resin to harden. above 75 degrees, it should harden in 4-12 hours. I also tried to use some resin with fast hardener in 90 degree heat, BAD IDEA. Within 5 min., it was smoking like hell and hardening! Use the application chart on the back of the jug. Be sure your surfaces have been scraped clean and wiped with Acetone before you try to use epoxy resin on them. Have fun!

crazy horse
08-02-2002, 06:54 PM
You should read the free info that west system has. 90 degrees is kinda warm even for the slow set, If you mix up that much you should put it in a flat pan and keep it cool while you are working with it. The free info has most of the info that you will need to use west system epoxy. I've been useing it for years and it is VERY controlable in most cases.

baddjonny
08-02-2002, 07:06 PM
don't we all , but try using two buckets a big one with ice water the other with resin put resin bucket in ice water that will at least give you a chance at 90* I'm reglassing a floor on my checkmate using standard resin using half the hardener you use at 65* still hardening in 15-20 min. this hot weather is a bitch.

jon b

Techno
08-02-2002, 08:12 PM
all this catylized stuff reacts by heat. It generates it itself so when you mix large amounts it generates a large amount of heat.

If you need much more than a few ounces - maybe 2-3 strokes of the pump then mix it, use it and mix more. Once spread out its life is much longer. You can also use large pans instead of small pots. Getting the resin spread out rather than confined slows the reaction down. In 90* try to keep down on the amount and spread it where you need it. You can mix more and keep going. Its when you have to add thickener that you run the risk of taking too long.

Small amounts, spread out on the part, larger containers- more like cookie sheets, and the slow hardener.

You also don't have to fill the slot. Just butter the slot or board and put it in. If you fill the slot you'll have to force all the excess out of the way to put it back in place.

With the filler stuff keep both parts of the resin cold and mix small amounts. Don't take a long time mixing the filler into the already mixed epoxy.

Wile E. Coyote
08-03-2002, 06:42 AM
What Techno said..., in adittion, epoxies are VERY sensetive to mix ratio. the ratio given is not a suggestion it must be followed as close a possible. If you mix too much catalyst you get what happened to you, not enough catalyst and it will NEVER harden. Good luck

Techno
08-04-2002, 01:47 PM
What you should do is paint the wood stringer with some epoxy before you put it in. You get a lot of advantages from doing it this way. Practice and experience with the epoxy. The wood is sealed. The wood will absorb epoxy anyway, by pre-sealing it it won't take as much later.
After it cures then bond it in.

The other thing with the channel is I don't think you need to use thickend epoxy. If its something where you can put a small amount in with out it running out, and then stick the stringer in then it will be bonded. The epoxy will displace and coat the stringer. A 1/4" deep channel shouldn't take a gallon of resin

If you don't already have the pumps- get them! It makes it clean to work with and easy to measure. 1 pump of the resin and 1 of hardener, want more then 3 pumps and 3 pumps. Its automatic measureing.

ssmith007
08-04-2002, 04:55 PM
Just want to let everyone know that I got the stringer in Sat. morning. Thanks for the suggestions. They all helped. I had a friend help me this time. We started about 8 AM before it got to hot. He mixed up small batches and I spread it in the channel. It still set up way faster than the container said it would. I did use the pumps both times. I would do a couple things different next time. I might try putting the resin in the refrig overnight. I'd definately have a friend help, that and having a plan really helped. You guys were right on when you said to keep moving with epoxy in high temps. I still can't believe how fast the stuff set up in the heat ! Non experienced guys like me, be forwarned, it sets up far faster than you think. Well gonna go to the garage and work a while tonight. A HUGE THANK YOU TO ALL WHO REPLIED. I hope I can return the favor some time. Smitty P.S. ain't it funny how a stringer installed in the middle of a 30 year old bare hull can look BEAUTIFUL. LOL

ssmith007
08-05-2002, 07:40 AM
Thanks Techno and everyone for your advice. You were right on. I'd just like to add that I think West Sys is an excellent product. The problem I was having was due to lack of experience. I think you all knew that, but I just wanted to be sure you all knew I wasn't blaming the product. It's excellent. Gotta go sand a while. Smitty