Serious help needed with epoxy

[herocomplex]

I'm building a D5, my first boat-building project, and I feel like I've read every post and how-to that there is on small boat stitch-and-glue. I'm extremely excited and I love this project but the whole epoxy thing is killing me. Seriously, I can't imagine how anyone can possibly use epoxy without it going nuclear in sort of reasonable amount of time. This stuff turns to stone before I can even figure out how to clean up my mistakes.

Full story: http://sagehobbs.com/index.php?option=c ... &Itemid=10

A few questions from a newbie:

• -What is a reasonable sized batch of epoxy for a beginner?
  -Is a 3/4 cup batch really that sensitive?
  -Should I be spreading the epoxy out onto another container after mixing to maximize surface area and minimize heat?
  -Should I even be worrying about gluing in the frames? Perhaps fillets are ok.

[fmiles]

Two questions:
* Have you inadvertently been supplied with RAPID hardner? You can get various 'speeds'.
* Can you use wider mixing pots? I found a source for these, and they are stronger, and can be used many times. Simply allow to cure, and with warm water, peel the unused epoxy out. The small plastic cups you have may be encouraging too much heat build up. I also found you need to be very careful with these cups, they have a coating that dissolves into the solution, and although it might not make any difference with epoxy, it really stuffed up my painting quality (loads of fisheyes)

Its odd the epoxy is kicking so fast.

[rjezuit]

Where are you located? What is the temperature at which you are working? Are you using slow, medium or fast hardener? It should not be kicking that fast if you are using the correct hardener. Rick

[herocomplex]

I am located in Arkansas and it was probably 50 to 55 degrees in my garage. The hardener is the medium speed from Bateau. I wanted to keep things as slow as possible since I have no experience. How long should I expect the reaction to take place under these conditions?

[herocomplex]

Two questions:
* Have you inadvertently been supplied with RAPID hardner? You can get various 'speeds'.
* Can you use wider mixing pots? I found a source for these, and they are stronger, and can be used many times. Simply allow to cure, and with warm water, peel the unused epoxy out. The small plastic cups you have may be encouraging too much heat build up. I also found you need to be very careful with these cups, they have a coating that dissolves into the solution, and although it might not make any difference with epoxy, it really stuffed up my painting quality (loads of fisheyes)

Its odd the epoxy is kicking so fast.

Unless the hardener is mis-labled, it's medium speed. I'll definitely switch to wider containers, these plastic cups are crap. As for a coating that dissolves, hell my entire cup dissolved.

[jacquesmm]

Look here for the cure times.
Those are for a 3 oz. batch.
At 55 degrees, a 6 oz. batch of fast (half a cup) should have a pot life of at least 20 minutes, maybe more.
Medium should be slower.
Even if it was mislabeled, the fast should not kick that fast.


We will test the resin from that batch but I don't think that is the problem.

[jacquesmm]

BTW, what is your name?
Email orders@e-boat.net that way I can track your shipment and test the resin.
We have sold a good amount of medium lately and nobody else reported problems but I still want to check.

We rarely sell fast. It happens so rarely that our warehouse guy does not even label it.
The small amount we have sits on a shelf far away from the slow and medium hardener so there is no possibility of mix up there.

Can you do a test with a 3 oz. batch, write down the temperature and tell us when it begins to gel?

Update: I did read your blog once more and see some problems:
You mixed two cups of resin, used one for glue and let the other one sit there.
Don't. Mix the resin just when you need it.
You installed a frame, had a problem with a bad brush . . . all that takes easily 40 minutes and in that time, the resin waiting for you has cured. That's normal.

Solution: mix only what you need, like 6 oz. at a time.

[herocomplex]

BTW, what is your name?
Email orders@e-boat.net that way I can track your shipment and test the resin.
We have sold a good amount of medium lately and nobody else reported problems but I still want to check.

We rarely sell fast. It happens so rarely that our warehouse guy does not even label it.
The small amount we have sits on a shelf far away from the slow and medium hardener so there is no possibility of mix up there.

Can you do a test with a 3 oz. batch, write down the temperature and tell us when it begins to gel?

Update: I did read your blog once more and see some problems:
You mixed two cups of resin, used one for glue and let the other one sit there.
Don't. Mix the resin just when you need it.
You installed a frame, had a problem with a bad brush . . . all that takes easily 40 minutes and in that time, the resin waiting for you has cured. That's normal.

Solution: mix only what you need, like 6 oz. at a time.

Thanks for the reply Jacques. Like I said, I have no prior experience, so things feel like they happen incredibly fast. I simply have no baseline for comparison for how much time I should expect to have before things go nuclear. It really feels as if the medium hardener, at 55 degrees F, had less than 30 minutes before it was unworkable. My perception of time could have been off due to the stressful situation, though. Also, this was in a plastic dixie cup with little surface area. I'll do a test tonight to get real data. I'm sure that the problem is with my technique...I need to do a bit more research on working with epoxy. As it is, I can't imagine how I could even fiberglass the seams inside a single bulkhead

[chrisobee]

Thanks for the reply Jacques. Like I said, I have no prior experience, so things feel like they happen incredibly fast. I simply have no baseline for comparison for how much time I should expect to have before things go nuclear. It really felt as if the medium hardener, at 55 degrees F, had less than 30 minutes before it was unworkable. My perception of time could have been off due to the stressful situation, though. Also, this was in a plastic dixie cup with little surface area. I'll do a test tonight to get real data. I'm sure that the problem is with my technique...I need to do a bit more research on working with epoxy.

I've done most of the epoxy work on my CV16 using 3oz batches. The smaller the batches the longer the pot life. 20 minutes is probably a resonable expectation for the amount of time that you have to apply the epoxy that you have mixed. The cadence goes someting like this:

1. mix up 3 oz of epoxy and precoat all the surfaces and edges . use any left over on the big surfaces of the panels.
2. mix up 3 oz of epoxy add wood flour to make glue ( catsup consistency ) use anywhere you need glue.
3. Add more wood flour and silica for fillets to the glue that you made earlier to use up an excess glue.
4. mix up 3 oz of epoxy add wood four and silica for fillets. Use left over for filling an gaping divots of which you are not proud.
5. cut fiberglass tape to size for all filleted seams.
6. Set the tape down on the still tacky epoxy precoated seams.
7. mix up 3 oz of epxoy and wet out tape. Smooth the fillets by running your gloved finger down the lenght of the taped and filleted seam. (very gentle pressure)

Work quick, work clean, plan on only doing what you can do in 15 minute blocks.

[jacquesmm]

BTW, use sturdier cups and also, if it feels too fast, you can, as somebody else proposed, spread the mixed resin in a tray.

Keep going with small batches at first, 3 oz, as Chrisobee propose is fine and as you get comfortable, increase the size if needed.

BTW, the cure time in the pot is different from the open time on the part.
Once the epoxy is spread on the part either as glue or fillet, you can work with it for a much longer time.
This means that you can install a bulkhead with 2 or 3 small batches.

Another trick is to put your resin jugs in the fridge but I don;t think that's necessary.
Try the small batches.