I am using West System resin to glass my boat.
I have mixed it one to five as per instructions.
The glass on the boat is still wet and before I had time to do the other half, the resin went off.
Ie...smoke, very hot and then solid.
What am I doing wrong?
I can only think that the resin container is too smaller volume.
Ie. To use a flatter saucer/ dish?
But I dont understand this as I had success before with the same mixture.
Ant help appreciated.
Pete

Air temp. affects curing speed, as does "which" catalyst you are using. How much resin, and the container, do have an effect also.
I also use their "pump system", so I get exactly the right mix, every time.

The best answer I have at the moment.

Ant Help!!!
Oh dear how funny.
Capt CB thanks.
I did use the pictured measuring jug.
Its happened twice now.
The day here was not abnormally hot.
I can only put it down to the fact that there was a lot of resin consolidated in a too smaller vessel and it didnt like it.
The lay up stayed wet for several hours so there is my clue.
It has gone off nicely now.

I will do the next mix in a much larger flatter thing like an old soup plate and report on my findings.
Pete

Try chilling it in the fridge first for a slower chemical reaction time?

Are you using the right size pumps?
Sounds like way to much Hardner in the mix.
West system is a 24 hour cure type of product.

I save microwave meal trays, after mixing the resin in a cup pour the resin into the trays,, the increased surface doesn't let the resin heat as fast,, gives you a longer working time..

Are you absolutely sure that you are using a mix that is both correctly proportioned and consistent between mixes? Measuring jugs can be very inaccurate.

I use jewellers scales accurate to 0.1gramme . Cheaply available from Amazon, Bangood, eBay etc.

I use the west systems pump system, 1 pump resin, 1 pump hardener, ect. Stir in the west system mixing container and then put in a frisby. Use a 4 inch roller and disposable brush. The mixing cup and frisby can be flexed after the resin hardens to remove it and reuse both. The west systems products I use are the type not used on chris craft boats but boats that will be painted. The cans are in my garage, I ll get the numbers later. Resin is 105, the hardener is 206. I glassed a 6 ft 6 in cruise ship hull, many coats, sanding inbetween each, and a 48 in. Towboat hull. I agree the aluminum foil idea would be helpfull but not necessary.
Bob

Epoxies are exothermic - they give off heat as they cure. When Pete applied the epoxy to the glass on his hull, the larger surface area of the hull let the heat out of the epoxy easily. The heat generated by the epoxy still in the cup didn't have an easy route out so just added to heat in the cup. Real soon a smoking hockey puck was created. Any time you get a smoking epoxy cup, get it outside and away from your lungs! Holding a container of mixed epoxy in your hand (should have gloves on), adds heat to the mixture, too. When I want to hold a container of mixed epoxy in my hand while applying to an object, I'll stack two or three cups before mixing to help insulate my hand heat from the mixed epoxy. If I can tell the epoxy is getting warm, I've screwed up and need to get that container outside.
To avoid smoke outs, either mix smaller amounts or get the mixed epoxy into a container that allows a lot of surface area to minimize heat retention. Any large, flat, plate-like container works well. Lay on a piece of aluminum foil, pour in the mixed epoxy, spread, then save any remaining mix until the next day. If the epoxy in your aluminum-lined pan has cured, the rest of the spread epoxy should also be cured. Good luck.

Originally Posted by crashprune

Epoxies are exothermic - they give off heat as they cure. When Pete applied the epoxy to the glass on his hull, the larger surface area of the hull let the heat out of the epoxy easily. The heat generated by the epoxy still in the cup didn't have an easy route out so just added to heat in the cup. Real soon a smoking hockey puck was created. Any time you get a smoking epoxy cup, get it outside and away from your lungs! Holding a container of mixed epoxy in your hand (should have gloves on), adds heat to the mixture, too. When I want to hold a container of mixed epoxy in my hand while applying to an object, I'll stack two or three cups before mixing to help insulate my hand heat from the mixed epoxy. If I can tell the epoxy is getting warm, I've screwed up and need to get that container outside.
To avoid smoke outs, either mix smaller amounts or get the mixed epoxy into a container that allows a lot of surface area to minimize heat retention. Any large, flat, plate-like container works well. Lay on a piece of aluminum foil, pour in the mixed epoxy, spread, then save any remaining mix until the next day. If the epoxy in your aluminum-lined pan has cured, the rest of the spread epoxy should also be cured. Good luck.

That just about sums it up EXOTHERMIC.
I was really pondering over this and came to the same conclusion.
Varification of the correct mix is accurate as the lay up on the boat hull took the correct time to cure Ie several hours.
The resin in the small pot as said, went off in 10 to 15 minutes, smoked, went hot and then rock hard.
I did all my glassing outside.
The only difference between the resin laid on the hull and the resin in the cup is that the surface area of the layup on the hull was far greater than the surface are of air exposed to the resin in the cup.
So what I thought is.....
The mix needs to be in a fllat vessel of a larger surface area ie a large flat plate or something.
A Frisby as suggested is an excellent idea ....thank you.
I am pleased that after having mulled the idea in my head that I reached the same conclusion as you have.
Thanks very much for your confirmation and a new word for me to learn that describes what went wrong.
Pete

Originally Posted by Robert Pulse

I use the west systems pump system, 1 pump resin, 1 pump hardener, ect. Stir in the west system mixing container and then put in a frisby. Use a 4 inch roller and disposable brush. The mixing cup and frisby can be flexed after the resin hardens to remove it and reuse both. The west systems products I use are the type not used on chris craft boats but boats that will be painted. The cans are in my garage, I ll get the numbers later. Resin is 105, the hardener is 206. I glassed a 6 ft 6 in cruise ship hull, many coats, sanding inbetween each, and a 48 in. Towboat hull. I agree the aluminum foil idea would be helpfull but not necessary.
Bob

Bob thats a nice big boat you have done there.
I have poured the mix into a larger flatter vessel and it was okay.
I messed up and cut the matting too short and made a mess of it.
It was awful so I peeled it all off and cleaned it up with meths ready for another go tomorrow.
My brush wasnt stubby enough. It was an artists flat brush and all I had at the time.
I will get some more brushes.
What type of roller am I looking for?
Rubber?...foam?
Can you explain how you roll it please?
Hope you can answer soon so as I can make a fresh start on the other side.
My West system is 205 and 206 the same as yours.
How many coats?
Pete

Originally Posted by Ol mate

I am using West System resin to glass my boat.
I have mixed it one to five as per instructions.
The glass on the boat is still wet and before I had time to do the other half, the resin went off.
Ie...smoke, very hot and then solid.
What am I doing wrong?
I can only think that the resin container is too smaller volume.
Ie. To use a flatter saucer/ dish?
But I dont understand this as I had success before with the same mixture.
Ant help appreciated.
Pete

I have to ask-could you have accidently mixed the batches at a one part resin to five parts hardener? And yes a tall container will trap heat and kick off much faster...as stated above a low flat container works best-sometimes when I want to work slowly I set the mix container in another container of cracked Ice..it slows the reaction time without harming the strength or finish. Technique works for both epoxy or polyester.

Hi Bob.
Hah ha....its okay to ask the obvious but no I didnt get the mix the wrong way round as said before, the hull lay up took several hours to set.
No worries there.
About the roller?
What type?
Can I make one if its special to role?
Pete

if you look around on youtube there are some very good vids for making surfboards. tools and methods transfer over very well..

Originally Posted by Ol mate

Hi Bob.
Hah ha....its okay to ask the obvious but no I didnt get the mix the wrong way round as said before, the hull lay up took several hours to set.
No worries there.
About the roller?
What type?
Can I make one if its special to role?
Pete

I got the roller at menards it is a yellow handle trim roller and the roller tu bes are very short knap for smooth finish. I had to tell them what I was doing to get their recomendation and it worked great. I was doing it on a warm day so I had to chase a few runs before the resin went off but it wasnt that hard.
Bob