Cooling Epoxy and/or Primer slightly?

[Franziska]

Hi,

while I am using epoxy for many years I am faced with the new situation where I need to glue some stuff under hot circumstances.
They announce 30 degrees centigrade and we want to use the good weather to the max.
Material is Sicomin Epoxy, we will glue plywood and fir.

While we have a slow hardener and large shallow mixing pans I am afraid it will be still going off to fast when gluing some big parts.

In winter we successfully warmed epoxy and hardener with a warm air blower.

Now I am considering slightly cooling the epoxy down before use.
Say to 15 - 20 degrees centigrade, to slow the reaction to some degree.
I would use a covered cup for this and put it for 15-20min in the moderately cold fridge and mix afterwards.

Has anyone tried this? Have you cooled both parts or only hardener or epoxy?

And no, unfortunately there is no change of epoxy or hardener possible at this time.

[tkeithlu]

My educated guess is that the exothermic reaction is the important part here, more than ambient temperature. You can slow that process further by applying thin coats. Are you having to cast thick parts?

Oh. You could put a freeze bag or two under your mixing pan - that would slow stuff down until you can get the goo in place and want it to harden. It would also give you better heat transfer than putting the epoxy and hardener in the fridge.

[Bill O]

Originally Posted by tkeithlu

It would also give you better heat transfer than putting the epoxy and hardener in the fridge.

+1 this would slow down the reaction. Would weigh the epoxy and hardener when using hot or cold material rather than using volume to the get the proper ratios. Once mixed could keep it cooled down w/a cold water bath. Especially important if you are mixing large volumes or need to do longer than normal mixing time to add fillers/thickeners.
Obviously if you could start early in the morning when it is the coolest, this would also be helpful.
Wasn't sure which Sicomin Epoxy material you have, but some were specially formulated to perform in tropical climates.

[Pete7]

Wouldn't it be better to put the containers in a water bucket for a couple of hours before starting rather than try to rush the cooling.

Use a swamp cooler, flannel over the top of the containers soaks up the water which evaporates taking heat away from the containers.

Pete

[psk125]

putting your pan of mixed epoxy in a bed of ice might help slow things down a touch. Sort of like clams on the half shell....

[Benz]

Yes. Cooling the epoxy will extend the pot life. Cool both parts before mixing (a fridge is fine), and spread it out fast after mixing.
A small batch spread out will kick off slower than a big batch you can't spread out all at once: in other words, you can mix small batches, trowel them on thinly, and mix more with less danger of losing the initial batches.
Of you start putting pots of epoxy into water, you risk dripping water in your glue-up. Not desirable.

[Franziska]

Thanks everyone,

so after all we will prepare a number of weighed out portions of resin and separate hardener in small cups and place them for a short time in our fridge before use.

Mixing will happen in portions, not all in one.

Mixing will happen in larger dishes reducing exotherm built up.

We always mix by weight :-)

[roverhi]

If you didn't know, West Systems has a slow slow #209 hardener. It gives significantly more working time and slower cure than their so called slow #206 hardener. Wouldn't use it in temps less than 80 degrees unless you REALLY want a slow cure.

Originally Posted by Franziska

Hi,

while I am using epoxy for many years I am faced with the new situation where I need to glue some stuff under hot circumstances.
They announce 30 degrees centigrade and we want to use the good weather to the max.
Material is Sicomin Epoxy, we will glue plywood and fir.

While we have a slow hardener and large shallow mixing pans I am afraid it will be still going off to fast when gluing some big parts.

In winter we successfully warmed epoxy and hardener with a warm air blower.

Now I am considering slightly cooling the epoxy down before use.
Say to 15 - 20 degrees centigrade, to slow the reaction to some degree.
I would use a covered cup for this and put it for 15-20min in the moderately cold fridge and mix afterwards.

Has anyone tried this? Have you cooled both parts or only hardener or epoxy?

And no, unfortunately there is no change of epoxy or hardener possible at this time.

[captnknopf]

I have cooled epoxy (and even polyester) by different methods and it really helps. One thing to watch if you are in a humid area (Florida) is the cool epoxy will sweat (attract water) like a can of drink. Putting plastic wrap over the container before putting in the frige and removing it just before mixing will prevent this. Putting the whole container before mixing will do the same thing. Just do not let it sit too long in high humidity.

[thinwater]

Originally Posted by Franziska

Hi,

while I am using epoxy for many years I am faced with the new situation where I need to glue some stuff under hot circumstances.
They announce 30 degrees centigrade and we want to use the good weather to the max.
Material is Sicomin Epoxy, we will glue plywood and fir.

While we have a slow hardener and large shallow mixing pans I am afraid it will be still going off to fast when gluing some big parts.

In winter we successfully warmed epoxy and hardener with a warm air blower.

Now I am considering slightly cooling the epoxy down before use.
Say to 15 - 20 degrees centigrade, to slow the reaction to some degree.
I would use a covered cup for this and put it for 15-20min in the moderately cold fridge and mix afterwards.

Has anyone tried this? Have you cooled both parts or only hardener or epoxy?

And no, unfortunately there is no change of epoxy or hardener possible at this time.

You can keep the resin and hardener on ice. I've done this many times, from large industrial jobs, to extending my transoms, generally over 30C and in the sun. It will warm and harden the moment it hits the surface. Dripping water is easy to avoid.


A fridge is better, but in the field, ice works.

[RaymondR]

I was in a boatyard once where they had an old refrigerator dedicated to storing mixed epoxy paint sealers and adhesives.

They would often pre cool the parts, mix them and put the catalysed mix back in and use it over extended periods.

No different than prepreg, where they pre impregnate the roving with catalysed resin, keep it cold whilst they lay up the entire component then raise the temperature so that the entire piece catalyses without layers or seams.

[double u]

https://www.amazon.de/Kompresse-Mehr...243010&sr=8-12

[Fore and Aft]

Franziska thanks for the laugh. A 30 degree day is hardly worth a mention down under. Slow hardener and a bit more speed/planning on the job should be fine.
Cheers

[Tupaia]

Originally Posted by Fore and Aft

Franziska thanks for the laugh. A 30 degree day is hardly worth a mention down under. Slow hardener and a bit more speed/planning on the job should be fine.
Cheers

We have done repairs in 35+ degrees, using slow hardener, the only thing that needed cooling was us.



Pick your time of day, morning, evening or middle of the night depending on humidity and have 2 people, one mixing and one applying, using constant stream of pre-measured small mixes. Have everything else laid out and ready, clamps, spare gloves, mixing sticks, etc.



It sounds like you are glueing stuff together so should not be a problem but be wary of very large thick repairs as it can result in fires.



I used a super slow hardened recently in more temperate climes and it took 3 days to completely cure.

[Nicholson58]

I use US Composites 635 thin epoxy. It is very slow reacting and excellent for large projects. In cool weather you could have more than six hours working time. I use a throw away brush both for mixing and application. Use the 2:1 pumps to get the mix precise. Obviously, anything you do to keep a large mixed batch cool will help prevent an exotherm from taking over. I have used many 3-gallon sets of this epoxy.

Epoxy :Â*Epoxy Resins and Hardeners