Epoxy Question

Howdy TRF members,

I have a question regarding Aeropoxy. This is not the first time it happens to me and I noticed it happens in the winter only, but what is the cause of the epoxy becoming so thick that it becomes tough to laminate? It even becomes so thick that it sticks like melted candy stuck to a table.

I always mix in batches of 100:25 so the mix ratio is correct. Just off the top of my head I am assuming if it could be the cold weather?

Your advice is appreciated


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet

I've had issues with 6209 after freezing. I stuck my bottle of hardener in a sink of very hot water until it de-crystallized and got running again. Been working great since. Cold didn't seem to bother the resin.

DizWolf said:

I've had issues with 6209 after freezing. I stuck my bottle of hardener in a sink of very hot water until it de-crystallized and got running again. Been working great since. Cold didn't seem to bother the resin.

Click to expand...

The hardener was probably too cold. Next time I'll put it in warm water to heat it up before I mix with the resin.

Despite the thickening of the resin, will the cured properties be affected?


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet

That, I'd probably email the manufacturer on. In my very unscientific "break the Popsicle stick" testing after each batch, it seems to do well.

The cold crystallizes the hardener. mine was thick even in the summer when it was 85 out. Heating it back up is a one-time thing you need to do.... then just store it room temp.

Which Aeropoxy product and what is the room temperature?


Mark Koelsch
Sent from my iPhone using Rocketry Forum

As a matter of general principle, during the winter months I move the epoxy from the workbench to the house and take it out the unheated shop when I'm building.

I believe there are temperature advisories for most epoxies.

There are minimum cure temps. Below that they won't fully cure, but as I understand it you can heat the part that's tacky and it should help finish the cure.

markkoelsch said:

Which Aeropoxy product and what is the room temperature?


Mark Koelsch
Sent from my iPhone using Rocketry Forum

Click to expand...

It is Aeropoxy PR2032/PH3663 mix ratio is 100:25. The temperature was at about just guessing here 65 degrees.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet

DizWolf said:

That, I'd probably email the manufacturer on. In my very unscientific "break the Popsicle stick" testing after each batch, it seems to do well.

The cold crystallizes the hardener. mine was thick even in the summer when it was 85 out. Heating it back up is a one-time thing you need to do.... then just store it room temp.

Click to expand...

I've contacted them before and believe me. They had no damn clue as to why it did that.

I'll be sure to warm up the hardener before using it again.

Thank you DizWolf


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet

65 degrees isn't a particularly low temperature.

Most epoxies cite 72 degrees as the "normal" working temperature.

SinfulDarkLord said:

It is Aeropoxy PR2032/PH3663 mix ratio is 100:25. The temperature was at about just guessing here 65 degrees.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet

Click to expand...

65 is probably a little low in my experience. Probably better off 5-10 degrees warmer. Not saying that it is cause. I have also seen problems caused by incomplete mix of resin and hardener. Also, I though it was 100:27 resin to hardener weight wise.



Mark Koelsch
Sent from my iPhone using Rocketry Forum

markkoelsch said:

65 is probably a little low in my experience. Probably better off 5-10 degrees warmer. Not saying that it is cause. I have also seen problems caused by incomplete mix of resin and hardener. Also, I though it was 100:27 resin to hardener weight wise.



Mark Koelsch
Sent from my iPhone using Rocketry Forum

Click to expand...

It is hardener 3663, which requires a mix ratio of 100:25.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet

o1d_dude said:

65 degrees isn't a particularly low temperature.

Most epoxies cite 72 degrees as the "normal" working temperature.

Click to expand...

Have worked in 60 degrees before when it was hot as nuts here. Never really had an issue at those temperatures. I would imagine the epoxy gets just a tad thick, but not as thick as I have experienced.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet