Marshall's FS17

[MarshallTX]

Is there a lower limit to effectively work with epoxy when taping/glassing? My guess is that I won't see anything lower than 45-50 degrees in my workspace. Any inputs?

[joe2700]

Is there a lower limit to effectively work with epoxy when taping/glassing? My guess is that I won't see anything lower than 45-50 degrees in my workspace. Any inputs?

The hardener of whatever epoxy system you use will specify the temperature range including a lower limit. Note at colder temps even if a fast hardener will still cure wetting out cloth can be more difficult since the epoxy becomes thicker. You may find you want to add heat somehow even if the epoxy will cure.

[TomW1]

Is there a lower limit to effectively work with epoxy when taping/glassing? My guess is that I won't see anything lower than 45-50 degrees in my workspace. Any inputs?

At those temps the epoxy will not cure it will just set there and begin curing as the temps warm up. At 50 it will begin to slowly cure. How big is your workspace? In my garage just 2 electrical heaters added 15-20 degrees to my temp. Cost $50. The type of and speed of the hardened will have some effect but not much at these lower temps.

Tom

[Fuzz]

I work in a pretty steady 60f. Slow will be set up but too soft to sand well over night. Fast will be ready for sanding the next morning. Put your epoxy some place warm a few hours before using and it will work much easier.
Like Tom says it should not take much to raise your temp enough to get good cures. 45-50f is not like working in -20

[fallguy1000]

Tom gave sound advice. Epoxy is an odd duck. Below about 55F and it'll do zilch. Around 60F, for most epoxies it'll cure.

Applying 55F epoxy is a bad idea. Why? You'll use more. I don't mean 10%, but like 25% more. It becomes honey-like.

Try to get the atmosphere to 60F minimum and heat the epoxy either by leaving it in the house or using a warm water bath. Warming it too much will speed the gel time.

I epoxied a small section of camper one day and it was only 50F outside. I literally used a hair dryer for an hour on the spot to get it to gel...

[TomW1]

I did not mention it but fallguy did keeping it in the house the night before using it then placing it in front of the fans will keep it warm as you use it.

Tom

[pee wee]

Warming the epoxy will make it thinner, but even if it's nice and warm if the material you're epoxying isn't also warm, you're wasting your time. Cold plywood and fiberglass will chill things down quickly, so it's got to be warmed up, too. If the hull is together and upside down you can put a heater under the boat and warm it up in a few hours, if it's right side up you may need to build a tent around and over the hull to hold heat in.
Working in cold temperatures is a pain, it requires extra effort and in some cases isn't worth it.

[MarshallTX]

Great advice; thanks to all. I'm unable to find a temp range on the epoxy provided, but will work harder getting that data. My workspace is part of a 3 car garage. The idea of a few electric heaters and synching with a good weather forecast may be the way to go (along with warming the jugs of epoxy/hardener before in advance). Again, much appreciated!

[narfi]

Warming everything up before hand is great, but very critical you let it cool down as it cures.
Heating plywood offgasses and will leave nasty blisters in your glass work.

Just think of the plywood as a big balloon. The air inside will expand and blow out when warming and will contract and suck in when cooling.

[MarshallTX]

Understood. Is there a good temp range that is considered optimal?