Hmmmm ...
What was the PR and PH numbers of the Aeropoxy product?
The 1-hour hardener requires no heat cure (well, 90 F is recommended), but the 2-hour hardener does and may remain tacky until it sets. From the PTM&W In dustries, Inc website:
PH3665 hardener should be given a cure of 12 to 14 hours at 120oF to 130oF to in sure a hard gel sufficient for demolding and sandability.
For laminating (for fiberglass or carbon fiber layups) I use Aeropoxy PR2032/PH3660 (1- hour pot life) or PR2032/PH3665 (2- hour pot life). If you have used the 2-hour hardener, put it in your attic (if it's warm up there) for a day.
Below is my primer on how to use epoxy systems successfully (I have been using Aeropoxy for FG for several years):
Greg
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1. Use nitrile gloves, not latex. Constant skin exposure to epoxy can lead to sensitization (body reacts badly). It does happen to people.
2. Get a digital scale that can weigh to the nearest gram and has a tare feature. Weighing the portions to get them to manufacturing specifications is important.
3. Mix thoroughly (and for 5 minute epoxy, quickly!). I am almost certain that I have had bad epoxy sessions because I didn't thoroughly mix the resin and hardener. I use a craft stick chucked in my drill press and let it do the job for me. An electric drill can do the same thing.
4. Epoxy gains additional strength by adding amendments. These can be milled fiber, fumed silica, chopped carbon, etc. It can be made lighter and more easily sanded by adding microballoons.
5. Use a quality epoxy (like Aeropoxy, WEST System). Use Loctite/Henkel 5 Minute is fine to use for quick bonds.
6. Use the right epoxy for the right job, typically either for adhesion (tends toward high viscosity) or laminating (tends toward low viscosity).
7. Use per the directions (when I had a question about the directions, I contacted the manufacturer for clarification).
8. Epoxy is a thermosetting compound, typically the more heat that is applied the faster it will cure, but to a point. Typically you dont want the initial cure to be higher than 140 F. Some epoxies benefit from a post-cure thermal cycle. Look for vendor data for specifics, and again, follow the directions.
9. Epoxy has a thermal limit called the glass transition stage, or Tg for short. At this temperature, the epoxy significantly weakens and bonding degrades and the condition is often permanent. Use high temp epoxies (like JB Weld, or Cotronics) for applications where bonds are exposed to a significant thermal soak.