Update:
This project has found its way to the back burner, no matter how I try. The time I had set aside for completing the tank was promptly taken over by a failed retaining wall behind my house. It was getting a real nice lean to it, and couldn't be ignored anymore. Oh well. We now have a sweet new retaining wall though!
In the back of my mind, I'm pretty sure I was delaying because I was a bit anxious about the post-cure heat cycling. Honestly, in my hubris, I had earlier scanned the post-cure heat cycle, found it to be easily accomplished, and didn't think much more thoroughly of it. Sadly, I should have thought it through
much more.When you're curing it in the oven, this heat resistant resin is much like other resins, in that it loses its structural stability. The way it
differs is that it is thereafter stable at that temperature, unlike poly resins that will continue to go soft-ish at whatever previously visited temperature. So, I should have made a plug (the original form) out of a heat resistant material, so when I made the mold (with the heat resistant epoxy resin), I could then heat cure the mold
on the plug, and then in turn, I could then heat cure the individual component parts inside
their molds, and then build the components to a completed tank, which could then be heat cured as a unit to make sure the epoxy resin used in joining was all copacetic. Instead of baby steps, I barged through in my ("how hard can it be?") hard-headed mentality, and was forced to problem solve my way out of a conundrum of my own creation. You know, the usual...
So, the fear was that while baking, the resin would go soft and tank would collapse. I came up with a bunch of hair-brained schemes, but I finally settled on building a wooden box, up tight against the tank's outer surface, and fill it with something to maintain the inner dimensions. To stop the tank from adhering to the wooden box, I coated it in the mold release, and then carefully covered it in aluminum foil panels, thinking the mold release would save me, but if it didn't, I'd rather have glued the tank to foil, rather than glued it to the inside of a wooden box. I'm not smart, but I'm pretty good at being dumb! I drilled holes in the box and ran bolts in, locating the various threaded fittings, so as not to have the tank slump inside the box. The filler cap and filter bung were stopped with corks. I coated the inside with the water soluble mold release, waited for it to dry, and filled the tank with rice.
I'm not sure if anything I did had any bearing at all on the outcome. It's quite possible that I was worried sick about nothing, and I'd like to think I can learn from a close scrape, rather than a Waterloo. Either way, the pine box and rice did their jobs magnificently, if a little stinky, and the tank came out great!
Here's the pine box, and all its pitch that had run out while hot in the oven. I was more than a little nervous when I saw the goo had run all over.
But... It came out great. A tiny bit of texture to be sanded off, but it needs a coat of filler anyway, so no biggie. The foil scraped off, the rice poured out, and the mold release washed away in a warm bath. I'll take it! There was a little air bubble at the front face seam that needed to get opened and filled with epoxy, but was easy force the epoxy into the void with a bit of air pressure. The void didn't make it inside the tank, so it was just an aesthetic thing with a bit of a bulge from the expansion of the air void in the heat. Better to heal that minor de-lam now. Easy peasy. With all the things that could/should have gone wrong, I'm feeling pretty good about it.
Gotta do the skim coat of filler and then primer and paint. The best riding weather is slipping away!
