Regarding heat curing/post curing, I recently made a large 'oven' out of reflective backed foam board with a couple of 250 watt heat lamps inside. I cut a little inspection port where I can look in and check out the temperature on a hanging thermometer. I control the temp with a regular ol' dimmer switch. I get temps of 160 F without any problem, and running two heat lamps is much less expensive that running space heaters. There is something about infrared heat bouncing around on a reflective surface that is really efficient in terms of getting the temp up. Oh, the oven was 8 feet long, 2 feet high, and 2 feet high.
G-man, how are you directing the heat lamps so there are no hot spots? I was thinking that would be a good solution but was concerned about hot spots and controlling the temp. The dimmer switch is a good idea. I already have that kind of controller setup for the hot wire knife I use to cut foam.
But, I’m working with ambient cure epoxies whose properties *benefit from high post cure temps up to 120deg F. as I think most ambient cure epoxies might. The folks using heated presses and epoxies that work at higher temps would not need to do the post cure. I would think that the QCM epoxies are fully cured during the heat cycle as well where the ambient stuff is not. $50-60 is cheap for an oven made like G-man describes compared to the cost of a heater and all of the controls. Not as fast of a temp rise on the part but still very reasonable in cost, and I think very effective for working this time of year in an unheated space. This type of oven, if I can get the temps G-man states would also allow me to try out the QCM epoxies with my vacuum system as well.
*Greg Loehr states his epoxy benefits greatly from post cure. (see links in other thread)
I don't actually use the large oven to post cure my skis... I use it to post cure other experiments that I've been working on lately. But, I see no reason that the same unit would not work for skis. Like I said earlier, the oven is 8 feet long. The parts that I'm post curing are a little over 6 feet long. To prevent hot spots, I mount the heat lamps on the bottom surface of the oven, about 6 inches away from the end walls. Then, about 12 inches from the end walls. I hang a piece of heavy duty aluminum foil between the heat lamp and the parts that I'm curing. The reflective surfaces do such a good job of reflecting the heat, I've never noticed any areas of significant heat build-up. I first used this sort of set-up 25 years ago for baking freshly painted bicycle frames... twenty five minutes in the oven and you could beat on the paint job with a hammer... I only actually beat up test pieces, though... not real frames.
Anyway, I like to use 1 1/2 inch foam board for the oven because it holds it's shape really well, and it's easy to make a box out of. One inch foam board is quite a bit less expensive and would probably work fine. The lamps at Home Depot are about $10 each, but if you have a farm supply close by (like Tractor Supply), they have the same lamp for $3... they just call it a brood lamp (for chicken coops). 'Infrared heat lamp' is what you're looking for. My oven has no problem getting up to 160 F. I've even thought about switching from 250 watt bulbs to 125's. One 250 watt bulb would only get the temp up to about 125 F, so I added a second bulb at the opposite end of the oven.
If for some reason you do have an issue with a hot spot or two, you can just attach a layer of aluminum foil so that it forms a heat shield about an inch away from the hot spot (works a lot like a heat shield around a wood stove). It's easy to attach things to the inside of the oven... just twist in a screw. Good tight joints are important to keep the heat in. And yes, I think you should be able to build the oven for about $60, depending on how thick you go on the foam board.
Good luck.
G-man
Iggyskier, I almost forgot you. With a heated press, a post cure is not necessary after the initial pressing.
Hotbox. I'm just at the research phase of building skis but I did build a hotbox last year for my racing skis. I keep it at about 125 degrees on a timer switch to let the wax penetrate the base. I've never cranked it up but I think a base board heater will get up to around 135. It would probably get hotter but I think there is a limit switch for safety reasons.
Cure in-production skis and make post-production ones faster.
