I've read here that a heat gun is a good option for heating kydex. But what about heating it for large applications, like making a sheath for a 21" machete? Can a heat gun do the job? if not, what do you guys recommend?
I'd not like to try a large sheath with just a heat gun. There's no good way of getting all of the material up to proper heat evenly so you can mold it. I guess you could do it in sections. I had trouble getting an even heat with a gun for a small sheath, so I just switched to an oven.
I would recommend just laying the material in your household oven set at 200 or so. Watch it closely and remove it just as it starts to curve up at the edge. For smaller sheaths, the toaster oven is the perfect heating appliance. The heat gun has its uses, for sure, especially in final fitting.
Sorry...that's right. 300, not 200. The fumes do smell a bit, and it will linger in the house for a while. As long as you've got some circulation, you should be fine, and I would think that after you air out the oven, it would be fine.
I'd say figure out something to use other than the kitchen oven. It's some form of plastic and when it heats up, it stinks and i'm guessing isn't all that good for you to be breathing the house. Probably not good for small children either to be breathing or sniffing. Try and find the largest toaster oven you can find at maybe a goodwill store or something, i'm sure you can purchase one rather cheap. Keep the kydex OUT of the house oven and leave it to baking and whatever else it was meant for.
I'd also say for the thinner stuff .06 kydex to set the toaster over between 250 and 300. That stuff will go from rather stiff to seriously warped in a matter of two seconds to melting and burned if the temperature is too high. Use a lower temperature and it will still work. There's no reason to rush the job by turning the oven past what is really needed.