does anyone have DYI plans of how to make a small to medium oven for curing part, any help will be highly appreciated.
thanks
This has been covered many times on here. Use the search button at the top of the screen it is your friend and will help you a LOT. 
What temps are you after?
First make sure post curing is necessary. Read the data sheets :D. I thought post curing always helps. I later found out that if you don’t post cure at the proper temps with the proper ramp up then all you are doing is making the product more brittle and weaker.
All datasheets I have indicate that postcuring will:
-increase Tg (up to ultimate Tg)
-increase tensile strength
-increase strain
-increase impact resistance
-decrease flexural modulus
This is even true for so called cold curing epoxy, but also for polyesters and vinylesters.
Temperature is dependant on what you are doing.
For a tensilte test piece it is quite common to cure 2h at 120C, even when the ultimate Tg is only 80C. This at least makes sure you have cross linked as much material as possible. For cosmetic parts you need to be much more careful and conservative
Ramp rates dependant mostly on part size and oven type.
You want basicly the same rate of cure throughout the part, even if the part is large, or your oven is crappy.
Since most of our parts are cosmetic should we just leave all parts to cure at room temp or perhaps an elevated temp of 100f?
Does it hurt to post cure at under the recommended post cure temperature? Obvioulsy that speeds up the cure, so would that make the product weaker?
So my question really is. Is it better and or ok to leave the part at ambient temperature and not post cure at all, (unless post cured at the recommended temp), or is it ok / better to elevate the cure temp as long as I don’t exceed the post cure max temp. Just to speed up production and hopefully increase the strength of the part.
I’m using a VE / PE resin blend btw.
VE/UP can generate quite high Tgs without postcure.
Will you need a postcure for cosmetic parts? If you do not postcure, the sun will do it for you, some day during the lifecycle of your product, away from your facility, and in the hands of your customer. Postcuring may generate surface defects, especially when postcuring free standing.
So in any case you should postcure to at least the temperature the part will see during its life. You can do this in a controlled environment, preventing cosmetic issues, or at least have the opportunity to fix them before the parts go to a customer.
Does postcuring at a lower level than recommended in the TDS hurt? No, just do not expect to reach the technical values given in the datasheet. It is up to you to decide whether that is critical or not.
“Small to medium” = what volume range?
Just thought I’d share this link because I’m going to start building something that’s low-med temp range and this seemed like it fit my budget/needs.
Interesting I have used an old metal locker before with a variable temperature hot air gun stuck in a hole cut in the bottom, it worked a treat for short periods but I would not leave the shop whilst it was running.
That’s a great idea for something quick. Of course not leaving it while unattended for this setup and also if you’re only post curing to 150 or so I think this would work well.
I would not recommend making an oven out of combustible materials (wood). If you want to go big, get some metalstud, rockwool and gyprock sheets, and a sauna oven.
Very small: A US Mail box and a heat gun.
I’m trying to do a simple oven with rockwool (80kg/m3) with aluminum foil on one side, like this: (see 12:55)
http://www.youtube.com/watch?feature=player_embedded&v=o6MwRBWHJD4 #!
As heat source I will use an old resistance of one stove.
Do you see necesatio include ventlador in the oven?
But the wool is quite difficult to handle, is weak and I need to make a external classis.
I have created the internal structure with rock wool and to stiffen the oven could use polystyrene plates, but I haven’t very clear as to stick the polystyrene rockwool because this is just wool and not sticks well with any adhesive.
Maybe with expandable polyurethane foam?
Or use some mechanical fixation?
Gyprock sheets, also sound like a good idea are more resistant to heat but maybe too heavy for the oven time I’m building and it isn’t a good thermal insulator.
I have also purchased adhesive tape fiberglass 3M 365, it must support 150ºC, I would use to seal the inside of the furnace, at the junctions between differents parts of the rockwool, to prevent heat escaping through the slots and destroy the polystyrene.
Regards
I built this makeshift oven after I was too impatient for an oil based primer to dry at RT. It is built out of 1/4" osb and 1x2" pine boards. It’s lined with a foil faced insulation and taped at the seams. Yes, some of the 1x2’s are exposed inside, but my wall mount space heater has a thermal cutoff at 180f. By insulating and mounting my thermostat outside the oven with a small 1/4" inlet opening, I have adjustments from RT to 180f. I monitor it with a meat thermometer mounted through the top. I never leave this set-up unattended at higher temps. For long term, lower temp curing I have found that I can simply put a small space heater inside and maintain 110f. For less than $100 invested it may be a home brew, but it serves the purpose of getting a little post cure on my molds and watercraft parts.
Well done!
Nice, I’m considering building my own oven out of pink foam insulation backed with wood, a stove-style heat plate venting through a flue at the bottom, and one of those 40 dollar temp controllers on ebay that switch a relay on and off which would connect to by heat plate. There was a good video on youtube (https://www.youtube.com/watch?v=81t1aYxJer0) that basically lays it out, mine will be slightly more ghetto because I don’t feel like cutting sheet metal 
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I hope to build an oven soon. It wil be a large oven around 1x 0,75 x 2 meters. I found a lot of good info at http://forum.caswellplating.com/oven-building-forum/ .
Thats the definitive oven link. Thanks Michiel.
Here you can find more
Guys what can be used as a fan/ventilator inside oven? it must be resistant for heat.