well... it's a very general way of curing powder, I must say. It's sort of me like saying : step 1) open mouth, step 2) chew burger, step 3) swallow, step 4) repeat 1-3. There.... that's eating. See how some of these guys don't want to give up the secrets and nuances of how to do any of this? sheesh.... Makes me angry. This stuff isn't rocket science here!
I'll maybe narrow it down to help you. We'll use my ever famous widget example. (stop groaning... you all know you love it! lol). For this case... our widget is a piece of cold rolled steel, approx 1/2" thick, by 4" square. Easy enough so far? Good. Now.... we're going to coat our widget with a standard blue TGIC Poly. Cure schedule states "between 330F and 410F for periods of 20 to 8 minutes PMT". HUH? I'll break it down to you.
PMT means nothing more than
Part
Metal
Temperature. When your PART is at the temp, NOT the oven....this is when your cure cycle starts. the time involved is
longer for the lower temps and
shorter for the higher temperatures. 330F for 20 minutes, or 410F for 8 minutes? Both will work. It all depends on your applications. Let's say we have 50,000 widgets and we are running a line conveyor. WEll then.... speed = $$$$$. The faster that line moves, the more money you make so certainly you are going to bump that temp up. Total WOV (Widget Oven Time....lol, I crack myself up sometimes) is however long it takes to reach 410F
PLUS 8 minutes. Are you with me so far? Good. Now.... let's say we only have the 1 widget and we are coating it and putting it into an oven all by it's lonesome. Well then.... we can slow things down a bit to acheive the optimal finish, as opposed to the optimal speed. 330F for 20 minutes PMT. Again... total WOV (
) is however long it takes for your PMT to reach 330F PLUS 20 minutes. If you happen to miss your "window" of time in a cure cycle...don't worry. ALL thermoset plastics (what you guys use at the moment) has a 100% overbake resistance built into the powder. This helps you in two ways. 1) if you are forgetful like me and let it set into the oven for 40 minutes at 330F, no need to worry. Just take it out like you normally would and nothing bad happened. Or 2) If there is a cold spot in the oven or something just hasn't flowed out enough, leave it in for longer. The parts that have melted and flowed already will not be harmed during the cure cycle on bit. Pretty sweet,huh?
So.... to basically answer your question. Yes, the times and temps that were stated on the "other" powder ( I should scream but I won't because all that is about to change soon enough for you guys *wink*wink*) was correct, but too general in terms. 350F for 20 minutes PMT sounds about right for what you guys are doing. Generally "flow out" happens just when the part reaches the low end of the cure cycle....so that's the reason they told you that. On the other hand.... they are of no help to you and you come to ask me about these things...so what does that tell you about "company X" and how much they care to assist you in your purchases,hummmm? At least with Caswell offerings (what you can purchase now AND in the future *cough* very soon) they have something Comapny X,Y and Z don't have. That would be me and this forum, my friend. And THAT.... will NEVER change! Okey Dokey? Hope that helps ya,bud......Russ