Problems with thick metal

[chromeitout]

I am coating several stands for the company I'm working for that are made out of 1 inch thick cold rolled steel. Some of the parts are as big as 8x1x11. I know that it will take a little longer to get them up to temp. but the problem is that they do not have a good finish to them after curing much like I didn't put enough powder on them, however I feel sure that I did. I know that some of you have coated some thick metals before (engine blocks, heads, etc.) and my question is are you having this problem or is there something that I'm missing? Do you think the slow heat soaking time is causing my problem or is it something else? Any help would be appreciated ASAP because I have to coat 2 more of them tomorrow. Thanks.

[Livinincolor]

Did you prep them properly?
Did you do a pre-PC burn off?
Did you try pre-heating them right before PC'ing?
Johnny
Sho Me Coatings

[chromeitout]

Originally Posted by Livinincolor

Did you prep them properly?
Did you do a pre-PC burn off?
Did you try pre-heating them right before PC'ing?
Johnny
Sho Me Coatings

1. Yes
2. What? If you are referring to outgassing it is machined cold rolled steel that shouldn't need outgassing. It doesn't show any signs of outgas anyway, just a rough finish that is comparable to "dryspray" in the automotive painting world.
3. Yes
Anyone else have any thoughts?

[Popeye]

I'd guess cure time, the BM probably wasn't up to temp. A big item 1" thick steel would probably take 1 to 2 hours to get to temp, maybe longer.

[chromeitout]

I did the stands a while ago. I coated them (one at a time) and put them in the oven @ 500 degrees. I kept an eye on them until they got up to 370 degrees and then turned the oven down to 375 and opened the door for a few seconds to help get rid of some of the heat. The parts cured @ 375 for 20 min.. They looked great this time. I think what happened before is that I set the oven to 375 from the beginning and it took like 40 min. to just get up to 310. Then I turned the oven up to 500 and didn't keep a close check on it. The metal temp was well over 400 by the time I caught it and I didn't leave the door open to let the 500 degree air out. I believe that it just didn't stay in its "flow" period long enough to get slick. Thanks for the help.

[Popeye]

That would do it
Glad you found the problem