[Jeff L]

Anybody have this happen?Friend of mine shot my frame RAL light green with a flat clear using the time & temp on the jug of powder.Where I had used some JB weld, it came through the color....it is kinda yellowed.I know it's not a lack of powder...he shot it heavy...to heavy in fact.Tried to get a pic of the yellowing but my camera sucks.Called the company where I got the popwder & was told that it could happen.I thought I researched the pros & cons of using JB weld overLab metal & never read anything about this.Will a primer stop this?The frame is what it is but I plan on doing the tins the same color & I'm a little worried that if I shot some kind of base first that it might change the what the color looks.

 

[TurboRoadster]

yes, to do a light colored powder correctly and evenly, there should be a basecoat color applied first.
Annnnd, that depends on the color chosen, really, in my experience and I use jb alot, I have never had a bleed through like that, but could easily see it happening if it was a candy or obviously as proven by your experience a light light color. I would think like your coater did that the RAL colors would have covered the jb with no stain as they are solid and mostly opaque, unlike candies. Was the frame pre-baked and allowed to cool before powder?
I would probably use a white for a base for that color, I'm a freak on powder correctness and like even bases to start with instead of metal thats different shades etc.
If I was to repair that frame, I would wet sand the area, pre-bake and shoot a solid color on the whole frame that covers stains etc with no problems like gloss white or black depending on if the customer wants the end result lighter or darker, then do the color chosen for end result.
and if your worried about end result color, always and I mean always have the coater do a chip for you in whatever combo you think will hit the nail on the head, you might find it to dark or whatever and adjust accordingly with the base color or another RAL to make the difference, they have em in every shade of every color almost.

 

[ckunsman89]

we powdercoat a lot of frames (automobile frames) and suspension componets when restoring cars at work, and I have had this happen to me on a number of frames. On black powdercoat, the staining was in the effect of a flat or dull area.

 

[TurboRoadster]

we powdercoat a lot of frames (automobile frames) and suspension componets when restoring cars at work, and I have had this happen to me on a number of frames. On black powdercoat, the staining was in the effect of a flat or dull area.

dang, other side of coin, I use it often on motorcycle tank dents and have never had an issue. and I do plenty of custom stuff to base this on.
one thing I have noted with jb weld is not to use the 4 hr or quick version, I always use the red and white tubes and give plenty of cure time, I wet sand it till its very very smooth and use several skim layers to get where I need to be and sand each and every layer to 600 smooth, some tanks dents, even though small take a week to get where I want them, I set them aside and work on stuff and give it attention when its ready blah blah blah, I also pre-bake and out-gas anything and everything I coat. I'm not saying you or the others do not etc etc, I am just providing my factual data to the mix.
weird stuff I guess

 

[Jeff L]

Thanks for the replies.......I dont think the frame was prebaked & allowed to cool.What exactlly does this do?I thought only cast aluminum needed to be outgased.Ill have to get some samples in white & maybe silver (my thinking that silver will more closely resemble the color of the metal) & shot a couple of test pieces with jb weld on them.

 

[Tim P]

The same bleed thru can happen on paint, it's almost always caused by too much hardner, the recomendations about preping are the same thing I would recommend.

 

[TurboRoadster]

Thanks for the replies.......I dont think the frame was prebaked & allowed to cool.What exactlly does this do?I thought only cast aluminum needed to be outgased.Ill have to get some samples in white & maybe silver (my thinking that silver will more closely resemble the color of the metal) & shot a couple of test pieces with jb weld on them.

if you dont sand the jb really really smooth, as mentioned previously, there will be a "patch" look to the powder over the spot. get it crazy smooth, jb is notorious for tiny teensy pinholes in the surface, skim it again with a firm card to fill those, also, everything needs to be prebaked, I wipe with acetone and prebake and I dont have to worry with oil seepage from a seam when I do put the powder on, or finger oils etc etc, but, again, I dont do mass production powder work, I do it differently and the results speak for themselves.

 

[ckunsman89]

dang, other side of coin, I use it often on motorcycle tank dents and have never had an issue. and I do plenty of custom stuff to base this on.
one thing I have noted with jb weld is not to use the 4 hr or quick version, I always use the red and white tubes and give plenty of cure time, I wet sand it till its very very smooth and use several skim layers to get where I need to be and sand each and every layer to 600 smooth, some tanks dents, even though small take a week to get where I want them, I set them aside and work on stuff and give it attention when its ready blah blah blah, I also pre-bake and out-gas anything and everything I coat. I'm not saying you or the others do not etc etc, I am just providing my factual data to the mix.
weird stuff I guess

I believe what you are saying is 100% right. I tried te 4 hour stuff once, but the temperature of the oven boils it, so now I always use the regular jb. I do not know if our powdercoater pre bakes, etc. I also did not sand the jb weld to 600 grit either, i think I only went as far as 220 dry. Thanks for the info.

 

[gudgean]

like they said . seems like you know what you are doing only i would suggest using epostrong by tigerdrylac. jb weld is tough to feather and can bubble or ougas on ya.

epostrong is hands down the absolute best i have found for filling. not best for deep stuff mind you . but thats when i use industrial jb weld and flash cure it in the oven sand it out re apply and repeat till your happy..totally out gas then use a coat of epostrong over the jb and feather away. then base coat with white or white primer. wet sand then coat the green then clear.

labmetal was tossed in the trash after using epostrong and i will never buy it again. so much easier to work with and no outgassing or pinholes....ever.

so now with what you have though. wetsand to 220 basecoat with white and ten color then clear