Keep having weird problem, why? Pic inside

[UnorthodoxCreations]

I am now on my 3rd valve cover because I keep getting terrible results with Caswell Super Chrome. I guess I'm doing something wrong but I dont know what. The piece is cast aluminum. My exact procedure this time was-
-sandblast piece
-clean off with nozzle then wipe down with alcohol
-outgas for 30 minutes @ 450-475 degrees
-i didnt like how clean it looked so i blasted it some more just to make sure it was perfect
-sprayed with aire and wiped down again
-placed in oven for approximately 10 minutes at 450 degrees or so
-take out of oven, let cool for a couple minutes then spray with super chrome
-place in oven for 20 minutess @ 380 degrees after 15 minutes i saw the finish was **** and shut the oven off. This is the pic

The first time I got this finish I thought maybe I picked something in the air but I really doubt thats the case. This is the second time this has happened and both times its with Super Chrome. I got my rear valve cover to come out good cleared it and its all good but I NEED this front one to turn out for a show next Fri.

Also when I get a crappy finish like this what can I do? Sand it down and respray? How well do the strippers made for PC work? Any help would be greatly appreciated.

Adam

[pickleboy]

first off bro, it appears in the pic to be bubbles, or is it more like lint? if it looks like lint then i suggest to not wipe the part down but to get a pump sprayer(like a windex bottle) and put your alcohol in there. this way you spray the part and do not risk the fuzzies. if its bubbles then it is outgas, it is possible to out gas a part and then when you pc the part and cure it will outgas more. as for strippers i have found that aircraft stripper that you can get at most auto parts stores or paint suppliers works good on most powder coat. you might also try to hit it with 400 grit paper wet sandind very lightly and see if it smooths out then reclear. best of luck bro.

[UnorthodoxCreations]

To me it looks more like lint but I'll investigate more tomorrow. I have a spray bottle that I use to spray but then I'll still wipe it down. I cant see any visible lint when I put it in to outgas or spray it. If its bubbles do I just need to make sure I outgas for longer and hotter?
thanx

[mtumbleson]

I've seen it before>>>
I found sand blasting aluminum prior to powder coating is a big no-no.

[UnorthodoxCreations]

Originally Posted by mtumbleson

I've seen it before>>>
I found sand blasting aluminum prior to powder coating is a big no-no.

What should I do then? I only have sand for my cabinet. I need the pieces cleaned and I dont know any better way. Front valve covers from a Probe GT which are cast aluminum are the only pieces I've had this problem with and only with Super Chrome.I've done a number of other pieces in aluminum and steel in 5 different colors and never had any other problems. Is there any chance I can sand it down and respray or is this piece done for?

[jtagger19]

I it was me I would
sand down with 220 ,pre heat to 150 and re coat

I've used sand a lot before and never had any problems

[UnorthodoxCreations]

Looking at it tonight it was definitely sand trapped. This one had a ton of sand so I grabbed one of my other screw ups and sanded that with 180 wet. Cleaned it well and recoated and it came out near perfect. I'm gonna try and touch up a few spots then hopefully be done with it.

[crazy_mtb_2002]

thats good to hear, good luck with it.

[mtumbleson]

Sorry, I forgot about this thread.

You did right by starting over and not re-blasting. What I did on parts that I had already blasted was either preheat or boil the part in water, then lightly wire brush. I found this gave better results, but I still seemed to get several grains blast media no mater what.

Since then I just quit bead blasting my parts and haven't had any problems.