I had my Bub Lakersters 2-1 shields and muffler powdered a regular high gloss black...they looked great.

After a 30 minute ride the top of the shields started to bubble up and melt.

The powder coater redid the shields and muffler in a high temp coat (not as smooth or glossy but they looked great).

They were holding up fine for a few short rides, however, after a long ride the powder started cracking and flaking off the shields near the top of the headers.

The coater is a great guy and wants to do his best to fix this, but has no idea why and thinks it's bad powder. I don't know or see why he thinks that though. I suspect bad prep, but I know they did blast all the chrome completeley off.

I know that because of the bend in the shields they do get hotter than normal..but not hot enough to burn up then high temp powder coat (and I'm not running lean) or can it? I really love the look of having actual black pipes and not the blueish ceramic color.

 

I'm not positive on this but I don't think sandblasting chrome will take it off, it has to be chemically stripped. My powder coater makes me take my chrome to a chromer and have it stripped before he sandblasts it and coats it. Maybe Joe the powder pro will chime in with his thoughts.

 

Strip the chrome and send to a pro like JET-HOT.

 

I'm aware of Jet Hot however I'm trying to get the High temp to work on the shields. No reason they shouldnt so I'm trying to get some schooling as to why.

 

Sounds like they didn't properly pre-treat your exhaust. Time to call Joe!

 

i feel your pain man! hopefully they get it figured out

 

orrrr.....maybe your engine temp is higher than it should be....high temp powder coat is designed with a temp range in mind.

maybe your ride is exceeding the temperature range, and running hot. causing the powder to bubble.

just sayin... there could be other reasons, im just pointing out one.

 

I am no thermal expert, but how would a bend make it hotter than any other exhaust?
If the powder is an exhaust heat rated powder, which is normally a higher rating than just high-temp, it is not being applied properly. This sounds like the case if your guy tried "regular" first, he doesn't know what he is doing.
Just like engine enamel will not last on headers, regular high heat will not work either.

Regular high heat is rated to about 500 I believe, header type paint is usually rated 1500 or higher. I have VHT 1500 on my pipes, not shields, and have no problem at all.

 

The forward bends in the headers cause the flow of exhaust to get hotter causing the shields to get hotter than normal. (sort of like what happens with the thunderheaders -these pipes run hot).

I'm pretty sure the high temp powder he used was good for up to 1200. I could be incorrect though. However, it's not like it melted and bubbled it just cracked and is flaking off near the top of the shields.

If I cannot get this to work my next attempt will be the VHT paint on the shields, but I would rather have them powdered I just need assurance (if this coater can't do it) that it can be done on these.

 

It is physically impossible for a bend to create MORE heat, it has no external heat source. Worst it can do is delay heat dissipation, but it cannot make it hotter.
Not sure where this rumor starter, but I would really like someone to explain how that is physically possible.
The hottest point on your head pipes is right at the head port, it cannot get any hotter after that point.