GM Inside News Forum banner
1 - 6 of 6 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
I have an '89 Sierra Sportside, slightly customized, and have ran into a problem with the fibreglass box sides. I have been getting the truck undercoated annually for several years and this year the box began breaking out. It looks like rust bubbles but it's only on the fibreglass. I contacted the undercoating manufacturer and they told me that the product can soak through the fibreglass and bubble the paint. Has anyone had this problem before? I would like to be able to fix it without changing boxes as I have already had several body mods done to the box. Any help would be appreciated.
 

·
Registered
Joined
·
4,660 Posts
I hadn't heard of this problem before personally. But if the manufacturer says that their product can seep into the fiberglass itself, then you already know the answer...and it's what you don;t want to hear. The whole thing would likely need to be replaced, or at least the fender-bulge parts.

That sucks....it seems you were trying to be proactive and prevent problems in the future, and sadly it did just the opposite.
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #3 ·
That's pretty much what I figured. I was hoping there was some sort of primer/sealer that would stop the rest of the undercoating from getting through. If not, then hopefully I can stop someone else from having the same problem. According to the manufacturer, only solvent free undercoating will not damage fibreglass or SMC
 

·
Registered
Joined
·
4,660 Posts
That's pretty much what I figured. I was hoping there was some sort of primer/sealer that would stop the rest of the undercoating from getting through. If not, then hopefully I can stop someone else from having the same problem. According to the manufacturer, only solvent free undercoating will not damage fibreglass or SMC
No doubt...this is a great thread. Like I said, I hadn't heard of it, but I have lived in areas that don't use much road salt. Hopefully someone has more insight into this.
 
1 - 6 of 6 Posts
Top