First of all, this is a topper for my '05 F150. While not the right generation, I use this truck to experiment for stuff with my 56 "kind of" making it relevant.


For this deal I am experimenting with the DIY spray in liner on the underside of the fiberglass.




The issue:


I bought this topper for $150.00. It had been sitting on the ground and was dirty and molding/mildew. I flipped it upside down, hit it with some water, and some blue wolf degreaser. Scrubbed it with a brush and rinsed it out.


It looked great, like new! As it started to dry, it started leaching out in places. First a light tan, then these darker spots. I thought it was just water that had gotten behind some of the loose strands. I put a heater under it for TWO days, and it still continued to have moist patches, now I have had a fan under it as well for FOUR days. 6 Days of total dry time. The moisture level has went down but I am left with these "tacky/sticky" brown spots.


What are they? is it resin from the glass, something leaching out of the mdf or plywood use in the topper?


How do I clean it off? Think it is safe to spray with the liner now?

 

No idea what it is, but if it is just cosmetic it wont matter. If it is moisture it has to be gone before spraying. You could try some alcohol on the spots which will absorb moisture and then evaporate.
Maybe something in the degreaser reacting with the fiberglass?

 

Did the topper used to have a glued-in headliner?

 

No liner, I think it is resin that wasn't sealed with the gel-coat very good. That is the reason I wanted to add the bedliner was to seal it, and give it a uniform appearance.


No Liner.

 

I can't imagine there being uncured resin on something more than a couple years old, and still tacky. Have you tried something that kills mold/mildew?

 

Yeah, I used a degreaser that specified mildew/mold.


The crap thing of it, was the ceiling didn't have any mildew to start with, just around the bottom. I just wanted to give it a good scrubbing before I painted it with the liner.


This thing is like 10 years old.

 

It looks like growing spores to me, flip it back over and wash it with a very strong bleach solution and let that soak for a while before rinsing and allowing to dry. That is what I would try if it was mine.

 

I don't think it is spores, there weren't any in the top in the beginning, and they literally popped up in a matter of hours. They are also tacky, reminds me of pine sap!

 

Just smells like stale urine.......

 

First of all, did you cut it 3 parts water to 1 part degreaser like it says for fiberglass?

It looks like the degreaser has had a chemical reaction with the fiberglass mat or resin. If you used it full strength, it may have been too strong and started to deteriorate the bond within the fiberglass.

 

Yes it was reduced, the more I look, the more I think it is something below the fiberglass.


If you notice, it is only on the area with the depression from the plywood, cardboard, mdf sheet.......

 

Hard to tell from the pics, but if that's what you're seeing, it can probably be covered by the liner with no further problems.

Why not try spraying a small area to see what it does? Or does the liner need to be mixed all at once?

 

Best idea yet, Im gonna pick up some acetone tomorrow and scrub them. Once dry I'll brush on some liner in a couple spots and see how well it bonds.

 

Acetone is a seriously strong solvent, I would stick with alcohol. Hopefully that acetone doesnt melt the fiberglass!

 

I was thinking the same thing. I wouldn't try acetone on fiberglass.