3m Undercoating Won't Dry

I have a 2006 Roush Mustang and just did the wheel wells with 3M Underseal Rubberized Undercoating #08883. On dry metal (no rustproofing) and on plastic, it drys fine but in the rear where Ford sprayed partial undercoating, it won't dry. It probably is not compatible with the undercoating. The instructions state to wait 1 hour before painting and I waited 24 hours. Does anyone have any ideas. I have had fans on it constantly and had heat on it for 24 hours. I hate to have to wash it off with lacquer thinner.

Yes, even if I touch it lightly, it will come off on my finger, its been 4 days now.

I have contacted 3M and they said they will get back to me today. I will probably have to wash it off with lacquer thinner. Its not a bad batch because I used 2 cans and they were bought a year apart. I did notice other forums had the same problem but no answer. 12 years ago I had the same problem with my 69 Mach 1 and only on the factory rustproofing but not on bare metal. I talked to my autobody supply store and they said the solvents are reacting together from both compounds and they have not seen that before but no quick fix. O well, if nothing from 3M, its time to clean.

This is what I got from 3M, but I don't think mineral sprits will touch it so it will be lacquer thinner. Pretty bad luck to have 2 out of 2 cars to have a problem. LOL

Hi Dan!

Here is the response from the lab:

“He is exactly correct 8883 can be incompatible with some (particularly PVC type) coatings. I have heard of this in some isolated circumstances. As for a fix, wash with a mild solvent such as mineral spirits, allow to dry, use a water based undercoating such as 08804 No Clean Up water based undercoating to replace. “

I know this is not the answer you were looking for, but it is an answer none the less.

Let me know if you have any additional questions.

Regards,

I cleaned out the rear wheel wells and used paint thinner like the techs suggested and it was fair. Lacquerthinner worked great till I ran out and used environmentally friendly lacquer thinner and it sucked so while my wife ran to the store to get more, I used gas and it worked well. Never buy anything environmentally friendly if you have a tough job. I had many fans and an attic fan running so I would not blow myself up. LOL. I wore a paint hood, goggles and respirator and long sleeve shirt with rubber gloves so in 85+ degrees, I sweat buckets and I did not stop till I completed the job which took about 12 hours.

The paint is slightly tacky but nothing like it was before. I will never use 3m undercoating #08883 again. I used 3m undercoating stage 4 and it scratches off easy but dried fairly well during my test and I tested Mar Hyde and it was stronger but seemed wetter with paint on it so I went with stage 4. I tried not to coat the factory undercoating, just the bare areas. Wouldn't it be nice if Ford would coat the whole wheel well!!! I used 2 coats of Rustoleum double coverage semi gloss for the finish.

The tech recommended to use a water base undercoating which would be nice but you have to order it and it cost $45 a can and research told me it does not go far so you would use twice the amount and you have to buy a spray attachment that cost more than the can.

Moral of the story is spot check the rustproofing and the top coat of paint before you do the whole thing and end up doing 4 times the work to complete the job. Looks great now and hopefully it will dry well.