Sound deadener spray won't dry on sealer...

[mungus]

Has anyone else encountered this before?

I'm using Rustoleum's (Motospray) spray on sound deadener.
Its been great in most places, almost replicating the factory stuff's appearance, and dries OK on the panels, etc. But I just noticed it is still wet where I have sprayed on top of some (not all) Sikaflex 227 seam sealer. This a week or 2 after application. All the other deadener I sprayed has set up nicely.

Where the Sikaflex was more than a few months old (ie fully set), it was OK, but on the 227 that was a week or so old, the deadener is still tacky, well gooey really. Its almost as if the sound deadener has partially dissolved the 227.
I'm now faced with cleaning the mess off and starting again. Uggggh.

I think Rustoleum's stuff is traditional butyl spray deadener, certainly it cleans up / dissolves instantly in petrol.
But then Sikaflex 227 appears to be a silicone adhesive type product. Perhaps its vulnerable to petroleum solvents for a long time?

Anyone else struck this?

[ozbilt]

Sikaflex 227 is polyurethane. The PDS is available online

[Stuart]

Yes, I've experienced something similar on a 69 Shelby restoration.
I sprayed Raptor bedliner in the wheel wells but bubbled up and cracked where the polyurethane sealer was applied but not over the areas where I used brush on seam sealer.
I had to remove the bubbled and cracked areas of the Raptor then apply the brush on sealer over the polyurethane sealer and redo the Raptor, no more problems.
I used Wurth brush on seam sealer.

[mungus]

OK. Well in my case it was fine over all the 227 sealer I used, except the most recent application inside the trunk around the rear panel support brackets. Just that part went gooey, the rest is just fine. Good be you really have to wait a long time for the 227 to be really cured hard before applying a butyl spray deadener?

[ozbilt]

[mungus]

Thanks Kerry,
However I should have been fine as it was about 2-4mm thick and was on well over a week. More like 10 days. It is getting harder slowly, so I may just wait and see.