Pu seam sealer

[dub-disaster]

After having the seams welded in my engine bay I used pu sealer to cover the seams as they where seam sealed before and I thought it may be important to replace this seal is this correct or should I of not bothered !?
  I used starchem pu sealer wich is what a mare had a tube of and lent me he said it worked well on his car. It says it's paintable over after 30mins but I put it on and let it set for 24 hours and it was still sort of tacky so I though that it mite just be the way it is so I carried on and etch primed over it . Now the etch primer has cracked and wrinkled anywhere where it touch the seam sealer.
       So is seam sealer realy important or can I just rip the crap out as it doesn't look all that great either even though I tried to be neat as posible and go over it with a brush or is it best to wait a few more days / weeks to see if it goes of completley then sand it ( is it even possible to sand seam sealer!) and re prime it ??
any help appreciated I know nothing about painting realy and starting to wish I'd never bothered !!

[ereeiz]

I too know nowt about painting, but I do know that metal attracts damp! Was it warm/ dry when you left it to set? If it was outside in the crappy weather of late then this may prolong how long it takes to set? I'd have thought coating it in primer would make it worse as it'd stay moist underneath?
AS I say, I know nowt about paint really, just something I noticed when stuff got sprayed in a garage I used to work at, it takes longer to go off if it's not warm/ dry (ie 20C +)

[abf]

what was the expiry date on the tube of sealer you used. if it was out of date then it wont set no matter how long you leave it. personaly i would re-seal all the seams in the engine bay as there may be very small gaps in the weld where water could get in and rot the seam from inside.
hopr this helps.

[dub-disaster]

That's exactly what I'm going to do , any suggestions of a good sealer that dries fast is painable and maybe even sandable? The date on it was 05/10 but the container said use within 9 months of date on the tin !!!
   Also should I be applying it straight on bare metal or is it ok to use it on tip of a rust remover/preventers like krust by hammerite or could this be causing it not to set ?

[Nick_S]

I used a tube of Sikaflex. Will have to dig out the bit I have left somewhere to get the correct type number. I got it in OEM light grey though

[GSBellew]

I used Dinitrol 401 brushseal, its fantastic stuff, is very easy to smooth and can be used to replicate the original factory finish be it a brushed or smooth finish.

[dub-disaster]

Yea I would like a grey one with as smooth a finish as possible there was so much sealer on there originaly it looked like a monkey had put it on! I'll have a look at both of them
      Did you guys brush those on then smooth them over with a brush dipped in thinners ?? And did you apply them to bare metal seam or after primer or after a rust treatment/preventers ?

[cheddarcheese]

And did you apply them to bare metal seam or after primer or after a rust treatment/preventers ?

U should do it after primer or after a rust treatment/preventer all the sealer is for is to stop water sitting in gaps and we all know what this courses! so no need to apply as much as factory just simply fill the gaps.

[jez1272gt]

as cheddar has mentioned, you need to a good coat of primer down before you use any sealer. The surface must be VERY clean to lay the primer onto because if the primer lifts underneth the sealer you have wasted all your time. All of the sealers i have used have dried within 24hrs in almost any sensible temperature. I wouldnt attempt to sand a rubberised sealer as this will cause peeling and cause you problems.  Make sure the sealer is nicely dry (and all is v cean) before applying your top coat... 

[dub-disaster]

Thanks for the info chaps I'm going to have another crack at it today