10 replies to this topic

[minipete]

Hi all i'm having some problems with seam sealer on the underside of my mini,i've painted the new metal with etch primer and now i have come to putting seam sealer on to all my welds and gaps etc,but when i do it drys and shrinks leaving me having to recoat the seam sealer. I've tryed two types the Upol Grey Stripe and some from my local paint suppliers same thing happens. I even bought a proper brush to put the ss on. Any ideas? Should i have ss before primer?

Edited by minipete, 08 August 2015 - 09:17 PM.

[minipete]

Basically has anyone had seam sealer react with acid etch primer?

[eean]

I haven't as yet, did all the boot floor repairs and shultzed after etch primer etc, I did lag it on though, don't be trying to spread it too much, put plenty on, etch primer should accept anything really

[Daz1968]

I had problems with seam sealer and zinc 182 primer as the solvent in seam sealer softened the primer maybe you are having similar reaction. I have since changed to only using 2 pack products as they have less problems and epoxy primer is very good. I also used seam sealer in a mastic tube not the brush on stuff as that seamed to have even more problems as when brushing on it was easy to disturb underlying coats

[minipete]

Thanks for that lads,might be i'm putting it on to thinly and it seem to disturb the layers underneath. Daft question but what sort of brush do you use? I bought a special ss brush but i was using a cut down 1" brush with short brissles and it was better to use. I just don't want to be putting on two coats of the stuff on.

[Daz1968]

I would just buy some pu sealant in a tube and put it on with a mastic gun then smooth over with your finger, panel wipe or water stops it sticking,

[minipete]

Just been out and put some more on alot thicker this time,see how it dries. Thanks.

[59 Speed]

I would just buy some pu sealant in a tube and put it on with a mastic gun then smooth over with your finger, panel wipe or water stops it sticking,

I also used panel wipe on my finger to smooth it, ends up with a very neat finish. I wouldn't use water as the moisture would get through the porous primer and start to rust the panel underneath.

Ps
If you apply etch primer on top of the seam sealer it may lift the edges of the seam sealer.

How long are you leaving the etch primer before you apply the sealer?

[spiguy]

Stick it on a decent thickness, say an inch wide and 1mm or so thick.

[minipete]

The etch primer has been on over a fortnight now,lastnights effort has worked i put a heavier coat on. Thanks all.

[JonnyAlpha]

Guys I am not an expert but just some observations and my opinions based on what I have learnt so far:

 

Etch Primer - Designed to go onto bare metal only, it eats into the metal to provide an effective protective coating, not to be use over anything else just bare metal, so I would not paint any Etch Primer over the Seam Sealer.

 

Seam Sealer - best applied over a primer, not applied onto bare metal, etch primer or Epoxy Primer would provide a better first layer.