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Solvent attack in 2k base coat.
po79 - 22/3/10 at 10:28 PM

Evening all,

I have a major problem with solvent attack in my newly applied base coat and need some help to fix it.

I applied 2k primer followed by my 2k polyester base coat and it all looked fine until I returned to the car to put the laquer on and there was several large areas of solvent attack on the worst panels possible (bonnet and roof among other areas).

I have rubbed these areas back with 800 wet and dry but Im sure that where the feathered edges are the solvent will cause some lifting again.

I was going to apply some more primer to these areas but I suspect that the feathered edges of that with be attacted to as the thinners may seep under the base coat that the primer will be on top of.

Now I have heard that the best solution would be to apply a light coat of my 2k lacquer to the repair areas and allow it to harden for a few days then give it a light rub down followed by dust coats of my base coat before recoating the whole car again with base coat then the lacquer.

Will this work? It sounds like the best thing to do as the lacquer will not suffer from solvent attack on its feathered edges but the one thing that does worry me is as the lacquer is so hard will I be able to feather the edges enough for it not to show through the final finish?

Sorry its a long post but I could really do with some help as my rent is up on the workshop space this coming Monday

Thanks,

Po79.


Glan Noye - 22/3/10 at 10:37 PM

http://www.u-pol.com/datasheets/tds/BAR-TDS-EN.pdf This will do the job!


austin man - 22/3/10 at 10:40 PM

use barcoat, I suspect you applied the topcoat too soon. Sometime you can get around these problems by putting a dust coat on. Warm the panel and apply light coats to create a barrier then spray your final coats on


po79 - 22/3/10 at 10:42 PM

Hi Glan,

I have some of that already but have been told not to use it a after a while it will sink under the paint.

Plus it still requires a high build primer over the top which will still mean feathered primer edges that will allow the solvent to seep under and lift the edges.

Thanks for the link though,

Po79.


po79 - 22/3/10 at 10:49 PM

Hi austin man,

I haven't put the top coat (lacquer) on yet as the reaction took place before I got to that stage.

I think the idea of using the fine coat of lacquer as a sealer sound like the most plusable way around this, it was something I heard many years ago from a professional sprayer, but just need to know if any one else has used this method or has any other suggestions other than the bar coat/high build primer route.

Po79.


steve m - 22/3/10 at 11:05 PM

I have just had all the fiberglass done one my 7 <<<<< in 2k BRG, and the Paint sprayer, did request that any primer be at least 2 days old, to allow for problems

Biggest problem for me, is all the bits are sooooooo shiney, they need to go on the car now, yet mate reckons i need to flat off with 1200 grit and soap, and then polish


Problem is I CANT DO IT !!!!!!

there all to shiney now !!


austin man - 22/3/10 at 11:05 PM

the laquer will act as a dry coat, I would make sure that the are to be sprayed is warmed the paint will dry faster, just had a problem myself with silicone and had to spay s dust coat or two on to cover the area I used a hot air gun to warm the area to be painted


steve m - 22/3/10 at 11:08 PM

Also why are you lacquering a 2k finish ??
2 k when its hard is like glass so will buff like a mirror


Peteff - 23/3/10 at 12:46 AM

I would think it's a basecoat and lacquer finish. Why do you have to flat off with 1200 and then polish if the finish is good ? I'd ignore anything your mate says, he probably read it in a book about cellulose paint.