Help with paint problems please (what a mess!)
Russell - 18/4/10 at 05:54 PM
I've just sprayed grey primer on my gearbox and it's done this:
Image deleted by owner
What's going on? I'd previously comprehensively cleaned and degreased every nook and cranny of the gearbox then hand painted it using
"special metals" (including aluminium) primer, which went on with no problems at all. That primer has had 6 days to dry.
I decided to give it a blow over in grey primer ready for a silver top coat since the ali primer is a sort of desert sand colour - you can see it all
yellowy where the paint has crinkled.
Please, can anyone tell me what's causing this and give me any tips to prevent it happening in future?
Airhead - 18/4/10 at 05:57 PM
That looks like a reaction between the two primers?
Anybody?
boggle - 18/4/10 at 06:02 PM
did you not want a crinkle effect??
gingerprince - 18/4/10 at 06:05 PM
Looks like this
Rescued attachment 090_024.jpg
MakeEverything - 18/4/10 at 06:07 PM
quote:
Originally posted by boggle
did you not want a crinkle effect??
Like Boggles skin?
I had this problem ona fuel tank. The sand colour primer was primer filler was it?
The only way to get around this now, is to get rid of all the paint and start from scratch, making sure the paints are compatible.
Russell - 18/4/10 at 06:08 PM
Nope, I definitely didn't want a crinkle effect 
. Maybe I could get away with a crinkly gearbox but it hasn't happened all over, just in
patches. The photo above shows the worst bit.
Russell - 18/4/10 at 06:10 PM
quote:
Originally posted by MakeEverything
quote:
Originally posted by boggle
did you not want a crinkle effect??
Like Boggles skin?
I had this problem ona fuel tank. The sand colour primer was primer filler was it?
The only way to get around this now, is to get rid of all the paint and start from scratch, making sure the paints are compatible.
No, it wasn't primer filler, just regular brush on ali primer
MakeEverything - 18/4/10 at 06:15 PM
quote:
Originally posted by Russell
quote:
Originally posted by MakeEverything
quote:
Originally posted by boggle
did you not want a crinkle effect??
Like Boggles skin?
I had this problem ona fuel tank. The sand colour primer was primer filler was it?
The only way to get around this now, is to get rid of all the paint and start from scratch, making sure the paints are compatible.
No, it wasn't primer filler, just regular brush on ali primer
ok, sounds like a similar problem to the one i had though.
Try rubbing off, and spray the whole lot over with a tin of normal white primer.
Ben_Copeland - 18/4/10 at 06:35 PM
Yep definately reaction between the two paints. I'd just leave it as you probably won't see it anyway
prawnabie - 18/4/10 at 07:01 PM
I take it the first primer was a hammerite product?
Russell - 18/4/10 at 07:02 PM
quote:
Originally posted by prawnabie
I take it the first primer was a hammerite product?
No, it was a Blackfriars one.
Fozzie - 18/4/10 at 07:04 PM
Another vote for dissimilar 'paints'....
Fozzie
Litemoth - 18/4/10 at 07:16 PM
You've put a cellulose based primer over an oil based one by the looks of things.
Same happens with dissimilar top coat/primer combinations. Try mixing a tiny bit of each together before you paint. If they 'curdle' then
avoid overpainting
Easy to be wise afterwards of course....
Gutting
Russell - 18/4/10 at 07:28 PM
quote:
Originally posted by Litemoth
You've put a cellulose based primer over an oil based one by the looks of things.
Same happens with dissimilar top coat/primer combinations. Try mixing a tiny bit of each together before you paint. If they 'curdle' then
avoid overpainting
Easy to be wise afterwards of course....
Gutting
Gutting indeed!!! It's going to take an age to sort out that mess. It's an Audi transaxle that's going in a middy so the gearbox will
be highly visible when the rear engine cover is lifted and I want it to look tidy. I can't just leave it.
Thanks for the useful tip about "curdling".
Mark Allanson - 18/4/10 at 10:05 PM
Its when you overcoat one paint with another when the lasts coats thinner is more aggressive than the first. eg You can coat celly with synthetic but
not vice versa
