Paint Blistering

[yg649]

Tried a search across the forums - but it doesn't appear to be too common.

Polishing this weekend, I noticed what could be the start of a couple of paint blisters.

Clearly cannot be rust, however, definitely the kind of bubble that I would've wet-n-dried and got some primer on pre-Cerb ...

Paranoid ... and infact has always been there ... or potentially some bird crap or whatever that's caused some damage ?

Next steps are straight forward - however, just curious as to how prevalent it is ? Cerb's now kept underground - however, spent the first years of life on a driveway.

_L

[JohnSW20]

Hi
I have just one small patch about the size of an old 50p. It's one the bit between the end of the bonnet and the wind screen? I have no idea whats caused it???

Cheers

John

[mike_e]

JohnSW20 said:

I have just one small patch about the size of an old 50p. It's one the bit between the end of the bonnet and the wind screen? I have no idea whats caused it??? John

Stress fracture, quite a common problem in that particular spot. Seen this on quite a few cerbs now, including mine!

[malman]

Only seen it on one car and it was along the top of the curve on the door next to passenger window 3 spots about 4-5mm across. It was in a dealer and I know it got sorted before the next customer got it cause I've seen the car since and its looks stunning now.

[J_S_G]

Had the same problem on my Elise. It was because of the fact the car's fibreglass - chemical reactions occuring under the paint where it's not been pre-treated/whatever the technical term is properly. It was on the hard top which obviously hadn't been done to as high a standard as the rest of the car... Over the course of a few months it went from a couple of 1/4" diameter bubbles to a chain of them half the way across the roof.

Had it resprayed and that was that.

[yg649]

Must admit - I am starting to pick up a fair few stone chips (and I've got armorfend) ... Maybe more than a straight forward touch-up.

I've got the 99 London Motorshow Cerb. Could well have been finished off quickly as I believe it was demo'ing spyders, headlight pods etc.

hmmmm .... Could be Cerb's Christmas present instead of the car cover ...

[J_S_G]

yg649 said:

Must admit - I am starting to pick up a fair few stone chips (and I've got armorfend) ... Maybe more than a straight forward touch-up. I've got the 99 London Motorshow Cerb. Could well have been finished off quickly as I believe it was demo'ing spyders, headlight pods etc. hmmmm .... Could be Cerb's Christmas present instead of the car cover ...

I'm assuming that the Cerb's body has whatever is going to be done to the fibreglass, then the painting all in one. If it's proper chemical-reaction related bubbling rather than stress-related, then there's no real reason any part of the car should survive any better than the rest.

Personally, I'd take pictures of it every few weeks to accurately gauge if it's getting any worse/how fast. Fingers crossed it's just a one-off bit that can be taken care of along with a front-end repsray. Although I did once see an early Elise in a very sorry state where it'd happened all over.

[kylie]

Hi guys blistering is caused by trapped air bubbles in the lay up of the glass which have now made their way to the surface from being exposed to new temperatures. It is almost impossible to get every single little bubble out even under modern vacuum techniques. Professionals use a proper bake oven to post cure the finished article before spraying to ensure moisture and air has been taken out also so the article does not warp. It basically ensures that the resin has exothermed completely and gone to max strengths and hardness. Some people wrap smaller items in black plastic and leave outside for two days in the sun before painting so the imperfections come to the surface, just as good. But the idea is that they take the temps to 80deg C for at least 20mins. Most people use ovens to 60deg c which IMO is not good enough.

After this high temp post cure it is ready for painting. This also needs baking at the high temperatures again because white paint under direct sunlight will only get as hot as 50deg which is good. Red or blue gets to about 60deg and dark paints like navy, dark grey and black gets to 70-80deg c!!! Thats why many people get the initial bubbles, stress cracks etc mostly on coloured cars. Quite normal.

Trouble spots can be hit with heat to speed up the process of bubbles comming to the surface. These need to be ground out and filled with catalysed polyester gelcoat. All areas then are to be cleaned with a prepsol before spraying.

Cheers
Kylie