The car got the bonnet, roof and spoiler resprayed last week at the time I thought they had done a pretty good job, the finish looked top notch however I was washing the car yesterday and noticed on the bonnet a few small lumps, they are small but they are there. It looks like small bits of dirt trapped under the paint and have been resprayed over causing the small lumps. I'll be taking it back tomorrow but i'd like to have some knowledge on any possible cause, i'm presuming it hasn't been thoroughly cleaned before they started painting. If anyone has had this and knows what it is any info would be great, I dont want to go back without having a clear idea of what could have caused this.

Got some photo's though not sure how well they'll show the lumps;

I should mention it appears to only be on the bonnet but will give the roof and spoiler a thorough inspection tonight.

Thanks guys

You are correct, it does look like a spec of grit/dust under the paint.

It's more likely to have landed on the paint between coats when it was wet, either in the black colour coat or the laquer afterwards. It's probably not from the original paint as the 'old' paintjob would be rubbed down to remove any imperfections such as this.

I've painted a few cars/bumpers in my time and this type of thing happens a lot, it comes down to money/time/reputation depending on wether the sprayshop will be willing to fix this for you.

They may be able to get rid of it with a bit of 're-finishing', where they rub the grit out using wet and dry, and then building up the gloss shine again using polishing compound. It's not without risk however, as the spec of grit may leave a tiny white spot where the black paint has been removed. Again, it's down to time and money, and the garage may be in the situation where they have to spray the whole ting again from scratch. I guess it depends on how good the garage is, and how pushy you are. Good luck

IIRC they are caused by silicones on the surface before painting. A result of using silicone-based polishes before painting, or bad/insufficient prep...

Cheers guys, I'll admit they did give me a very good price but in my oppinion they haven't correctly finished the job so they have to fix it or do it again. The guy I dealt with is a friend of mine and he said any problems to come back so I think thats what i'll do!

Can be hard to avoid in a busy bodyshop, if people are working on multiple cars at the same time. Really good shops will have a sealed spray booth well away from other work being done.

Can be hard to avoid in a busy bodyshop, if people are working on multiple cars at the same time. Really good shops will have a sealed spray booth well away from other work being done.

From what I remember the bodyshop I used seal of the main work area when spraying is being done, all other work is done outside or waits intil respray is complete. I find it strange that only the bonnet is showing signs but then again it was removed from the car where as the roof and spoiler where done in situ.

Spoke to my mate who works in another bodyshop, unfortunately his professional eye picked out some bigger problems.

Bonnet

3 dings

Crap under the laquer causing lumps

Roof

Not properly polished

Spoiler

One edge has been burned with a DA

He thinks that they probably haven't polished or if they had not very well. Will speak to them tomorrow and see what they say.

IIRC they are caused by silicones on the surface before painting. A result of using silicone-based polishes before painting, or bad/insufficient prep...

Silicone based products cause's the paint to 'fish eye' and leave's circles in the paintwork, what were seeing in the pic's above is little bit's of crap in the clear coat, by either not flatting and polishing the paintwork to leave a smooth glass like finish to remove contaminants which are present in the air whilst the car was being sprayed.