Cellulose Paint Cracking/Spiders Legs

[NeilThornely]

Hey everyone, just spraying up a bumper in cellulose. It's been sprayed for about a month or so now, just been tidying up the lacquer and these little f****rs have appeared all over it! Many of these have appeared in the last week or so and the bumper hasn't moved or flexed at all.

Any idea what could have caused this? I know I did't use a plastic specific primer...that could be an issue. But I have another bumper (same ABS plastic, same primer/paint/lacquer combo) which hasn't had any issues like this at all....

I know everyone is going to say 'stop using cellulose and use 2k'...it's on the cards but not an immediate option.

All help welcome and thanks in advance

 

[the snooper]

they are cracks in the surface of the bumper not just the paint

 

[ajlelectronics]

Stress cracks. The only cure is to grind the surface out and replace it. Ideally some reinforcement on the back.

 

[steveo3002]

looks like its in the surface /paint to me

cant explain why it didnt do it with your other bumper ....id have blamed it on being celly myself its rather brittle

 

[500e]

If it is fiberglass & cracks are in the jell coat a tissue & flow cote will cure never had much luck just grinding jell on either Lotus,s Reliant or Gilberns
Looks as if they are lurking on bonnet as well
If it is modern stuff best of luck

 

[norsa]

Definitely not what you did but in the original substrate. As said, stress fracture. Probably in the paint. Flatting back is the only cure. By the way, plastic primer wont work on a painted surface, it only works on the plastic.
Nick

 

[Championship White]

I noticed something like this occur on plastic due to wiping off uncured paint (my stupid fault) with thinners - the thinners seemed to have caused similar damage. If this is an MX5 nose cone then they are hugely floppy too. I'm priming my plastic bumpers with epoxy - no idea if it's the right thing to do, but the stuff is very flexible and is as lung friendly as poison gets.

 

[the snooper]

I noticed something like this occur on plastic due to wiping off uncured paint (my stupid fault) with thinners - the thinners seemed to have caused similar damage. If this is an MX5 nose cone then they are hugely floppy too. I'm priming my plastic bumpers with epoxy - no idea if it's the right thing to do, but the stuff is very flexible and is as lung friendly as poison gets.

if it has original sound paint no need to prime

 

[Championship White]

Lots of stone chips and some deep scratches sadly

 

[the snooper]

Lots of stone chips and some deep scratches sadly

if you are flatting right back and expose plastic, get some plastic primer (aerosol) for the bare plastic then on with the epoxy should help stop it flaking off later on