As above really,

I have a auto ds cada front bumper, zender sideskirts and rear skirt which I got off the forum which are in red and scotts green so I want to paint them in portofino.

Do I have to re-prime them before painting and if so can I use a plastic primer... though I have read on a previous post that fibreglass doesnt need primed.

Thanks

Never use a plastic primer for fibreglass.. If the parts are painted, doesn't need primed.. for unpainted fibreglass parts use primer as for the metal parts..

Thanks Mariusz,

All parts are painted... Should I use a scuff pad to give the the paint a good key? then apply the basecoat?

The problem with leaving the old paint on is that everytime you pick up a stone chip it could show through red or green.

Yes key up all parts , if any sratches sand and feather paint edges.

I my self would prime the whole parts too, Porto doesnt cover too well . Its mostly a binder a clear base , 1ltr is roughly 1000g and around 800g is binder in the paint systems ive used.

And yes the stone chip problem 16veetee has said .
Also do any sanding dry dont want any water getting trapped in the fibreglass if you get down that far . It can/will cause other problems.

Are the grey 3m scotch pads okay for that?

The bumper is in red at the moemnt so not sure how the portofino paint is going to cover and the skirts are green. I colour coded the sills and the black sections on the original bumpers when I first got the coupe and it turned out pretty well, didnt seem to have any problem covering and I done it all with spray cans which I shall be using again with the skirts and bumper.

The chip problem is a little bit of a worry but what else can be done!

Not much really which won't be:

A. Time consuming (sand it off).
B. Costly (Soda blasting).

Alsong as paint is sound yes grey scotch till nice even dullness is acheived.

I wouldnt put porto over red myself . It will look covered but under sun gun or different types of lighting you may notice different shades even if good match .

Either prime to one colour or block it all off. Try not to go through gel coat though.

No.. no.. Portofine, in fact.. Portofino doesn't cover too well, but probably if you will use light gray primer varnish, everything will be OK..

I have a better solution.. buy new parts from me..

Maybe I should go with a grey primer for all the kit first then! Is there a fibreglass primer you would recommend... Upol etc

On the old painting use you standard primer (not for plastic or fibreglass).

Something like this Upol do for priming?

When I was painting Fibreglass the advice was to use an etch primer. This was over 10 years ago so maybe normal primer has come on a bit. Anyway the etch primer did the job.

I did some layers of spray filler before paint, and sanded. To even out the wobbles you always get in fibreglass things. Did wonders and they look like plastic now!

Ive not had a proper look at the parts since they arrived but on quick inspection the bumper has a few scuffs on the underside and I think one on the sideskirts so Ive ordered some glassfibre filler, 3m scuff pads, portofino paint all from .paints4u.com

Would a primer filler be any good for filling stonechips on the bumper?

No dont fill stone chips with primer

2 options

1.Sand them out
2.Key up item and use a stopper on them flat back prime, repeat if needed with stopper after flattin primer if some still show. Do not use a 1k putty type product.

If you want to prime whole item to one colour white or grey then i would use a good 1k spot repair primer if the old paint is sound.
Most major auto paint manufactures do one such as Sikkens/Lesonal/Octoral nice stuff drys and sands good. It will need to be preped well if you use this i.e ready for basecoat. The can or website will have the TDS on how to use these products.

Thanks Think I shall go with this option... which stoppers from paints4u.com would be suitable? some seem to be putty.

Before you go ordering any more stuff , what have you got and how are you going to prep and with what?

I have:-

P40 glassFibre filler for filling the scuffs on the bottom of bumper.

Grey Scotch ultra fine pads to give the parts a key

Tack rags.

3 porto 466 colour match cans.

cans of Upol primer and Upol lacquer though I will need to check what type of primer it is and if suitable for glassFibre.

Not sure whats else I need for the job? The local spraystore should hopefully have it if need be

Still need more stuff, What tools do you have ?

While i said dont fill the stone chips with primer , it all depends how deep they are.

In ideal world you would sand them all out , but for the primer prep some will go anyway .

Get the bumper in primer . Once primed they may still look to be there but as you sand it all down the low and high spots will level out. Then check for any stonechips remaining, that way if there is any then get some stopper.

When it comes to flattin the primer leave till its dry and ready to flat down.

If you choose to wet flat the primer dont paint it too soon as you dont have compressor and air blower to dry it off and get mositure out. but do rinse the flattin residue off with clean water and wipe dry with blue workshop tissue. Leave it over nite say to dry out more .

Read all the data sheet on the products you are using to fully understand how to use them.

What sort of tools will I need?

I think it's chipped down to the primer if that's of any help, I shall get a proper look at it tomorrow.

Do you suggest that the bumper is primed purely because of it being in red and it may show through the portofino?

Blimey you have been a fountain of knowledge for all my painting questions...