Painting my conversion bumpers.......

[BoBbOrAzE]

Hi, a while ago I purchased a used white 2gb front and rear bumper. My car is black and I plan on hanging up the bumpers and painting myself with my HVLP gun, compressor and the correct kalapana black and clear coat. I have read through a ton of the diy threads and they primarily all are concerning painting the entire car. A while ago after I messaged a guy he responded that the factory primer on the bumpers is fine and that all you have to do is correctly sand down leaving a thin layer of basecoat and paint over that then reclear and that will hold up just fine. My question is is that correct? Or do I need to sand down to the plastic and reprimer? and or do I need a "flex" additive as a shop told me? Or basically can anyone with paint experience please help me out.

 

[Liquidus]

Clean it with a wax and grease remover first, then sand it down using 400 grit sandpaper, then follow that up with 800. Blow off the dust and clean it again. You don't have to sand all the way down to the plastic and reprime unless the old paint is peeling off. The flex additive is added to the paint so that it can "flex" on the plastic without cracking.

If you really wanted to, you could prime the whole thing, it would help with paint adhesion. But depending on how good you sand it, you shouldn't have a problem with paint peeling.

 

[BoBbOrAzE]

hey thanks! So sand down to a thin layer of basecoat or down to the primer? and would you recommend wet sanding?

 

[ez1286]

Sand it down really well with 400, then clean it with acetone or you can go to a paint store and buy a cleaner specific for that purpose. Then prime then sand with 400 again. Clean it with cleaner again. Then paint, you may want to sand the basecoat depending on how it turns out. I don't know if you've eve painted before but with an hvlp it is really easy to make runs so go really lightly. You don't need a flex additive, thats only for old school paint.

 

[Liquidus]

Just sand it down lightly, try not to hit primer, if you do it's ok. Also, sand it down evenly, don't sand one area more than others. But definately don't sand down all the way to the plastic.

As for wet sanding, I wouldn't do it unless there was something wrong with the paintjob afterwards.

 

[BoBbOrAzE]

Thank you sooo much liquidus

edit: and you too ez

 

[BoBbOrAzE]

oh one last thing figured I would ask, if noone knows its cool. I have no idea how much paint is really used when spraying. To paint the front and rear will I need pint/quart/gallon?

edit: ha ok I just found another explanation site where the professionals said almost the same as the both of you. and also I am going with 1 quart.

thanks again

 

[Liquidus]

Just to warn you, painting a car isn't very easy. There are many things you have to consider. Two things you have to worry about are temperature and humidity, that'll affect what type of reducer you have to use in the paint. You should follow the instructions that came with the paint, you should also use the same brand, don't mix and match.

So to answer your question about how much paint to use, follow the instructions. But it's always good to have a little bit extra, that way you could use it as touch up paint, just don't put any catalyst in the touch up paint.

 

[BoBbOrAzE]

Thank you that is very good advice. and yes I definitely have done a ton of research and figure I have to start somewhere, and at least its not the entire vehicle and the bumpers are already off. The quart claimed to cover 40 sq ft and they claim 2 quarts covers a small car so I think I am set plus some extra.

I will be using all the same brand ordered from http://www.paintscratch.com/ , all they say is that for paint guns their paint has a 1:1 ratio with their laquer thinner, and it doesnt look like they offer hardener and reducer so I have already emailed them with questions about that.