Guys,

 

Need some advice. I'm spraying my BMW front bumper and have just finished the final colour coat. It's metalic so I have flattened it down with soapy water and 1500 grit. All looks great and it's not patchy. So I'm ready for my 3 coats of clear lacquer.

 

I'm thinking that the first coat goes on until dry. Then the 2nd and 3rd can be put on wet i.e. 2nd coat leave until tacky then 3rd coat on.

 

Question.

Do I 1500 and tcut after the last lacquer coat or just tcut or neither ?

 

Thanks in advance.

Why on earth did you flatten down the base coat!?!?!?! Don't ever do that if it's metallic, you'll screw it up. Repaint it.

 

It's the lacquer you need to flat back after you've painted. Lots and lots of thin layers of lacquer.

Are you sure. I was under the impression that you always flatten metalic before the lacquer coat !

as si said the base coat should be from the gun.

 

if you are using 2k laquer then the finish should be good without wet sanding. 1st coat should go down thin then the final two coats can go on wet.

 

i would only do 3 coats of clear unless you intend to flat it back alot, i would also add some flex addative into it. without the addative and with too many coats you will end up with cracks when the bumper expands.

 

im by no means an expert but i have been doing lots of research as im spraying my zed in the next few weeks

 

also just as a bit of advise make sure you correct any problems at the level where they occur, you cant fix a problem in the base coat once the clear is on.

Ok, I'm out voted so I guess I'm wrong (plus Si is always right ;) )

 

I'll repaint it tomorrow without the sanding before the lacquer.

Are you sure. I was under the impression that you always flatten metalic before the lacquer coat !

 

Absolutely not, under no circumstance. You'll have ruined the natural way the metallic particles fall on the surface, thus making it a different colour. Because you can't polish it, when the lacquer is applied, you'll be able to see sanding marks through the clearcoat. You'll NEED to repaint it.

As Dougal said, do you have plasticisers in the paint? I know some BMW bumpers are very rigid, but the newer models use a thin ABS plastic and flex a lot. If it's an E34, you'll be ok, but anything newer, the whole thing is made out of a flimsy lightweight plastic that will flex.