Advice spraying metallic

[eric_knapper]

I've done several paint jobs using solid colours but this is the first time I will be spraying a Metallic. I will be spraying the same system 2K clear over base and I've wet sanded down to 800 grit the same way I do with solid colours. I have a few queries though do I have to change my technique of spraying in any way also for this project the doors will have to be sprayed off the car I have them mounted on stands and they would be sprayed at the same time but wondered if this would show up on the doors as a slightly different shade?.

The other issue I might have is shown in the picture below although I have done several 800 grit wet sanding passes I still have some dark areas in the primer and although feels glass smooth if you look at them with a magnifying glass it a slightly rougher surface. With the solid finishes I've done before they were not a problem but will these show through in a metallic?

Thanks
Eric.

 

[the snooper]

first of all its not any different with metalic base just apply as any other base
rough primer showing through did you flat it before the base coat ? also i suppose it could be dry base coat with not enough coverage

 

[steveo3002]

hmm yeah the primer doesnt look that flat , did you use a guide coat ?

for basecoats go a little bit lighter than if you doing gloss , you should see it even up as it dries , after its covered make sure the fan is wide open and hold the gun a little further back and put on a drop coat , basicly just wafting a light coat over it so that you dont see any patches or stripes

 

[the snooper]

also spray coats at 90 degree angles for even coverage

 

[the snooper]

just looking at that picture did you use a spray gun or cans

 

[eric_knapper]

Yes it applied with a spraygun. For the primer coats from the bare gelcoat it had 4 coats all the pin holes were then stoppered it was guide coated and sanded with 240. then another 4 coats sanded with 400. Then 4 more coats guide coated then wet sanded 600 grit 2 passes and 800 grit 3 passes.

I couldn't do a 90 degree spray pass on the roof or bonnet as it's impossible to reach though.

 

[steveo3002]

dont have to do 90 deg passes...just make a effort to be nice and even and watch out for stripes /heavy patches

 

[eric_knapper]

I'll add another couple of coats of primer to the body and see how it comes out again. As it's been wet sanded with 800 though will I have to go over the body with a lower grit to rough it up for some more primer to key?

 

[steveo3002]

no real need to apply more if you havent gone thru , id just give it another tickle with 800

if you do want to put more on...no need to rough it up further

 

[eric_knapper]

Ok thanks Steve, I think most of these dry lines are overspray the lighting is poor and difficult to see the fan on the panel and although i keep wet sanding it they don't seem to sand out very well although to the touch feel smooth. I assume that I would be wasting my time putting the base on until I get this evened out.

 

[the snooper]

i dont get the 3 passes bit do you mean that the same are only got (for want of a better description ) 3 rubs if that is the case forget it flat until you can see and feel it is smooth or you could be creating problems with it not been totally flat between coats

 

[eric_knapper]

Yeah sorry it's not clear what I ment by passes there what I should have said is that the panels have had three wet sanding sessions with 800 grit the surface is flat and smooth but these dark areas are when I think I had some overspray due to not seeing the fan in bad light conditions and although visible when running your hand over then it's just as smooth as the none darker parts. But if you get a magnifying glass out and have a real close look the surface is slightly rougher. So I tried extra sanding sessions but these areas remain may be I'm just not cutting it enough.

 

[steveo3002]

i recon it will be okay then if youve sanded it well

 

[eric_knapper]

I have the same issue on the back of the body but on a smaller panel that's not to bad to paint so I think I'll make a few gun adjustments put 2 light coats on that and then sand it back to see if it fixed the problem if it does then I might as well do the rest I've spent months getting this far an extra couple of days getting the primer right is the right thing to do.

 

[pearse9000rpm]

what best technique at spraying base coat metallic or pearl?

im now used to spraying 2k paint and 2k clear coat and have no problems in this area,

what best thinners should i be mixing my base with

all my base coat in mixed 2;1 with thinners

i tend to mix it with average good quality all around thinners out gallon jar

about 12quid for gallon

should i be useing different thinners

when spraying 2k paint/clear coat i tend to spray at 2-2.25 bar with gun 8-10inches from panel

what pressure and distance from panel should i be spraying base coat and in what way

very light coats or nearly wet coats or what


then when finsihing base coat and moving onto clear coat,

what best way to apply fade out thinners??

does mater if you do this when base coat is wet or dry

is much point using fade out thinners when fading out clear coat?


thanks

 

[pearse9000rpm]

anyone

 

[langy]

Although you can use normal 2k thinner in basecoat i find you get a better job using basecoat thinner.

anyone

 

[pedrobedro]

I use basecoat which is 1:1 mix with fast basecoat thinners. Your £12 a gallon thinners sounds like cellulose, fast thinners is more like £6 a litre. I use the same technique as anything else keeping the gun even distance from the surface and moving smoothly.

 

[pearse9000rpm]

so fast thinners would be better mixed with my basecoat???

and cellulose thinners is not as good

what the difference and what differences would i see in the paint

 

[langy]

2k thinner in basecoat, cellulose thinner in cellulose paint.

Basecoat thinner is for basecoat, sorry to repeat myself.

so fast thinners would be better mixed with my basecoat???

and cellulose thinners is not as good

what the difference and what differences would i see in the paint