How To Request - Priming

[Headlight]

Hi Guys,

I know that there have been many threads on how to prepare a body for priming and stuff , but I know that there is no thread or "How to" for priming to properly follow with "step by step" instructions. Maybe it is a simple concept for some, but I'm sure that there are people that would like to have this "step by step" guide. I was wondering if someone could do an in-depth "How To" for priming .

Thanks
-Headlight

[dag65]

This one by P-man pretty much sums it up
http://www.automotiveforums.com/vbul...ad.php?t=59123

What kind of in depth detail are you looking for? Or do you have some specific questions?

[Headlight]

Originally Posted by dag65

This one by P-man pretty much sums it up
http://www.automotiveforums.com/vbul...ad.php?t=59123

What kind of in depth detail are you looking for? Or do you have some specific questions?

It seems that no-one has asked the question, "Should you sand in between Priming coats?" . If so, then can you just wash it again after the sanding process to remove the paint particles and if you do then should I use soap again???

-Headlight

[dag65]

Originally Posted by Headlight

It seems that no-one has asked the question, "Should you sand in between Priming coats?" . If so, then can you just wash it again after the sanding process to remove the paint particles and if you do then should I use soap again???

-Headlight

You can sand between coats if needed. But if its smooth move on to the painting. Be careful not to sand too much or the paint won't stick to it if its too smooth.
If you do sand you should wash it to remove all the sanding particles and more importantly remove any oils that may have gotten on the model from your hands. I should mention that any sopa you use should not have any hand moisturizers or lotions in it, I use Dawn dish detergent.

Good luck

[Headlight]

Thanks, that does help. What I think I'll do is after the 1st coat, I'll sand it down to remove any defects and dust particles that got in there after the paint job. Then I'll add a 2nd coat and then a 3rd not sanding in between the 2nd and 3rd coats. After the 3rd coat, I'll just sand very softly to get the surface level all over.

Should that do it?? Any advice would help

Thanks
-Headlight

[dag65]

Sounds good

[primera man]

I would only sand the primer if it needs to be done.
If you have orange peel etc...then sand.
If the primer is OK dont bother to sand as all this does is cause dust which if not cleaned off properly will show up in your finish coats.

[Hiroboy]

I use Halfords primer which IMO always needs sanding down to get smooth. if its a straight OOTB kit with no mods one good coat then top coat.
But if you are making putty etc mods often you prime 3-4 times so you can check the smothness etc, but in the end, I also wash in plenty of luke warm water with no cleaner and let it air dry so you get no fibres etc.
I think everyone has a different way, in time you will find what suits your make of primer and top coats.

[David_]

is primer actually nessecary? could i make a shiny model without primer?

[Headlight]

Originally Posted by Hiroboy

...I also wash in plenty of luke warm water with no cleaner and let it air dry so you get no fibres etc.....

How long should I leave it to dry in between coats?? I remember once before Primera Man saying that you should leave it for a full week after priming to allow it to harden to prevent shrinkage. Is that also between coats? ie. If I am putting 3 coats of Primer, Do I really have to wait 3 weeks before I put on the finish coat??

Also, I put on the second coat of Primer last night but I just cannot seem to get rid of at least 1 or 2 Dust particles getting under the paint. I mean, I wash it and all and then put it straight into a container, but when I take it out and dust it off with a Soft brush but there will obviously be 1 or 2 particles floating around which settles on the surface !! What can I do to prevent this and do I have to now sand those particle out again and add a 3rd coat??

[Hiroboy]

Originally Posted by Headlight

How long should I leave it to dry in between coats?? I remember once before Primera Man saying that you should leave it for a full week after priming to allow it to harden to prevent shrinkage. Is that also between coats? ie. If I am putting 3 coats of Primer, Do I really have to wait 3 weeks before I put on the finish coat??

Also, I put on the second coat of Primer last night but I just cannot seem to get rid of at least 1 or 2 Dust particles getting under the paint. I mean, I wash it and all and then put it straight into a container, but when I take it out and dust it off with a Soft brush but there will obviously be 1 or 2 particles floating around which settles on the surface !! What can I do to prevent this and do I have to now sand those particle out again and add a 3rd coat??

I leave forabout 5-6 hours at Ambient room temp to dry. if you then have a few bits of dust, you should be able to carefully sand off/out with micromesh etc and not have to re-prime

[Headlight]

Originally Posted by Hiroboy

I leave forabout 5-6 hours at Ambient room temp to dry. if you then have a few bits of dust, you should be able to carefully sand off/out with micromesh etc and not have to re-prime

Is micromesh some sort of special sandpaper?

[ratdat]

My priming process always involves flatting the primer. I also use Halfords grey primer. After the normal prep/sanding, I wash the body in warm water and mild detergent then let it dry for 2-3 hours. I find using warm water actually makes it dry faster. Then I do three mist coats of primer at 10 minute intervals followed by one heavy coat. I let this dry overnight then wet sand it with 1200. This sorts out any imperfections and allows you to find any obvious defects. After sanding I wash it as before and allow it to dry. Then I prime again...same process as before, only this time I only mist coat bits where I sanded through the primer. The heavy coat is a complete coverage though. This I allow to dry for a couple of days before wet flatting it with micromesh (it's like an abrasive, rubbery cloth), usually with 3600. After this I wash it thoroughly in warm water with a little detergent. I scrub it with a very soft brush to make sure all the residue from sanding is out of all the panel lines etc. After drying it's ready for paint.

I have to admit I dont store the washed car in any kind of container, I just sit it on the paint stand in the booth (okay .taped to a spray can in a cardboard box ) I don't seem to have a problem with dust in the paint though. I do use car paint where possible though as it drys much faster. I find I do get little bits in the paint when I airbrush enamel but I expect it's because of the drying time involved. Even then, it usually polishes out with micromesh.

I guess if you are using a proper model primer, or you are airbrushing the primer on it would probably go on smooth enough to not require flatting but I like to do it anyway for peace of mind..that way i know there are no little bits or lumps in the primer before the paint goes on.