Primer....how Many Coats?

[Wandy 1527]

I've been priming the body of my Buggy Champ with Tamiya's fine surface primer in readiness for paint. I laid down 4 coats then left it to dry for a week. I have now just given it a wet sanding with 1500 grit paper and the primer came off instantly. Am I doing something wrong or do I need more than 4 coats?

[Olly_Lunchbox 28]

Urgh....priming was the bane of my life a couple of weeks ago. I had exactly the same experience as you (and with the same car).

I wanted to make a real good job of my BC so did the same as you - three coats of primer then tried to wet sand (someting I'd never done before) but like you it just came off!

Started over and the same happened so the third time I did two coats of primer that I bought from Halfords - didn't sand it and just sprayed colour over that. Four coats of orange later and I think it looks fine. Haven't clear coated or polished it yet but I think it's going to look good.

I'm not good at painting and priming is a mystery to me!

Just wanted you to know that if you ARE doing something wrong you're not the only one!

[Wandy 1527]

Cheers, good to know it's not just me! Don't know about yours but I found that the primer came away easier at the angular edges of the body, of which there are many on the BC. I think it may have something to do with the primer itself, what with it being very fine. The upside of the stuff is that it goes on beautifully.

Anyone else out there with any tips? Is it necessary to spray across the body with fast or slow strokes?

[30cms 7]

rattle can primer is monumentally thin.

if you plan to wet sand it, put many coats on!!

or get some "high build" primer - panel man in a can as it is effectionately known in body shops

for spray painting with rattle cans - heat is the key

get everything warm - including the body. leave it in the airing cupboard before painting.

with the cans, get them warm too. a jug of almost boiling water helps!!

i sprayed my BC body with tamiya TS paint directly onto the white plastic, and it came out flawless.

[VagabondStarJXF 350]

Nice. Where did you get the TS paint from?

[30cms 7]

i got the ts-10 paint off ebay. 6.99 a can.

i used about a can and a half of the stuff. it goes on beautifully!!

i sprayed the shell in my "spray booth" in my garage

to get this paint to go on nice, i heated the body in the airing cupboard (above the hot water boiler) and heated up the cans before use in just boiled water in a jug.

heat gets the pressure up in the can, and helps it go on.

i sprayed the inside first, and let it dry.

then the following day did the outside.

do thin coats at first. when the body was dry enough to handle, i put it back in the airing cupboard for about a week

remember it takes 7 DAYS for spray can paint to fully harden!

[raysan 38]

I can share some tips with the wet sanding of the primer. When you use water the paper stays clean and this will make it cut vey well, which in normal situations is ideal. One way i use to stop to much paint from coming off when sanding off the high points (dust dried in the paint) between coats is to rub the paper ( 1500 grit works fine ) on a clean scrap of plastic without water. This will 'dull' the cutting surface of the paper so it doesnt remove too much paint. Another thing worth trying and i do this also is to not use any water. The paper will fill up with dust after a bit but you throw it out and get a clean piece as soon as this starts to happen, important not to sand with gummed up paper, you can even wash it out in water and use it later sometimes. The beifit of this for modeling is that between the work and the paper will be the dust particles also helping to keep the paint where you want it but at the same time the paper is cuttng down the high spots. Another benifit of dry sanding is the paper stays firm and wont bend around corners with the water suction thus helping to save your nicely painted/primed corners. Also using a small piece of paper folded neatly in half will concentrate the sanding area and you're less likely to get the corners without meaning to.

Hope this will help.

[30cms 7]

another tip for primer sanding is to apply a "marker"

after you have primed, give the shell a LIGHT dust of another colour (eg a dark blue or red, or whatever you have just NOT too similar to primer colour)

that way, as you are flatting, you can see easily where you have been, so you are less likely to go through the primer

keep going until the marker has all gone, and you are golden.

also never wet sand filler. you'll just annoy it.

[raysan 38]

also never wet sand filler. you'll just just annoy it.

Annoy it it right , it will also drink the water and moisture is bad.

[Wandy 1527]

So dry sanding the primer is the way forward....but do you have to dry sand the paint colour too before applying clear coat? And what about sanding of the clear coat?

[raysan 38]

On my models i give a gentle sand between paint layers but thats it. The clear coat goes on fine in my experience without the need to sand but it would depend on the finish of the paint and the type of final finish you're after. On the BC i did the other week there was only 3 coats of the TS french blue and no clear coat and no polishing. If you like ill try and get some pics up for you later on. I'm pretty happy with the result, its going to get scratched up anyway so i didnt worry about the clear coat. It was also done on the balcony 18 floors up so it was a bit windy. Keep in mind, the more layers that go on also increases the chances of something going wrong.

[chris350z 0]

what is the best plastic primer?

[igbandy 34]

I recently repainted my Hilift, and for a long time I have been a fan of Halfords plastic primer. This time tho I gave the Tamiya extra fine primer a go, and I am impressed. It shoots lovely, and it dry sands great. I too found out that it doesnt like being wet sanded. But its that fine it doesnt need alot of sanding anyway.