Questions regarding dust/primer application.

[adzest]

Hi there, I'm from New Zealand, and just started modeling. My first car is a Fujiwhateverwhatever Nissan Silvia S14 K Autec.

I have removed the mould lines, and sanded the whole body down with 800 grit sandpaper.

I bought some clear automotive primer, espically for plastic. I made sure I shook it for the full 2 minutes, and put it in a jug of hot water to warm up. I sprayed it on, in a very fine coat first, and before I managed to put my cardboard box over the car/front bar, a few fine bits of dust settled on the wet primer, almost as if they were attracted to it. So I thought hmm this isn't good, but I applied another 2 coats with five minutes drying time between each one.

My first worry, is that when you run your finger over the car body, the primer has made it very rough, like bumpy, is it supposed to do that? Or are you meant to apply more/have the can closer so it goes to a clear glossy kinda thicker coat?

Also, I used the search function, and found that dust in primer doesn't matter too much, just sand with 1200grit paper and move on was the advice I got, but if it happens now, it will happen with paint and clear coat I reckon. What on earth do I do? I had the jug of water there, as pro painters have like water around them in a booth to attract the excess spray, maybe more trays of water around my little painting area?

This was done in my garage with the door closed also.

Thanks for the help guys/gals.

[ShOrtyOC714]

That is the primer dust, just wait until its dry and wet sand with 1000 grit. Good Luck!

[adzest]

Are you sure? Because I can definatly see red and black fibres sitting in my primer job, and the primer is clear...?

Here you can see the bumpy effect created, and the black but of dust:

[ShOrtyOC714]

Originally Posted by adzest

Are you sure? Because I can definatly see red and black fibres sitting in my primer job, and the primer is clear...?

Here you can see the bumpy effect created, and the black but of dust:

Like as i said, sand it. After reprimer and see if it improves, my recommendation to you is not to use "clear primer" because it is hard to see your mistakes because clear wont pick up the flaws like white or gray does.

[minniebanister]

I too am new to car modelling. At first I had a terrible time with getting dust in my paint - primer, mist coats, AND wet coats. I too, paint in my garage but keep the door open for ventilation.

Then one day the sun was shining in and it dawned on my what was happening. As I sprayed, the excess spray was hitting the garage wall and kicking up a huge cloud of dust! (Well it seemed like it was huge). So I want out and bought a $2 shower curtain liner and tacked it up behind my spray bench - to make a poor man's apology for a spray booth. It works like a charm and I haven't had dust problems since. So my advice to you is to check to make sure that the act of spraying is not what is kicking up the dust. Also, get yourself a plastic "tupperware" type of box to put over the model immediately after painting. There is too much danger that your cardboard box will be a dust source.

As for your bumpy primer: it is probably supposed to by "bumpy". Subsequent mist coats should smooth out the bumps. Don't put so much on that it becomes glossy. Primer is supposed to give a mat coat. Also, as ShOrtyOC714 says, try using gray or white primer - so that you can see errors easily and fix them before continuing.

[blueboost]

I have been applying coats of white primer to that exact model in your pic and my surface right now feels gritty and you can see/feel it has texture to it (its not smooth) as they've explained more lite coats of primer and a good wet sand will fix that, but its actually supposed to be like that in this stage of the game.

my question is, should some of the preliminary paint coats be rough like this also?

[adzest]

Thanks for that great piece of advice, I have done just that and bought a cheap shower curtain, I shall sand and reprimer later to see if it makes any difference. I did vacuum the box carefully, and I don’t think it will be causing the dust as the dist landed after spraying, and before putting the box down. So we shall see. Also probably too late on the white primer front, already started, and it might react…

Another thing, you said you have your garage door open when spraying? Wouldn’t that increase the risk of crap blowing inside and landing on your model? I had mine closed, and just opened it after spraying each coat to get the fumes out.

I’m thinking if this doesn’t fix the problem, I will make a booth (rather than spraying on an open table) out of a cardboard box, and use an old power supply to power a computer 12cm fan to suck all the dust out before it lands on the model .

Thanks guys.

[adzest]

Gah, just tried sanding it, 24 hours after application, and it kinda mushed around rather than sanding, so I assuse it hasdn't dried yet, dammit!

So its in a tupperwear container in the sun at the moment (not direct sun), and before it gets cold tonight I shall stick it in the nice warm hot water cupboard, hopefully dry enough this time tommorow to resand.

[ales]

I am not sure clear primer is sandable, guys. Besides, you shouldn't use it anyway because it doesn't have the filling properties that the white/grey primer has. So I suggest you strip it and use white or grey, depending on your final colour, primer. Good luck.

[adzest]

Argh! that would make a whole lot of sense. How on earth do I remove it from the body without it turning into a pile of melted goo?

[ales]

Well, for that, my friend, you'll have to read the FAQ (you should anyway) and perhaps search the forum

[adzest]

I have read the FAQ, and searched, and have come up with brake fluid and oven cleaner that remove paint but not primer (no help), and Castrol Super Clean which may or may not remove primer (but isn't avaliable in New Zealand).

I think the whole point of making a primer, is to be able to sand it, so even though I respect that you have been making models far longer than me, an unsandable primer defies laws of stupidity. I will wait and hope it dries. Unless someone else can reccomend something avaliable in New Zealand to remove primer...

[ales]

Brake fluid removes primer as well as paint. And if it's not dry after 24 hrs, I highly doubt it will be any "drier".

[adzest]

Man I love you guys, thanks so much for your advice and time spend reading my ramblings. Off comes the plastic primer tommorow, and on goes some white automotice primer :>.

[adzest]

So 10 days later, the body has been sitting in brake fluid all that time, I brushed the whole body with a tooth brush each day, and the primer is still there, hasn't even touched it.

So what do I do now? :<

Also broke one of the pillars scrubbing, how do I fix that?

BRAKE FLUID DOES NOT GET PRIMER OFF!