The Spray Painting Thread

[JZA70R_92]

another question is painting mettalics that hard....guy at shop said due to doing it in a carport its best to do jetblack rather then ruby pearl....he said better to spray jetblack with clear coat to get a glossy shine...do I really need clear with a jetblack???

[-==L=a=N=c=E==-]

of all the colours, black is the worst to paint, as it will show every single flaw. Your better off with the metallic!


Also with a solid colour, they are often single stage, so don't need clear on top. They buff up real good.

[JZA70R_92]

he said something along the lines of if the metallic goes on not so ok you cant colour sand it only the clear coat and with solid black you can sand it.

[o_man_ra23]

He is correct, however I managed to spray my YZF fairings with metallics in open air during a very windy period without muffing it. The clear got a few specks of dust in it and wasn't perfect, but the colour was good. Found it easier than spraying a solid colour.

Agree totally with Lance, Black should be avoided at all cost unless you pay big dollars for a really good body worker to get the prep work straight first.

[JZA70R_92]

lol ive been sanding like hell for 2 weeks now still working on primer as I waint it 100% flat....I may go with jetblack as its cheap and in a few months time ill be replacing the rear panels so no need o waste mettalic

[timbosaurus]

lol ive been sanding like hell for 2 weeks now still working on primer as I waint it 100% flat....I may go with jetblack as its cheap and in a few months time ill be replacing the rear panels so no need o waste mettalic

No offence, but sanding doesn't get panels flat. Planishing does

Through experience... the more you sand, the wavier it gets. Spend more time planishing to get the metal smooth, then you only need a quick etch/highfill/spray putty and single sand/guidecoat. Two coats max.

[o_man_ra23]

You should be using a long board sander if you want it smooth. You can get pretty good shape by sanding, but as Timbo said, your panel won't be flat.

[timbosaurus]

A lot of people (myself on my first car included) over-sand their car.

The impression I had was that the more sanding i did, the smoother/better it will be. Unfortunately smoothness is only part the job... flatness is more critical other.

Metal wants to be flat, applied properly bog likes to go on flat, but the more you spray/sand/spray/sand/spray, the more you fuck with the flatness.

I understand that some people like to use bog, but you should use a file to get bog to 99% of the shape in 10 mins... no need for days of sanding

Minimal use of a long flat block (as mentioned above), as opposed to days of hand sanding, will dramatically improve the finish.

[o_man_ra23]

http://www.thefind.com/office/info-2...-sanding-board

These are the types of sanding boards I am talking about (for reference). Your local paint supplier should stock them and the sandpaper to suit. Make sure the sandpaper is readily available in the size and grades you want before deciding on a sander to buy.

[DrNick]

What size board do you recommend? I mostly use a cork sanding block now, but it only really works for small areas of repair. Anything bigger than a few inches ends up with ripples and takes ages to get them out.

[o_man_ra23]

Big. But you need to size it according to the paper available, so go to your local supplier and find out what sizes of sandpaper they stock. The longer the better. I have used the 2" wide ones, and they are fantastic.

[timbosaurus]

What size board do you recommend? I mostly use a cork sanding block now, but it only really works for small areas of repair. Anything bigger than a few inches ends up with ripples and takes ages to get them out.

Yeah, that's exactly the problem with small boards a long (30cm) flat board with not-much-give in it is the best.

Also, use the coarsest paper you can (within reason). Two or three strokes with 120 grade paper will give a make flatter surface than two or three hours with 600 grade. You'll obviously need to progress down to the smoother stuff for finishing though.

One thing you need to be careful of when using the coarse paper is... if you have deep gouges or scratches in the bog, do not just leave them there and fill them up with multiple layers of spray putty. They'll always end up showing through, or worse... bubbling up with the moisture that seems to collect there from the air.

[DrNick]

Sanding board is next on my shopping list now I will see what is available.

What is the technique for avoiding ripples around areas that have been filled ? It seems to be pot luck with me, sometimes they are very visible. To practice a bit I took off part of the spoiler from my celica to fill up the antenna hole. I fitted a metal plate to the underside and did the following

1. Filled the hole with 2 part polyester filler
2. Sanded this back so it was level
3. Filled the small pit marks with K&H "Stop Putty" (Red stuff in a tube)

Now, I sanded this back but I find that as I am sanding it I can feel it raised, so I keep sanding more and more and then suddenly I can feel an edge with my nail. This piece im working on has a perfect circle cut out of it so I can feel this through all the filler.

Next I sprayed some primer surfacer on it, I had this mixed quite thick so it should fill up any little grooves.

I wet sanded this first with P400 to get rid of a big raised edge and then more carefully with P800. Again same problem, I could feel the raised edge, but as I sanded more the surrounding areas started to rub through (this can be seen as it is red underneath the primer).

Finally I stopped when it felt smooth to touch, but if you hold it up to the light (or camera flash) the circle of filled area is totally obvious.

What steps am I doing wrong here?

Pics :

Metal plate on back to cover circular hole from antenna

.

The results which has a very distinct circle showing through the primer

["Z" UTE]

Hi mate, yeah been there done that.

The problem is the metal plate underneath is FLEXING!

And for gods sake piss that K&H stop putty off. That stuff is effectively paint solids, and will pull out with sanding. Use a high quality poly filler such as PPG Microfine. The good polly fillers such as PPG Microfine will fill all your little scratches, and it is made to adhere to paint.

cheers Chuck.

[DrNick]

Oh I only recently discovered the K&H stop putty and I thought it was a good find Is the PPG Microfine a 2 part filler or is it the same sort of deal in a tube?

You could be right there about the metal plate flexing, although it is quite rigid to touch. However I have also had the same issue with the edges showing up even in areas where I'm filling up a small dent which has normal panel underneath it. Does this mean the filler itself is too soft?