The Spray Painting Thread

[Steve M]

How many coats of clear (acrylic) should normally be applied to allow for sanding, cutting and polishing?

Do I need to sand between coats of clear to help it stick or just do the coats within a small amount of time (enough to avoid sag though).

My paint tin (protec) says three double header coats. I think that's not enough as I'm using quite a thin mixture.

Advice would be appreciated on this topic.

[o_man_ra23]

I normally blow a couple of coats on, let it dry off, then lightly sand with a big board to get a smoother finish. Another couple of coats and repeat. Then the final coats go on really thin just to cover the sanding marks.

["Z" UTE]

How many coats of clear (acrylic) should normally be applied to allow for sanding, cutting and polishing?

Do I need to sand between coats of clear to help it stick or just do the coats within a small amount of time (enough to avoid sag though).

My paint tin (protec) says three double header coats. I think that's not enough as I'm using quite a thin mixture.

Advice would be appreciated on this topic.

SteveM, the "double header " coats refers to a pass in both directions with the gun in the same area. 3 double header coats effectively gives you 6 layers of paint. This will be more than adequate for colour sanding. Mixed as per the manufacturers recommendations you will probably have a fair amount of orange peel, necessitating the colour sanding.

If you add 10-20 more thinners in each coat, you will reduce the thickness of the cover, and also reduce the tendancy for orange peel. , so a fourth double header would be required. A 4 litre can of clear is most adequate for a Celica sized car, with some left over.

Allow a reasonable flash time between coats, you will see the paint haze over as it dries, but generally when you have totally finished applying the coat of paint/clear, you are almost ready to paint again from the original start point. Allow time for a quick smoko/coffee break, and then get back into it. After applying the 4 double headers, mix the remaining clear to a 90% thinners 10% clear mixture, and give the entire job a complete single header, then walk away. This final coat blends all the surface paint together, and dramatically reduces orange peel. Just do not go too heavy as you will get the dreaded runs. Temperature of the day, will play a vital part in the paint process, and please use the best quality thinners you can lay your hands on. For best results, I use 2K reducer.

cheers Chuck.

[DrNick]

Any advantage to doing a double header coat?
The way I was taught is ot do a single pass, I try and do this as wet as possible so its really close to the point of running.If I went back over the same area again it would run for sure. Is the end result the same?

["Z" UTE]

DrNick, yeah the end result is the same, some people can get away with a thick coat without runs some can't, same with double headers. The main advantage with a double header, is that you actually put some paint in the areas that may have been missed with the single pass.

cheers Chuck.

[Steve M]

Cheers guys.
I've been using a pearl matellic and have got that sorted out now.

Those tips shall be used on the clear coats for sure.

[TRD184]

hey guys,
my RA23 is in need of a respray, some parts need a good rub back before they can be painted, as a beginner, whats my best option when it comes to prep, sanding it back by hand with wet n dry, then spraying it with high fill primer? thats what i gathered from reading some posts here. i cant really afford to pay the paint shop to prep for me atm.

[o_man_ra23]

What is wrong with the paint that is requiring a "good rub back"?? If it has shrink cracking and compromised filler under it like my paint, then I would start with a random orbital sander and some 40-60 grit paper to get rid of all the stuffed paint and filler. Then go with a long board and gradually finer paper. I never use wet'n'dry until the surface has been sealed. So for a 2 pak paint job, you can use wet rubbing after priming, but for acrylic I would wait until the colour is on before wet sanding.

If your paint has just gone chalky on the surface, then you should be right to start with a long board and some 120 grit white paper (it has a soap in it to prevent clogging) to get the compromised layer off.

[TRD184]

depending on the area, its damaged by different things, most of it is just cracks in the paint, where it starts to flake off. my friend said the paint on the roof is "heat damaged" but i dont know, it just seems to flake away, back to the primer underneath, i might get some pics of it a bit later

[o_man_ra23]

If it is flaking away, then the layer under it is compromised. So you need to remove the flaking bits, plus the layer under. Depends on how thick the under layer is as to how roughly you need to sand to start with.

[TRD184]

oh. ... mmm bit of work to be done then, maybe im best just taking it to a professional and asking their honest advise on what to do.. or if i can get the car prepped and undercoated, then leave the car like that for a bit while i get the cash for the rest of the paint. thanks for the help

[o_man_ra23]

Depends what undercoat is used. If it is a 2 pak undercoat, then it will be non-porous, which is the important part, and you will be able to leave it a while without a top coat. Acrylic primers are porous and can't be left without top coat. Not sure about enamel primers or cellulose, as I really doubt you will be using it it shouldn't be an issue.

[TRD184]

oh ok, swell, thanks mate

[Z2TT]

Hi Guys.

I'm spray painting a plastic strip on my car and got a few questions.

1. I'm applying an adhesion premoter first. Does the colour coat require a flex agent added, or not needed since I have allready sprayed on an adhesion premoter?

2. Is this process ok that im using so far?

1. Sand old paint off with wet/dry paper 300 grit (Any problem with using 300 instead of 600 or finer?)
2. Wax/Grease remover to clean it up before paint
3. Adhesion premoter 2 coats, 10 minutes between coats to dry
4. Paint, 3 Coats I'm using Acryllic Enamel, 10 minutes between each coat
5. Allow 24 hours before driving car.

Thanks, is there anything I missed out?

Also I went and got the paint matched, but the paint seems a bit off, its similar but you can notice its a different colour by looking at the strip next to the painted one. Is it normal when getting paint matched to be off, or should it be pretty much spot on as the paint card the guy put next to the strip was exactly the same, but the paint he made up was different?

Thanks.

[H1TMAN]

Hey guys, can i use metho spirits or must I use was + grease remover on the car before priming?