Paint Advice Need!

[ryan-92]

Hi there i am going to paint my car from green to black i have sanded the whole body down filled any dents or imperfections in, but i am stuck as i have been reading about different types of paint reacting badly with each other, so before i go and buy a big tin of paint to spray on the car i wanted to make sure the paints wont react. I think my car has 2k paint on it at the moment which i have sanded rather than stripping back to bare metal, i need to use high build primer which i was going to get 2k, and then probably use a high gloss black enamel for my top coat, will the primer react with the original paint i have on and will the new primer (2k) react with the enamel top coat or would it be best to use a celleous top coat instead of enamel? and which would give me the best finish out of the two? any help would be much appreciated or advice Thanks.

 

[chopolds]

There are many ways to do things in the paint biz, i will give you MY idea of what I'd do. First, it is not necessary to shoot the whole car in hi-build primer. I would only put in on the areas you have filled, to be sure to get out all the imperfections and sand scratches. Guide coat and block out carefully. Clean, and shoot a coat or 2 of sealer over the entire car, and you're ready for your paint. Paint reactions are getting less common, due to the use of better quality paints. The only paint you might have to be wary of, for reacting, is a cheap enamel. Either synthetic, or acrylic, uncatalyzed. Just about all other paints will be fine to refinish in this manner.
If you believe you car was an object of a cheap-o paint job in the past, then you may have a problem paint on it. Then you need to re-evaluate what you are going to do with it.

 

[TAZ]

Normally if the paint job is in decent condition and it's an older job, then you're fine in putting your primer over the existing paint.
You will also be fine putting an enamel over the primer. Enamel is not a very aggressive paint anyway (actually it's the reducer or thinner that is normally what causes any problems).
Like chopolds mentioned, it's not as common to have problems anymore like maybe 20 years ago or so.

 

[ryan-92]

Ok then brilliant, Thanks you for the advice, the cars about 15 years old the car but the paint is in good condition i also now know for sure its been painted in 2k paint and its never been resprayed. I am going to go with cellulose paint, they sell high gloss thinners also which it says to mix 1:1 the top coat however says its cellulose acrylic a and you said something about acrylic reacting possibly what would you recommend knowing that the paint is professionally factory done? and i am going to primer straight over the existing paint i have sanded it down and filled the bits that need to be filled so there's plenty of key for the new paint paint. but what's the difference between cellulose and cellulose acrylic or are they the same or is there none? and do i have to put sealer on the car before i paint it or is it a thing i must do?

 

[chopolds]

I think we are going to have a bit of a problem with terminology, as the British seem to speak a different language, than we do!
I don't know what you are referring to when you speak of cellulose paint. In the distant past, we had a lacquer paint that was called nitrocellulose, but it hasn't been used on "new" cars since the late 50's. It was surpassed by acrylic lacquer, which held up better.
But nitro is VERY hard to find any more, available only through specialized antique dealers. Even acrylic lacquer had been banned in may areas and getting hard to find.
So, hopefully to answer your question, if the car is about 15 years old, never repainted, and is 2 stage (color+clear) most likely it is a modern urethane system. Good news is, that paint is pretty easy to paint over with no problems. I believe whatever paint you buy will probably be a modern style paint, base, clear, which should be compatible. Just be sure to use a good sealer right before you put your color on it.
Just a note...in the US, we have 2 different systems of paint, lacquer and enamel. Lacquer is air dry and has been explained.
Enamels are broken up into categories depending on chemistry. The first enamels were called synthetic (DUpont-Dulux)....air dry, slow to dry and stay soft for a long time, still available as a cheap paint.
Next came acrylic enamels (Dupont Centari) faster drying, still air dry, and more durable. Later, they sold a hardener for it that made it even tougher, glossier, and used chemistry to make the paint HARDEN instead of air dry. The hardeners were also pretty toxic, so you had to wear a charcoal filter to be safe.
The next step was urethanes, ( Dupont Chroma-one, and Chroma-base paints) now completely hardening paint, no option for air dry. VERY hard and durable. High gloss, chemically resistant, and good abrasion resistance. This is what we use today. There are also versions called polyurethane (available in the past, as Imron) that are very similar in chemistry, and also very tough and glossy. Mostly used as industrial paint, and for trucks, buses, and planes. The finishes are not as glamorous as the modern urethane base/clears.

 

[ryan-92]

Yes the terminology is quite different, but i think i know what paints you mean the cellulose paint is just the paint with a 1:1 mix with thinners i don't think you use hardeners either, but i think i know now what to use, so thank you for all your help and advice

 

[satatom]

I think we are going to have a bit of a problem with terminology, as the British seem to speak a different language, than we do!
I don't know what you are referring to when you speak of cellulose paint. In the distant past, we had a lacquer paint that was called nitrocellulose, but it hasn't been used on "new" cars since the late 50's. It was surpassed by acrylic lacquer, which held up better.
But nitro is VERY hard to find any more, available only through specialized antique dealers. Even acrylic lacquer had been banned in may areas and getting hard to find.
So, hopefully to answer your question, if the car is about 15 years old, never repainted, and is 2 stage (color+clear) most likely it is a modern urethane system. Good news is, that paint is pretty easy to paint over with no problems. I believe whatever paint you buy will probably be a modern style paint, base, clear, which should be compatible. Just be sure to use a good sealer right before you put your color on it.
Just a note...in the US, we have 2 different systems of paint, lacquer and enamel. Lacquer is air dry and has been explained.
Enamels are broken up into categories depending on chemistry. The first enamels were called synthetic (DUpont-Dulux)....air dry, slow to dry and stay soft for a long time, still available as a cheap paint.
Next came acrylic enamels (Dupont Centari) faster drying, still air dry, and more durable. Later, they sold a hardener for it that made it even tougher, glossier, and used chemistry to make the paint HARDEN instead of air dry. The hardeners were also pretty toxic, so you had to wear a charcoal filter to be safe.
The next step was urethanes, ( Dupont Chroma-one, and Chroma-base paints) now completely hardening paint, no option for air dry. VERY hard and durable. High gloss, chemically resistant, and good abrasion resistance. This is what we use today. There are also versions called polyurethane (available in the past, as Imron) that are very similar in chemistry, and also very tough and glossy. Mostly used as industrial paint, and for trucks, buses, and planes. The finishes are not as glamorous as the modern urethane base/clears.

hi from over the pond i think nitrocellulose is cellulose here in the uk, so you never know what been used here unless you test or barcoat/seal coat first , cellulose paint do not use harder hope this helps