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Cellulose Paint Re-action

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NickDeAth
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Cellulose Paint Re-action

Post by NickDeAth »

I decided to spray a couple of wheels a few weeks ago. All went well to start with. The wheels had been steam cleaned, de-greased, rubbed down and wiped over with a tack cloth. Primer went on OK, left it alone for about 4 hours put the top coat on. Everything looked great, I was quite pleased with the result. Put the wheels in the shed to dry off properly.

Looked at the wheels the next day - shock horror - the top coat looked like crazy paving with the primer showing through the joints. Now I have seen things like this before usually involving synthetic paints, but I know all the paint on these wheels is cellulose.

Move forward a couple of weeks, I found the best way of removing the "crazy paving" was with a wire brush in an electric drill. Under all the layers the bottom, first original coat, was what I believe to be chassis paint. If I remember correctly chassis paint never actually goes hard only dries out. I wonder if this caused the reaction.

Any way I have now got 1 wheel down to bare metal. I had to use thinners to get rid of the remains of the original paint.

I am going to use a coat of Barcoat (an isolater paint) when I re-spray because there are so many nooks and crannies on a wheel I can't be sure I've got rid of all the old paint.

Question, can you put Barcoat on bare metal or would I be better priming the wheels first?
"Nick - do you think you will ever put that old car back together again?"

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theoldman
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Re: Cellulose Paint Re-action

Post by theoldman »

Yes, Barcoat over the surface you have left and then prime - a good 3 or 4 coats - then flat off and gloss.
Don't flat off the Barcoat.
Hope this helps
Neil
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Stan Thomas
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Re: Cellulose Paint Re-action

Post by Stan Thomas »

Origibally, I'm sure your wheels would have been stove enamelled.

tThe best way now is to take the wheels to be powder coated in primer, then apply your top coats.

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theoldman
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Re: Cellulose Paint Re-action

Post by theoldman »

You shouldn't get a reaction from celly and stove enamel, Stan..........................
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Vortex O'Plinth
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Re: Cellulose Paint Re-action

Post by Vortex O'Plinth »

Stan Thomas wrote: Mon Jul 10, 2017 6:35 pm The best way now is to take the wheels to be powder coated in primer, then apply your top coats.
Can you powder coat a primer that can be subsequently wet painted - I thought any powder coated surface was very difficult to paint?
Nick

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NickDeAth
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Re: Cellulose Paint Re-action

Post by NickDeAth »

Thanks for the replies Gents.

I am no professional sprayer but I did a bit many years ago. As far as I could see the reaction shouldn't have happened, but there was obviously something there that didn't want to mix.

Didn't want to go the powder coating route as I don't want to take the old tyres off yet, just wanted to make the wheels look a bit tidier and make me feel better. So much for a quick coat of paint, took ages to get all the old paint off.

When I get the paint off the other one it'll be Barcoat and then primer.

I'll know better when I come to do the other 3 wheels!

Thanks again.

Nick.
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Stan Thomas
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Re: Cellulose Paint Re-action

Post by Stan Thomas »

Whilst you should not get a reaction applying cellulose to stove enamel - it depends upon the interpretation of just what the terms mean.

Nowadays, I think it fair to say no-one (or very very few companies) actually stove enamel - but rather just oven bake (or force dry) paint. Similarly, and just to add to the confusion, there is no such thing as actual "cellulose" paint in the strict meaning of the term.

So unless you know just what paint is on there, your likely to get a reaction applying any form of coating.

That said, powder coating primer forms an ideal basis for the spray application of (so-called) cellulose or any form of synthetic coating.

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Re: Cellulose Paint Re-action

Post by Phillmore »

I always thought you could enamel over cellulose but not vice versa?
Andy

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theoldman
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Re: Cellulose Paint Re-action

Post by theoldman »

The mains culprits of celly reaction are paints which use Xylene as a base solvent, eg, Synthetic types, or those people who insist on using Dulux...............(yes, they do, honest!!!!)

Still say the best way to go is with Barcoat............................
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NickDeAth
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Re: Cellulose Paint Re-action

Post by NickDeAth »

I was recommended Barcoat by a paint supplier some years ago when I was buying cellulose paint. I was sure then that I was only dealing with cellulose and turned it down. That bit of painting went OK. I have also heard people say that if you have paint problems Barcoat is the thing to use. So I'll give it a try.

Nick.
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