I am spraying up a lot of parts with normal black cellulose paint for the bike build.

I sprayed up the primary drive bits about 3 weeks ago, but the paint is still fairly easily marked with a finger nail. It had a coat of etch, hi-build then 2 finishing coats.

There will be a lot of parts during the build that will have the same treatment, and I dont want to be having to wait a month or more to be able to get it flatted and polished up.

Probably a question best posed to bodyshop people, but is there any better paints to use other than 2 pack? I dont really want to powder coat stuff as I want to do it myself.

Smaller parts I can probably bake, if so what sort of temps and time should I be looking at?

Thanks

[Edited on 29/9/10 by flak monkey]

You probably didn't use enough thinners

Probably I mixed around 50:50 but done by eye and not measured so could be +/- 10%

I am pretty inexperienced at spraying - I can get a mirror finish no bother, but it takes some experimentation

I will say the coats are pretty damn thick which probably doesnt help.

did you use any hardener

I have used 2 pack, its was 1/3 hardener 2/3 paint + 15% thinners, when hard enough to buff in 2 hours !

The thick coats don't help, cellulose cures outside in via evapouration, hence with a thick coat a semi cured skin forms which traps uncured paint beneath, which as it cures through the skin causes orange peeling.

You need warmth to cure it, thin coats, and a flat off between coats, as well as taking out imperfection the flatting takes off the cured surface allowing the underlying paint to cure before the next coat is applied, and on............

[Edited on 29/9/10 by r1_pete]

I cant use 2 pack as I dont have air fed masks. My local bodyshop is really helpful and advised me not to use 2 pack or synthetic and said cellulose was the best thing for what I am doing.

I can flat it back with wet and dry, which is how the parts stand at the moment.

I just want the paint to be fully hard so I can finish the parts off (Not impatient....much! )

You DON'T need an air fed mask for 2 pack paint. 99% of the toxins (cyanide) have been removed, a respirator is mote than enough. Have used it for the last 4 years sometimes with only a cotton wool mask, no problems, and it is a far superior paint to use.

quote:

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Originally posted by marcjagman
You DON'T need an air fed mask for 2 pack paint. 99% of the toxins (cyanide) have been removed, a respirator is mote than enough. Have used it for the last 4 years sometimes with only a cotton wool mask, no problems, and it is a far superior paint to use.

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quote:

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Originally posted by marcjagman
You DON'T need an air fed mask for 2 pack paint. 99% of the toxins (cyanide) have been removed, a respirator is mote than enough. Have used it for the last 4 years sometimes with only a cotton wool mask, no problems, and it is a far superior paint to use.

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the guy in my paint place has a normal respirator type mask which he says is certified for 2 pack paints.


anyway, this question is about cellulose. not 2 pack.
i've found the paint pretty brittle and chips easy when i've used it but i have found it takes a while to fully harden. infra red heaters would be my choice to speed up the curing

[Edited on 29/9/10 by blakep82]

The cellulose should be well hardened by now, why did you use high build primer? If I want it to go quicker I just use a hairdryer to waft over it but if I want shiny quick these days I lacquer.

ive tryed loads of types of paints and cellulose is just poo end of, once its on you cant spray anything else on it or it will react unless you use a blocker.
but 2 pack you can buy a normal type mask from 3m and even off the bay make sure its 2 pack compatable.
all that airfeed stuff is bullshit. if you ask for a 2 pack mixing stick about 3 quid it shows you what you need to measure.
prawnabie is right its strong stuff so wear a mask when mixing.
adam

Very little reacts when painted over cellulose, cellulose sprayed over other paint finishes is the dodgy combination.

2K IS nasty stuff, here is some more info, and links to the HSE and real experience of the problems it can cause LINK

The Isocyanate in 2K can permiate eyes and pores, not just via breething it, you should be fully covered.

Don't risk your lungs/health David, you're only young and have a lot of life to live yet.

[Edited on 30/9/10 by r1_pete]

Well said Pete bout time someone spoke some sense. 2 packs toxins are also cumalative they stay in your bloodstream you can use it a few times and be OK, ten years later use it and drop down jed.
From the sound of it Flak you never let your primer and first coats dry off properly. Celly dries by evaporation so youve painted over uncured paint leave it and it'll be OK.
Cheers,
Bob

[Edited on 30/9/10 by splitrivet]

David
Thre is a lot of rubbish being talked here! Believe me I used to spray for a living! Cellulose actually nevre really goes off, it just gradually gets harder & harder over a period of months/years, basically as the thinners evaporates from the mix.
Temp makes a massive diference, I used to use a home built infra red oven to bake off in - can't give firm temps, but would say anything up to about 150 deg C should be fine, experiment with some small scrap bits first, you just don't want to get it to the point where the thinners boils off as this creates tiny bubbles in the paint.
For small parts I don't think 2 pack is worth the hassle, if you can't get on with celly, try powder coat, there are some cheap systems around now.

Thanks for the advice, I would never consider spraying 2 pack at home for precisely the reasons stated above. And the fact my friendly and knowledgable bodyshop said exactly the same.

I am also aware that its celly over acrylic/water based paints that causes a reaction, you can over paint celly with almost anything once its cured.

I'll have a play around with baking some scrap bits and see what happens

I need to stick with spraying as I will want to be doing a lot of bodywork etc.

Thanks,
David

As Flaks thread is about celly, and a few have mentioned 2 pack, I have made a separate thread about the info on 2 pack.....Thanks r1 pete for the link in your post ^ ^.

As the facts about 2 pack are too important to ignore, it would be wrong to hijack Flaks thread here.

Fozzie