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Discussion Starter · #1 ·
I've ordered some shells off Patto and I noticed on his site that he warns against using Pactra spraycans as they will eat the plastic used. He mentions acrylics instead.

So, those of you who have sprayed them, what brand names have you had success with? In my box of rattlecans for vacforms, apart from Pactra, I have Custom Colour, Tamiya Polycarbonate and Humbrol (new type, supposedly OK for polycarbonate) and a few car colours, some of which stick to lexan and some of which don't.

I know that in theory all modern car colours from Halfords should be water-based acrylic but in my experience this seems to be a bit hit and miss and I've had some colours that are fine on BSCRA-style vacs and some that just fell off as soon as the shell was flexed.

Ideas?

Coop
 

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Hi Coop, I have also had problems in the past with various paints flaking off lexan and PETG shells, and I think the answer is cleaning the shells properly. I use CIF bathroom cleaner and a small brush and avoiding the windows really scrub to get a key in the plastic and remove all traces of release agent and then rinse with warm water. Since I have done this it seems to have got rid of the problem. I havent tried Pactra on Pattos shells I but have used Hy Cote double acrylic spray from my local car parts shop. Hope this helps cheers steve
 

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Coop, I've used Halford car sprays (Acrylic) in the past without problems.

As Steve says I think the important bit is to ensure the shell is completely clean. I go over the whole shell with washing up liquid and a toothbrush an then leave to soak overnight and scrub again. Then I key the surface with 600 grit paper before applying paint.

Regards,MAF.
 

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Discussion Starter · #4 ·
Traditionally I just clean the inside of the shell (lexan, Betta, JK etc) with a piece of kitchen towel dipped in lighter fluid then I find Pactra and Custom Colour stick with no problems, even amidst the sort of carnage found at Oaklands when four Super16D powered 24th cars attempt to enter the esses four abreast. I've never "keyed" the inside of the shell because I've never needed to do so in my experience.
I don't use the washing up water method because I live in a hard water area and it leaves stains behind on the shell.

Steve, I've tried two cans of Hycote before and found that while one of the colours (Ford Arizona Gold) stuck beautifully the other (Ford Velvet Metallic) behaved like an old-style enamel and was flaking off even when the shell was being cut to fit. As it happens the only place locally where I ever saw Hycote was a branch of Wilkinsons who stocked a very strange range of colours and now they, perhaps sensibly, only stock the primers.

I don't think when I've had paint flake off in the past it's been my approach to it, just the wrong kind of paint. I've painted dozens of shells for Oaklands members and none of those have suffered from flake-age when I've stuck to Pactra and Custom Colour.

As for Halfords MAF you've clearly had better luck than me!

I have an theory that since car manufacturers are now obliged to use 'greener' paint (which is why modern 1:1 cars only have to look at a piece of gravel and they stone-chip back to the bare metal or plastic) the newer colours are acrylic but the older colours could be anything. In my findings the Halfords paints that have let me down on lexan have been 70s and 80s colours even though they have been bought new inside the last couple of years. So my theory is that by checking the era of the paint in the little Halfords book should indicate the suitability for lexan use but I've been loathe to spend large amounts of moolah on proving or disproving this!

I will give the 600 grade sandpaper a try this time then.

It's a shame really the shells I've ordered are repops of the Classic 'thingies' and I have some gorgeous metalflake and pearlescent cans that I had intended for them but they are all Pactra!

Coop
 

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Coop just a thought but you could always try a clear barrier coat first,Clear acrylic laquer or even Johnsons Klear assuming Pactra paint doesnt attack that as well. cheers steve
 
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