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Author Topic: Painting plastic card.  (Read 3468 times)

ukmike

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Painting plastic card.
« on: August 08, 2012, 06:26:03 PM »

Hi.

This is the first time that I have used plastic card and have found a problem following painting.

The picture shows the pelmet covering the sliding door mechanism on my model.

It has been sprayed using Holts Acrylic enamel and as you can see has taken on the finish of unsanded English Oak.

I did not sand the plastic in any way and other parts comprising the pelmet have not suffered this phenomena.

As I have made several other more important parts that have to be painted, I need to establish the cause of this particular problem.

Your thoughts, Gentlemen.

Mike.

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TheLongBuild

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Re: Painting plastic card.
« Reply #1 on: August 08, 2012, 06:34:19 PM »

No Idea to the problem but it looks quite good..

Lash151

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Re: Painting plastic card.
« Reply #2 on: August 08, 2012, 06:35:45 PM »

If you could repeat that effect it could be really useful!  What did you clean the styrene with?
Lee
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ukmike

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Re: Painting plastic card.
« Reply #3 on: August 08, 2012, 07:09:26 PM »

If you could repeat that effect it could be really useful!  What did you clean the styrene with?
Lee

Hi Lee.
just a quick wipe with meths, the same as the other parts which have not been affected.
Mike.
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boatmadman

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Re: Painting plastic card.
« Reply #4 on: August 08, 2012, 07:48:17 PM »

I have always given a quick rub over with fine grit paper followed by a wash with warm soapy water, allow to dry.

Its always worked for me.

Ian
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ukmike

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Re: Painting plastic card.
« Reply #5 on: August 08, 2012, 07:56:44 PM »

I have always given a quick rub over with fine grit paper followed by a wash with warm soapy water, allow to dry.

Its always worked for me.

Ian
Good info Ian, thanks.

But, what has caused it to only happened to one particular piece and not the other two pieces, all cut from the same board of course ?

The other, quite complicated pieces, that I have made are far more important than this little pelmet, but I am reluctant to continue without some idea of what to avoid from now on.

Mike. 
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boatmadman

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Re: Painting plastic card.
« Reply #6 on: August 08, 2012, 08:03:22 PM »

Is it possible that the meths hadn't fully evaporated on that one part?

Another thing I forgot to mention, after I have washed and allowed to dry, I take great care not to touch the plastic with fingers so as to avoid oily contamination.

One other advantage of washing is that it gets rid of any static build up on the plastic.

Ian
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Circlip

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Re: Painting plastic card.
« Reply #7 on: August 08, 2012, 08:06:46 PM »

As t'other Ian has said, you should abrade the surface to break the glaze and leave a matt finish and wash in a detergent water. Possibly picking up finger grease or more likely surface lubricants from the rollers that the styrene goes through when being "Thicknessed" when manufactured.

  Regards   'Nother Ian

  Edit. We were both typing at the same time so you got it in stereo
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Stavros

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Re: Painting plastic card.
« Reply #8 on: August 08, 2012, 08:13:13 PM »

Mike if I was you i would defo go out and invest in some Panel Wipe.....available from any Good MOTOR FACTORS yes I know it will cost you around a Tenner BUT it is well worth it,wash down your Plasticard before use,this is to get rid of any residue on the plastic,yes I do fully realise that you use Meths BUT if Meths was used for degreasing well everyone in the Motor trade would use it for degreasong cars prior to spraying.Also tbh with you washing it with detergent is also poo poo as previous sentence states !!!!!!!

Now what has caused your paint reaction well it is down to a couple of causes really.It could well be residue left over from cleaning,it could well be that as it was (MAYBEE ) the first part of the degreasing that was sprayed that on the first pass of the aerosol you got a concentration of thinners,Had that today when using black as a guide coat on a car bonnet even though it was shaken for 2 Min's.

As for not sanding the plastic in anyway well sorry to say this and I know the well it works for me brigade will have a pop You SHOULD allways prepare your artice for paining in the appropriate way.It should have been sanded with either 600 Wet Dry or even a Grey Scotchbrite abrasive pad...reason I say this is simple really.If it is not prepped properly the paint will eventually come off your model in sheets...........OK you might think well thats how I do it anyway ............I know I am right in what I say .

My Thoughts on what has happened on your superstructure is bad Prep and Solvent attack sorry to be so blunt but hey ho such is life


Dave

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ukmike

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Re: Painting plastic card.
« Reply #9 on: August 08, 2012, 08:25:27 PM »

Mike if I was you i would defo go out and invest in some Panel Wipe.....available from any Good MOTOR FACTORS yes I know it will cost you around a Tenner BUT it is well worth it,wash down your Plasticard before use,this is to get rid of any residue on the plastic,yes I do fully realise that you use Meths BUT if Meths was used for degreasing well everyone in the Motor trade would use it for degreasong cars prior to spraying.Also tbh with you washing it with detergent is also poo poo as previous sentence states !!!!!!!

Now what has caused your paint reaction well it is down to a couple of causes really.It could well be residue left over from cleaning,it could well be that as it was (MAYBEE ) the first part of the degreasing that was sprayed that on the first pass of the aerosol you got a concentration of thinners,Had that today when using black as a guide coat on a car bonnet even though it was shaken for 2 Min's.

As for not sanding the plastic in anyway well sorry to say this and I know the well it works for me brigade will have a pop You SHOULD allways prepare your artice for paining in the appropriate way.It should have been sanded with either 600 Wet Dry or even a Grey Scotchbrite abrasive pad...reason I say this is simple really.If it is not prepped properly the paint will eventually come off your model in sheets...........OK you might think well thats how I do it anyway ............I know I am right in what I say .

My Thoughts on what has happened on your superstructure is bad Prep and Solvent attack sorry to be so blunt but hey ho such is life


Dave



Thanks for that Dave, but, tell me this, how come the other plastic parts that form the sliiding gear covers were treated in EXACTLY the same way, painted at exactly the same time, but didn't suffer the same results ?

Spooky, suppose it's the same dilemma as why some Bellybuttons are "Innies", and some are"Outies", mines an Outie BTW.

Mike.
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Stavros

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Re: Painting plastic card.
« Reply #10 on: August 08, 2012, 08:43:23 PM »

As I said Mike could be you held can TO CLOSE to that part etc etc

How come a car I sprayed today suffered a reaction on the rear 1/4 panel after a small repair and other areas of the same side of the car were spot on even I cant work it out and as I have over 30 yrs in the motor trade spraying car if I cant work it out then what hope is there,the only differece I know how to get around it and did with ease,but it is NO point telling Mayhemers how as you cant buy the products I use

Rub it down with what I have allready mentioned and sart again


Dave
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Norseman

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Re: Painting plastic card.
« Reply #11 on: August 08, 2012, 08:45:20 PM »

I read a thread last year like this and on that particular item it was static related.

Dave
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Colin Bishop

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Re: Painting plastic card.
« Reply #12 on: August 08, 2012, 08:48:18 PM »

Quote
Thanks for that Dave, but, tell me this, how come the other plastic parts that form the sliiding gear covers were treated in EXACTLY the same way, painted at exactly the same time, but didn't suffer the same results ?

Maybe the plastic is of a slightly different formula. I have a bedroom suite in which some of the drawer fronts have retained their pristine whiteness while others have yellowed for no obvious reason.

Personally I'm not too much in favour of plasticard as it is a fundamentally unstable petro chemical material with suspect longevity. Traditional materials such as metal and plywood require more preparation but they will last a lot longer.

Colin
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nemesis

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Re: Painting plastic card.
« Reply #13 on: August 08, 2012, 10:38:01 PM »

Hi,

I always use Halfords Plastic Primer, it really etchs the surface.

 Nemesis



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essex2visuvesi

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Re: Painting plastic card.
« Reply #14 on: August 09, 2012, 09:33:30 AM »

I have always used panel wipe
Have a big can of the stuff now, but before I had a pack of panel wipes.  These looked just like a pack of baby wipes and were much more convenient.  Cant find them anywhere now tho :(
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Lash151

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Re: Painting plastic card.
« Reply #15 on: August 09, 2012, 10:33:51 AM »

I know Halfords do a plastic primer... does anyone use that?
Lee
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Norseman

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Re: Painting plastic card.
« Reply #16 on: August 09, 2012, 09:03:38 PM »

 
Have you tried painting again on some scraps after more cleaning Mike?

Dave
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colin-d

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Re: Painting plastic card.
« Reply #17 on: August 10, 2012, 07:19:25 AM »

i don't use the Halfords plastic primer.

all i use is Humbrol enamel straight onto the plastic, never had any problems at all...

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ukmike

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Re: Painting plastic card.
« Reply #18 on: August 10, 2012, 09:01:20 AM »

I hope you really enjoy your games Ian ....
and I'll enjoy the 2012 - 2016 lull  {-)

Have you tried painting again on some scraps after more cleaning Mike?

Dave

Hi Dave.

You are right, that's exactly what I will do before I use more of this styrene board.

Will let you know if I find the cause.

Mike.
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Martin [Admin]

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Re: Painting plastic card.
« Reply #19 on: August 10, 2012, 10:47:24 AM »


Topic tidied up. - Admin    :-)
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