Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Painting, Finishing and Care. => Topic started by: CJ1 on February 21, 2012, 05:38:46 pm
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Help guys please! I've just put the second coat of Halfords white primer onto lightly sanded perspex (Speedline Tamar).
I had noticed a small patch of pickling after the first coat, so I rubbed it back down with a little detergent and wet and dry and rinsed it well. You can see the areas that I rubbed down as a bit darker. I had left it to dry in the airing cupboard all day and have just misted over a second coat......and got this!
(http://s16.postimage.org/9p8tnjr6p/P2210003.jpg) (http://postimage.org/image/9p8tnjr6p/)
What have I done wrong?
Chris
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Hi Chris
Have you used two different cans?
Russ
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Strange that it pickled, is it absolutely identical? I tend to wet mist coats on, but I warm the can & the item being sprayed so they are quite warm. This means the paint dries almost instantly & doesn't get a chance to pickle. After 2-3 coats wet on wet, let it dry for a few days before rubbing back. Are you using washing up liquid as the detergent? Be careful a lot contain silicones & can contaminate your work.
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Where's Cymraeg Dewin when you need him {:-{ {:-{
Ned
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I'd agree with tvr7v8, it looks a lot like surface contamination. I use liquid hand soap when I use anything it's never given me any problems. Try rubbing down again and then swab the surface with rubbing alcohol (from the chemist). Was there anything on the acryllic before you used it like paint or stickers? That big patch looks suspiciously like an arrow.
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Thanks guys.
I initially rubbed down the perspex with 400 wet & dry, and gave a mist coat with primer. Yes, the second coat was from another can of primer and it is quite cold in the workshop at present. There was a gap of a couple of weeks between coats too. I see what you mean about the arrow shape, but the Perspex was quite clean.
Today, I washed down with a couple of drops of Fairy Liquid on the wet & dry, rinsed with running water and let it really dry before the second coat from the new can.
Chris
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I use a fan heater to warm the item in the garage & pop the can in a kettle full of cold water, then flick the switch. after 3-4 minutes, as the kettle warms against my hand I take the can out. As I said the warm paint on the warm item dries virtually immediately aka no reaction.
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I am here not gone anywhere lol
I suspect it has got contaminated most defo with something that has been sprayed anywhere...........Putting it in the house is a DISASTER
WHY ...........well simples really Your good lady has probably sprayed furniture polish in the house thus contaminating your perspex I will Gtee you that
Fairy liquid will NOT remove the contaminant BUT panel wipe will......................Available at most good motor factors unless you personally know someone who works in a body shop and can sell u some.
Everyone should go out and buy some Panel wipe when painting it is available in 5ltr cans and is the MOST important part of kit anyone MUST have,it is used in body shops to degrease paint panels prior to painting and should be USED at every stae of paint prep.
Dave
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Thank you all, guys. This is why I enjoy Meyhem so much. So much help so quickly.
Chris
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Hi All,
Before rushing for chemicals ... you might want to read this -
Interesting read for those that use acrylic...
Regards,
Kim
http://www.theplasticshop.co.uk/plastic_technical_data_sheets/working_with_perspex_manual.pdf
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Just as a bit more info.
I've gone into the workshop this morning, and checked. I had coated the whole of the built cabin structure with a coat of the primer, and it's only the perspex parts that have pickled. The grp and the brass parts are all fine. Where a perspex part is glued to grp, the pickling stops at the join. It's not extensive and doesn't include all the perspex; only patches of it.
Something I've remembered this morning. I wiped the brass parts down with meths to get rid of any traces of flux, dirt and sanding residue. I would have used tissues with meths around these areas as the brass is stuck to or goes through the perspex.
Meths residue and Halfords primer?
Chris
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Just as a bit more info.
I would have used tissues with meths around these areas as the brass is stuck to or goes through the perspex.
Meths residue and Halfords primer?
Chris
Hi Chris,
Perhaps the tissues are building up static - Higher static areas usually develop where the print on the protective film was and might explain why there is an arrow shape noticable. (Plexi Glass covering has arrows on it )
Regards
Kim
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Meths should be ok. But what else is added? Colourent, something to give it a bad taste. Do these ingrediants vary? would some cause problems? No idea myself. John.
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Well, thanks to all you guys out there in Meyhem land, you seem to have solved that problem. I used every tip for good measure!
(http://s17.postimage.org/67f7a5mez/P2260008.jpg) (http://postimage.org/image/67f7a5mez/)
I'm now quite nervous about how the orange colour will lay down but, fingers crossed.
Thanks again for your help.
Chris