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8th Aug 2020, 3:15 pm | #1 |
Dekatron
Join Date: Nov 2003
Location: Near Leeds, West Yorkshire, UK
Posts: 4,609
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What sort of plastic?
Mods, please delete if this is too far O/T, but the contents could well be radio or television related.
I have some white fascia board, several years ago, which I need to prime and undercoat; because of this I need to know what sort of plastic it is. I have scraped a sliver off and burnt it in a flame to see what happened. It went black and burnt with just a few small sparks; no flame and no apparent smell, then going out. Any ideas folks? TIA.
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Mike. |
8th Aug 2020, 3:19 pm | #2 |
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Re: What sort of plastic?
I would sand it down using 400 grit wet and dry and then almost any primer will stick.
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8th Aug 2020, 3:24 pm | #3 |
Dekatron
Join Date: Nov 2003
Location: Near Leeds, West Yorkshire, UK
Posts: 4,609
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Re: What sort of plastic?
Wow - thanks for that - instant reply! I'll see what everyone else says before I head for Amazon.
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Mike. |
8th Aug 2020, 3:30 pm | #4 |
Heptode
Join Date: Jul 2014
Location: Boston, Lincolnshire, UK.
Posts: 992
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Re: What sort of plastic?
If you mean fascia board as in roofing, then it's almost certainly a UPVC grade, and could be primed & painted.
It's maybe worth noting however, that if it's indeed a roof fascia board that's 'yellowed', the yellowing would not be just a colour change, but indicative of UV degradation of the plastic over the years. It used to be quite common with the cheaper UPVC grades after a few years, especially those with higher recycle content. Alan |
8th Aug 2020, 4:09 pm | #5 |
Dekatron
Join Date: Nov 2003
Location: Near Leeds, West Yorkshire, UK
Posts: 4,609
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Re: What sort of plastic?
Hi Alan,
It is indeed a roof fascia, but not yellowed at all, though being probably twenty years old facing the sun. My question was really what sort of primer and undercoat to use. Thanks,
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Mike. |
8th Aug 2020, 5:18 pm | #6 |
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Re: What sort of plastic?
UPVC, there are "proper" plastic primers that contain a solvent which (slightly) dissolves the substrate. They stick like s**t to a blanket.
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8th Aug 2020, 6:09 pm | #7 |
Heptode
Join Date: Feb 2006
Location: Marlborough, Wiltshire, UK.
Posts: 915
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Re: What sort of plastic?
A rub down with wet and dry followed by a degreasing is usually needed as the production process sometimes involves lubricants and polish may well be present if it’s a used piece. Standard alkyd primers and paint will stick well, as do the special primers etc of course.
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8th Aug 2020, 6:22 pm | #8 |
Hexode
Join Date: Dec 2018
Location: Sheffield, South Yorkshire, UK.
Posts: 364
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Re: What sort of plastic?
I would try a etching primer as used in the motor trade
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8th Aug 2020, 6:48 pm | #9 |
Dekatron
Join Date: Nov 2003
Location: Near Leeds, West Yorkshire, UK
Posts: 4,609
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Re: What sort of plastic?
Hi folks,
Thanks to all, I've ordered some brush UPVC primer which will arrive tomorrow, so we're all sorted. A quick IPA degrease first. Mods, you may close this thread; thanks.
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Mike. |