Cloudy Perspex

[Martin Bush]

Hi all

I think I know the answer to this already, but is there any way to rejuvenate cloudy clear plastic/ perspective?

I've just received a nice radio from a forum member and will set about cleaning and tweaking it at some point, but my guess is that the cloudy perspex will have to stay cloudy or be replaced.

I'm not complaining about the radio... it's on now and sounds great. It's an Indesit in case anyone is wondering...

Martin

[mark pirate]

It really depends on the specific material used, but T-cut is very good if it is only surface deep.

Mark

[G6Tanuki]

Apart from afflicting us radio-types this is a problem that blights loads of elderly [pre-2005] cars with plastic headlight-covers.

There are various "polishing" kits available via the usual auction-sites: they report various levels of success.

If faced with this issue I'd try buffing with very fine Jeweller's Rouge and a mechanical orbital polisher [because doing it by hand will give you "Filer's Thumb" and you really don't want to do any repeated long straight buffing-strokes because they'll do horrible Moire-grating diffraction-pattern things to the result] then applying a suitable silicone polish to fill in the remaining micro-grooves.

[Martin Bush]

Thanks for those responses. I will on into those methods.

If all fails I guess I can call it period patina...

[McMurdo]

If it's a 30's radio it's more likely to be celluloid, in which case the cloudiness will be oxidation. It can be polished clear with t-cut or brasso but it will eventually bloom over again.

Matt or cloudy perspex is more likely due to weathering, scouring or scratching over years of dusting with a rough cloth. The best thing I've found for this is the dedicated range of acrylic polishing compounds sold online. I have a small tin of compound sold for the dust covers of record players that works really well but RS used to sell something similar and I guess autosol would work as well.

I have to say I prefer hand-rubbing as you're in control. It's all too easy to press too hard with a powered buffer or polisher and then you risk overheating the surface leading to a groove or permanent depression.

[cliff2112]

toothpaste might work

or a drop of acetone based nail varnish remover on a soft cloth

[Martin Bush]

Cheers Kevin. It's a 1970s Indesit and my guess is that it's sunlight that's caused weathering. This is the model http://www.radiomuseum.org/r/indesit_r15.html on mine the top of the panel is more affected than the front.

I know I can bring most of the set up to a nice standard as it's been looked after, but the perspex will be a challenge.

[paulsherwin]

Beware of acetone, as it can dissolve plastics.

UV light unfortunately causes structural changes to clear plastics after years of exposure. Rubbing down with T-Cut or similar cutting compounds is certainly worth a try, but don't get your hopes up. Some radios are just unrestorable and the best you can do is to return them to a decent usable state.

[Martin Bush]

Thanks Paul.

I wonder if trying to improve it will make it worse?

[McMurdo]

Oh that's definitely perspex isn't it! I agree with P.S. if the damage is sunlight or prolonged heat. I've seen it develop barely-visible crazing after this sort of thing which fogs it over and the damage is right the way through...it's 'cooked'. Sometimes it makes it very brittle. Dad has bulldozers with perspex screens that have suffered the same fate.

[Junk Box Nick]

I have an elderly car and had to rejuvenate the plastic headlight covers.

I worked with a couple of grades of extremely fine grade wet and dry paper, starting with the coarser of the two. This was somewhat disconcerting as the lens went opaque as I worked. I then worked with the finer grade and then finished with some headlamp lens polish (which, I guess, is a similar substance to T-Cut) and I got my nice clear lenses back. They didn't sparkle like those on a brand new car but were perfectly clear.

[dseymo1]

It looks as though it would be possible, though perhaps not trivial, to fabricate a replacement, which might look better than the refurbished original.

[sp10mk11]

I always remember 1970s Hitachi Cassette doors were prone to yellowing and misting up, no amount of polishing would get rid of it. if I am stuck I would replace it.

Good Luck

[AC/HL]

One post deleted, please bear in mind we're primarily concerned with Perspex in relation to electronics applications.

[G4XWDJim]

The large large perspex screen of my Wurlitzer 1100 jukebox, referred to by Wurlitzer as the 'Bomber Dome' was very scratched and bloomed when I first got it. I spent a full day gently rubbing it down with 1000 grade wet or dry used with water and soap to take out the scratches.
Once it was scratch free I spent another day with progressively finer grades of abrasive paste until I got down to Brasso, finally spending a third day with T cut. The result was a very clear screen but I would never want to do another.

Jim

[kalee20]

Whatever you do, after finishing take care to keep this away from sunlight! It's a menace to so many clear plastics long-term.

[Martin Bush]

Thanks to everyone for the responses on this one.

I have yet to decide whether to try to refurb it or live with the fog. I will give it some thought - the radio has been around for more than 30 years so there's no rush.

I do like the idea of fabricating a new one. But, although it looks to be quite a simple piece, I don't have the equipment or skills.

[Goldie99]

Hi Martin - if you're tempted to try replacing it (safest option, with no down-side) - try googling custom perspex, acrylic, or polycarbonate, all come in 1mm sheet form, and can be fairly accurately & cleanly bent with just heat. There's loads of custom pc builders, aquarium owners, etc. using similar materials, for their own custom designs.

There must be someone out there who'd be prepared to bend you a piece to match the contour of the Indesit part - from what I remember, the only critical part is likely to be the bend radius where it goes from the side of the radio to the top, the rest I think is probably fairly straightforward..... or maybe have a word with a couple of the custom fabricators, e.g., eBay user "a1_acrylic_solutions" (I have no connection to the seller - just saw the username, and what he sells).

[kalee20]

Perspex is acrylic sheet - Perspex is just the trade name (ICI). So, same stuff basically.

But polycarbonate is quite different, and I believe is immune to the effects of degradation in sunlight. It is used for vehicle lamp clusters on modern cars, and it seems to survive pretty well. So, use with confidence!

[Martin Bush]

I may ask if someone can fabricate a new one at some point. Thanks for the pointers.

The reason I keep quoting "Perspex" is because I am originally from near Blackburn. Perspex was the sponsor of Blackburn Rovers at one point and I think it was made there too. I think it's called "Lucite" now.