Polycarbonate canopy blemishes

[Skippydiesel]

Hi All,

On removing the upper protective cover (the lower had been removed for installation 12 months ago), of my brand new Polycarbonate canopy, I have found strange blemishes, that do not come off with the application of VuPlex cleaner - anyone have a suggestion?

My thanks in anticipation

[GraemeSmith]

If they are abrasions or "dulling" of the shiny surface caused by friction:

Headlight restorer from the aviation aisle of your AutoZone.

I use this one AS DIRECTED:

https://www.autozone.com/wash-cleaners- ... 452390_0_0

[Skippydiesel]

Thanks Graeme -
My blemishes appear to be on the inner surface, quite random in distribution & shape and mainly on one side of the windscreen.
They present as a stain, rather than fog/hazing.
There is no damaged surface (raised/abraded) and a finger nail scrape makes no impression.

If they were on a shiny metal surface I would describe them as water marks.

[Skippydiesel]

Hi All,

I have decided to replace the blemished windscreen.

I see that Sonex parts offers a Lexan product (type & dimension unknown??).

Importing, to Australia, of a single sheet of Lexan, from the USA, is extraordinarily expensive and the potential for damage is equally high (a double whammy!!).

Lexan comes in a bewildering range of products and in Australia only in a few thicknesses

If I can find the product locally, at least the potential for damage will be eliminated, however to do this I will need to know what the Lexan product is and its thickness.

If anyone knows the Lexan product (code & thickness) please advise????

[daleandee]

If I can find the product locally, at least the potential for damage will be eliminated, however to do this I will need to know what the Lexan product is and its thickness.

If anyone knows the Lexan product (code & thickness) please advise????

I believe the information you need is in this thread:

viewtopic.php?f=3&t=1871&hilit=lexan+windscreen

BTW ... you will need at least a 4'X6' sheet to replace the windscreen. Sometimes a 4'X4' sheet is easy to find but it's not quite large enough ...

Dale
3.0 Corvair/Taildragger

[sonex892.]

Polycarbonate is the type of plastic used in the windscreen and acrylic the plastic on the canopy. All other names these are called are brand names. You can measure the thickness on your existing windscreen. The rough dimensions to cut are in the plans

If you can live with a clear non tinted windscreen, finding a replacement polycarbonate sheet here in Aus will be easy. Bronze probably not so easy maybe impossible. I think I worked out can get 3 windscreens from 2700 x 1200 sheet but only
1 from 2400x x 1200 sheet.

I also need to look at replacing my windscreen

[Skippydiesel]

More information;

I was trying for an abrasion/scratch resistant polycarbonate, however I am now convinced this is not a suitable product for cold bending.

All that Sonex will divulge is “Lexan + .118” thick Bronze.” which can also be got from the plans. No information on the actual Lexan product (number) of which there are many. So not much help from that quarter.

Interestingly if you Google “Lexan + .118” thick Bronze" you will get Lexan 9034.

Lexan 9034 turns out to be a general purposes Polycarbonate principally aimed at indoor applications, so no UV resistant treatment.

Without conducting more research, it would seem this product has been selected by Sonex, because it is available in various coloured tinted sheet ( Bronze ). I am a little disturbed by what would seem to be Sonex's focus on aesthetics over function.

In Australia polycarbonate, matching or close to Lexan 9034, is widely available in clear (some tints are available), 3mm thick sheet, of varying dimensions - other brands include Makrolon, Zenolex, Exolon

So far, the Lexan alternatives all offer UV resistance - don't know if this is an important factor or not - your comments?

Some Australian suppliers:

Mulford Platics
KF Plastics
Plastral
EPlas

[Area 51%]

The tree-huggers will tell you that plastics remain viable for 500 years. Not much worry about UV protection if they are to be believed. I personally have to purchase a new plastic watering can every 6 months or so because of the sun's degradation. I stumbled across a 3 month old wayward milk jug that crumbled to the touch.

Go with the UV protected product regardless of the color.

By the way, a sheet 4' 9" by 3' is what's needed for a Legacy windscreen.

[Skippydiesel]

Thanks Sonex 892/Arear 51%

Just waiting for the polycarbonate (UV) quotes to come in before purchasing.

Always have an eye on the dollar, so will be purchasing a larger sheet than necessary, so as to have some spare in case of "cock-ups" and some stored away for future replacement (if required in my lifetime)

[Skippydiesel]

I have ordered Zenolex, Clear, UV2, 1220 x 2440 x 3mm from Mulford Plastics