Windscreens

Does anyone know how to decipher the engraved codes on windscreens - I need to know if it's laminated or toughened and neither word is present. It's an MG Midget BTW. At the top it says WHP TYNESIDE. In the centre around the BS kitemark it says 12 71 (I guess dec 71 - that bit's easy) and L F. Then at the bottom there's ASI M31 DOT64. Any knowledge or website pointers appreciated. TIA.

has it got any chips or small cracks in it? if it has it is laminated otherwise it would of shattered, you can usually spot a toughened screen by looking through it at an angle in the right light the toughening shows up as vertical stripes sightly rainbow-ish in appearance

No chips or cracks - it's a sound screen which is one reason why I want to know. I know what you mean about the visual check for stripes, but if it's a lammy I need enough knowledge and info to convince a scrutineer... :D Thanks so far.

every screen I've ever had says toughened or laminated on it

I'd suggest if its a genuine Dec 1971 screen and its laminated you'd be seeing a bit of milkiness around the edges by now where the plastics ageing !

If it's not in the car, take a look near the edges, if it has a couple of dimples it will be a toughened screen. The marks are where they are gripped to be heated up and toughened.

You can normally see the layers in a laminated screen edge on, if it's out of the frame of course!

thanks for the ideas, keep 'em coming - it's in the frame (which on a Midget is a complex bolt-together jobby) and it's on the car, so no edges and no dimples and no milkiness. Hence my quest to find a source of factual info about manufacturer's marks !

Funny this, I personally bought and fitted the laminated screen in my yellow Camaro many years ago so I knew it was the real McCoy and it has probably passed 50 plus scrutineer sessions. Yet at Silverstone WHT meeting the scrut was all over it like a rash telling me that he could not identify it as laminated because of American markings???? Although the fact is all yanks for years have had laminated screens as far as i am aware. Try looking at it through a pair of poleroid glasses preferably with the sun out and you should be able to see toughened zones if it is not laminated.

Good idea with the glasses Al but I suspect MGD will still have problems convincing a scroot even if it is laminated.

Well at least he would have the confidence to tell the scrut to hit it with a hammer (or not!) :-).

Another source came up with this, exactly what I needed as evidence.
http://www.ltsa.govt.nz/publications/vir-manual/general-vehicles/5-vision-v2-3.pdf
Thanks to all.

So MGD - is it a laminated screen? Can I borrow it if I decide to put the roof on?

yep it IS laminated which means I've sold one of the others instead, and yep you can borrow if needed.