Vintage TV glass

[beery]

Hi all,

I am restoring my HMV 905 and I need to replace the missing safety glass.
The original glass seems to have been 3mm thick.

So my question is, was it toughened glass or just ordinary float glass?
Would float glass be ok?
I am asking this because it seems just about impossible to get toughened glass below 4mm and anyway the small dimentions (150x204mm) are apparently a problem for standard glass rollers.

I would apreciate any suggestions.

Cheers
Andy Beer

It was toughened glass originally, polycarbonate (bullet proof plastic) would do the job. Ordinary glass would splinter if the tube went.

[emeritus]

In the 1950's dad used to get the front screens of old TVs from our neighbour, who used to break up old sets for the scrap metal. Some were Perspex (usually tinted grey or pink), some were laminated glass, and some were armour plate. I still have one of the armour plate ones somewhere, as I used to use it to hold negatives flat on bromide paper when making 10" x 8" contact sheets from negatives. I learned about the different types when dad tried to cut down some of his collection to repair a broken pane of glass in his shed. After scribing the first pane with his (diamond) glass cutter, the first attempt (a laminated screen) cut neatly on the scribed side, but not on the unscribed reverse. The second attempt (armour plate) just wouldn't break, and I remember dad eventually hitting it very hard with his hammer (a carpenter's claw hammer) in frustration, only to have it bounce off. It was then we looked closely and saw "Armour Plate" etched in one corner. (He ended up having to buy a pane from the glazier). From memory, 3mm is consistent with laminated glass: my armour plate screen is at least 1/4" thick.

[ms660]

3mm toughened glass is commonly available.

Laminated glass tends to start at 4.4mm.

Lawrence.

[PJL]

I had replacement laminated glass cut for my Pye v14c and it came to about £11. As you say, it was thicker than 3mm but was about the same as the original that had delaminated.

[G6Tanuki]

These days I'd go for a bit of Lexan - the bullet-proof stuff they use for the windows in banks/post-offices. For a given level of impact/explosion protection it's **vastly** better than glass for light-transmission, specially at non-90-degree observer angles. What for protection might previously have needed 1cm of plate-glass can be achieved with a couple of mm of Lexan - and the light-loss is similarly reduced!

[Restoration73]

My Ferguson 991T has a grey tinted glass.

[FERNSEH]

Hi Andy,
I'm sure my 7" CRT Marconi 707 employs a similar safety glass as the HMV 905. I can arrange to have a piece cut to the correct dimensions for you.

DFWB.

[Boater Sam]

Safety film on plain glass, seems to be used in buildings more and more?

[beery]

Hi all,

Thanks for your suggestions.
I have found a suitable supplier, but it will be expensive. I guess it will be worth it though to get the correct look. I don't like the idea of using plastic instead of glass, but Boater Sam's suggestion would be my fall back option.

Actually in the end the glass worked out to be thicker thank I first thought. I was measuring the glass space in the tube mask (3.2mm), but there is also a recess of 2.6mm in the cabinet. The cabinet recess is lined with felt which has been squashed to about 1mm, which leaves a total of 4.8mm or 3/16". The other dimentions become 150 x 182mm +/- 2mm.
I plan to use thinner felt that will squash to 0.8mm and then 5mm glass.

BTW, during the TV80 get together at the museum, Mike Barker and I were peering at the screen of the Marconi 707 trying to guess the safety glass thickness. It looked to be more than 3mm, but of course it was hard to tell. Maybe this activity can take the place of guess the weight of the cake contests!

Regards
Andy

[Jac]

My Ekco TA201 has safety glass of 5 mm thick.
Since it is roughly from the same period, it might have been a common thickness amongst manufacturers?

Jac

[PJL]

Safety glass is a generic term and includes tempered glass that shatters into small pieces. I guess you mean laminated glass which was already in use on cars in the 30's?

[beery]

Hi PJL,
The glass would definitely have been toughened (tempered) glass, which at 3/16" must have been quite strong.

Regards.
Andy