I've got to make some gauge glass protectors. Any suggestions for the guard glass? Is ordinary window glass ok? or is some sort of toughened glass reqd? if so where is it available and how is it cut? I've rejected plastic (perspex?) expecting it to discolour or suffer surface damage, but maybe someone has found a satisfactory material.
regards
Dave Burrage
In message , snipped-for-privacy@tesco.net writes
I'm no expert on the subject but my understanding of the main purpose of protectors is to protect the operator rather than the gauge. In the (rare) event of a gauge failure this is best done by diverting escaping steam and hot water vertically upwards and/or downwards. On that basis I would suggest that although toughened glass may be desirable it may not be essential.
Clear polycarbonate, sometimes branded as Lexan, tougher than old boots and doesn't yellow.
Greg
Have you tried your local glazier shop? Should be one on an industrial estate or somewhere . They should have the equipment to cut toughend glass, and probably the suppliers
On the other hand, you may be able to cut Lexan discs in the lathe, using the Pressure Pad method, as described in Mr Sparey's book.
If you do cut them in the lathe, I would suggest making a wooden blank, of the finished size required, and using that as the chuck side of the pressure pad, giving the lexan as much support as possible. I've cut some small plastics discs fairly sucuessfuly, but unsupported larger ones shattered most effectively.
Also, to paraphrase Mr Sparey; 'do not stand in line with the disc, as in the event of a jam/shatteration, the disc or bits there of may fly out and cut your head off'
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