We're starting on our first proj build, and I was wondering what thickness to go for with the tempered glass. I hadn't found info in plogs or the guides (cue half a dozen examples I missed no doubt!). Can anyone using tempered glass give advice on this for what worked for them? I've no idea whether the order of 4 or 6mm is fine, or whether it needs to be much thicker to be in any way effective. Cooling will follow the standard recommendation for a horizontal build. Trying to do better than tempered or lexan, I also looked at some specialist glass companies in the UK, but more fancy glass from the likes of Coherent with IR and UV filtering, and is used in standard projectors, was ballpark £175 for a 15" LL proj, so I ruled that out as not having enough upside for the cost. Antireflective glass was much cheaper though, so maybe next to the LCD will increase image brightness.

Advice on the tempered thickness most welcome as this is the main missing bit currently.

Nick

ummmmmm i have only ever used the glass from an old flatbed scanner,, never lost a patient yet

just dont use normal window glass

Exactly, tempered glass is heat treated, and you can't even cut it. Window glass, well we don't even want to go there lol (although I bet some people have!)

I'd read a few plogs where folks were using scanner glass, although if it's just A4 (~ US letter) that would be a bit smaller than I wanted. How thick would you say it was? 6mm, 12mm? I'm guessing 6mm would be fine, but would be good to be in the right ballpark. Would be a shame to document a disaster and only then have someone reply saying "oh yeah, we used that and it's didn't work for us either" Bits of Lexan show up on eBay, but it's excel-D and not XL10, and I'm less sure about the specs of the excel-D hence the glass route.

why not? what could happen? it may crack from heat after a while (a long while) but so what.. you just slip in a new piece... whats the big deal?

May not only crack, but also bust.
Little knife blades falling against my fresnels and back towards the lamp and anything else on the hot side doesn't sound too fun to me.
spend a little extra and save the self doubts.
my 2/100$

All my tempered glass came from junk flatbed scanners and never paid more than $5. Width of the glass is pretty standard at about 9 inches. Length varies on the scanner "bed", but the standard scanners are fine for a 15" panel. Glass is about 4mm thick and works just fine to reduce IR. LCD panel temp is 85 F.

Great, thanks for that. This helps a lot.

so... with the tempered glass from a flatbed scanner do you need to buy a uv filter still or does the flatbed already have it?

i'm assuming i could position this glass closer to the lightsource... ie use a lightgate and have the glass attached on top of that. i'd do this because the glass isn't wide enough to cover the LCD screen... would 50mm be too close to the lightsource? (this will be in a vert projector... heat rises... so yeah...)

There's no dedicated UV filtering from tempered glass. I used Lexan for UV filtering and also to keep the rear fresnel from bowing since it is closer to the light source. There are many examples of light gates with tempered glass as part of the enclosure. The light gates all have substantial cooling with plenty of air flow over and around the lamp. 50mm appears to be an acceptable distance between the lamp and the glass.