Perspex, 1 inch thick! The uses of....

Just got my hands on some 1.2m x 0.6m sheets of 1 inch thick Perspex (transparent)! £5 each.... 9 in total. I'm thinking of using 2 of them them as window, view into recording room (doubled up in stud)..... or, make some portable partitions that u can see through..... use the rest to isolate windows.... Any other ideas? Yes / No's? PS. is Perspex a fire threat?

it seems like it's very lightweight "It has a density of 1.17–1.20 g/cm 3 which is less than half that of glass" so the 1" may be the equivalent of 1/2" glass. on the fire safety, being plastic, during a fire it will release gases which may be toxic. e.g. http://www.gcip.co.uk/pdf/safetydata/pe ... _sheet.pdf

Thanks Gulffo! Good link! it says: flammable - not applicable.... and all things are toxic when burnt, some materials more than others.... but I guess perspex is ok to use in wall as window. I imagine they would be good windows in CR. Two of them separated by 2 x 2 timber. Rest of wall would be 2x4 (leaving 1inch for perspex). Then add drywall / decorative beading of course.... All together, 2 inch of perspex with 2 inch of air inbetween... fitted air tight of course. I've checked the clarity of view - pretty good! They could also be polished for even clearer view...... How would this idea compare with double glazing? Sound Isolation wise (not look etc)

I imagine they would be good windows in CR.

Maybe not, as Glenn already pointed out: There isn't much mass in those panels. It is only equivalent to 1/2" of ordinary window glass. The idea with windows is that the glass must at least match the surface density of the rest of the wall. What are your walls made of? That is the factor that will decide what type of glass you need in your windows. If you use something that has less surface density, then your windows become the weak point, and all the sound will leak through there: Thus, you will have wasted a lot of money making good walls if you put bad windows in them.

Two of them separated by 2 x 2 timber. ... All together, 2 inch of perspex with 2 inch of air inbetween... fitted air tight of course.

Bad idea! A 2" air gap is nowhere near enough! Even if you had proper laminate glass of the same surface density as the rest of the wall, you would STILL need at least 8 inches of air gap between the two panes to get decent isolation.

How would this idea compare with double glazing? Sound Isolation wise

It does not compare at all. You will not get good isolation at all out of that plan: you don't have anywhere near enough mass in the perspex, and you don't have anywhere near enough air gap between them. The MSM resonance of that would probably be way up in the low-mids, so your wall would isolate terribly for the entire lower end of the spectrum. (I didn't do the math: just "guesstimating". You can do it yourself to confirm).

Rest of wall would be 2x4 (leaving 1inch for perspex).

It sounds to me like you are planing to build a fully coupled wall only 4 inches thick, with drywall on each side? If so, that will not give you decent isolation at all! Maybe 20-something dB, or perhaps 30-something at the very best. Even speech will be audible through that. Not what you need for a studio. Maybe you could post a diagram of the cross section of your wall? - Stuart -

i don't know - 1/2" glass should be OK, worst case, you have to make it 2" thick per window :) i agree with Stuart though - increase the air gap to at least 8" if possible.