Coldframes and Greenhouses - Page 2

**Eire_Ade** · 15-11-2006, 10:09 PM

Wow, Dan I hounestly thought it was a glass, yes perspex is an acrylic / plastic sheet material and is quite expensive, it is very brittle to cut.

But I always thought this also filtered out the UV too.

Ade

**Eire_Ade** · 15-11-2006, 10:10 PM

Sorry Kelly!!!!!

Ade

xx

Henry-flash · 15-11-2006, 10:11 PM

Someone laugh at my joke

yam yam · 15-11-2006, 10:14 PM

sorry pete i was laughing

**egyptiandan64** · 15-11-2006, 10:17 PM

How thick is it Ade? It doesn't sound like the same thing. Plexiglass isn't brittle and is pretty easy to cut. You can get it pretty thick here and it doesn't yellow in the sun. It only filters out about 2% of the UV light. Where glass does like 95%. It sounds like perplex might do the same as glass in filtering out the UV. I'll have to look into it

Dan

and yes Pete your joke was very funny

**Eire_Ade** · 15-11-2006, 10:22 PM

Dan it can be got in various thicknesses, from 3mm upwards.

This stuff is clear like glass, doesnt discolour much definately not yellowing, tends to go opaque, (less see through) as it ages almost white looking.

It is flexible in position but cutting it to size it is fragile as it can split / crack like glass and before you know it the split is across the front of it.

Ade

**egyptiandan64** · 15-11-2006, 10:23 PM

Polymethyl methacrylate (PMMA) or poly(methyl 2-methylpropenoate) is the synthetic polymer of methyl methacrylate. This thermoplastic and transparent plastic is sold by the tradenames Plexiglas, Perspex, Plazcryl, Acrylite, Acrylplast, Altuglas, and Lucite and is commonly called acrylic glass or simply acrylic.
PMMA is lighter: its density (1190 kg/m3) is less than half the density of glass which is 2400 to 2800 kg/m3 .
PMMA does not shatter
PMMA is softer and more easily scratched than glass. This can be overcome with scratch-resistant coatings.
PMMA can be easily formed, by heating it to 100 degrees Celsius.
PMMA transmits more light (92% of visible light) than glass.
Unlike glass, PMMA does not filter UV (ultraviolet) light. PMMA transmits UV light, at best intensity, down to 300 nm. Some manufacturers coat their PMMA with UV films to add this property. On the other hand, PMMA molecules have great UV stability compared to polycarbonate.
PMMA allows infrared light of up to 2800 nm wavelength to pass. IR of longer wavelengths, up to 25,000 nm, are essentially blocked. Special formulations of colored PMMA exist to allow specific IR wavelengths to pass while blocking visible light (for remote control or heat sensor applications, for example).

Dan

yam yam · 15-11-2006, 10:29 PM

my hubby has just used some Perspex, and when you buy it ,it comes in a protected seal and he said it has written on the pastic seal Plexiglas now i even didnt know that

**Eire_Ade** · 15-11-2006, 10:40 PM

Thats great info Dan,

Perpex is fine then, brilliant. Thanks.

Ade

**egyptiandan64** · 16-11-2006, 03:31 AM

Everybody is very welcome

Dan

15-11-2006, 10:09 PM	#11
Eire_Ade Super Moderator Adult Join Date: Jun 2006 Location: Ireland Posts: 8,422	Wow, Dan I hounestly thought it was a glass, yes perspex is an acrylic / plastic sheet material and is quite expensive, it is very brittle to cut. But I always thought this also filtered out the UV too. Ade __________________ Ade ----------------------------------------------- Y.O.B 1971 (40 years young! ) My Tortoises :- Dug (Testudo Graeca Ibera Terrestris (Syrian), Penny, JJ (JennyJack), Buttons and Gem (Testudo Graeca Ibera)

15-11-2006, 10:10 PM	#12
Eire_Ade Super Moderator Adult Join Date: Jun 2006 Location: Ireland Posts: 8,422	Sorry Kelly!!!!! Ade xx __________________ Ade ----------------------------------------------- Y.O.B 1971 (40 years young! ) My Tortoises :- Dug (Testudo Graeca Ibera Terrestris (Syrian), Penny, JJ (JennyJack), Buttons and Gem (Testudo Graeca Ibera)

15-11-2006, 10:11 PM	#13
Henry-flash Senior Member Adult Join Date: Jun 2006 Location: Cheshire Posts: 9,304	Someone laugh at my joke __________________ Peter Keeping: Testudo hermanni, Testudo graeca (graeca & ibera ), Testudo horsfieldi, Astrochelys radiata, Malacochersus tornieri and Kinixys belliana. The North West Tortoise Group

15-11-2006, 10:17 PM	#15
egyptiandan64 Super Moderator Adult Join Date: Jun 2006 Location: USA Posts: 14,171	How thick is it Ade? It doesn't sound like the same thing. Plexiglass isn't brittle and is pretty easy to cut. You can get it pretty thick here and it doesn't yellow in the sun. It only filters out about 2% of the UV light. Where glass does like 95%. It sounds like perplex might do the same as glass in filtering out the UV. I'll have to look into it Dan and yes Pete your joke was very funny __________________

15-11-2006, 10:22 PM	#16
Eire_Ade Super Moderator Adult Join Date: Jun 2006 Location: Ireland Posts: 8,422	Dan it can be got in various thicknesses, from 3mm upwards. This stuff is clear like glass, doesnt discolour much definately not yellowing, tends to go opaque, (less see through) as it ages almost white looking. It is flexible in position but cutting it to size it is fragile as it can split / crack like glass and before you know it the split is across the front of it. Ade __________________ Ade ----------------------------------------------- Y.O.B 1971 (40 years young! ) My Tortoises :- Dug (Testudo Graeca Ibera Terrestris (Syrian), Penny, JJ (JennyJack), Buttons and Gem (Testudo Graeca Ibera)

15-11-2006, 10:14 PM	#14
yam yam Senior Member Sub Adult Join Date: Sep 2006 Location: ESSEX UK Posts: 1,501	sorry pete i was laughing

15-11-2006, 10:23 PM	#17
egyptiandan64 Super Moderator Adult Join Date: Jun 2006 Location: USA Posts: 14,171	Polymethyl methacrylate (PMMA) or poly(methyl 2-methylpropenoate) is the synthetic polymer of methyl methacrylate. This thermoplastic and transparent plastic is sold by the tradenames Plexiglas, Perspex, Plazcryl, Acrylite, Acrylplast, Altuglas, and Lucite and is commonly called acrylic glass or simply acrylic. PMMA is lighter: its density (1190 kg/m3) is less than half the density of glass which is 2400 to 2800 kg/m3 . PMMA does not shatter PMMA is softer and more easily scratched than glass. This can be overcome with scratch-resistant coatings. PMMA can be easily formed, by heating it to 100 degrees Celsius. PMMA transmits more light (92% of visible light) than glass. Unlike glass, PMMA does not filter UV (ultraviolet) light. PMMA transmits UV light, at best intensity, down to 300 nm. Some manufacturers coat their PMMA with UV films to add this property. On the other hand, PMMA molecules have great UV stability compared to polycarbonate. PMMA allows infrared light of up to 2800 nm wavelength to pass. IR of longer wavelengths, up to 25,000 nm, are essentially blocked. Special formulations of colored PMMA exist to allow specific IR wavelengths to pass while blocking visible light (for remote control or heat sensor applications, for example). Dan __________________

15-11-2006, 10:29 PM	#18
yam yam Senior Member Sub Adult Join Date: Sep 2006 Location: ESSEX UK Posts: 1,501	my hubby has just used some Perspex, and when you buy it ,it comes in a protected seal and he said it has written on the pastic seal Plexiglas now i even didnt know that

15-11-2006, 10:40 PM	#19
Eire_Ade Super Moderator Adult Join Date: Jun 2006 Location: Ireland Posts: 8,422	Thats great info Dan, Perpex is fine then, brilliant. Thanks. Ade __________________ Ade ----------------------------------------------- Y.O.B 1971 (40 years young! ) My Tortoises :- Dug (Testudo Graeca Ibera Terrestris (Syrian), Penny, JJ (JennyJack), Buttons and Gem (Testudo Graeca Ibera)

16-11-2006, 03:31 AM	#20
egyptiandan64 Super Moderator Adult Join Date: Jun 2006 Location: USA Posts: 14,171	Everybody is very welcome Dan __________________

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