UV filter in Toronto? Home Depot???

[ancorp]

Hi, still working on my first LCD projector, anyone know where IN TORONTO, Ontario, Canada (or the surrounding area) I can find a UV filter? Could a store like Home Depot have it?

Thanks in advance

[Guy Grotke]

Go to your local Home Depot store and buy a piece of Lexan XL. I got a piece 11" by 14" by 0.093" for $4.57 US. Lexan polycarbonate is optically clear, much stronger than glass, heat-resistant up to 800 degrees F, and absorbs >90% of the UV. The XL variety has one side coated with a UV blocker, so it absorbs even more UV. (Put the coated "outside" surface toward your lamp.) You can cut it like glass: Score it with a razor knife, support the part you want to keep on a flat clean surface, and then snap off the part you are removing. Or you can cut it like you do acrylic fresnels with a mototool abrasive cut-off disk. I think the HD guys will even cut it to order for you, but they will charge you for that.

You can use it as the bottom layer in your lower fresnel tray. It will remove UV and support your fresnel!

[projectile]

guy
i located lexan locally but it turned out to be lexan mr10 which ia uv ressistant... now being uv ressistant i understand it good for the polycarbonate as it won't yellow fast... but is uv ressistant same as uv block.????
.. cause it could as well be letting uv pass and still be ressistant to it effect...

[ancorp]

Guy Grotke,
Thank you so muich for the quick reply, I thought I would never get an answer for such a specific question. I will go down to Home Depot asap! What would be better - closer to the LCD/fresnel of to the lightsource?

[ancorp]

btw, sorry about posting in the wrong part of the forum, I forgot about the new changes...

[tetutigre]

Hi,

I tried to search for lexan at Home Depot but it gives me no results at all, it only shows a fluoresent wall fixture.... should I look for it under another name, or ask personally about it???

[ancorp]

I think if you can get down there without much trouble or time, asking about it would be best.

I have another question... Where can I get a Cold mirror in Toronto and area? Does Home Depot carry them too?

[Guy Grotke]

No, Home Depot does not carry cold mirror. They are not even particularly aware about lexan's properties, if you ask them for a UV absorbing material. They just sell it as a replacement for glass so you can make hammer-resistant windows.

In my experience, homedepot.com can be very frustrating. You should call them on the phone and ask if they have lexan or polycarbonate in precut pieces to replace glass in windows. If not, then you can also use acrylic (plexiglas) sheets, This also absorbs UV, but not as well as lexan.

I would put the lexan between the lamp and the first fresnel. For example, you could use it at the bottom of a fresnel tray with the UV coating facing the lamp.

I have seen cold mirror for a VERY high price from various optical supply places. For example, Rolyn has 100 mm by 100 mm 45 degree angle cold mirror for $272 US. Surplus shed sells a 4.75 diameter piece for $5!!!!

[tetutigre]

I went to Home Depot, very doubtful, I stood at the window aisle, and I asked the first person there if they carry a material called lexan... and he pointed me right into it.... sweet!!! I was going through the specs, and seems to be a great thing... it takes up to 800 F and blocks UV... and not too expensive (sweeeeeet)

BTW, which side should be the one facing the lamp? The one that has the green sticker?

Now I'm wondering, could I use this as a heat stopper? I'm thinking about using between 50w-250w dichroic... that would make my projector smaller.... would I still need a cold mirror?

[Guy Grotke]

The side with the white material with red printed instructions, should face the lamp. Not the green side.

You can use it to isolate an area containing hot air from another area in your projector, since it will take 800 F. But I don't think it reflects or absorbs IR at all.

With a dichroic reflector lamp, the heat will not be reflected, but the light coming directly from the lamp without reflection will contain a full dose of IR. If you are thinking you can avoid heat by using a halogen lamp, you are mistaken: They are less efficient than MH, so they actually put out more of their energy as heat.

All of the lamps with dichroic reflectors that I have seen are parabolic. So they send out a wide near-parallel beam 2 to 5 inches wide. To use this in a projector, you will have to find a negative lens with the right focal length to spread the light into the cone accepted by your lower fresnel.