Laser Safety Window

Anyone got a good cheap supply for some red plastic
to make safety window for blue laser 445nm?

Plastic has to show bandpass diagram -- not transmitting 445nm

Tnx

... look in the toolstore for orange PMMA sheets - founs some from Evonik with specs that show total blocking below 500nm ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I'm also looking for good sources in the US and will share findings... There are lots of places that sell tiny windows or red sheets for ridiculous prices. I need blocking for 445nm and my cheap goggles seem to work but don't have optical density data. It should be a function of the density of the tint measured through the thickness of the glass, although some of the very expensive ($$$) goggles seem to be reactive.

It seems something like this in dark red should work fairly well: [www.tapplastics.com]
There's no OD data for this but it should provide some level of protection.

Opinions?

Well, I'm back after a long hiatus - new baby meant less garage time for me.

I had found some laser safety film but it was ridiculously expensive (around USD $500).

I've ordered this stuff, which was cheap (came to less than $50 with shipping):
[www.globalindustrial.com]

By area it works out to much less than the TAP Plastics acrylic (also much easier to cut).

I don't have a good method to test its blocking for 445nm but the plan is to use this to cover the front window of a cutter cabinet, perhaps doubling the material, to protect against reflections.

It's supposed to arrive tomorrow, and I'll give it a test.

... you can test the absorption rates by beaming through the sheet on white paper or 'look' through it with a webcam.

My orange sheets absorb all of the blue, but I can see a faint orange spot when engraving ...

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I received this material day before yesterday and I did some experiments at low to moderate power - very pleased with the results. It's a very dark orange and at low power ("focusing" range) the bright blue center on white paper is a dim yellow. At cutting power the normal reflections on other surfaces disappear and primary reflections from a white cutting surface are bright yellow but not enough to transmit light. I wouldn't use it as a substiute for safety goggles but at around USD $7 per square meter (including shipping) it's a bargain.

The material is 12mil plastic (like heavy shower curtains) in a 54 inch width with grommets. It's flexible and should easily laminate to viewing windows. At this price one could afford to just have an extra curtain around the cutting equipment.

I have some optics equipment available at work and will check to see if there might be something that can measure spectral transmission.

Guys, the only safe mode to test the real absorbtion is to measure transmitted power having some laser power meter devices....
I would not rely safety of my eyes on home test. A small laser safety window with certified OD worths the money. IMHO.

Yes, I would not rely on this alone. However, you cannot have too many extra precautions and for that it seems to work quite well.

There are probably some reasonable techniques for measuring incidental reflected optical power. I'd like to figure out how to do that affordably.
It's easier to get a rough idea with the visible spectrum (than, for example, IR) but I would't rely on that.