Cheap home made bounce mirrors?

[Displaser]

Dnar,

If you're looking for cheap cost, these aren't a bad start:

Bounce Mirrors

I purchased a set awhile back - easily worth the cost for the mirrors alone. Not sure what size you are wanting, but at least these can be adjusted. Seller is very reputable, as he has been in business 30+ years.

Greg

[norty303]

It may be me, but do the pics on the ebay auction not look as if there are massive losses from the mirrors?

[Laserock]

Hi dnar,

What size mirrors are you needing,I have hundreds and hundreds of first surface mirrors that come out of copier machines and laser printers--most are over an inch up to two inches wide and anywhere from 8 to 12 inches long and you can cut them with a regular glass cutter to the length you need.You can have them for nothing if they will help you out.Of course you will need to pay for the shipping as I am always broke these days but it can't cost that much!
Just send me a PM if you want some of them and let me know what size and I will send you the ones that best fit your needs.Also the guys are very right about the projection tv's having huge first surface mirrors in them and they are high quality--I have several over three feet square.
Also I am planning on going to Selem in a few days but I can send them to you when I get back home.

Kevin

[dnar]

I think 2x2" or 3x3" would be perfect. I don't want them too big as I don't want to hit them unless required (I'll zone attenuate them out).

I found the perfect mounting method, although reading AS2211 they call for very firm mounting with baffles etc... Bloody Nanny state...

[norty303]

I have to say that I use 4x4 and even they can be problematic to hit efectively at range, especially if either your projector mount or mirror mount are not 100% rigid (the slightest sway on a truss for example)
Don't forget that the resolution available in your DAC may mean that even the smallest increment in the targetting settings can mean you jump from missing on one side to missing the other side.

[dnar]

Hmm. I was not planning doing such large shows... Famous last words... I never planned to do public shows from the start, look at me now...

Thanks for the advice.

[norty303]

Hmm. I was not planning doing such large shows

These were not large shows. Even at 15 metres its like hitting a postage stamp. Its more fun when you are coming off the laser on the front truss to a bounce mirror 15-20m away then back to a 4x4 diffraction mirror back on the truss again

[Insanity]

And remember, your nice little 3mm beam won't still be 3mm by the time it hits the mirror, so as Norty says, bigger is definitely better, I use 4" and they are pretty hard to align and keep aligned...

Another point to note when designing mirrors is that the mount should be such that if it becomes loosened due to vibration for example, it must not be able to tilt vertically. This would result in full power beams dropping into an audience...

Just my 2p
Mark

I have to say that I use 4x4 and even they can be problematic to hit efectively at range, especially if either your projector mount or mirror mount are not 100% rigid (the slightest sway on a truss for example)
Don't forget that the resolution available in your DAC may mean that even the smallest increment in the targetting settings can mean you jump from missing on one side to missing the other side.

[dnar]

And remember, your nice little 3mm beam won't still be 3mm by the time it hits the mirror, so as Norty says, bigger is definitely better, I use 4" and they are pretty hard to align and keep aligned...

Another point to note when designing mirrors is that the mount should be such that if it becomes loosened due to vibration for example, it must not be able to tilt vertically. This would result in full power beams dropping into an audience...

Just my 2p
Mark

Yeah thanks. The regulations and standards here are very specific about bounce mirrors and their mounts. And rightly so!

[dnar]

Double post apologies.

A quick bit of Math (tm) for isosceles triangles, were the base is the scan width at a given distance.

With 40 degree optical, FB3 with 12 bit resolution, each step represents 2.73mm @ 15M scan distance. Much smaller than I would have imagined.

Feel free to correct my math, just finished an 11 hour day and my brian is fired.