Outside Laser Powers?

[mixedgas]

Don't know how long you need the smoke but with a good fan and a couple of this things: http://vimeo.com/4117000 you have a decent smoke that would burn for a minute of 5. So if you want to do a quick show you could try it :P

Nice try, however, this is based on experience.
Pyrotechnic white smoke uses a vaporized scattering material, something like ammonium chloride or zinc chloride . It is too dense, and usually strongly adsorbs the beam. It is very hot and does not diffuse well, rising rapidly.

Pyrotechnic colored smoke uses a vaporized dye, and strongly adsorbs the beam. Fluorescent dyes used in smoke, even rhodamine, do not glow when vaporized in air.

The amusement park/theme park solution of using large amounts of airburst pyro at altitude works, because gunpowder smoke is about the right size and the blast distributes it. Even then, they use distributed fog machines, and fans to aid in dealing with shifting winds.

Steve

[White-Light]

Thanks for all the replies.

However, I'm a little confused now as to whether to not I need a large smoke machine and a fan a la Norty's suggestion or several small machines a la Green Alien's suggestion.

This is my garden (taken from an upstairs window):



Below the window is a patio.

The whole garden is about 30 feet square.

I'm proposing to put the projector diagonally across the area by mounting it in / next to the tree at the back left hand corner (next to the light green leylandi).

As I intend to keep people on the lower patio area seen which the blue coloured BBQ is standing on, there's a reasonable distance between the projector and the nearest person.

Traditionally I'm in a windy area which is very exposed with wind coming from over he garage and also from the right over the hedge which is out of view in the picture. Wind from the right tends to swirl around in a vortex in the garden.

[Rizard]

I would say that you have enough with a (big) smoke machine that has an continues output and a decent fan. And based on the comment of mixedgas I wouldn't try pyro smoke Probably some smoke of the BBQ will still hang around too. Maybe it's worth testing (don't know if you have the stuff laying around)

[White-Light]

I think I have 4 options:

1. A 3KW Machine - 40,000 Cu/M

2. A 2KW Machine (like Norty's) - 20,000 Cu/M

3. A 2KW machine 20,000 Cu/M + a 1KW machine 10,000 Cu/M

4. 3 x 1KW machines @ 10,000 Cu/M each


Cheapest option is 2.

Btw, I would plan to follow Norty's suggestion and put the main machine under the tree at the top with a fan and blow the smoke out from directly under the projector.

Any other machine would maybe at one side at the bottom.

Views?

[mixedgas]

Option two is fine for your situation. In such a small venue you can move it to match the wind. If your fog is too dense or rises too much, a tiny amount of water added to the tank will cause it to droop or thin out. But once you add water, you cannot go backwards.
It is worth experimenting.

Large muffin fans are great for this, so are big house fans. If you have a old oscillating fan, even more fun.

If you have 20 knot winds, then I would start thinking of two machines, but at that point, your guests are moving inside, anyways.

Steve

[White-Light]

2kw above should have read 1.5kw!

Ok thanks Steve, I was thinking anyway that might be a good place to start then experiment. I was thinking I could always add a 1KW machine as a side machine down range of the main smoke machine if needed.

Thing is its always a battle between machine and cost. The 1.5KW costs approx £15 an hour to run at full tilt as consumption is 9 minutes a litre.

[norty303]

The 1.5KW costs approx £15 an hour to run at full tilt as consumption is 9 minutes a litre

Don't forget it won't run continuously on full volume, so you won't use that much due to heating cycles.

It will run continuously on lower volumes, but will obviously use less fluid doing so

[steve-o]

I put on a show every 4th of July at my neighbor's house. He supplies the fireworks (the big stuff) and I supply the laser show. The firework smoke (even from small fire-cracker strings) works incredibly well with the lasers. The gunpowder (as mentioned by Steve) must be the gift.

[White-Light]

Just wondering Norty have you ever tried the Stairville E-HD fluid?

Its recommended for outdoors but I wasn't sure if it would be too dense.

[Yag]

If the weather's right, you don't need a lot!

BBQ picture attached is a 100mW green, with a £30 Soundlab fogger.

(Blue from a £30 LED Parcan)

(Not everything in my life costs £30 )