Build Plans: How to make a rain machine

POSTED BY Erik Beck, 08 August 2007

How to make a rain machine

by Erik Beck

Hey, everyone, and welcome to the technical blog for Episode#13 (rain machine). All you people who wanted a cheap way to recreate good-looking "movie rain" read below. The coolest thing about this project is you probably have a lot of the parts laying around the house. Remember you can submit your project ideas here!

Warning: I'm using power tools to build this project. Always have adult supervision when using power tools if you are younger than 18. Seriously, people, be careful.

Shopping List

1. 25- to 50-ft garden hose.
   (I bought a 50 ft one, but the water only came out about halfway. I'd try a 25-footer)
   
   
2. Some cheap wood.
   (I got about 20-ft of 1"x2" beams. If you have some old 2"X4"s laying around, just use those.)
   
   
3. Cable ties.
   (I used these to fasten the hose to the frame. You could use duct tape in a pinch.)
   
   
4. Plastic hose cap.
   (This was like a dollar and screws on to the end of a hose to cap it off.)
   
   
5. Female-to-male hose adapter.
   (This is a simple piece that allows you to screw the end of one hose to the beginning of another. Mine came with a nifty valve.)
   
   
6. Four eye bolts.
   (To provide a good place to hang ropes.)
   
   
7. Rope.
   (I used some leftover nylon rope I had from the samurai armor, but whatever you get, make sure it is strong enough to support the rig. You don't want this thing falling on your actors.)
   
   
8. Some screws, nuts and bolts.
   (Basically something to hold the frame together. I used wood screws.)

The frame

This can really be made out of anything that is reasonably light and will hold our hose in place. I chose to build a simple wood frame and would suggest you do the same. Start with two beams that are 5- to 6-ft long. Using some wood screws, or even better a bolt, nuts and a few washers, secure the two beams in the middle. You should end up with a big "X."

Now add some cross-bracing using more wood and wood screws.

Now add some eye bolts where the cross-braces meet the "X." Four in total. It should look like this when done.

The hose

So instead of using PVC, I decided to try a flexible hose. Rain is a part of nature so it should come from a naturally occurring shape like a spiral. OK, I just made that part up. Anyways, spread your garden hose in an even spiral across the surface area of the frame. Start from the outside.

Once you have it evenly spread out, use the cable ties to secure the hose to the frame.

Right now you have a giant dream catcher. So you need to drill some holes in it to make it a rain machine. Using a very small drill bit, drill holes in the top side of the hose every 4 to 6 inches. Make sure not to make these holes too big. You'd be surprised how much water will spray out of even a tiny hole. You can always drill them bigger later if you need to, so start small.

Last, screw on the plastic cap to the end of your hose (should be in the center of our rain machine) and the valve adapter to the beginning.

The set up

So unless you have a crane, you'll need to hang this rig from a tree. Using the four eye bolts and some rope, hang the rain machine like a chandelier. I figure the higher you can get it, the better, but for our test film we had it about 8 to 9 ft up and the rain looked fine. Now, just connect a second hose to the adapter at the side of the rig and go.

When you hang this thing, you want the holes in the hose to point up. This will make the water spray up and then fall down with gravity. This provides a much better spread and droplet size. The first time we set it up we had the holes pointed down, and it just looked like a big shower head coming out.

Conclusion

This rig provided at least 50 square feet of quality rain. Roughly a 5' by 5' space to shoot in. This is perfect for dramatic scenes between two or three characters. You could always build a few and create a bigger rain area.

Check out this build in action, from Episode 13 of Backyard FX