PVC piping or other “track” for dolly “train” for filmmaking?
I am a filmmaker & we use PVC piping as the “tracks” for dolly (a little board on wheels that we put the camera on).”train.” The problem we are encountering is that when we place the PVC piping together with makeshift rods bridging the gap between them it causes gaps & bumps on camera. Furthermore the PVC pipes seem to get dirty & aren’t really smooth which the camera is sensitive to.
The questions I had if you wouldn’t mind sharing your wisdom:
1. Is there another type of piping you may recommend? (remember we use the exterior & don’t much care about the exterior of the pipe)
2. Is there an internal threading/screw in system you might recommend (they don’t need to be waterproof tight just a snug fit that would endure screwing in & unscrewing over & over again).
3. Is there something other than Pledge or WD-40 that you might recommend placing on the pipes to get it frictionless & clean?
Thanks so much. I appreciate it.
Interesting problems. I’m very familiar with PVC pipe, having been a commercial electrician for years and even was the sales rep for a major manufacturer of the fittings briefly. Problem with trying to couple it flush is that all the fittings sleeve OVER the exterior of the pipe — there is nothing that would stop it if you tried to cement a connector inside the pipe. Also you don’t say what size you use. I checked the spec charts for Carlon Schedule 40 electrical PVC and have a suggestion. The O.D. of size 1″ is just slightly (.065 inch) smaller than the I.D. of the next size, 1 1/4″. The same is true of 3″ pipe fitting inside 3 1/2″ (which is likely bigger than you need.) I would try cutting a 6″ piece of 1″ pipe, coating half of it with PVC glue and slipping it halfway into the flush cut end of a stick of 1 1/4″. Once it bonds you should be able to slide another stick of 1 /14″ flush onto the piece of 1″ jutting out for a fairly snug butt-to-butt connection. Note this will only work for Sch. 40 electrical, since the OD/ID of plumbing pipe is completely different. You could easily experiment with other sizes.
Another suggestion would be a metal u-shaped track called Unistrut (google it to see the product). It’s used to fabricate supports in construction. You can buy it in 10′ or 20′ sections and it has a bunch of sizes and profiles. It’s kind of like an erector set for grownups and has a variety of fittings that will allow it to be butted flush and assembled and dissembled. The solid 5/8″ green enameled would be your best bet — it’s strong, smooth and rigid. You can buy it at contractor supply places. But it does have a squared profile, not round, so I don’t know if that would work for you.
For lubrication you might try using T-9 Boeshield. This is a spray-on waterproof lube developed by Boeing for use in aircraft. It isn’t sticky and won’t degrade rubber or harm metal components. I use it to lube the breakdown aluminum frame of my folding sea kayak and protect it from saltwater corrosion. You can buy it at marine supply stores.
ADDITION: A way to keep the pipe section tight together (if you use my glued-in reducer suggestion) would be to run bungee cord through the pieces and tie each end off to something that won’t slip down the pipe. Same design as they use for self-assembling tent poles. Carry an electricians fish tape to push through and snag the length of bungee cord to pull it through the assembled PVC run.
Now that I’m thinking of tent poles — those might be the ticket. Check an army-navy store or awning supply vendor/renter to buy aluminum tent poles that sleeve together, with or without bungee cord inside. You should be able to locate various sizes and click together as many as you need for length. The polished aluminum would have less drag than PVC. But it might not have the diameter and strength you need for the dolly.
I see someone recommended cable — as someone who has pulled and tensioned a lot of cable (from aircraft stainless to copper power lines), I can attest that building structures that will withstand tensioning is tough and it’s also impossible to totally eliminate sag (any weight on a tensioned cable will either sag it or break it.)
