PVC dolly track - what do you use for rough terrain support?

[Bob Woodhead]

As the title sez, wondering what you folks have found works best to support PVC dolly track over rough/uneven terrain. Is it necessary to have a method to keep the PVC "attached" to the support, like a channel cut into wood, or a clamping thing?

Where do you find large shims? Home Depot only has little ones for aligned doors/windows.

[John S. Cooper]

If the surface don't slope to much, then you probably don't have to support it (even if it don't hurts to do it).

[Ron Coker]

Originally Posted by Bob Woodhead

As the title sez, wondering what you folks have found works best to support PVC dolly track over rough/uneven terrain. Is it necessary to have a method to keep the PVC "attached" to the support, like a channel cut into wood, or a clamping thing?

Where do you find large shims? Home Depot only has little ones for aligned doors/windows.

For 2". PVC tube 9 ft length, have a length of timber 1"w x 2"h x 80"L+. Wedge length 10"
Mark them out for cutting, two per 10" length. You will produce 8 sets for the two rails. Use wedges in pairs, one either side of tube. This will give an adjustment range 0 to about 1.5"

Cutting wedges will require a power saw bench. A handy man friend could do this for a bribe I'm sure, or speak to your local furniture maker for a quote, what ever it takes.

[Michael Hutson]

Bob,
Try using unistrut. The pvc should rest in the groove and then shim the unistrut to level.

[Terry Lee]

Bob, I am currently putting together a track and dolly kit as well. My design is similar to train tracks. However I'm not sure it will stay that way. What I plan on doing is getting (and this is because its available to me) scrap cuts of timber and just axing wedges out of them. I am estimating about 20 or so wedges of various sizes. Along with this will be extra ties. I am assuming you are making ties for your PVC tracks..

I have a few shots that I will be doing that I know one end of the track will be way up off the ground as appose to the other end which will more than likely be level. So to compensate, I was thinking jack stands. That way you can raise and lower them but with jack stands you can't do much fine tuning.

Another thought would be saw horses. Rig the PVC tracks to saw horses and wedge the difference to make it level. Don't forget to bring your level.

But if a shoot is dead serious, the best thing to do would be to bring a load of wood, screws, drill and a skill saw and build it to the terain. Thats assuming you have a couple hands to help as well.

[Michael Hutson]

here is an example of the unistrut.
http://www.unistrut.com/Browse/cart....+Part&PN=p3300

[Terry Lee]

Unistrut is what I used to build my entire crane. Good stuff.

[Robin Davies-Rollinson]

Did you mean to use Unistrut to run the whole length of the track - or am I missing something here?
If you are, then would it not be better (and cheaper) to just swop the PVC track for aluminium tubing which wouldn't bend so much?

[Martin Catt]

Aluminum or metal tubing costs $$$, and once bent, STAYS bent. PVC pipe is relatively inexpensive, and does not bend permanently, but WILL shatter or break if taken past the failure point.

PVC pipe on top of unistrut is a good idea for extremely irregular surfaces, as the unistrut will support the flexible PVC and will require fewer shims and wedges to support a given length of track. The cross-sectional shape of unistrut makes it very resistant to bending, plus the bolt holes in the unistrut make it easy to stake down your track using large timber spikes and washers through the unistrut into the ground.

Martin

[Robin Davies-Rollinson]

Understood - I just don't know the relative cost of a length of Unistrut to that of metal tubing...

[Terry Lee]

What Martain is saying is to use the unistrut as ties for the PVC tracks. PVC pipe is WAY cheeper than anything metal. Just drop by Home Depot and check it out.

I haven't figured out how you can bend PVC so as to make a curved track...

[Martin Catt]

Originally Posted by Robin Davies-Rollinson

Understood - I just don't know the relative cost of a length of Unistrut to that of metal tubing...

A ten-foot section of unistrut is about $14 at Home Depot here. I use it as cheap construction material for "Erector Set" type contrivances.

Martin

[Martin Catt]

Originally Posted by Terry Lee

What Martain is saying is to use the unistrut as ties for the PVC tracks.

Not as ties -- lay a length of unistrut along the path, U-side up, and then lay the PVC in the channel of the unistrut. The unistrut provides continuous support along the entire length of the PVC, and any chocks or wedges support the metal unistrut. That way there's less sag between the wedges and chocks.

Originally Posted by Terry Lee

I haven't figured out how you can bend PVC so as to make a curved track...

There are heated sleeves you can wrap around plastic pipe to heat them to their softening point and then bend them to a desired curve and allow them to cool. They're relatively short, though, so you'd need a bunch of them to make a long, gradual curve, or else get real good at getting the final curve one section at a time.

Martin

[Terry Lee]

Originally Posted by Martin Catt

Not as ties -- lay a length of unistrut along the path, U-side up, and then lay the PVC in the channel of the unistrut. The unistrut provides continuous support along the entire length of the PVC, and any chocks or wedges support the metal unistrut. That way there's less sag between the wedges and chocks.

Oh I see. Thats a better idea than what I was thinking. I was thinking that you could fold the two pieces of PVC track so that they come together long ways for protability. I think i'll be re-designing my track..