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Old January 23rd, 2007, 06:57 PM   #1
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How do you make curved PVC track?

Okay. . . forget the previous two questions. . . (PVC versus ABS, etc.). . . perhaps you can tell me how you make curved tracked out of PVC pipe. . .

I'd love to hear your suggestions.

Stephen
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Old January 23rd, 2007, 08:45 PM   #2
 
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there's a limit to the bend radius...but 10 penny nails work pretty good.
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Old January 23rd, 2007, 10:33 PM   #3
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Thanks Bill. . .

Are you just driving these into the floor? Some folks might not be too fond of me nailing into their floorboards.

:-)

I am wondering if some sort of a reel system could be invented that would work sort of like a cross-bow. If one put a steel cable at each end of a PVC tube, and then tighted up some sort of a reel, the tube would naturally bend. And, even more interestingly, marks could be placed on the metal cable to create the proper curvature for both inside and outside track.

What do you think?

Stephen
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Old January 23rd, 2007, 11:55 PM   #4
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your intuition is right on. But it may even be simpler than that. You're absolutely right though - take advantage of the flexibility of the PVC. If you run strong yet thin line through the tube, and tie a loop on one end, as well as a series of loops, spaced out on the other end, you can do exactly what you want. Make 2 lines, and use a caribiner to hook the loops. You can adjust the curve by clipping to progressively longer or shorter loops. The only problem with this setup is that you can't connect more sections to it (with line hanging out of each end), and that you can't really cut the tube for portability (or you'll end up with extremely stiff sections where you have joints. One possible solution would be drilling holes on the sides of the tubes, and running the line through the holes, so the ends are clear. As long as the holes are low on the tube, they wont interfere with the wheels on the dolly. I've done the curved track (worked great), but only with full 10' sections. Let us know what you come up with, and how it comes out!
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Old January 24th, 2007, 12:27 AM   #5
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If you packed a PVC section tightly with sand rammed home firmly, plugged the ends, then slowly bent it around a former like a bicycle rim or large diameter winding tower cable wheel, heating the PVC with a steam cleaner as you progress around, you might get there.

Automotive exhaust pipe formers are probably too tight a radius.
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Old January 24th, 2007, 03:35 AM   #6
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I've looked into this, and really your best option is to simply just wait until you can save up enough money to buy Long Valley Equipment's 1.5" schedule 40 PVC pipe curved tracks. They're like $95 bucks per section, and $800 for a complete 360 circle. I keep telling myself I'll buy the set one day, but never do; it's a luxury, but a straight track is still good and there are so many other more important items worth being concerned about such as a follow focus system, or a Steadicam (which I undertook building with the help of a machinist, but couldn't finish due to getting injured). In other words better to have a steadicam and straight track than curved and straight track but no steadicam. You can simulate a curved arc anyway if you put a jib on the tracks.
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Old January 24th, 2007, 08:27 AM   #7
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I actually thought about that Long Valley track and their dollies, but in the end I made the decision to buy the Glideshot (I felt that its more sturdy handle and ball bearing wheels would last longer than the Long Valley). But my decision carries a cost: I have to make my own track.

Jaron:

I like your simple idea! I think I'm going to look for a reel-type device and see how much bend I can put into a piece of PVC before it breaks. I hope the reel has a long handle, though, as I'm not sure I want to be standing next to it when it goes.

"Ah, I didn't need that eye, anyway."

:-)

Eugene:

You are probably dead on on the use of curved track. It seems that most dolly shots are straight anyway. Since I'm the director, I can always set the shot up in such a way that the curves are less relevant. And, as you note, a Steadycam-type device could probably just about get me there, anyway.

Thanks!

Stephen
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Old January 24th, 2007, 08:49 AM   #8
 
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absolutely a workable idea. run a steel braided cable thru the inside of a section of PVC. cap the ends of the PVC to provide a stop thru which the cable runs. if you want to get really slick, using sailboat rigging, available from any sailboat jobber, you could actually put threaded swages on the ends of the cable. Then, to curve the PVC, just screw down on the threaded ends where they pass thru the caps.

Back on the 10 penny nail approach...no matter what you do you're gonna have to anchor the track to the floor in some way to keep it from sliding around. If you nail the PVC track to a 3/4 inch plywood base, then set that base on the customers floor...presto. Low dollar, replaceable. Instead of nails, tho', dry wall screws are probably better...and removeable with a cordless drill.

Last edited by Bill Ravens; January 24th, 2007 at 10:28 AM.
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Old January 24th, 2007, 10:23 AM   #9
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Quote:
Originally Posted by Stephen Pruitt
I actually thought about that Long Valley track and their dollies, but in the end I made the decision to buy the Glideshot (I felt that its more sturdy handle and ball bearing wheels would last longer than the Long Valley). But my decision carries a cost: I have to make my own track.

Jaron:

I like your simple idea! I think I'm going to look for a reel-type device and see how much bend I can put into a piece of PVC before it breaks. I hope the reel has a long handle, though, as I'm not sure I want to be standing next to it when it goes.

"Ah, I didn't need that eye, anyway."

:-)

Eugene:

You are probably dead on on the use of curved track. It seems that most dolly shots are straight anyway. Since I'm the director, I can always set the shot up in such a way that the curves are less relevant. And, as you note, a Steadycam-type device could probably just about get me there, anyway.

Thanks!

Stephen
Actually, I used Glideshot wheels and built the rest myself, a doorway dolly and platform dolly out of the same Russian baltic birch wood Long Valley Equipment uses, not easy to get as it's not commercially available at hardware stores, I had to go to the distributor. 3/4" thick but stronger the hardware store stuff.

The advantage of the Long Valley wheels is that they're track width adjustable.

I also didn't buy their track pack, but instead two sets of their track connectors as I wanted 4 ft. sections for portability (i.e. to fit into a golf case for easy rolling, transport, and too fit length wise across the back seat of my SUV).

Ease of transport and modularity is a big deal to me. If I were to get their curved track, I might well cut them down in half. My only problem with the self-bend solutions is size. Also, on a paying gig, obviously pre-curved pvc would obviously look better and instill more confidence.

You could buy the $400 Losmandy snake like track, but that thing is like a massive boa constrictor, it's heavy and a large radius. Plus, the Losmandy spider dolly wheels are better, in that they not only swivel but they also pivot in and out, thus allowing them to adjust for the slight variance in width induced by a coiled curved track.

There's also curved fuel hose type stuff, but they're hallow, and can't take the weight of a stand-atop of Napolean Bonaparte style dolly. They would however work in a pinch for a lightweight tripod dolly or doorway dolly. You could get this for about $75, not bad at all.
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Old January 24th, 2007, 10:25 AM   #10
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Steadicam and Dolly (curved or straight track) are two different tools. While extremely good operators can make steadicam moves which are almost indistinguishible from dolly moves, it takes a LOT of skill, practice, and good equipment to make that happen. So if it's an argument of which is more cost/time effective - curving a piece of PVC is hundreds or even thousands of hours easier and cheaper than practicing enough with a stabilizer to mimic a curved dolly move. Even then, for extremely slow moves, it's still easier to just use the dolly. Plus, if you want to invest the time and money into a stabilizer system, you'll have the discipline of working out exact blocking for dolly moves.... and that's usually the first thing thrown out the window in the low-budget stabilizer approach.
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Old January 24th, 2007, 11:01 AM   #11
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Quote:
Originally Posted by Jaron Berman
Steadicam and Dolly (curved or straight track) are two different tools. While extremely good operators can make steadicam moves which are almost indistinguishible from dolly moves, it takes a LOT of skill, practice, and good equipment to make that happen. So if it's an argument of which is more cost/time effective - curving a piece of PVC is hundreds or even thousands of hours easier and cheaper than practicing enough with a stabilizer to mimic a curved dolly move. Even then, for extremely slow moves, it's still easier to just use the dolly. Plus, if you want to invest the time and money into a stabilizer system, you'll have the discipline of working out exact blocking for dolly moves.... and that's usually the first thing thrown out the window in the low-budget stabilizer approach.
Actually, I don't know that it was a low-budget stabilizer for me. I was trying to bridge the gap between say a Glidecam Smooth Shooter and a Steadicam Flyer after going through all the trouble. I haven't finished, because to do so I want the best possible gimbal and a professionally machined socket block. No point in doing it half way in my opinion if you're thinking long term. I'm talking strictly from a "catch-phrase" marketing standpoint as much as I am creative. Both are tools, and neither should be ignored, and I did not mean to imply that a curved dolly should be replaced by a Steadicam outright. My old parnter was a trained Steadicam operator, and I've used heavy as heck, rented, professional curved track dollys on set before...but I'm just talking from a budget standpoint for those trying to put together their own in-house, all under one roof, "package" which I believe many of us our. From that perspective, it made sense to go the steadicam route, an arudous process to say the least but to just get it over with as soon as possible, when I already had an acceptable straight dolly track...this with the understanding that the practice time is for real, but why put it off? Take on everything that you can when you had the funds to go for it. Now I don't, so I don't finish it. Simple as that, but I've made a dent at least for future inroads. With that said, I'm actually focusing on novel writing for the time being in grad school, because I believe it's actually a lot more achievable short term and more practical than movie making, my perspective has changed. There's just so much that goes into the whole film dream and it requires so many things and people to get on the same page. I'm focusing on the writing now as a result, and on the side, there are gigs, equipment additions whenever possible, and a whole lot of frugality everywhere else...but most importantly, the technical training and practice is a life long commitment in my opinion, or at least, I suppose until Bill Gates keels over and leaves me in his will (crossing my fingers). For me, it's a much better side gig than say what most students have, so perhaps my perspective and logic is a bit skewed and ideosyncratic in that sense, i.e. most on here are film making oriented, and I've switch off that part of my mind for the time being in favor of generating literature. If given the choice, however, I hold the "film dream" in a much higher esteem than "literature." After the struggle of L.A., I realize that the writer's plight of my fellow classmates is actually a LOT less daunting. Just writing is so much simpler in terms of what you "need" to focus on, albeit with the caveat of course that if you don't have the actual talent, there's really no work around or solution that can change that or enhance or make up for what isn't quite there unfortunately. So I guess from that sense, it's a "purer" medium albeit far less of a challenge. Filmmaking is liking winning a feverish political race, it's not just the candiate, there's so much behind the churning involved it's awe-inspiring. Literature is writing by the candlelight in a desolate room alone with your thoughts, sweating bullets, then you decide to take a Starbucks break and it's ALL GOOD!!! Woo-hoo, party time.

In any case good luck either way, the heavygrade fuel hose thing would probably be the cheapest and easiest solution back on topic again.
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Old February 18th, 2007, 11:56 AM   #12
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I'm still trying to find a way to describe the traditional film industry without making it sound too pompous..."studio-level production" is the closest I can come up with ("high-end production" is a bit vague, and "Hollywood" is sort of corny; I'm always amused when I see on the DV boards a post that goes "this technology has got Hollywood scared" like a bunch of people are running around Sunset and Vine, all freaked out...as usual, I digress) but in that world, we use curved track perhaps 1 percent of the time a camera move is called for. It took me a long time to understand why I so often see it discussed in the low-budget and indie world; I was thinking that there was a fondness for roundy-rounds of people talking at restaurant tables in that style of filmmaking (and funny enough, there is that) but I eventually realized that a large percentage of the moves in question are "normally" done on dance floor with a crab dolly. My question is, for those who enjoy homebuilding, is a four-wheel steerable dolly that hard to build? I would imagine trying to duplicate the performance of a Chapman or Fisher would be a bitch, but for most moves you don't need the roundy-round or two-wheel steering mode, so having the ability to turn all the wheels simultaneously should do it, and you gain the ability to design much more subtle moves than can be done when confined to track. Of course, there is the bummer of having to shlep all of that dance floor around, but you guys have strong backs, right?!
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Old February 18th, 2007, 02:28 PM   #13
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Charles is right. It's not that hard if you really want to put your mind to it.

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