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Henry12 · Oct 25, 2008, 04:33 PM

Please help me! I am looking for any and all advice on how to create a clear, rubbery coating of roughly 1/4" thick, around a 38" long piece of curved 1.5"OD aluminum tubing. The coating needs to be firm holding, and not slip at all; nor can it be clouded with glue or something. Nice and clear is ideal. First, I tried to find a way to slide 1.5"ID, 2"OD clear vinyl tubing over a 1.5"OD aluminum tube bent in an arc with a 36" radius. The obvious problem is that the inner vinyl diameter is the same as the outer of the aluminum. This causes so much friction that I can't get it on more than a couple inches, let alone the 38" I need. If I could get it on, it would be perfect. But, I have resorted to using heat-shrink tubing. The problem with it is that it has extremely thin walls which means it will be really expensive to layer it up to 1/4". So, I am looking for any and all advice on how to create such a clear coating. Please, please help me!

Milo Dolezal · Oct 25, 2008, 04:36 PM

What is the pipe going to be used for ? Any hot liquid flowing through it ? How about the ends ? Overlap ?

speedball1 · Oct 25, 2008, 04:52 PM

Originally Posted by Henry12

Please help me!! I am looking for any and all advice on how to create a clear, rubbery coating of roughly 1/4" thick, around a 38" long piece of curved 1.5"OD aluminum tubing. The coating needs to be firm holding, and not slip at all; nor can it be clouded with glue or something. Nice and clear is ideal. First, I tried to find a way to slide 1.5"ID, 2"OD clear vinyl tubing over a 1.5"OD aluminum tube bent in an arc with a 36" radius. The obvious problem is that the inner vinyl diameter is the same as the outer of the aluminum. This causes so much friction that I can't get it on more than a couple inches, let alone the 38" I need. If I could get it on, it would be perfect. But, I have resorted to using heat-shrink tubing. The problem with it is that it has extremely thin walls which means it will be really expensive to layer it up to 1/4". So, I am looking for any and all advice on how to create such a clear coating. Please, please help me!

Why does it have to be clear? I'm thinking a piece of 1 1/2 or 2" Armoflex Tubing,(see image) This is a spongy rubber like covering about 1/4" thick. It comes in five foot lengths. Will that work for you? Regards, Tom

mygirlsdad77 · Oct 25, 2008, 05:08 PM

Just curious, what is the purpose of this?

Try using soapy water to lubricate the tubing. May help.

EPMiller · Oct 25, 2008, 06:18 PM

Make sure the plastic tubing is nice and warm, then try silicone spray inside the vinyl and on the aluminum. Plenty of it. Can you slip it on a straight section of the aluminum and bend it later? It will be easier that way as you can PUSH the vinyl tubing. That way it will bunch up and expand instead of pulling it, which causes it to elongate and reduce in diameter.

mygirlsdad77 · Oct 25, 2008, 06:32 PM

Great advice epmiller, but still want to know what purpose this will serve.

ballengerb1 · Oct 25, 2008, 06:33 PM

Yep me too, waiting silently in the wings.

Henry12 · Oct 25, 2008, 06:59 PM

Tom, Thanks a lot for your input. Yes, the product needs to be as clear as possible. The consistency is really important too, with a vinyl tubing being just about right (could be a hair stiffer when pressed on with a fingernail). Overall the covering tubing needs to be very abrasion resistant, as it is being put on a product that will have constant moving contact with the ground. I am not sure I have seen the Armoflex you noted, but it looks like it would be too soft for my application. Other thoughts? Does anyone have experience manipulating clear vinyl tubing (stretching, heating, shrinking, other... )? Thanks!

ballengerb1 · Oct 25, 2008, 07:04 PM

Vinyl tubing won't take ground friction for long either. If you are inventing something then maybe you can't share too much info but it would sure help. Most products or tools that have that much ground friction just employ a sacraficial steel plate.

EPMiller · Oct 25, 2008, 07:08 PM

Manipulating vinyl tube... It expands when heated, but it will not recover to original diameter when melting point is passed. It also discolors.

Abrasion resistance... You can get clear heat shrink tubing that is tougher than the vinyl tubing I think you are talking about. But you probably will have to take out a home equity loan to pay for it at the size you want. Armorflex is soft and black, not what you want.

WHAT THE HECK IS THIS FOR? Curiosity is killing me.

EPM

Henry12 · Oct 25, 2008, 07:09 PM

Sorry, folks... didn't know there would be so many response so quickly. Here's the deal: I am making what is called Roue Cyr. It's a circus performance prop that looks like a giant hoola-hoop turned on its side. The performer stands inside and rolls around, and does a lot of spinning (like a coin spun on a table). The apparatus is made in five sections so it can be deconstructed, with an overall hoop diameter of roughly 6 feet. The diameter of the tubing, including the rubbery covering needs to be 2". The metal is 6061 aluminum, ideally at 1.5"OD, with a skin of something that looks and feels just like clear vinyl with 1/4" thick walls.

I like the idea of using some sort of lubraicant on the inside, but I would be concerned that the soap or silicone (mentioned to date), but am concerned with the esthetic results, and possible slippage afterwards. The skin covering needs to be tight enough on the metal that it is not going to shift around. Is there some sort of clear, silicone lubricant that will harden eventually? Plus, the prop needs to be stage ready, and have a crisp look (it should look like metal, as seen through a clear coating. Thank you all for your thoughts. I'm new to this forum thing, so bear with me as I try to address further questions.

ballengerb1 · Oct 25, 2008, 07:11 PM

He's building a widget

mygirlsdad77 · Oct 25, 2008, 07:14 PM

You may want to go to an auto body shop. They may have what you are looking for. Just a suggestion. This is plumbing page. Little out of our league. Im sure there is a way to achieve what you are trying, but I honestly don't know if you will find it here. Hope I'm wrong. Good luck, and please let us know where we can see the finished product, in performance, sounds like a good show.

Henry12 · Oct 25, 2008, 07:16 PM

Questions... EPMiller, could you please describe the vinyl's expansion when heated? Does it become soft and malleable, or actually increase in size? Do you know what the temperature limitations are, roughly? As in, hair drier or heat gun?

Also, the covering can't be put on later. The tubing is going to bent with a hydraulic Hossfeld Universal Bender, and besides the tubing fitting perfecting into the die set, I think the covering would get destroyed in the bending process. Thanks!

EPMiller · Oct 25, 2008, 07:21 PM

Hah! Much clearer picture. Try silicone adhesive, Dow Corning number, can't remember it here at the computer. It is a high temperature adhesive in a green "toothpaste tube" rather like a caulk. It would provide a good amount of slip until it sets up. Maybe several minutes. Don't know how it works with vinyl tubing though, not much sticks to that stuff. You definitely would have to experiment. As to the durability of vinyl tubing for this type of abuse, I think it will get abraded quickly and lose it's clarity. Also if it gets compressed at high psi (think small contact patch with weight of person on it) it most likely will stretch and delaminate from the aluminum core. Will definitely require some experimenting. Good luck and keep us posted.

Henry12 · Oct 25, 2008, 07:22 PM

Here is a link for those of you who care to see what the prop looks like in use: YouTube - Cyr Wheel Act - CORTEO (Cirque du Soleil) Sorry, no rewards for successful methods, but pride in knowing that you are well versed in obscure electrical-plumbing-fabrication techniques, and many thanks from me!

Henry12 · Oct 25, 2008, 07:26 PM

Dow Corning huh? I will give it a try. Thanks EPMiller! Other thoughts suitable covering materials from anyone? Requirements are clear, stiff enough to resist abrasion, but soft enough that it will grip a stage floor when the hoop is rolling around at an angle (it can't slip out from under the performer).

EPMiller · Oct 25, 2008, 07:33 PM

Originally Posted by Henry12

questions... EPMiller, could you please describe the vinyl's expansion when heated? Does it become soft and malleable, or actually increase in size? Do you know what the temperature limitations are, roughly? As in, hair drier or heat gun?

It will increase diameter slightly, but once it starts to melt it will not return to it's original size. Variable temp heat gun would be my tool of choice. It really gets soft and floppy, if you could heat the aluminum tube and use a slightly undersize vinyl tubing it might shrink on tight. I know I've gotten it on 3/8" diameter tubing so tightly that I couldn't remove it later, but not 3 feet of it. I did it just by warming the tube a little and pushing it on. I don't think silicone spray lube will show once everything is together.

Also, the covering can't be put on later. The tubing is going to bent with a hydraulic Hossfeld Universal Bender, and besides the tubing fitting perfecting into the die set, I think the covering would get destroyed in the bending process. Thanks!

Sounds like your core is so stiff and it is large enough radius that I think you could use my method even after forming. If the vinyl doesn't last, you could cut it off and recover it with little ill effect to the core.

Got to sign off for tonight. If you need more info from me I'll try and get back tomorrow.

mygirlsdad77 · Oct 25, 2008, 07:41 PM

Wow, just watched the vid. Very cool. Is this your act or someone else's. If its yours you already have the hoops. Are you trying to improve on them, or can you not find the origianl builder of the hoops? In an act like that I would think it best to leave the hoops as they are. Maybe you could use other colored coatings, maybe a fluorescent color under a black light, really make the ring stick out.

Henry12 · Oct 25, 2008, 07:48 PM

Mygirlsdad77, no the hoop is being made on commission. I am a performer, but have never seen one up close. I am making to the buyer's specifications, that's why it needs to be clear and of such specific sizes. I agree that fluorescent colors under a black light would be nice; for now though, I think I have to go with clear. Thanks for your thoughts!