Looking for thin sheet of super-stretch rubbery material

[Marc_G]

Hi folks,

BAck when I worked in a lab, we had some material... might have been butyl rubber, not sure... that came in a roll and it was very thin (probably <0.5mm thick) and super duper stretchy. I think it is the same stuff used for dental dams and stuff, where a pinhole opening can stretch over a tooth during dental procedures.

Anyway, I'd like to take a small sheet of something like this, punch a small round hole with a hole punch, and use it as a nose cone bib to allow me to mask the bottom part of LPR / MPR nose cones. As in, put the nose cone in the hole, stretch the rubber around it so that just the portion I want is exposed at the tip, and the stretch force of the rubber acts as a seal to keep paint from seeping through.

I probably need material that can easily stretch 5x its size to be practical. And very thin.

I live in the Indianapolis area, so have access to all the usual city conveniences for shopping... but what consumer application do I investigate to find a supplier? Dental dams are "dam expensive."

I've found butyl rubber 1/16" sheeting on Amazon. Looking for something maybe 1/32" preferably.

Ideas ?

Marc

 

[shreadvector]

https://www.google.com/search?q=phy...&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=

https://www.google.com/search?q=phy...&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=

 

[dixontj93060]

A large balloon (where you can cut a fairly flat portion out of) at a party supply store (they are cheap).

 

[paul.nortness]

Marc, I am not sure that would work. I think paint would still seep, and there is nothing from preventing the rubber to stay in place where you want the line.....that is, if the rubber is stretched enough to prevent paint to seep...it's going to be stretched enough to try to return to it's original size meaning it will "walk" down your nose cone.

 

[Marc_G]

I've tried with limited success the balloon material (tried a couple different types). It's not quite the right feel to it. I remember the material I used in the lab was perfect... it had "cling" to it and wouldn't walk down a tapered part. Between the tightness and the cling, it was a good joint. I was in a microbiology lab; we did some weird stuff with anaerobes and used this material for ports in gloveboxes and stuff. Surprisingly tight joints without reinforcement. And the hole you made wouldn't tear unless you really abused it.. it would just stretch.

Fred- interesting idea. I wouldn't have thought of physical therapy! OK, time to investigate some of those links some more.

Good ideas all, keep 'em coming. Thanks!

 

[cvanc]

Hmmm. There's this laboratory film they use to seal beakers and test tubes and such. Very stretchy. I have a great big roll of it at home but I won't be there for a couple days. I'll reply here when I know the name of it...

 

[Marc_G]

That's ParaFilm. Thin stretchy wax. Great stuff in its own right but not for this application.

 

[DizWolf]

you know.... Trojan's come immediately to mind. If it'd work at all, they'd be perfect. I do however think it may seep.

 

[DizWolf]

Marc, I am not sure that would work. I think paint would still seep, and there is nothing from preventing the rubber to stay in place where you want the line.....that is, if the rubber is stretched enough to prevent paint to seep...it's going to be stretched enough to try to return to it's original size meaning it will "walk" down your nose cone.

I'm thinking, snip the tip off....pull over the top to desired location, and then duct tape the bottom around the NC shoulder. it could work....

For the uninitiated, get non-lubricated....

 

[dave carver]

you know.... Trojan's come immediately to mind. If it'd work at all, they'd be perfect. I do however think it may seep.

...oh, god, let's hope not

 

[Marc_G]

you know.... Trojan's come immediately to mind. If it'd work at all, they'd be perfect. I do however think it may seep. ...

I'm thinking, snip the tip off....pull over the top to desired location, and then duct tape the bottom around the NC shoulder. it could work....

For the uninitiated, get non-lubricated....

Oh gosh. So many jokes, all at the same time, trying to burst out of my head. But this is a family friendly forum so I will, with great effort, refrain.

The problem with a prophylactic in this situation is that I don't think that thickness of latex will give me the strength around the hole that I want (snicker! chortle!!). Seriously, my experience with thin latex is that it tends to split well before the amount of "compression" I need where the cone goes through the hole. (titter! guffaw!!)

The beauty of the material I used 20 years ago in the lab was that a very small hole could be stretched over a quite large object... the more stretch, the more pressure at the point the rubber material touched whatever was put through it. And the material just wouldn't split unless you did something outrageous. Latex, like in condoms or balloons, generally will split around the hole quite easily.

I'll continue to research. Fred gave some good google search links... just haven't yet found anything is quite what I need. I could always try the sheet of 1/16" butyl rubber I saw on Amazon, just kinda pricey, for something that may be too thick, is all...

 

[Marc_G]

So, I ordered a sheet of butyl rubber off Amazon, thanks largely to Prime free shipping, and also will stop by an auto parts store tomorrow at lunch if time permits... some do-it-yourself gasket materials may be appropriate.

This has been stewing with me for a while and I'm bringing it to the front burner.

 

[Rex R]

mc master-carr lists 0.005" high purety silicone rubber...
rex

 

[Marc_G]

Nice. Pricey, but definitely a possibility if my obsession isn't sated with lower cost products. Thanks!

 

[Marc_G]

Got the 1/16" butyl rubber today. It's way too thick, as I expected. I will stop by a Joanne fabrics or Michaels or maybe Hobby Lobby and see what I can find cheap.

This relates to my S.S. Cassiopeia project so I'm anxious to find a solution. McMaster Carr would be an expensive way to go but if I get desperate I will do it...

 

[BEAR]

Find yourself a tire inner tube. Slice off a patch bigger than you need. Poke a hole in it and have at it. It stretches real good. I used to make rubber band rifles using inner tubes. Wicked. I hope this helps. BEAR

 

[krusty]

You might want to look at the Yoga Stretch bands...



Long flat sheets of stretchy rubber

Krusty

 

[Marc_G]

Inner tube rubber is too thick, sadly. But those stretch bands Krusty shows above, and that were in the links Fred supplied near the top of the thread, look promising. Tomorrow if lunchtime permits I'm going to go hunting for material at some stores near where I work.

Marc

 

[Marc_G]

OK, Fred and Krusty get the honors here. I went to Walmart and for $8.97 plus tax got a set of three thicknesses of latex rubber (I think 0.3 to 0.55 mm thick) sold as Gold's Gym stretch bands. Using a hole punch from a grommet set I punched a hole in the thinnest. Here is what it looks like, exactly what I was shooting for:



Experimenting with creating different sized holes and using different thicknesses should allow me to create some interesting effects!

 

[Marc_G]

Here is the painted result. I moved the sheet forward a bit (so as not to interfere with the "cockpit" decal I will be using, and flipped the material the other way so I could spray blue on the aft part of the cone.



It gives me pretty sharp edges and allows me to get the "tilted cross section across the ogive curved surface" look I was shooting for. If you zoom in you'll see some roughness at the edge, but I believe at this point that most of that is due to a raised lip at the joint... once the paint is all the way dry, tomorrow I will very lightly buff the surface to smooth it out and I think most of that will go away. In any case, it will look good on the pad!

Marc

 

[krusty]

That's looking good and a very cool idea!

I've always struggled on how to paint the end of a nose cone. With the few that I've done, I have mounted the nose cone in my lathe where I turned it with one hand and applied paint (on a brush) with the other. Results are ok - but your idea looks like a better solution!!

Krusty

 

[gdjsky01]

A long shot. All you ex or current aircraft mechanics... Back when I worked on fighters in the late 70 and early 80s there was an orange rubber with a green strip we wrapped ( and memory does not serve me well here ) hydraulic lines in to keep them from chaffing. It was very stretchy and sticky. Especially to itself.

Anyone....???? Then again maybe a was wrong. I thought my scrounge box always had some back then. And yes I know scrounge was against regs. You fly or read regs all day??