Forum Index » Make Your Own Gear » Heat shrink tubing instead of vinyl tubing for gravity filter?


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Colin Krusor
(ckrusor) - M

Locale: Northwest US
Heat shrink tubing instead of vinyl tubing for gravity filter? on 04/07/2012 16:07:57 MDT Print View

Crosslinked polypropylene heat shrink tubing is less than a third of the weight of vinyl aquarium tubing for a given diameter, and it packs much smaller. Six feet of 3/8" heat shrink tubing could be rolled up and stuffed into a film canister with room to spare. Has anyone tried this as an alternative to vinyl aquarium tubing for gravity filters? It would only be exposed to hot sunlight when it is in use, and then it would have cold water running through it, so I wouldn't expect shrinkage to be a problem.

Zach Verhey
(overshot) - F
water quality / taste on 04/07/2012 20:10:59 MDT Print View

Not too sure that you'd want to drink water from heatshrink tubing. There may be adhesive, mold/die release chemicals, and other contaminants in it. You can try, but I wouldn’t try it.

Colin Krusor
(ckrusor) - M

Locale: Northwest US
Heat shrink tubing on 04/07/2012 21:48:06 MDT Print View

Zach, that is a good point. The material (polypropylene) is a very inert polyolefin that is used all the time for food and beverage packaging (including drinking straws), though, and it doesn't contain any plasticizers, BPA, phthalates, etc. Residues on the inside surface might be a problem, though. I'll wash it out thoroughly with acetone and alcohol (clean, lab-grade) before using it.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Heat shrink tubing on 04/08/2012 00:44:36 MDT Print View

> I'll wash it out thoroughly with acetone and alcohol (clean, lab-grade) before using it.
The heatshrink behaviour is often due to stresses created in the tubing during manufacture. As such, the heatshrink nature does not depend on extra chemicals.

I suggest a good wash in luke-warm (NOT hot!) soapy water and a rinse in cold water.

Cheers

Rusty Beaver
(rustyb) - F

Locale: Presence
Re: Heat shrink tubing on 04/08/2012 08:27:00 MDT Print View

"The material (polypropylene) is a very inert polyolefin that is used all the time for food and beverage packaging (including drinking straws)..."

If it's the same as used in drinking straws, then drinking straws could be used as heat shrink tubing?

Colin Krusor
(ckrusor) - M

Locale: Northwest US
Heat Shrink Tubing on 04/08/2012 10:34:13 MDT Print View

Rusty, yes, drinking straws can be used as heat-shrink tubing. I've used them for that. They also heat seal well, and I use large-diameter "bubble tea" drinking straws with heat sealed ends to store a few things in my first aid kit.

Rusty Beaver
(rustyb) - F

Locale: Presence
Re: Heat Shrink Tubing on 04/08/2012 20:05:46 MDT Print View

Cool, Colin! That's good to know. Thanks.

jason blake
(jasonbl) - F
Hi on 10/12/2012 02:03:52 MDT Print View

If i would be going to use it this way then i might be doing some tests and analysis before proceeding!
Heat shrink tubing's are wrapped over target wire's and heated until it regains its original form by contracting. This heating process is Instantaneous with large amount of heat with in just couple of seconds !
In the case If we keep on heating a heat shrink tube at 30 deg's (heated rooms) at constant 24 hr's then it will start to contract very slowly over time.
So we can say above situation is a force from [ outside -> Inside ].

We know when water/Air or some thing Travel's trough a tubing or stays there ; exerts a pressure at inside walls of that body ; So, in this situation it is a force from
[ Inside -> outside ].

These two pressures will exert a resultant force which will be added to faster water flow ; Hence Tubes due to their thin walls would crack at joining or where it suits to ! So , using these in my sense is not feasible , it may stay for some days but .. at last it has to be leaked after all !

That's why they use normally a thick material to supply liquids . So that if however Pump pushes water with more flow some times due to change in electricity then it must withstand that shock !

But ; Better Try using it as it costs to nothing ! and get your personal conclusion over it !!

Jason
turnkey pcb

Edited by jasonbl on 12/10/2012 16:19:21 MST.

Kevin Beeden
(captain_paranoia) - F

Locale: UK
re: pressures on 10/12/2012 07:30:41 MDT Print View

> We know when water/Air or some thing Travel's trough a tubing or stays there ; exerts a pressure at inside walls of that body ; So, in this situation it is a force from
[ Inside -> outside ].

Yes, but we're talking a gravity feed filter here. At most, it's likely to be a 2m hydrostatic head. It's not thousands of psi...

> Hence Tubes due to their thin walls would crack at joining or where it suits to

The heat shrink tubing in question is commonly used to make a protective outer for cables that are required to flex. I'd say it's low risk.

Even if a hole develops, you could cut the tube down to remove the leak, or patch it with duct tape; it won't be the end of the world. You might have to go back to boiling water, or, shock horror, drink water without treating. <faints>

> So that if however Pump pushes water with more flow

Pump? Again, we're talking about gravity-fed water filters. There's no pump involved.

The other advantage of heat-shrink tubing is that you could shrink it on to the filter...

I'd go with the non-adhesive version.

Edited by captain_paranoia on 10/12/2012 07:32:12 MDT.

Colin Krusor
(ckrusor) - M

Locale: Northwest US
Tubing on 10/12/2012 09:57:30 MDT Print View

Jason, I've been using the thin-walled tubing since mid-summer, and it works well. No leaks or perceptible shrinkage so far.

David Thomas
(DavidinKenai) - MLife

Locale: North Woods. Far North.
Polyethylene over vinyl on 10/12/2012 10:19:43 MDT Print View

For a tubing that is lighter than vinyl, you could use the milky-white, thin-wall polyethylene tubing such as is sold for connecting ice makers. Almost anything in a small diameter will handle the pressure just fine, but making a good connection and having it survive repeated handling is a more demanding criteria.

Also, consider going to a diameter smaller than 3/16". Check what flow you get without the filter attached, I suspect it is much faster than with the filter attached. If so, you could go to a smaller tubing size.