Airbags and beachballs

mrodoc

mrodoc

Well-known member
While reading a book on US cave exploration I came across a description of beach balls being used in narrow passages to modify or exclude draughts. Set me thinking that this technique might be used in caves to detect draughts by obstructing narrow sections. OR then suggested that airbags would be even better as they would expand to fit an irregularly shaped hole more snugly. The question is where could one obtain used airbags and has anybody seen a diagram of what the inflation point looks like. It would obviously need modification for pump or hose inflation? I have somewhere in a cave where the idea can be tested by the way.
 
aricooperdavis

aricooperdavis

Moderator
I'm not sure how useful a car airbag would be for this - I was under the impression that the fabric that they're made of is vented to allow the bag to rapidly deflate/deform on impact? You're looking for something that can be inflated like a kayak buoyancy bag but is more flexible I guess. Hmm...  :-\
 
pwhole

pwhole

Well-known member
Tough rubble sacks for gardening etc. might be usable if the neck can be gathered with bungee or similar? Wilko sell them quite cheap, but they're very strong.
 
M

MJenkinson

Member
Jim Lister showed us some buoyancy bags he had made using Ortleib heavy duty drybags and some low pressure inflator gubbins.  They would do the same job.
 
Duncan Price

Duncan Price

Active member
Bin bags?  One inside another to protect it?  or heavy duty ones...

Gather end around a tube and secure with insulation tape.  The hold a lot of air - I've filled them with helium in the past to hang cameras from.

 
C

crickleymal

New member
Someone must make large balloons like those in the series The Prisoner. I remember Ian Anderson pushing huge  balloons out into the audience at the end of Jethro Tull gigs.
 
braveduck

braveduck

Active member
The Navy use large fabric coated ones for mooring ships.They were used at Derwent Dam
when they needed to replace the Valves in the wall .There were two tunnels and each was
blocked by two bags placed by divers . The bags were inflated and the valves were successfully
removed and replaced from the down stream side while keeping the dam full. Those of you who know
Derwent Dam will know it is very large. In case of any leaks the bags were connected to air commpressors
at all times. To make sure nothing went wrong there were 3 separate air compressors systems all connected
and to be very sure if the air compressors started up, it sounded an alarm in the chief engineers hous if he was not
on site at the time. Worked a treat ,job done and no water lost . 
 
braveduck

braveduck

Active member
The Fire brigade use super tough fabric coated on ones for lifting car and lorries to extract
people from underneath. Those are the ones you want for caving use .
 
C

crickleymal

New member
https://www.balloons.co.uk/72-uninflated-giant-balloon-fuchsia-12462?zenid=tkm7cbos32tjv6rcfqttj83gm7

they also do balloons you can climb into but they're about ?36
 
pwhole

pwhole

Well-known member
I wouldn't want to be digging next to that mofo when it bursts. Of course, it might be more fun if filled with N2O instead... :halo:
 
mrodoc

mrodoc

Well-known member
braveduck said:
The Fire brigade use super tough fabric coated on ones for lifting car and lorries to extract
people from underneath. Those are the ones you want for caving use .
Click to expand...

I recalled they use such bags today and thought they might do the job. They would be expensive I guess and I wonder where you would acquire one. One wants a bag that will expand into an irregularly sectioned passage, can be inflated by manual means and is not going to leak rapidly. Sizewise I am talking about crawling size passage, no bigger.
 
M

mikem

Well-known member
Lomo do drybags of all shapes & sizes, up to 150 litres, that would work in some passages:
http://www.lomo.co.uk/acatalog/Dry-Boxes-dry-bags-uk.html

Or beach balls up to 1.5m, but they would need protecting:
http://www.ebay.co.uk/bhp/giant-inflatable-ball

Mike
 
cooleycr

cooleycr

Active member
What you need, mrodoc, is a chimney balloon.
I fitted one in our (unused) fireplace and it works a treat.
If fully inflated it makes a wonderful seal, though of course to prevent damp I don't fully inflate it, but I'm sure you get the idea..
They come in various sizes and are inflated with a flexible pipe so you don't even have to have your head in the passage (if ingress is an issue).

try
https://www.chimneyballoon.co.uk/
https://www.amazon.co.uk/Chimney-Balloon-Medium-Chimneys-60cmx30cm/dp/B009MYL5PO
etc.
 
pwhole

pwhole

Well-known member
Wow, that's wonderful. I guess the only real issue might be that chimneys are probably a lot more regular and less abrasive than cave passage. Still, with a bit of wall-trimming (or even just draping a rubble sack over it before inflating), I'm sure those issues could be overcome.
 
Roger W

Roger W

Well-known member
The airbags thread seems to be linked to the ladder safety one..  I've got the two threads at the top of the Home page (after the 3D printer one) but clicking on the ladders and ladder safety thread just gives me the one on airbags and beachballs. 

I suppose one could use some airbags or beachballs at the bottom of a pitch to cushion the fall of anyone falling off a ladder - but I rather think we have a bit of a glitch here.

Can someone technical sort it out?
 
cooleycr

cooleycr

Active member
I agree Roger W, I too spotted that I had added the latest post to the Ladders thread and yet I clearly haven't!!!

But I do like the idea of an airbag attachment to my oversuit  ;)


Charley..
 
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