Tube for blowing out 8mm holes

andrewmcleod

andrewmcleod

Well-known member
If there was an award for most niche equipment question, I suspect this would be in the running...

What is the best tubing for blowing out 8mm drill holes? Ideally I guess you want something thin-walled with roughly the same surface area inside the hole and between the tube and the drill hole. In any event it is going to be much harder to blow down than a larger bit of tubing (which won't fit in an 8mm hole). If you were going to massively overengineer it, you could put a short 4mm (or whatever) stub on a bit of larger tubing...

PS there are a set of nice Raumer double expansion bolts in a cave I have bolted (abroad) where the holes weren't blown out. The bolts that weren't blown out have all crept out significantly further before biting (and violated the Raumer 'good bolt' criteria) so it does make a difference!
 
langcliffe

langcliffe

Well-known member
I use this (and also for larger holes). It's a short length of flexible tubing bought from an aquarium shop, attached to some larger diameter carbide tubing. The latter allows me to get a good supply of air through to the flexible end.

blower.jpg
 
andrewmcleod

andrewmcleod

Well-known member
PeteHall said:
Bit overkill perhaps and a bit bulky for caving, but we used these at work and very effective. Generally known as the "Big Puff"
Click to expand...

I've got a cheaper variant of that which I've used before but the tube doesn't fit down an 8mm hole; is the tube on the Hilti one small enough? I think I'm going to construct some sort of fat tube/metal straw hybrid tube and also get some airline tubing based on suggestions.
 
SamT

SamT

Moderator
You blow out capping holes???

Done a lot of capping but never bothered blowing out the holes.  :confused:

Other methods - yes. Capping, cant see the point really.
 
andrewmcleod

andrewmcleod

Well-known member
SamT said:
You blow out capping holes???

Done a lot of capping but never bothered blowing out the holes.  :confused:

Other methods - yes. Capping, cant see the point really.
Click to expand...

I don't know about capping, but I have previously been told it is important for plug and feathers as otherwise the dust absorbs the expansion force (as it is softer)...
 
Cave_Troll

Cave_Troll

Active member
I'd have thought the dust only absorbs a bit of force until it's compressed and the force is transferred.
even then it's not really "absorbing" the force.
imagine laying on a foam mattress. your weight (force) is still transferred to the floor.

 
Q

qwerty

New member
;)



9396207386654.jpg


https://www.hilti.co.uk/c/CLS_FASTENER_7135/CLS_ACCESSORIES_TESTERS_7135/CLS_CLEANING_ACCESSORIES_7135/59725


 
Pitlamp

Pitlamp

Well-known member
Langcliffe mentioned flexible tubing; in case it helps to know (for those in the Dales) Ashfield's DIY in Settle sells a wide range of diameters of flexible PVC tubing by the metre.

http://www.settlediy.com/
 
langcliffe

langcliffe

Well-known member
Pitlamp said:
Langcliffe mentioned flexible tubing; in case it helps to know (for those in the Dales) Ashfield's DIY in Settle sells a wide range of diameters of flexible PVC tubing by the metre.

http://www.settlediy.com/
Click to expand...

I remember now - that's where I got it from!
 
J

Joel Corrigan

New member
Andrew: I recommend a pink Curly Wurly straw as thats right up your street ;-)  Failing that (and as others have mentioned) some skinny flexible gas pipe is ideal. Make sure it?s long enough so u can clear the hole from a bit of a distance (maybe half a metre or longer depending on how athletic & ?reachy? your bolting is) & bear in mind that over time you might chop bits off that have become blocked so thats another reason to start off longer than you think.  Then attach some skinny bungee to it near the end (secure with a barrel knot & duct tape). Options: make a big bungee loop that goes over my head but that can become a snag point so possibly have a single length with a teeny accessory krab to clip to your chest harness instead. Most of the time the pipe gets stuffed down my oversuit. On your travels can you pick up a few metres for the Dachstein, please?  Make sure it doesn?t get brittle in the cold but presumably someone switched on in a hardware store will be able to advise.
 
braveduck

braveduck

Active member
Today went to Ashfields DIY in Settle .They sell plastic tube from 3mm to 15 mm by the Metre .
For 30p I got the perfect blowing out tube ! :clap:
 
Pitlamp

Pitlamp

Well-known member
braveduck said:
Today went to Ashfields DIY in Settle .They sell plastic tube from 3mm to 15 mm by the Metre .
For 30p I got the perfect blowing out tube ! :clap:
Click to expand...

There you are - I told you so!  ;)
 
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