Hot air gun / blow torch

Slightly at a tangent to Model Engineering but worth a try.
I need a hot air gun to shrink some 'heat shrink' onto some cables.
No power available. Not feasible to use a genny. I thought of adapting a gas blowtorch to provide heat at the nozzle instead of a flame. I have a choice of 3 types of blowtorch. Plumbers gas bottle type with a hose and torch Plumbers disposable gas can type DIY 'ronson type' " " "
Problem is I do not know the best way of doing it.
Cables are quite hefty 400mm^2 each core!! but I want to keep away from direct heat.
All advice gratefully received, thanks
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snipped-for-privacy@eanx100.co.uk wrote:

There are several small gas soldering irons with hot air adapters - they use a catalytic element to avoid putting a flame into the hot air stream. The Weller Pyropen is the most easily found, but there are others, mostly cheaper - I've got a fairly large unit made by Radiospares and previously used by a double glazing fitter. They work very well on heatshrink.
-adrian
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On 20 Mar, 22:17, snipped-for-privacy@eanx100.co.uk wrote:

Didn't know you were supposed to use a hot air gun (don't have one anyway), I have always used my hand 'Ronson' type gas torch and wafted it in the general direction until the shrinkage level was about right - but then I am only an amateur, and its usually small bits on the car or an electric motor, but I don't see why it wouldn't work on bigger stuff.
Steve
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On Thu, 20 Mar 2008 14:17:22 -0700 (PDT), snipped-for-privacy@eanx100.co.uk wrote:

Given all the negatives described above I would not use heat-shrink. Consider self amalgamating tape. If you are using a joint box which incdes heat-shrink which MUST be used then reconsider the generator and standard heat gun. I use a gas powered heat gun (catalyst type) for heat shrinking but 120mm2 max, and it is a bit slow on that.
--
Richard

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I haven't tried this, just a wild idea. get the heatshrink in place and wrap in tinfoil, warm the whole lot up gently. Or use self amalgamating tape!
Steve
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Might work, but I don't really want the severity of a naked flame more a sort of difused indirect heat. The idea behind the blowtorch adaption was for portability, but it is looking like a non starter.
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Too right that 400mm^2 cable isn't normally used in model engineering.
There's various types of heat shrink tubing. Some shrink at temps as low as 90C so boiling water may be a possibility if the rest of the system can dry afterwards. They also have different physical properties that you may want to consider. Google "heat shrink" and there's lots of info. Have you looked at other insulating sleeves. Silicone rubber is a good alternative on smaller cables. I don't know if you can get it in this size though. Amalgamating tape is good, so is cloth insulating tape in the right location.
John
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