This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
Fletcher, of Warrington, the well-known inventor of so many improved appliances for the employment of gas in the workshop, has published some interesting remarks on the use of the blowpipe. Where available, there is no fuel to equal gas for general blowpipe work, and in using the blowpipe with gas, it is usual to cut a notch or groove in the upper side of the open end of a 3/8-in. brass tube, so as to allow the top of the blowpipe to rest in it, pointing in the same direction as the opening in the gas pipe. The blowpipe tip should then be placed in the notch, and a wire bound round both in such a manner that the blowpipe is held firmly in position, and still can be easily drawn out backwards. This arrangement forms a carrier for the blowpipe, which leaves the hands at liberty, and enables the whole attention to be directed to the work. A short length of tube made like this could be carried in the tool-bag, and connected to any available gas supply.
For hard soldering, where the solder used melts at a heat approaching redness, and sometimes at a still higher temperature, the same form of blowpipe and the same source of heat are commonly used, except that as the work is usually done in fixed workshops, the sources of heat do not require to be portable, and are therefore usually confined to gas, or, where this is not available, to a lamp, having fixed on the upper side of the wick tube, in a convenient position, a support of wire, or other material, to carry the front of the blowpipe. Sometimes the blowpipe is made as a simple straight tube, sliding in a loose collar, the blowpipe in this case being about 3 or 4 in. long. At the opposite end of the jet is fixed about 14 or 16 in. of small indiarubber tubing (feeding-bottle tube), which is used for blowing. The sliding motion of the blowpipe is necessary, so that the jet can either be drawn back, giving a large rough flare for general heating, or it can be pushed into the flame, so as to take up part only and give a finely pointed jet on any part where the solder requires to be fused.
When gas is used, the sliding motion of the blowpipe is not necessary, as the flame can be altered equally well by the gas tap, and it is therefore usual to make gas blowpipes with fixed jets.
Another form has the blowpipe coiled as a spiral round the gas tube, both gas and air being heated before burning by a Bunsen burner underneath. This gives a very much greater power for small work, but possesses no advantage whatever for large flames. On the contrary, when the maximum bulk of work is to be heated with a mouth blowpipe, a better result is obtained with a cold blast of air, and the advantage of the hot blast is only perceived when a small pointed flame is used. When this blowpipe is used for soldering, the bulk of the work should be heated up first with the cold blast, and the lower Bunsen turned on a few seconds before the small pointed flame is required for finishing the soldering. The hot blast has one advantage peculiar to itself in addition to the high temperature of the small flame; it requires no chamber for condensed moisture. The moisture of the breath, instead of appearing as occasional splashes of wet on the work, at critical times, is converted into steam, and goes to assist the blast from the lungs.