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Fire Monitors Part 2

Some thought has to be given how to hold all these remaining parts, firstly I need to make sure that I can replicate an upward incline since there won’t be any up and down movement, only rotation. Here comes another jig, a simple block of ½ inch hardwood with the angle cut at 200 and the corner removed to allow all the soldering to take place. Carefully marking out a centre line I used small brass pins to hold the pre silver soldered pipes in position on the flat sides. I now used some clamps to hold the brass pipes in place, check all the alignments then flux is applied. Very gently apply the heat with a soldering iron until the solder flows, it’s important to tack both ends of each pipe first on each side as at this stage the set-up is delicate to say the least and can be dislodged very easily. Then follow round to complete the joints making sure you don’t overheat the whole assembly and melting the parts already soldered. Next I need to test for leakage, if all OK I can carry on to fettle the joints, I don’t use files or abrasive paper to do this I only use a scalpel to remove any excess solder it’s so easy and better results are achieved. This also applies to cleaning up the white metal fittings; the main posts need to have a better base with some sort of fastening arrangement made, so an aluminium piece is machined up with three holes for fastening to the roof, this was then epoxied to the main post. The next job is to make the handles, for this I used some 3mm plate which I cut some slices off with a slitting saw. In its raw state it is hard and needs annealing before bending. The pieces were all cut to length and then drilled in a jig to ensure all the pieces were exactly the same, I can now leave a drill in both the end holes which keeps the pieces together while they are placed in the machine vice with a piece of round bar at the back to give a nice radius. The handles need a cross bar with “knobs on” so a little bit of machining and then the assembly can be done. The handles are soft soldered in place at the correct distance; I now need to drill and tap 10 BA the main to hold the handles in place. When these are assembled they will be put together with some epoxy on the screws and between the faces. Whilst using the epoxy I can glue the white metal exit pipe in place, this now completes the assembly. Next a coat of etch primer followed by a coat of grey primer then finally bright red, these will be left to fully dry before I attempt looking at the rotary system

5 years ago by mturpin013