No 6 (or 26)

By Journeyman

It is now some six months since I wrote ‘In from the Styx 5’, and  looking back I find that it is over a year since I wrote of things model engineering, the intervening three Styxes having been devoted to my blacksmithing career, which I hope you found interesting. Since May, activity in the workshop has been at a low level for reasons I won’t bore you with. However, I finished reassembling the two cylinder vertical engine, whose refurbishment I described, and it now sits on the side where it will be for display only. I made a new exhaust manifold with flange mountings, a better arrangement than the original where the old one was just soft soldered directly into the exhaust passage outlets.
I then started to think about ‘what next ?’ House removal burnout was, and rem
ains, a factor, so a small project was what was needed without any interdependent and close fitting components. I settled on a Pressure Testing Rig as described by Norman Barber in ME no.4346, March 2009. The article had no drawings, just photos of the finished rig and a general description, but since Norman is  the mentor behind the construction of my 5” gauge Terrier “Boxhill”, I was able to contact him with any questions, and in his usual generous way he sent me drawings of the valves and pipework.
I already had a 4” diameter pressure gauge I had bought for this purpose from the Miniature Pressure Gauge Company, so the first job was to make the base and the vertical centre board, the two being joined by two right angle brackets made from my stock of 5/16” square BMS. The positions of the gauge and the three valves and pipework holes and the
pressure chamber were marked out and cut and drilled, that for the gauge being finished to a close fit to hold it in by friction, and then it was on to the valves.

I made all the nuts and nipples, and then - having mounted the finished components in their positions - it was on to making up all the pipes, some of which run under the plinth connecting the reservoir to the pump, the pressure chamber, the vent valve, and the valve to the external outlet for connecting to a boiler via an hydraulic hose. The brass pressure chamber cylinder is for testing boiler fittings.

I made the mistake of ‘using up’ copper pipe from my box of odd bits, only to find that all of it was slightly under size, so the soldering of the nipples led to a number of leaks : lesson learned - use materials of known provenance !!

Once all was tight and leak proof I used it to do an hydraulic test on my 5” gauge LBSCR Gladstone that I was preparing for its official test, something I always do at home before presenting it to our club boiler tester, as also with the  steaming test. They give their time to us, and a clean and  well prepared engine is the best way we can show our appreciation for their services.

And now, not quite model engineering but:

I have two grandsons. My son is a dairy farmer (and doing well - it is possible despite all the tales to the contrary !) and so his house is full of farm toys of every description, mostly made of plastic these days, but also incorporating parts made from diecast metal known as Zanak or Majak, an alloy of zinc/aluminium/magnesium/copper in various proportions and notoriously difficult to mend once broken. The plastic parts are equally difficult, and so who was presented with a tractor and mower with just these two problems?

Considerable time was spent on web searches and I found a new Loctite - ‘Loctite All Plastics’ - which claims to stick all those ones previously unstickable. Internet purchases are usually pretty quick to arrive and so the mower for cutting the silage grass was duly put back together, and it really did stick ! The Loctite comes with an activator pen, like a felt marker, to apply to both surfaces, then the glue is applied to one side and the parts are brought together and held ‘til the glue is set.

The broken link arm on the back of the tractor is made of Mazak and was an  altogether  different problem. I had to make a new part from brass as the original bit was lost, and an ‘A’ piece to reinforce the joint. Research came up with no answers for sticking Mazak other than the need for good cleaning, so I first tried some two part epoxy I had, but with no success. Then came some ‘super glue’ boasting its magic powers on anything and everything, again with no success.

It was time for more in-depth research, which revealed that the best degreaser is trichloroethylene, but it’s banned, being carcinogenic. Finally a ‘phone call to a club member with a huge depth of knowledge (we have two or three of them!) gave me what proved to be the answer.

Loctite 7063 is the degreaser to use, £10 delivered, beware some much higher prices on your Google search, and Hafix Professional Glue, a cyanoacrylate. I held the parts together with surgical forceps which are ideal as they lock together with one hand while you orientate the parts against each other with the other. A dab of paint of similar colour from an ancient mini pot of Humbrol completed the job. Result, one happy grandson, what more could Grandpa want?