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A Copper liner for an old small Glue Pot

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xy mosian

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Hi all.
I recently posted an image of a copper liner for an old glue pot on the 'Last thing you made' thread. In response to questions by AndyT my answer was rather long, and rambling. Therefore I decide to post eveything here. .

AndyT,s questions:-
AndyT":kskacodk said:
That's impressive! Any more pictures? How many pieces and how big? Did you solder them together then beat it out? I'm intrigued and impressed.
.

Thank you Andy, sadly no more pictures, to be honest I barely thought this to be worth posting. However, the inner is in four pieces. Two handle brackets, the bottom and the outer.

The inner needed to be 55mm diameter, roughly 150mm circumference. The depth 45mm, or thereabouts. A 150mm length of 15mm copper pipe was split along its length, standard hacksaw used there. Then it was flattened, I use the term loosely. An 8 oz hammer against a piece of Oak did a reasonable job but it was never going to be a mirror. Cleaning the two shorter ends, for the overlap, was tricky and difficult with wire wool and scotchbright, but I managed it, just. Then a little beating to encourage a slight curve over a piece of some pink hardwood with a curve to an edge. Once I had the curve to a state where I could 'help' the copper into a curve with my hands I tied the curve with an encircling soft iron wire loop. Standard plumbing solder and flux used with a propane torch, a soldering mat used to protect my vice. A brief pain reminded me that blow torches make things hot, that didn't last long fortunately.

Now the suprising part, for me a least. I had expected that the upper support ring would need to be separate, believing that the copper would split if beaten out too far. As I don't have a heat source large enough to heat the copper to red, for annealing by quenching, I was prepared to raise a slight 'flange' merely to aid with the positioning of a suitable washer, for soldering. As luck would have it the copper beat out nicely against the end of a steel tube mounted in the vice to define the height. The earlier solder joint split partly at the corner, but well above any Glue level and therefore no problem.

A piece of 60mm long, 22mm copper pipe was split as above. Flattening was no more succesful than before, but then I was not really very confident of success in the whole thing so just carried on. The tube was placed onto the bottom and a line scribed around the inner to define the size of the bottom. I cut the handle brackets, the copper being large enough to grip before the cutting of the bottom. In a discussion about Jeweller's saws on here, I found out about the benefits of a well tensioned blade. As I used an Eclipse fret saw I shortened the blade by shortening, about one half an inch I think. It worked a treat.

The flange at the other end, bottom of the pot, was more thought provoking. Metal forming the upper, outgoing flange is stretched of course, quite natural when being beaten by a hammer against a hard place. Forming the inward going flange means compressing the metal, unnatural, at least in my scant experience. A piece of scrap ash was used in the vice, small end up, to use as a stake. Soldering was as before, but the first attempt leaked. I did clean the mating surfaces but it would have been a lot easier had I cleaned the pot before forming the lower flange. Still the second attempt worked well. The pot didn't leak anyway, and a suprise, the earlier sprung joint had re-soldered, must be my lucky day.

Attaching the handle brackets was a real head scratcher. My blow torch gives off too much heat and I don't have an electric iron with enough. I do have a large lump of copper on a long rod, which might have worked, but all surfaces are flat and so totally unsuitable. Thinking around the problem I latched onto the low temperature of the glue, from memory, just hot enough to be uncomfortable on the flesh but not searing heat. Epoxy, I hope this will be the answer. That is what I used anyway. It the joints fail in use, unlikely I think then I shall have to use a rivet in each side. I rejected this idea earlier for the brackets with respect both to getting some sort of anvil inside the pot, and lack of space for some sort of 'head' outside. There is a distinct lack of suitable space between the outside of the inner and the cast iron outer.

The handle is of Soft Iron Wire. Does anyone know how to straighten this without also hardening it? I have used both spinning and stretching, very fiddly stretching, but both resulted in hardened wire. Suddenly not so easy to work. Still I managed the process here, if the wire bends I can bend it back.

Sorry this has been very wordy. I learned a lot perhaps to be of use later who knows?

xy.
 

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AndyT

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Many thanks for that really fascinating, detailed answer.
 

Bm101

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Fascinating post xy. Thank you for taking the time to write it up. Nothing wordy about it. I find heating and cooling of metals fascinating. I've done the odd plane iron or marking knife but nothing really . Easy to see why its been equated with mystical properties historically.
 

xy mosian

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Thanks again Andy and yourself BM101.
I am quietly chuffed that it came together. Although I don't use animal glue often it has to be better than a tuna tin balanced in a steak and kidney pie tin.
Now heat treating steel for blades. I am trying not to get into that. Yes it's fascinating, and sometimes useful. I can however see my lack of a suitable heat source, for hardening, being sorted with a Mapp blow lamp at some point. That would sort my occasional absolute certainty that I need brazing facilities at the same time.

xy
 
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