Woes of the hard soldering.

Well that looks about as fit for purpose as an England football team Michael! As Jason pointed out you'll be wasting expensive solder continuing with your current attempt. I would start again and get hold of a suitable length of copper tube to form the basis of your boiler barrel and go from there.

Martin.

Ok, you got to me, i'm starting over!

I'll show you Tubal Cain! You and your stupid sheet metal work can go to hell, I'll buy some tube(much more "tubal" than it is at the moment) and screwcut the ends and make two end caps to fit it. i'm sorry if any of his relatives see this. (however unlikely that is, unless someone upstairs has it in for me on that day) . I promise this will be the first and only time you ever see me try to roll a tube.

Respectfully ranted,

Michael W 

Edited By Michael Walters on 27/06/2016 22:45:28

Hi Michael,

I am afraid that is scrap as a boiler part assembly. Just put it down to experience, and next time buy proper copper tube of the correct grade and some decent silverflo 55 silver solder. Also make the parts to the drawings rather than bodge it. If you had shown that to the boiler inspector in my first club it would have been a 'window job' and thrown out of the window by him into the nettles on the edge of a field of a cabbages.

Why would you screw cut the ends? Have you tried screwcutting copper flanged plates or tube? This isnt as per the drawings for the boiler!

These are pressure vessels that are ultimately a bomb if not properly made!

Cheers,

Julian

Edited By julian atkins on 28/06/2016 00:24:45

Edited By julian atkins on 28/06/2016 00:31:18

Yep, It's going to be scrap, unfortunately i can talk about it alot but not really do much about it until i get some more solder(N' tube) which i suspect i went through like water given how much needed jointing. This obviously isn't a desirable arrangement but i'm confident enough in my machining skills.

I was never a good fitter, i hated learning fitting as an apprentice but knew i had to. The moment i got onto a lathe changed that. Then later worked as a miller, I was literally just given drawings and left to get on with it. The people who were nice to me i helped them get through their problems, i'm of a quiet temperament and the noisy ones (some of them superior to me) would come round just to laugh at my handiwork for fitting tasks.

Well tis either screw cut or press fit, although given the wall thickness i'm probably going to make it push fit with a groove for solder, so it will be air tight.

I would probably not join a club so i'm not really too worried about any inspectors. I suspect he was simply helping the magpies make a nicer looking nest for themselves when they go foraging through the field.(depending on how heavy the copper is).

As far as safety is concerned, a safety valve would be never be deviated from it's design, that i wouldn't dream of changing.  

Michael W

Edited By Michael Walters on 28/06/2016 01:08:11

Hi Michael,

For silver soldering you need a minimum 2 thou gap and maximum 4 thou gap for the silver solder to penetrate. 'Push fits' indicate a complete mis-understanding of the basic requirements of silver soldering principles.

Apologies for being so blunt.

Cheers,

Julian

It's okay, i'm used to engineers

I'm afraid i must've missed that book.

Michael W

Michael, have a read of Cup Alloys site about good practice.

As I said earlier, the end caps can be flanged and THEN TURNED TO FIT which should suit you and give control of the joint gap so that they sit correctly inside the tube.

Also have a search around the net for TC's Polly there have been loads made so you should be able to pic up some photos etc of how it should be done such as this . Also worth noting that the original design is quite old, things have moved on from rivited & caulked joints so the likes of SMEE who run courses on making this engine now use tube and silver soldered joints.

Look on the bright side, plug the bottom and you have a nice Art Deco pen holder

It will remind you to take more care - like the pretzel-shaped flywheel on the back fop my workshop door.

Neil

.

Art Deco Baroque

... Or did you mean a nice holder for Art Deco pens

... or maybe 'a holder for a nice Art Deco pen'

etc. ad nauseam

MichaelG.

Edited By Michael Gilligan on 28/06/2016 10:39:57

I think it's more Steampunk or Ratrod than Deco

I didn't want to upset him further by saying 'Shabby Chic'.

Neil

If you really wanted to upset me you could say it's modern art. It's a metaphor for british politics.

Michael W - M.A fine art practitioner.

If I can add a comment without upsetting you I would suggest that you need some practice ( or tuition ) in the art of silver soldering Soldering, silver soldering, and brazing seem to becoming a lost art these days It was something my dad taught me at an early age

Roy

Michael, while waiting for your solder to arrive you could pass the time watching this series of four videos by Myfordboy where he shows the construction of a very similar boiler to the Polly.

You can see the endcaps being turned to final light push fit that I mentioned and also how the solder is drawn into the joint when the gap is right as per Julian's comments.

He does not say but you should be using a clean faced hammer not a dirty thing that also gets used for DIY

Thanks jason, some very interesting things i noticed, the first is that by the sound and look of the flame it looks like a propane burner? the flame from a butane/propane torch seems alot less aggressive (although the copper heated at about the same rate)

He annealed several times forming the copper and radius-ing the end cap, something i didn't take into account on my attempt. 2 bits of wood to keep the material clean, probably better than using steel shims.

Not a major thing but i noticed his lathe had what looked like a spindle clutch on the handle he keeps pulling to the right of the camera shot?

I did actually know about leaving a gap and soldering the joint, but he jumped onto my wording and implied i was therefore a poorly read serf. Theres something to be said for assuming and arrogance but i'm sure his sovereign grace has the finest engines, i should expect no less of his countenance.

Michael W

Yes looks to be just Propane, its not so much the gas that matters but the size of the burner as the larger thay are the more kW they put out. (he has a big one)

The more you need to bend the more often you need to anneal, its not worth keeping beating away at a hard bit of copper as not only is it hard work you risk creases or cracks.

Sandwiching sheet material between two bits of wood stops it flexing about and makes cutting a lot easier as well a sprotecting teh surface.

Yes looks like a clutch, not sure I would want to keep reaching over the spinning chuck/work though.

.

I believe Myford intended it to be a motor belt tensioner

Nicely illustrated on lathes.co.uk **LINK**

... But a clutch is still a clutch, by any other name.

MichaelG.

Hi,

I'm sorry it's been a while since i lasted updated this thread, progress had been slow getting the materials and some production work took precident for the past few days, more money to spend on my foolery that way!

I got a piece of 54mm plumbing pipe and cut and filed it to size, as machining a piece of tube to an accurate length seems nearly impossible without tearing or crushing the wall. I got on the lathe and machined the flange to size from 60mm, you may notice that i drafted away from the face so that theres less metal for the boiler to heat, I got a nice push fit on the flange, but i dont dare push it the whole way yet or i may never get it off again! I plan to silver solder the end caps after riveting them into place with small copper rivets. It was nice for the fixed steady to get some use.

So there you have it, thankyou for the encouragement to try again, i'm much more pleased with the result so far.

Michael W

Is that endcap brass or bronze?

If the fit is too snug from endcap to tube you will again have trouble silver soldering it. There has to be clearance for the silver solder to penetrate. Suggest you a)re-read the CuP Alloys guide b) follow a published boiler design c) use only bronze and copper in small boilers.

Don't become a statistic. JD

To overcome the dezincification of the brass I have often wondered if 'wetting' the entire inside surface of the brass end plate, with a coat of silver solder, would afford sufficient protection from the chemicals in the boiling water. What does the team think about this idea?

I've read you can get tablets to slow down the dezincification process (for the boiler I mean).

Steve