Bog's Paddleduck Engine

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bogstandard:
Kirk,

PM sent to you.

John

shred:
The welding supply place I went to did have silver solder, but what they had available was pretty thick stuff that didn't do so well for little parts. The flux they had was ok. If you've got a few days, I'd surf on over to http://store.sra-solder.com/section.php/89/1 and get some 0.031" dia BAg-1 wire or the like (they have Cd-free if you prefer). $20 will get you plenty for more than 10 of these engines and the thin diameter works well for pre-formed rings (silver soldering with pre-formed rings like John says below is highly recommended)

bogstandard:
If you go down about half way on this post, it shows what you should be aiming for, and how I achieved it.

http://www.homemodelenginemachinist.com/index.php?topic=1500.msg13808#msg13808

I hate wastage and extra work. Use only enough materials to complete the job. Any excess and you will be trying to clean it off to a satisfactory condition for hours. You should be able to pickle the part, a quick rub over with wire wool or scothbrite, and the soldered assembly should look presentable and ready to use. Not like most silver soldering you see, like a bird has crapped all over it, with flux and excess solder dripping all over the place. I only hand feed flux and rod in dire circumstances, all other times I do it as shown.

OK, it is a bit like a black art, but once you have mastered it, a little bell rings in your head, and from then on, you should be making perfect silver soldered joints whenever you want them.

A special little trick to use. If you can't get the bits to hold together while you solder it up, deform the end of the tubing slightly so that when pushed into the hole, it stays where it is put. With soft copper tube, that is maybe pinching between your fingers to get the effect you want. For larger bits that fit together, use centre pops on the joint areas to expand the metal so they become a slight interferance rather than a slip fit. Once it is all done, you will never see you little 'bodges' ever again.

John

Bernd:
kvom,

Here's a link to a guy that has silver soldering down pat. Scroll to the bottom of the page and you'll see one or two of his drawings showing his method of silver soldering.

http://www.craftsmanshipmuseum.com/Hiraoka.htm

Bernd

kvom:
I had a few hours today interupted by several honey-dos. Got the steam chest holes drilled. I am going to hold off on reaming the valve bore until I'm ready to fit the valves. I decided to go with a .375" bore and ordered some drill rod of that size today. In any case I drilled the bore 1/32 smaller. The steam ports are .177". The flange mounting screws will be 5-40. I didn't tap these yet (did I mention I dislike tapping?). For mounting the steam chest to the block I will use 8-32 screws, hence the mounting holes are drilled accordingly.

I also made a flywheel from the Cedge mystery alloy (silver bronze). It's hard to work with, but is very "pretty" when polished. I used the badsaw to cut off a 5/8" slice from the 2" diameter rod, but since the saw didn't cut straight the wheel ended up .55" thick rather than the scale .59". I wanted to machine a rim/hub recess, and normally would use a parting tool. However because the cross slide on my lathe has a very short travel, the parting tool in the QCTP holder won't go close enough to the center. So I needed to grind a HSS tool blank into an appropriate cutter. That took quite a while, but gave me a chance to use the new 46-grit grinding wheel for the first time. I plan to bling it up a bit, but here's the first version mounted up for a trial fit:

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