That is soldering. Not soddering.
Today I soldered the large flange which holds the flat end plate, to the boiler shell. The flange is a large piece of LG2 bronze, but it is quite delicate because the centre is removed, leaving only the rim.
Here is a photo of the flange in position, fluxed, and ready to apply heat and silver.
But before this step I made a special tool. Can you guess its purpose?
Soldered the bushes, the boiler supports, and the engine support. Did not quite have time to tackle the boiler main end flange.
Actually, this was not the first brazing session. It was the third. I had previously silver soldered the firetube. And if you have been watching this build you might recall that I bronze brazed the domed boiler end and the boiler wrapper, and the vertical cylinder into the domed boiler end. Despite the copper reaching red heat during today’s session of silver soldering, the bronze joins remained intact. Bronze has a higher melting temperature than silver solder. Which was one reason I did the bronze brazing first.
Today I fitted the chimney right angle piece, drilled and soldered on its flange, and drilled the end plate to accept the flange. Then I CNC drilled the big bronze end plate to accept the flange.
Then I carefully positioned the bronze end plate, the firebox and the firetube, and silver soldered them together.
Next, the inspection hatch will be soldered to fill the rectangular hole.
Then the main bronze flange will be permanently attached to the boiler shell. I intend to silver solder it, but considering bronze brazing.
These are the boiler supports for th Trevithick Dredger Engine, which need a little more finishing.
As you can see my CNC mill is working nicely. The slow feed rate is because the brass is just super glued to the mounting base and I did not want to risk it coming adrift.
And I have also been working on the 6″ vertical boiler. The brazing with silver solder is almost finished. I have been redoing some of the joins, and can now get the pressure up to 200psi. There are 101 soldered joins in the construction (so far), so I am not too upset that a few of them were not perfect and required a redo. SWMBO was wondering about the bills from the industrial gas supplier. I have used several fills of oxygen. Totally abandoned acetylene and using propane now. It delivers more heat (at a slightly lower temperature), and much less costly.
I needed some brass plate 6mm thick, 50mm wide and 150mm long for the Trevithick boiler-engine..
Prices on Ebay were horrendous for thicker material, and I could find no local supplier.
Silver solder, when properly used, is said to be as strong as the parent metal.
And I had some 75 x 75mm brass square section about a meter long. I bought it years ago for a project and most of it was unused.
So, I cut some slices off the end, sliced bread fashion, and silver soldered pieces together.
I also needed a large thick piece of LG2 bronze for the Trevithick dredger engine. The middle round piece needed to be bronze because it is exposed to boiler pressure. The outside pieces could be bronze or brass so I used brass.
So I silver soldered brass edge pieces to the central piece of bronze. The soldering was done on the very flat Hebel aerated concrete block, and the final piece was very flat, requiring minimal machining.
This is the non machined underside of the brass-bronze-brass piece. It has been rubbed on a surface plate covered with emery paper, just to demonstrate the flatness of the soldered piece.
So what is the big deal?
Well for a start, this is a big deal financially. The materials to be joined are expensive, and some are difficult to obtain.
And the silver solder itself is expensive. We ended up using 4 sticks of 45% silver solder, and an unknown quantity of oxygen, acetylene and propane.
And the end result will be inspected by an expert boiler inspector, and if it is substandard, it will be rejected. No argument.
So yeah, it was a big deal. Look at the pics. A few friends called in to watch and help. It was a cold wet winter day, and I had the workshop wood heater working to keep the troops happy.
So, not a perfect result, but not bad for a beginner. Stuart opined that the job would have been better if my silver solder was the older, (more dangerous) but more runny type which contained cadmium.
Tha firefox wrapper is made, and today I fitted a butt strap. The butt strap will be riveted to the wrapper, and brazed later. In order to drill the rivet holes, the parts needed to be held together, Clekos proved perfect for the job.
Then, a Bit of fun on the TRACTION ENGINE
Oh Bother. Where did that hole come from? And why isn’t this traction engine a 4 wheel drive? Had to uncouple the trailer, and two men to push it out of the hole.
The redesigned steam regulator worked very well, as did the steam driven suction pump. The new oiler filled up with steam, so I need to fix the non return valve. Probably a bit of grit in it.
Yesterday the spindle was wired to the Variable Speed Drive – single to 3 phase converter, and to power. It span smoothly and quietly, and very fast. Much quieter than a woodworking router of similar power and RPM.
Today I hooked up the coolant, after testing the pump. But when I ran the coolant through the spindle, there was no movement of the coolant. So I reversed the fluid connections in case it was direction specific, but still no action.
The pump and lines were OK, so there was a blockage in the spindle.
I removed the coolant connectors on the spindle, and I could see something white and foreign deep in the works. A bit of poking around revealed that it was probably a bit of packaging foam. I dug out some, then blasted the rest out with compressed air. Testing with the compressed air showed that the way was now clear, so I reinserted the supplied fittings.
And one of them snapped level with the surface of the spindle cover. Bugger bugger.
I managed to get the broken buried thread out of the spindle using an “Easy Out”.
The broken fitting looked complex. I certainly did not want to wait for one from China, and I was very doubtful that it would be available locally. I could have made one, but it looked like a half day job.
So I silver soldered it!