| Boiler build
HI
At last time has been found to write up the boiler build on the 2 inch traction engine. Il spread it over a 14 days or so just so I can sort the photos and such.
A word on safety;
I am writing this as a description of the way I build a copper boiler and not as a full detailed lesson on how to make steam pressure vessels. please think about the following for a few moments before you think about trying the job.
Boilers are pressure vessels and have to be of a very high mechanical standard to be safe and insurable.
In the process of the build I will use sulphuric acid both dilute and 99% it burns either way and hurts like all hell if it splashes on you.
The soldering equipment is both propane and oxy acetalyn both are dangerouse and should be treated with a lot of respect. The chances of burning a hose are real and the end result is almost always very bad be carefull with what you are doing.
The only silver solder to use is Easy flow 2 it contains cadmium and all care should be taken not to breath the fumes.
During the soldering the copper hits 650 degrees in places and 250 degrees all over be aware that its easy to get a very bad very seriouse burn from the boiler gas jets or dripping molten brass/silver.
Ok the good bit.
The plates and tube have been ready for some time in the basic formed state. Now at the start of the assembly work
the plates and tube are made ready to fit together this is essential as during the forming of teh plates some roll will be put on the flanges of teh boiler plates. Picture 2 shows me bashing out the over bend on a 7/8th steel bar held in the vice. Once this has been done the flanges are filed and then given a clean up with scotch bright. Keep the flanges square and as dent free as you can it uses less solder and gives a good tight joint.
Picture 3 shows the throat plate after dressing with a file and scotch bright you can just see the pop marks for the boiler stays and the drilling for the blow down valve that sits just above the foundation ring.
Dont worry about cleaning the copper too much at this stage its only going to tarnish as its worked and the pickle in sulphuric will do the best of the cleaning just prior to soldering.
Picture 5 shows the lip thats left inside the boiler tube on the throat plate for soldering. This lip will later be filed out after soldering the firts joint. I find it helps promote the flow of solder during the first heat up and joining.
Picture 4 shows the tube sat on the throat plate. This is the very first joint and great care should be taken to ensure that it goes together square and tight. Theres a lot of stress on the joint once the engines up and runing. The boiler is teh chasis of the engine after all.
Picture six should give an idea of the positioning of the throat plate on the tube. its about to go to pickle for teh first time in 30% sulphuric to remove any oxides or grease. The flux will go on as soon as the boiler parts come out of the pickle.
The first picture is just to give an idea of size and some of teh parts in the boiler. from the left the parts are;
Front plate (called the backhead on a locco), tube plate, firebox tube plate, firebox rear plate and the throat plate.
The next post will be showing the fitting of the fire tubes and the stud plates for the cylinder and motion saddle.
Cheers Kevin |