Water Tubes Proving Impossible To Install

I did say, when starting this project that I had misgivings about the boiler, and for several reasons. But here’s the worst thing – it’s impossible to install the water tubes!

I managed to install three water tubes, but as explained on the previous page that was only by brute force and mauling them into place.

Here is a repeat of the photo of three (of five) tubes in place:-

Beautifully Bent water Tubes – Ruined

Here are some photos of the water tubes being bent, beautifully bent and mangled:-

Boiler Shell Holes -or – Boiler Hell Holes!

First a simplified CAD drawing showing what the boiler and water tubes are supposed to look like:-

I’ve circled the boiler (s)hell holes.

And here’s a photo of reality:-

You can see what a mess it is.

• The tubes are supposed to lie flat along the boiler shell because a boiler casing covers the tubes very closely
• There are huge gaps between the tubes and the boiler shell at the (s)hell holes. These tubes have to be silver soldered into the boiler and silver solder doesn’t like large gaps.

But It Gets Worse – The Last Two Tubes

OK, so maybe I can fit these three tubes. But I found it totally impossible to fit the last two.

If the tubes were rubber hose no problem. But even annealed copper although it can be bent easily by hand (and often does especially when you don’t want it to) , can’t be manipulated to enter two fixed-position holes without totally mangling the tubes.

My original intention was to silver the whole boiler (except the water tubes0 first then add the water tubes at the end.

Now, I thought maybe I could add the water tubes at the same time as the throatplate thus allowing space for the tubes to pass through the throatplate without torturing them.

No chance. With the Throatplate being free to move the water tubes wobble all over the place.

 

Look, it’s impossible to get the tubes into the holes in the Throatplate and the Boiler Shell at the same time.

So How To Solve This Problem?

What to do?

Honestly I don’t know. At the moment the boiler build is on hold.

I did a test braze (silver solder) of a spare water tube into a larger tube to see if silver solder  could fill the large gaps and indeed it did. The pics show a sizable gap and a pretty decent fillet.

In the photo above the water tube is 3/16″ diameter.

The pics show a sizable gap and a pretty decent fillet.

One Idea Being Considered

I particularly don’t like the way the copper boiler shell has to be distorted to take the water tubes. I’m thinking about putting a bronze pre-machined 90 deg elbow at each hole (5 holes, 5 elbows) to take the water tubes.

Although it looks neat, I see the following disadvantages:-

• More joints to silver solder = more potential leak points
• Joints touching or almost touching the boiler shell difficult to silver solder
• Still have the problem of inserting a pipe into two fixed holes.

What do you think? Please share your thoughts below.