Welds and Soldering and Drawing techniques

[Drewpan]

Hi All,

Quick technical question about ACTUAL joining techniques.

I have to model a Boiler in sheet metal that is quite small, think large coffee cup size.

The original Plan models a tube and two ends but before I draw it I was wondering about strength and if it would

be better to instead model it as one piece and fold it. Hence my question here.

In the real world, on normal size objects, welding is much stronger than soldering. If you were making a boiler

of normal size it would be welded and a tube with two ends would be strongest. This boiler is for a model steam

engine, so welding is not an option it will have to be soldered.

Would it be stronger to model the boiler as a tube with a seam and separate two ends, or in one piece of folded

sheet metal where the ends are part joined as flanges and everything was soldered on both models?

My head says that the flange part of a join would be much stronger than a soldered join but there is an element

of doubt.

This model may not ever be built but I would like to design it as if it would be built. That means that ease

of manufacture and fabrication are important. You could argue that laser cutting one or three separate pieces

is not really going to make much difference. Soldering two entire seams or soldering partial seams because

the flange forms part of the seam would make a difference. The seams would be shorter and the flanges would

hold the ends in place for soldering.

For @TheCADWhisperer - there is no picture because I haven't drawn it yet. This question affects HOW it will

be drawn.

I can model it both ways but what I am concerned about is overall strength if the boiler was actually bought

to operating pressure.

Cheers

Andrew

[Drewpan]

Supplementary Question.

What is the Brass Rod that connects the End Caps in this picture actually called?

I can see it is there as a structural support for the end caps and will be partially load bearing under pressure.

The Soldering from the previous question will bear the rest of the load. Since I didn't design this model, I am

drawing it for practice, I haven't calculated what loads would be on  the boiler under pressure - Yet.

Ok @TheCADWhisperer - you win. I noticed in the picture after that the flanges on the end caps appear to go

all the way around. This means that manufacture will be a Stamp Press so my original question about how

to model this is probably redundant. Which method would be stronger is still valid from a design point of view.

Would a Soldered seam be stronger than a flange of the original material? In a larger scale a Weld would

certainly be the strongest option.

Thanks again.

Andrew

[davebYYPCU]

Ever tried to flatten a curved flange?  

Can't always make what can be drawn.

Might help.....

[Drewpan]

Hi,

I know what you are saying about flattening curved flanges. Isn't this why we would Stamp it?

The only other way to make the part I can see would be to Turn or Mill it which would waste large amounts

of material unless you re-cast your own stock. A Hobbist "might" do this but a Business certainly would not.

A Sheet Metal cutout with tabs might also work, but this would make weakness near the joins in the tabs. It

seems that the drawing is using the flange to help seal the boiler.

Cheers

Andrew

[davebYYPCU]

Ah, but Fusion (Sheet Metal) does not have stamps, we have to draw the part.

Might help....