Steam Powered Lawn Mower!.

[Martin Johnson 1Participant @martinjohnson1]

The  appearance of the weld is not necessarily the cause of failures.  It’s just that an experienced welder lays down better welds than those shown in Richards post of 19 March.  The weld around the periphery of the firehole to shell weld is uneven, the seam inside the firehole has not been finished by filling up the weld pool, for example.  Both “beginner’s stuff”.   The longitudinal weld down the barrel looks better (perhaps a different welder) although the view in the photo is not great.

Just leads me to question the statement “The boiler was was fabricated by him and assembled/professionally welded by a highly qualified welder.”

Martin

[Roy BirchParticipant @roybirch29994]

How on earth is someone taught that they cannot weld, the statement quite literally contradicts itself, if you were taught something that would imply that you learned the subject.

I was trained at BOC on a course but I am not coded so does that mean I cannot weld so do not trust me?

Also the statement seems to imply that if the welds are not pretty then they must be poor, fusion and penetration is what is important and not looks, we are trying to be helpful here, after all we are not rebuilding Concorde.

[Martin Johnson 1]

On Martin Johnson 1 Said:

The weld around the periphery of the firehole to shell weld is uneven, the seam inside the firehole has not been finished by filling up the weld pool, for example.

Martin

Hi Martin, I was wondering if anybody was going to mention that, it’s one of the most often places where cracking starts, but also the weld height ratio to its width is wrong, which suggests the heat input was too low, and the penetration may not be very deep.

Good welds don’t have to look pretty, but the shapes and uneveness can tell a lot, and so can the shape of the ripple on the weld, too pointy can mean it was welded at a too fast rate, or even too hot.

Regards Nick.

 

[Roy Birch]

On Roy Birch Said:

How on earth is someone taught that they cannot weld, the statement quite literally contradicts itself, if you were taught something that would imply that you learned the subject.

I was trained at BOC on a course but I am not coded so does that mean I cannot weld so do not trust me?

Also the statement seems to imply that if the welds are not pretty then they must be poor, fusion and penetration is what is important and not looks, we are trying to be helpful here, after all we are not rebuilding Concorde.

Eight of us arrived at a new section of the apprentice training workshop, the fabrication section, on another Monday morning in our freshly cleaned white overalls. The instructor, wearing a blue lab coat, said “we will do welding today” and took two small sheets of 16 gauge stainless. Saying “watch me” he did a nice argon arc weld joining the two sheets. “Now have a go”, giving us similar sheets of stainless. After 30 minutes two of us had managed to “join” the sheets together but we all had produced big holes in the metal. On being released for lunch (the works canteen was half a mile away and you had 45 minutes for lunch) we found that we were suffering from arc-eye. We go sent home early but the training never returned to welding. I strongly believe that this was quite deliberate.

Looking back on my workshop training as a mechanical engineering apprentice NOTHING we covered was of any use in my later life as a professional engineer. However it has been of great use to me as a model engineer.

Returning to the boiler, I am still trying to understand its construction. To me the actual boiler appears to be copper within a steel chamber. Such a construction makes sense to me. If so, the actual weld quality is irrelevant but on the basis of “fit, form and function” form, or how it looks, is always important in model engineering.

JA

 

[Richard S2Participant @richards2]

Passed the first test with flying colours. Minimal degradation in plate thicknesses. All welds are sound-

Will now engage the inspector for pressure testing etc, once we receive and present the paperwork.

[noel shelleyParticipant @noelshelley55608]

Marvellous ! who is this man – I need to talk to him.   Noel.

[JA]

On JA Said:

I am not sure what I am looking at. This is a vertical fire tube boiler. Is the boiler contained within the steel work? If so, the welds in the photographs are not subjected to boiler pressure and would be adequate for the job. However as welds they are not impressive.

As a mechanical engineering apprentice I was taught that I could not weld and have been happy with that ever since. My experienece is that you should always use the best welder you can find and if anyone says they can weld just disbelieve him.

JA

The lower part of the boiler is constructed from two concentric steel” tubes” so there is a water space all around the fire. The inner tube stops at the lower tubeplate so water surrounds the smaller expanded in tubes and extends all the way to the full length outer shell. So all the steel is under boiler pressure. Something like this.

I’d be happy if my welds were half as good as those😂

[JAParticipant @ja]

Jason

Many thanks.

JA

[noel shelley]

On noel shelley Said:

Marvellous ! who is this man – I need to talk to him.   Noel.

Hi Noel. Check your inbox.

[Richard S2Participant @richards2]

Making progress with rebuilding the Mower and refurbishing the power unit. Several items need attention, one of them is the Gauge Glass, which had no protection. I’ve just finished making a Protector for it-

Have a date for the next stage of boiler Inspection/Pressure testing at the end of the month.

[Richard S2Participant @richards2]

Just to update the progress on this project. The boiler has passed the inspection and hydraulic pressure test today.

The next certification stage will take a while, as there is the Mower rebuilding work and some redesign of the power system and layout, partly to satisfy current compliance for public display. I’ll update when reasonable progress has been made.

N.B. I mistakenly wrote initially that this Mower was a 14″, it is actually a 17″.

[Author]

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