Bending flat bar the hard way

OK I tried the kerf bending technique as a demo:

What plans for the scroll ends?

I ordered 4 of these :

Pity about their hammered edges.

I have some blocks salvaged from an educational pottery kiln which can be used to form a hot tunnel. I stopped gas welding when BOC prices got silly so they are taking up space!

Yes, but not so good for the OP's decoratively "scalloped" strip.

However it is a very useful demonstration indeed. I once tried to recover an angle iron structure (frame of a trailer) that had been severely bent and buckled by having a very heavy load dropped on it. I had no success with levering or hammering, and could not get it hot enough to "forge" for various reasons. But actually this technique would probably have worked very well, and allowed me to get it back into its previous "shape", and even without welding to restore the strength of the kerfed flange, I could have done that by bolting on flat strip.

Don't throw them away! There is always propane.

I've never tried it, but at school we had an air-propane torch supplied by a little blower. I know that in theory it won't reach oxy-propane temperatures, but it certainly gave significantly more heat than the the straight gas torches.

Come to think of it, I am not even sure if it was propane, it might just have been coal gas. This was nearly 60 years ago.

This was a state grammar school, but it had a very well equipped workshop for metalwork. A Myford super 7, a mill, pillar drills and a grinder / polisher. Best of all, a traditional charcoal forge with about a 2 foot square bed and proper extractor hood, and a slightly smaller gas fired forge with ceramic "pebbles".

I also have one of those:-) Ex Verulam school, St. Albans. The pipes have long since disintegrated and the motor/pump (3 ph.) is on my pallet of pallet of recyclable electric motors. I suppose the torch and rotating forge might be usable with compressed air and propane.

Indeed. I took woodwork at O level but metalwork would have been interesting and was available.

I guess the bottom stream might have been allowed to take it for O-Level at mine (Glyn Grammar), it was certainly never on the radar for me or any of my friends. PE was compulsory all the way through, I think Woodwork and Metalwork fell off my timetable options after 3 years (at which point I was allowed to drop one "academic" subject, history in my case).

Metalwork was as near as I ever got to formally studying any sort of engineering, and I don't believe any of my "science" contemporaries took anything other than physics, chemistry, maths, or medicine at university.

Well they match the handrail (at least in theory - I have not seen those yet as they were out of stock)

Have you looked at the rental free suppliers like hobyweld? You pay deposit it on a cylinder, and then just exchange them for refills when required. Probably not cost effective in a commercial setup, but not bad for personal use.

I was toying with getting a set of Oxy/Acetylene bottles for messing about with such things.

I am the OP :-)

In the trial, I did the kerfs much closer than I will for the real thing

- I suspect I won't actually need many - perhaps 3 or 5 per segment, since its a gentle radius.

I figure if I cut in the right place so I am not going through a "hammered" edge, it should be easy to hide them (and the opposing edge will be hammered at that point, so less to bend)

Yup, in some ways it is more a woodworking technique, but it seems to work well with steel because its so easy to replace the removed metal and consolidate it all again with the hot metal glue :-)

When doing it for real, I might, after bending, "vee out" the top of each kerf a bit with a grinding disk to get a bit more weld into the "gap" - especially at the "closed up" end.

I think your house insurance would far prefer Propylene. Since this a DIY group, have you considered the old fashioned way of making Acetylene with Calcium Carbide?

My insurance makes no mention of it...

No is the simple answer...

Not least because to be useful you need a way of storing it and a supply of oxygen as well.

Oxygen generators? Often used by glass blowers with propane.

Picture shows decorative hammered edges.

I still have the kit but I don't suppose I'll ever use it now. BOC forgot to collect my last Oxygen bottle! 2/3rds. full last time I looked.

For that sort of thing you need a Jim Crow. It would be fairly easy to make one for such light steel.

For the very limited use I will have for it, a rental free cylinder will probably be more than adequate.

I think we may be talking at crossed purposes here :-)

My design called for a handrail that was somewhat decorative and would give a little more grip than a plain convex bar. So I went with the "heavy hammered" rail. This is a picture of it in real life with a hand for scale (beside the twisted "post" material):

The Shepherd's hook I linked to above hopefully matches the pattern (but they might not have those in stock until November). So I will build it first and either leave the ends plain to start with, or do my own scrolls if I have enough handrail material spare.

OOI roughly how much were they charging for O2 etc?

DIY opportunity? Second hand medical oxygen concentrator, I believe they do >90%. Compress and store in an old gas cylinder, huge safety margin if you restricted it to (say) 300 psi. You would need a suitable compressor of course. Or would the residual nitrogen give you bad welds? Probably.

:-)

I expect most uses of O2 for general fabrication these days are for non welding use - general heating, brazing, and flame cutting.