Has anyone found an easy way of making the reverse bend to the bunker corner?
At the moment I am looking at using copper pipe and quartering it, but the problem with this solution is bending the pipe to the correct radius to start with without formers such as in a conduit bender. Another possible way is to copper beat flat plate (or even half a tube) around a former.
The full height of the bunker would be of three pieces with the two vertical pieces either side of the reverse bend.
Hopefully a plate work master can give me the best solution.....
I have pondered this several times as I need 3 pairs of these as all GWR bunker backs are the same and for painting preferably made from steel sheet. One idea is to have a former like the ones used in boiler plates with the sections opposed then the curves filed in. Next an outer section cut the thickness of the sheet bigger is pressed over guided by pins that also hold the sheet in accurate register as there is a cut for the corner which has been arrived at by trial and error. hence the use of steel. the bottom curve is a compound one that even in Swindon works gave problems hence all the bunkers being the same so they must have made up a press tool or two to form them. Now if we all club together and invest in some 20mm plates being water jet cut out and filed, this can solve our problem. David. Who once spent 2 years working allongside a sheet metal expert of 32 years!!!
Builder of far too many projects, but I love them all. The more Locomotives you have building, the more solutions to other Projects Problems get Solved. Reworking Simplex into a Fowler Complex. Making a Jinty more to scale. And going up a size in the shape of a Jessie.
hi alan, ive done one GWR bunker in 5"g. i made the sides (full height) and back (up to the reverse curve) out of one piece of steel. the top part of the back (straight) was a separate piece - the sides were curved round at the top from the large piece and fixed to the top of the back with thin sections added on the inside and rivetted together.so thats most of the bunker done including most of the side curves. the reverse curve was bent and fitted with a strap rivetted on the inside on the lower half. the reverse bend radiused ends were done in copper and soft soldered in position. hope this might be of some help. cheers, julian
Hi Julian,Alan and all. Thanks for posting those pics,they've very helpful,although I'm a long way off making the bunker on my loco. Attached is photo taken at the SVR shareholders/members weekend last year,that may be of interest.