Hornby Dublo A4 with a Bent Cab Roof

[Kend]

I have never tried to remove a bend from a HD loco. I would guess that this one is about 1955/56 and has been dropped on to the floor. The bend is even with no scoring or creases. Before I try to bend it back does anyone know what heat is best to apply before force is applied please?  Ken

[34theletterbetweenB&D]

My experience with thin sections of mazak is that the transition from rigid to a puddle of liquid is so rapid that there is no useful 'malleable state' available by heating. 

 

I would attempt reshaping with a small ball pein hammer, supporting the model on a wooden block, and fill any resulting cracks with an epoxy resin adhesive if successful. And if not successful, saw out the damage site, form a new all metal roof, glue on with epoxy.

 

(I have never done anything more ambitious than successfully correcting small deformations in H-D wagon chassis. An attempt to correct the cab roof profile of a Wrenn 'N2'body was a miserable failure, and I immediately lost interest when the Airfix GMR/Mainline N2 was advertised.

[John Isherwood]

1 hour ago, Kend said:

I have never tried to remove a bend from a HD loco. I would guess that this one is about 1955/56 and has been dropped on to the floor. The bend is even with no scoring or creases. Before I try to bend it back does anyone know what heat is best to apply before force is applied please?  Ken

 

Support is the essential in this operation.

 

A block of wood with a concave surface, approximating to the correct profile of the roof, will serve as an anvil.

 

A length of wooden dowel with the end sanded to a half sphere can be used as form tool - applied to the inside of the roof with very light taps of a small hammer.

 

Slow and steady should produce the desired results.

 

CJI.

 

[Kend]

Thank you very much, will try tomorrow, Ken

[Il Grifone]

Good luck!

It's very much a 'bend once, break twice' material.

[roythebus1]

Good luck, you'll need it!

[cypherman]

Hi all.

You might try arving 2 pieces of wood to the inner and outer shape of the roof. Use the shape from the undamaged side of the roof to get the formers right. The placing the roof between the two formers slowly squeeze them together. a small pair of molegrips would do.

[Kend]

Thanks everyone, I have a couple of pairs of GPO special grip pliers and with very slow, gentle twists the cab roof is now where it should be as well as stressing the cylinders very slightly outwands. Tomorrow i'll clean up the motor and see if she will run.