Bending Brass Rail

[Peaky 556]

Can anyone offer advice from personal experience on a good way to pre-curve GRS brass rail?  I don't have any sort of rail bender, but I have heard it said that "belly-bending" can be done.
I'm asking because I think that prebending the rail ought to prevent any cusps forming at rail joints as and when the fishplates relax.  This would need curving right to the very ends of the rail though.
My radius is down to 4.5m.
Many thanks,

[cabbage]

Tim,
I have some machined & unmachined wheel blanks that you could make a rail bender from. Failing that I do have my Fabricator!!!

Regards

Ralph

[Peaky 556]

Thank you Ralph, but I've dropped off here and not left myself time to procure or make some kind of gadget.  I suppose I'm looking for some advice along the lines of ...'bend it carefully around a water butt and tweak the ends with grips to make sure the curve reaches the rail ends...' or something else pragmatic.

[IanT]

Try to avoid using the "grips" - you will probably get a kink.

Never used GRS rail (which I think is quite heavy section) but for Society rail, you could curve it around something (I guess you could use a water butt) or simply hold it at each end and gently bend it using your thumbs. For the ends try using a hard'ish rubber mat (I had some of that heavy multi-coloured rubber packing about 2" thick) and bearing down with a hardwood roller (something like the wife's rolling pin if you can get away with it). When bending anything, the 'ends' are always difficult because there is nothing to leverage against, unlike the mid-section.

So if you are going to do a lot - then some from of bending rollers would be better for this reason and will give a more predictable/repeatable curve.

Regards,

IanT

[cabbage]

I curve the rail by narrowing the distance between the sleepers on the inside rail. I do have a 4.5m rail curve that I can throw you?

Regards

Ralph

[Andy B]

Tim,
Is your rail bull-head or flat-bottom?

Andy

[cabbage]

Andrew,
As far as I remember Tim has code 330 Vignoles profile track. The flat base will make it difficult to bend without some distortion...

Regards

Ralph

[Peaky 556]

Yes, it's Code 330 FB.
Is the general concensus that pre-curving Rail is a good thing?
After all, in a tunnel it's going to be rather awkward to realign/re-lay.

[cabbage]

Tim,

Most of my American Gauge One people pre bend the rail with a rail bender, all of them seem to use code 330 Vignoles profile.

Regards

Ralph

[John Candy]

Tim,
I used a GRS rail bender tool which you are welcome to borrow.
If you are worried about the tips, you could anneal ends before bending.
Alternative would be to crop ends after bending (since inner/outer tails will be different lengths, you will need to do that either way).
Regards,
John.

[Peaky 556]

Tempting John, and if I had more time, I'd love to come over, thank you very much.  I'll have a go with other means over the weekend.
Btw, no-one has commented on the merits/demerits of pre-curving rail.  I've never done it before, but my tightest curve to date is more like 6m rad. I don't think I have any cusps at joints, so I think the combination of track adhesive and ballast is doing a good job.

[John Candy]

I could send it by Hermes, if you can wait a few days.

The code 330 rail is very bend-resistant (by comparison with code 250) and the GRS sleepers are not very strong in the area of the rail clips.... bending the assembled track will likely over-stress clips and result in breakage.

Regards,
John.

[Peaky 556]

I could send it by Hermes, if you can wait a few days.

John that would be magic, as I am schedûled for track laying on Wednesday.  Hermes have been doing good service for me lately so if you can get it in the system ASAP there's a very good chance.
Many thanks, will refund your postage of course,