It's Still a Cylinder

Having rolled the boiler the next step is to fit the smokebox door (or what amounts to the smokebox door on Ivor). This is basically just a flat circular part that cabs one end of the boiler. It has a slight half etched rim around the edge to help positioning the two parts. I gently cut away the sacrificial pieces (needed to help during rolling) and then carefully taped the two parts together as best I could.

Even having removed the sacrificial pieces there isn't a huge amount of space to get a soldering iron inside the boiler but I managed to avoid burning my fingers and am pretty happy with the result.

In the cruel larger than life photo I can see a couple of tiny spots that might need a little filler, although I can't really see them with the naked eye. Either way, I'm really happy with that, given it's the first boiler I've rolled and assembled. Now I just have to solder it to the cab front hopefully straight so that the chimney will be properly vertical.

Mangled Brass or a Brass Mangle?

Those of you who have followed my modelling adventures for a while may remember that all the way back in 2014 I bought a Hold and Fold tool to make assembling etched kits easier. At the time I said it was nice and easy to use and in the years since it's become an indispensable tool. Also in that original post I mentioned not having a tool for rolling metal. Over the years since I've not found myself needing to do much rolling, mostly just needing a slight curve in cab roofs etc. For those parts I've made do with using a metal bar to gently introduce a curve. That works, but it's difficult to be precise. What I've not needed to do, until now, was to turn a flat sheet into a cylinder.

To date all the steam locomotive models I've built have used either a tube or a casting for the boiler, but for Ivor the boiler has to be rolled from a flat sheet to form a cylinder which then has a circle soldered on one end, while the other attaches to the cab.

Given all the time and effort I've put into this build the last thing I want to do is completely mess up the boiler, and there is no way I could accurately roll that part using a simple bar so.... I've invested in a new tool.

This is a set of 6" rolling bars from GW Models. I would normally point to a website when talking about a new tool, but they don't have a website, in fact I had to ring to check they had any in stock and then post a cheque to pay for them. Even before I tried using them I was impressed. They are just a lovely bit of engineering in their own right.

For anyone who doesn't know how they work, essentially the handle turns the two bottom rollers and thetop roller can be moved up and down. So you gently feed the metal through the gap and turning the handle moves it through. You then move the top roller down a little and repeat. Each time you move the top roller down it produces a tighter curve. I did about a quarter turn of the bolts each time so that I slowly increased the tightness of the curve until I had the right shape.

Once happy you can undo the bolts and lift the top roller off which allows you to simply slide the part off the end. A quick check against the circle for the front of the boiler and everything looks good.

Of course I still need to solder it all together so there is still plenty of time for me to mess it up!

Given how easy it was to roll the boiler you will be unsurprised to know that I think the rolling bars are fantastic and well worth the initial investment. Obviously it won't get as much use as the hold and fold (most kits will have tens of folds and possible only one part needing rolling) but it's one of those tools that does it's job so well and easily that it's worth having in your toolbox.