If there is one scary task with Garratts it's the waggly bits. Like it or not, any build is going to involve 4 sets of Walschaerts valve gear - the most feared set of waggly bits on any model locomotive. And the bit that everyone is impressed with when you see the model.
My plan had been to use proper valve gear rivets to hold it all together. I've done this before with the 4mm scale model I built and it worked well. So well in fact that the last set only took 20 minutes to assemble and worked first time. I bought what the packet said were 7mm scale rivets, but when I came to use them found there wasn't enough metal in the rods. If I reamed out the holes large enough I'd only be left with a wisp of nickel silver around the edge. Not good.
Soooo, I bit the bullet and dug out the brass pins. Each joint would be made with one carefully soldered in place. What fun.
I've been here before. Several hours of pain where solder ran everywhere I didn't want it to go and locked joints up solid. The pin then had to be filed away, solder cleaned up and another attempt made. In desperation I pinched an idea from somewhere and tried sandwiching aluminium foil behind the part being soldered. The theory is that the foil stops the molten metal and as the solder won't stick to it, you pull it out after the joint is made.
Guess what, it works !
Of all the joins made on the loco I only managed to gum up three. Pretty good and much , much better than I expected. Sometimes it was fiddly to hold the two parts to be joined and the foil in place while piercing it with a brass pin. Some took 2 or 3 goes and where I ended up with problems it was probably carelessness meaning the hole made was too large. Keeping the joint tight was fun too. A couple of times I had to reheat the solder to push the parts closer together. It's very easy with Walschaerts to end up with a very saggy collection of rods if you don't. Those joints that were forked went well, the others are OK.
The tin foil technique made a huge difference. It's certainly better than using cigarette papers. These work but not nearly as well and tend to go soggy with flux. I still just about prefer rivets, and I will try to get some thinner ones for the next attempt at this kit, but I'm not so scared of soldering now