The sole plate of my loco tender is 20g brass sheet. It is 26" x 9 1/2".

There are eight wheel splashers to be soldered in place the splashers being 20g and 2 1/8" long by 9/32" high in 7/8" wide slots in the sole plate.

Now the heat needed to solder (at 180 degrees) causes the sole plate to bow when using a large soldering iron (1/2" tip) which means the splasher plate cannot adhere to the sole plate in a level plane. The same occurs if I use a gas torch (naturally so).

An advice on how to make a sucessful joint would be appreciated.

Thanks for the reponses.

I have a resistance soldering unit but it is not man enough to provide the heat required.

I prefer not to use epoxy if possible but it is not ruled out.

A big lump of metal as a heat sink made it more difficult to heat so I did not pursue it further.

I did however discover that if I used the soldering iron from inside the splasher components and the bits were adequately tinned I could get the solder to flow and make a join. This way I am not heating up the big mass of sole plate and letting the small bit get very hot and the heat transfer through the solder occurs. Its very fiddly as it needs the big iron. That worked for the splasher side plates OK. Getting the top of the splasher on I used a lower melting point solder (140 degrees) to try to avoid desoldering the sides and because it is curved the big iron was even more fiddly but evenyually it made the joint. So that was one done as a trial to get the method. Just another7 to do.