Question for roof plumbers

[quote=familyguy;764076]Posting here as I'm assuming that roof plumbers might know this. I'm renovating a period house and want to use metal down pipes for the stormwater which means that I'm going to have to make up some bends in the galv downpipe, I don't want to use pop rivets and silicon as this would not be in keeping with the period, which leaves only solder.

You can also get "crimp bends" in gal metal downpipes. (May not suit period home)

If you are making them by cutting, just remember to keep the seam on the back of the downpipe (ie against the wall), and on the top section of the "horizontal' piece (coming from the gutter back to the wall). This prevents you from rotating 180 degrees as you did with the expansion chamber for motorbikes.

Ideally when you join the angle cuts, they should be cut so the upstream piece fits just inside the downstream piece (ie in the direction of the water flow), and the downstream piece should be cut on a slightly wider angle so that the overlapping 3-5 mm can be dressed around the other piece. This gives you a small lap with will strengthen the joint when you solder it. Its fairly tricky work. Thats why rectangular downpipe and PVC are so popular. Hope this helps.

You may have a problem soldering zinc alum. Never tried it myself but I beleive it is at least very dfficult to do.

Good luck
Bradford

Thanks for the replies, I probably wouldn't have noticed the seam until after it was soldered and I also hadn't thought about soldering zincalume so I'll make sure that I get galvanised steel not zincalume.