SpudFiles

can aluminium be soldered with regular lead free solder? I searched on Yahoo and it came up with a few things, but they are kits for soldering aluminium with what appears to be special solder?

i need to solder aluminium to copper for a small bore hybird (parents wouldn't let me make a 2.5" bore tennis ball hybrid... their reason is it would be dangerous... well a teapot is dangerous in the hands of a mad man... or a fish! although the madman probably wouldn't be able to make the fish go supersonic ) so i'm making a 6mm bore for airsoft BBs

i don't know much about soldering....

but i know you can't weld different metals together. so am thinking no you cant solder them together. but again i don't know much about soldering

I soldered aluminium to aluminium a couple of times and it held up nice. As far as to another metal I would say it will work because when you solder copper wire the solder has aluminium and tin in it.

do you need flux to solder aluminium?

you can solder aluminum to copper, but you cannot use regular flux and solder. you must something like this,
http://www.aladdin3in1.com/products3.htm

My mistake. I've never heard of the stuff Grumpy put up.

hmm so you do need special solder, does anyone know what the difference is?

it has to do with the possibility of electrolytic corrosion between to different types of metal. and also different solders have different melting points and fluxes have different acids or no acids cause different metals oxidize at different rates.

I always heard it wasn't possible, but I just tried it, and it is indeed possible to get normal solder to stick to aluminum. However, you have to get the aluminum very close to melting and the result comes out sloppy. If you have a large part that needs soldering you'll need a very large torch to get it hot enough.

Edit: by "normal" solder I meant lead/tin solder, not the lead free stuff. You should probably try both though.

When joining different materials, try to use threads, or maybe epoxy.
Also compression fittings can make good connections on different materials.

Just use epoxy. I think modern technolohy has made it possiable . I would think that epoxy would be just as strong, maybe even stronger. You just have to make sure the surface is ready to accepct the epoxy. Like clean and free of oil and dirt. You could even scuff up the surface so the epoxy could stick better. Like on a subatomic level. :drunken:

Or use explosion welding to permanently bond two different materials:D