aluminum soldering report

I just tried a few minutes ago soldering aluminum with tinning flux. The tinning flux didn't seem to give any advantage over regular flux. I used a .09 thick sheet of 6061. First I tried a brass brush to clean the aluminum but the brush was too soft to abrade away the oxide coating. So I used a piece of coarse sandpaper to sand through the flux. This is not ideal as it leaves particles behind but I'm down to my last clean SS brush and didn't want to contaminate it. After cleaning I tried three different solders, tin/antimony, tin/silver/bismuth, and 50/50 tin lead. After heating the aluminum I applied the solders and used a flat bladed screwdriver to abrade the already abraded surface and spread the solder around. The tin/antimony solder just would not wet the aluminum. The other two solders wet the aluminum just fine. I still like the mainly zinc solder that's made for aluminum best for joining two aluminum parts but if I needed to attach a wire to aluminum or needed to keep things at a lower temperature I would use the tin/silver/bismuth solder. Eric