Hey guys, I’m just wondering if anyone has used or thought of using pewter to tin your diy busbars. Newer pewter has a high tin component in it ( between 85 & 99%) with the rest made up with antimony , copper. I have a stash of pewter here and doing some tests last night it me easily and wets the copper well as long as you clean the copper meticulously.
Pewter for tinning copper busbars
- Thread starter Slave
- Start date
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
What process do you use?
RCinFLA
Solar Wizard
- Joined
- Jun 21, 2020
- Messages
- 3,564
Tin has seven times the resistance of copper but you have to take coating thickness into account.
Keep it thin.
Most of the no-lead plumbing solder sold these days is 96% tin with 4% silver with 260 degs C melting point. You can find mixes that have up to about 7% silver with about 300 degs C melting point.
Need to use a lot of flux to make it level out well. Making coating level is likely more important than its actual resistance since surface contact area is very important.
Aluminum gets an oxide coating in seconds so you need to clean cell terminals with alcohol and bolt down lugs soon after cleaning. Salts from fingers touching aluminum terminal surfaces is a no-no.
Tin plated bus bars should have a nickel barrier between copper and tin to prevent the copper from migrating into tin over time. Electro-plating allows much better control over the thicknesses. Nickel is about four times resistance of copper, but again it is deposited very thin.
Nickel is almost impossible to solder to which is reason why terminals are tin plated. For pressure contacts you don't really need tin coating so some bus bars are only nickel plated.
Aluminum is about 1.5 times resistance of copper. Nickel and tin have the worse thermal conductivity of all conductor metal types.
Keep it thin.
Most of the no-lead plumbing solder sold these days is 96% tin with 4% silver with 260 degs C melting point. You can find mixes that have up to about 7% silver with about 300 degs C melting point.
Need to use a lot of flux to make it level out well. Making coating level is likely more important than its actual resistance since surface contact area is very important.
Aluminum gets an oxide coating in seconds so you need to clean cell terminals with alcohol and bolt down lugs soon after cleaning. Salts from fingers touching aluminum terminal surfaces is a no-no.
Tin plated bus bars should have a nickel barrier between copper and tin to prevent the copper from migrating into tin over time. Electro-plating allows much better control over the thicknesses. Nickel is about four times resistance of copper, but again it is deposited very thin.
Nickel is almost impossible to solder to which is reason why terminals are tin plated. For pressure contacts you don't really need tin coating so some bus bars are only nickel plated.
Aluminum is about 1.5 times resistance of copper. Nickel and tin have the worse thermal conductivity of all conductor metal types.
Last edited:
