How to Attach Spade 10 AWG Solid Copper

First solder at high heat using the least amount of solder to make a perfect connection. Then you can crimp. Do not crimp first and then solder.

I one crimps at all, it should be done first, to obtain the best/most metal to metal contact. Minimum solder between the actual conductors is preferable. Once soldered, a crimp is wasted effort. Obviously- solder is a conductor also, but none will be as good as the spade or cable's metal.

It never ceases to amaze me how much information you read on the internet that is outright wrong.

If the average person with average skills solders after crimping, the crimped connection will tend to be compromised.

In this case, we are talking about a solid core wire. So once again, I advice soldering at HIGH heat using a minimal amount of solder. Then crimp the connection.

If the wire to be connected to the spade is stranded, I would advice crimp only.

I have done this several times in the past, being in the building trades. I have also done it wrong several times. The strongest, least likely to fail connection for solid core is exactly as Elizabeth said, a screw down. You could add a drop of screw lock to the screw and your connection will never fail. The allen screw is also a very good idea, you can torque it down better than a standard philips. Very good Elizabeth.