Soldering Procedures
Using cobra core solder 63/37 type with flux core or.... the type of solder makes too much difference.
The diameter of the wire does make a difference. It needs to be small 0.012" to 0.020". The solder wick is either Solder-Wick by Chemtroncs. Or Hex-Wick by Hexacon Electric Co.
Most important is using a liquid flux between the wick and silicon.
The liquid flux defines where the solder will flow. Don't get the flux anywhere you don't want solder.
Once the heater is soldered, clean the whole thing off with alcohol. A wood toothpick and cotton swab is useful to rub off some of the remaining flux.
Also rinse the remaining wick with alcohol as it contains dry flux and looks nicer when its cleaned off.
Cobra core solder 63/37 type with flux core
Solder-Wick by Chemtroncs (Left). Hex-Wick by Hexacon Electric Co. Diameter ~ 0.012" to 0.020"