'd probably go 7018, solely due to personal preference. Or, if you are a fan of 6013, or any other rod, go for it. The weld metal 

King Home Health Center – Boiler Installation – Schaumburg, IL

American Industrial Werks crew installed two new CFH Steam Boilers into the basement of the King Home Health Center in Evanston, IL.

One interesting point found in these references deals with rods such as E6010 with cellulosic coverings (flux). They actually need a moisture level of 

Boilers – boiler manufacturers, wholesalers and retailers in Kansas City. Boilers in Kansas City, Kansas/Missouri. Boilers in Kansas City, KS/ (816) 795-6010.

'd probably go 7018, solely due to personal preference. Or, if you are a fan of 6013, or any other rod, go for it. The weld metal 

American Industrial Werks crew installed two new CFH Steam Boilers into the basement of the King Home Health Center in Evanston, IL.

Basic Weld Inspection – Part 2 – The National Board of Boiler and

One interesting point found in these references deals with rods such as E6010 with cellulosic coverings (flux). They actually need a moisture level of 

Boilers – boiler manufacturers, wholesalers and retailers in Kansas City. Boilers in Kansas City, Kansas/Missouri. Boilers in Kansas City, KS/ (816) 795-6010.