The strut materials are 4130 Chrome-Moly aircraft grade tubing.

I have modified struts as you wish to do and have used a Carbon Steel / brass coated, 1/16" dia. rod in conjunction with Oxy-Acetylene gas to weld.

Remove the Scissor fitting using a Dremel Cut-off wheel by cutting thru the existing weld but do NOT penetrate the tubing itself.

I was told by Eric at Robart that they use TIG to attach these fittings during manufacture.