Welding Tips and Tricks

hi im new here and am going to be building a trailer here soon. im going to be building a 20' equipment trailer with 2 7K lbs axles. im makeing it out of 6" channel and 3" i beam. i got a miller 211 and i am wondering what would be the best wire for this job. i am running solid wire now but was wondering should i get flux core for this job or stick with my solid wire. steel is a little dirty but i plan on cleaning it up first. any advice would be appreaciated
thanks

If you are going to build it outside in the open, then use the flux core wire, however there is some clean up work to be done when you use the flux core, as it doesn't burn as clean as the gas wire. You are on the right track cleaning up your steel first, the cleaner the steel the better the weld. I use an angle grinder with a wire brush or a flap grinding disk, just clean up where you are going to weld, the get whole frame sand blasted and then paint it before final assembly. Just my thoughts.

ya i was thinnking gas sheilded flux core. im going to be building about 3/4's of it inside then the rest has to be done outside

Lincoln NR211. Nothing more can be said.