Welding Tips and Tricks

We just bought a use lowboy trailer to haul around a dozer and all the stringers are rusted through we are going to just weld plates where needed over the holes but can't figure out which rod would be the best to use with rust and new metal

7018 is pretty popular as long as the position supports its use. How thick is the metal and the new plates? It would also be useful to clean some of the rust away.

Welcome...
Not to be a smart azz if you don't know what rod to use your in over your head.

Now Mike, to be fair I'll give him some props for checking and asking to make sure cause I know I don't want to follow some guy with a jank trailer hauling a dozer and bam a weld breaks. That is not where I want to be.

Remove ALL rust before welding new metal. Trailers in general are dangerous. Trailers with patches "welded" to rust are very dangerous.

Depends on the rust. Is it just surface rust? How far down into the surface do you have to grind to get through the rust? I.e. 1/2 base metal grind down a 1/16. Probably fine. 1/8 base metal grind down 1/16 .... better cut out more metal to get back to a good solid place.