I was going to use ER70-S2 tig filler rod.
I have had to get a new sump as they are stuck on, so i'll be modifying the new sump by welding the fitting on and swapping them when I come to the job.
Thanks again.

Thanks for the advice.
I'm in England.

Hello, a question regarding welding a mild steel fitting onto a mild steel sump/oil pan. The fitting is 22mm OD, and the end is machined with a step 1.5mm in from the end, with a diameter of 20mm. This 20mm diameter will be through the side of the sump which I will drill for a 20mm hole. The fitting...