This is not my expertise at all BUT I have helped the students at a tech school do about 7-8 of them over the last couple of years.
What we are doing to avoid the problem you had is BONDING a piece of metal in stead of welding. Than we grind with a 24 grit
spray two coats of epoxy and finish out from there as needed over the epoxy.
Long term this has held up good.
Like I said this is way above my skills so beware of above advice!