as far as welding chrome moly steel it is heat treated so must be pre heated to make a proper strong weld and not over anneal the weld area and cause stress fractures or failure of the structure of the tubing distorting and embrittling those areas to the point of failure when loaded so a good weld is just that done right with all the right equipment and materials that you currently do not have at hand it appears many machine shops will do small spot jobs like what you need to have done to you frame call around google it yeehaw