Dont weld it as it ruins the heat treatment thats gone into it and it will simply crack. If you use bearing fit it will come apart easy enough. It should work depending on how bad the splines are. Its well worth a try though. It works by filling the gaps that are causing the play when its in a liquid form then it sets and should hold everything in place. I used to have a hope rear disc and the rotor was mounted to the hub on splines with a lockring to hold it in place. The same thing happend to that, it would come loose alot and even when it was as tight as I could get it there was still play in it. Bearing fit fixed it though.