Paul, thank you for this advice. This is what I will do. I’ll go forward with this plan. I like it.When you have drilled the end use that as your start point for welding and work towards the edge, this will allow a little movement of the open end of the crack as the weld progresses and reduce the chance of it cracking while welding, make short runs say around an inch maximum and allow to cool between welds, do not quench it,
I wouldn't attempt to fully weld it, half a dozen short runs evenly spaced out will be good enough for that,
At risk group...Diabetes for me. Also my wife beat Stage 4 Hodgkin's Lymphoma and as a result of the cancer & chemo...she has a **** immune system. So, we’re riding it out.Are you in a "At risk group"? If so wise move.
If not, are you showing symptoms?
It not you will be safe to go out doors.
So the 99% Nickel rods?It is vital that you get good rods.
Some rods are sold for welding cast iron but are useless. Don't get ones that are suitable for welding cast to steel as they will fail, you want proper cast iron to cast iron rods which have a high nickel content. I think they're something like £1.50/£2 per rod, quite pricey.
It's important that you keep it cool at all times, just weld an inch at a time then peen it (tap the weld metal with the chipping hammer which causes it to expand, very important to do this while it cools).
It's going to be a little tedious on a long crack like that but it's a very reliable method.
So the 99% Nickel rods?
I've a small brazing job to do and wondered if I could use my tig welder; looking for filler rods I found these on eBay;
20 X SILICON BRONZE C9 TIG BRAZING FILLER RODS 1.6MM X 300MM
AWS ERCuSi-A (CuSi3Mn1) C9
Copper rod containing 3% silicon and 1% manganese
TIG brazing filler rods for fusion welding metals of similar composition, copper alloys (brass) and TIG brazing steels. Ideal for joining dissimilar metals
CAN ALSO BE USED WITH OXYACETYLENE
I also bought 20 normal brazing rods for use with my canister blow torch; I don't know what difference there is between the two types of rod so it's a case of suck it and see.
Kind regards, Colin.