I love metal spraying

it earns me pounds because they use it where it's not suitable.
True story:-
One day the rewind company roll up just as I was leaving to go on site with a large armature, one bearing journal was very badly damaged and it was wanted immediately.
I told them that I could do it first job the following day but not that day. This wasn't good enough so it went somewhere else. They metal sprayed it and turned it back to size and returned it. Motor was rebuilt and sent out and fitted to the job which was a large travelling crane.
Motor fitted and at switch on massive bang that removed about 10 foot of very heavy bussbar from the roof and sparks galore from the motor.
Turns out they had not screened the armature when metal spraying and some of the dust had gone up the vent slots and shorted the comm out from the inside.
Bottom line was one team had to go in, remove the motor and rewind the armature working all thru the night and the following day, not an easy task as most big DC motors do not use wire but copper strip which takes a lot of bending without destroying the enamel.
Another team had to work all night to replace all the burnt out bussbars.
To add further insult about three weeks later I got the same armature back and the bearing was rattling about on the shaft but it couldn't be removed as it had hammered the metal spraying out both sides to resemble a dog bone.
I had to turn the dog bone off, remove the bearing, remove all the metal spraying as you can't build up on this stuff, then rebuild with solid weld and turn back to size.
I have had plenty of other shafts that have done exactly the same, hammered the metal out from under the bearings.
John S.