Thread: Bearing Journals, Tig, Spray Welding? Q

Hey guys a really cool video just popped up on my youtube feed of a guy repairing a electric motor shaft the bearing journals were over worn now he spray welded the journals how come u cannot just tig weld something like this to build up the material? something i have wondered for a while since spray welding and machining one journal i have been quoted $440

so interested to hear why tig welding journals is not a common practice

To much heat, to slow.

Thanks Pipe, does the excess heat warp the sgaft or change the structure of the steel or something?

Hi Guys,

From a hobbyist point of view, yes you can tig the shaft and build it up, then set it up in a lathe to turn it back to size ! Though to get a good bearing surface after turning you would grind it to finished size.

As Pipeclay says too slow to be done that way commercially.

Thanks Baron

It can be done quite successfully with the old welding rod as well as metal spraying, both need to be turned to size after being done.
Some jobs you needed to use the big lathe ( 5 mt bed ) to do them.
Tig welding is far to slow compared to a big rod turned up high.


Done heaps of them both ways over the years.

Metal spraying has now got a few restrictions on who and where it can be done to, something about the over-spray dust having to be removed so it doesn't harm the operators lungs.
Not a nice sort of job to be doing all day either, noise and the dust are real bad.

I inquired about a outboard crank journal and was quoted $440 and said its not worth doing i think the machinist didnt know the value of the engine

How come the cost is very high to have a crank journal repaied by welding?

Hi Gazza,

Probably because they didn't want the job !

Originally Posted by gazza2009au

Hey guys a really cool video just popped up on my youtube feed of a guy repairing a electric motor shaft the bearing journals were over worn now he spray welded the journals how come u cannot just tig weld something like this to build up the material? something i have wondered for a while since spray welding and machining one journal i have been quoted $440

so interested to hear why tig welding journals is not a common practice

I think there is less skill involved metal spaying than tig welding. plus less heat ect.
i worked in work shop once where there was a lathe away from the other that was used
for rough jobs like metal spaying.

Originally Posted by gazza2009au

I inquired about a outboard crank journal and was quoted $440 and said its not worth doing i think the machinist didnt know the value of the engine

How come the cost is very high to have a crank journal repaied by welding?

how did you fix it?

I didnt fix it i just sold parts to recoup my money i paid out on buying it, the engine i have now threw a conrod and absolutely demolished the crankcase so i bought another powerhead from ebay and had it crated down from darwin to sydney this was back at the start of the year and i only just a week ago done a compression test on the used supposedly good running new to me powerhead and it was down on compression on one cylinder so it may need that one journal repaired

Originally Posted by gazza2009au

How come the cost is very high to have a crank journal repaired by welding?

When you look at being charged $110 per hour or part thereof, it's not hard to see the cost.
Welding time possibly 1hr+ as you have to watch the distortion, setting up the crank in the lathe to machine the journal, an other hour as it's not the sort of thing that can be shoved in and she'll be right Jack type of thing.
Another hour and a half, it's hard work machining weld metal, hang on "SMOKO" break by the time he gets back to work, there's 20 minutes gone, the BOSS wants his profit out of it, call it 1/2hr, so there's your $440.00
That is a reasonable hourly rate for work like that, some can be upto $200 for real specialised work.
HTH
Kryn

Kryn when u stretch it all out it seems like a lot of work i know lathe work takes time and being prescise too eats up time and the bloke i seen is by far the cheapest machinist around

Wish it was a job easily done at home but its far out of my capabilities and the tooling is next level industrial equipment

I saw that video, I was not impressed at the final finish maybe I'm just too fussy

My old Boss use to use Paul England to do the outboard crankshafts. He had used some other repairers before Paul, but there work was crap. I remember Paul stopped doing outboard crankshaft repairs, but that was a long time ago. Paul England does have Marine Engines listed on his website, but he may be referring to bigger engines. I seem to remember that it was about $200 to $250 to do a crank journal, but we are talking around 1996 to 2005 when we were doing a lot of rebuilds so wages were a lot less then (the $440 sounds reasonable at current labours rates). I know you sold the motor off and not knowing what motor you had, but did you think to look for a secondhand crankshaft ?.