Refinishing SS blades

[c-bolt]

How does everyone refinish their blades?  Weld up outer diameter (TIG or MIG work?) then turn on lathe or home built fixture?


Any tips or pics? 

[Jimmy Jet]

Sorry no one has replied earlier, you probably have it sorted already.
I personally TIG weld up blades but there is no reason you couldnt use a MIG if you have the right grade wire, almost fiddlier with the MIG though and almost certain to go harder for some reason.
There are a few ways to go about remachining, the way I use is to have a small dummy mandrel(shaft)that suits the bore size of the impeller. My one has a keyway cut that replicates the jet unit main shaft and a nut to hold the impeller onto a shoulder. I ensure the shaft is running dead true with a dial gauge and use a live centre in the shaft for extra rigidity. Experiment with rpm,cut depth and feed rate so the blade doesn't 'sing'(vibrate) and machine down until the required diameter is achieved. Dress up any sharp edges with a file and flap disc is you are careful. Use coolant when machining, it will improve finish and prolong tool life when intermittent cutting.
Get into it.

[Paul]

Pics below are of a tool I've made to achieve this on my SS blades.  My welder is a MIG, and I tried it with both 100%Ar and 90%Ar/10%CO2 bottles - both had similar amounts of spatter\BB's (- I didn't have access to the 'proper' SS MIG gas 98%Ar/2%CO2).

You need a flap disc to clean up the surfaces.  I also discovered that one of the fins on both of the impellors was bent about 6mm, so just used the MIG to spray on more metal and then grind all fins back to the same profile.

[mohawk]

Stainless arc rods work mint paul  . Very impressive tool you have there . I shall comense  construction of my own imediatly.

[Jeff B]

Stainless arc rods work mint paul  . Very impressive tool you have there . I shall comense  construction of my own imediatly.

I hope there is not a patent pending on this machine?
I have half built a similar contraption(bit flasher) with a cross slide......one of many projects

[Paul]

Stainless arc rods work mint paul  . Very impressive tool you have there . I shall comense  construction of my own imediatly.

I need to find some SS arc rods somewhere - there were only big packs in the places I was looking.
The jig works quite well.  It mounts in the vice, it's a stand to weld them on whilst giving you a 'wrist rest', then you're able to trim them back with good accuracy.
I suggest you get a friendly fitter\machinist, to turn down a piece of ~32mm tube down to 1.247" - which will give you a couple of thou clearance to rotate the blades around without having slop.

I hope there is not a patent pending on this machine?

You've helped me out quite a few times - call it quits! 

[swifty]

I saw the pictures of your rig Paul and automaticity thought it was mohawks , although it was to tidy looking and the welds were abit to good. Nice rig Paul 

[Paul]

I saw the pictures of your rig Paul and automaticity thought it was mohawks , although it was to tidy looking and the welds were abit to good. Nice rig Paul 

Mohawk, have you got one similar already? I could have just borrowed yours (assuming grinder fits). Mine was done without knowledge of anything similar.

Since the above pics, I've added a spring that pulls the arm back in so it rests on the depth-stop, then you don't have to push the grinder in as much.

[swifty]

I don't think he has Paul it just looked like his bush mechanics.

[mohawk]

Yup. Just have a shaft (old stub axel ) and screw adjustable guage for ODs.
its easy as too free hand them with it but i need a project.

[mohawk]

http://www.nzjetboating.com/yabbse/index.php?action=dlattach;topic=25546.0;attach=49740

[mohawk]

 

[mohawk]

 

[swifty]

The patent belongs to Paul 

[mohawk]

Hes got the pretty weld and shiny steel patent , I got the make it out of rubbish laying around and too lazy too clean up welds patent .
Anything is better than waiting for blades too come back  and the jigs are stupidly easy too make