Help for an amateur

[Merccooper]

Hi Guys,
I'm an amateur welder. Only doing it for home projects. A (non welding) project I'm working on is rebuilding an old outboard engine. The drive shaft had pitting where the oil seal goes. I'm hoping to spot weld the pits then put it on a lathe to smooth it back down. Attached are some pictures. I have a couple of questions

- is this feasible?
- any special instructions?
- I'm not able to tell what kind of steel it is. Could it be stainless steel?

Thanks for any help you can provide

[dondlhmn]

I tend to think of welding as a way to fix things (and it usually works), but in this case I'd consider:

Seals tend to be all standard sizes and very little investigation may be all you need to find one that will be what you need. It is RARELY an absolute necessity to replace a bearing or seal with an OEM replacement part (which could be either or both EXPENSIVE or nearly impossible to find). A lot of seals of various sizes and applications are available from bearing suppliers, industrial parts suppliers and etc., so if you can find one in the right size....that is to say you can find one where OD is correct for your application ( the same as the OEM one) and the thickness is OK, too (sometimes if there is nothing that has to be installed that is "spaced" by the seal a thicker or thinner one will work fine as long as it is made of the right material to work in the fluid or temps that are found in your application) and the ID is what you need to fit the shaft after it has been either turned down or maybe ground down to eliminate the pitting, you could be good to go, especially if the shaft is NOT hardened (which usually is not very deep). If it is hardened there where the seal contacts it, you might wind up removing the hardening if you weld OR if you reduce the diameter there and that would likely NOT be a good thing.

Looking at the pictures, it appears that the shaft is smaller in diameter not too far from where the seal goes, so it turning or grinding it down will likely not affect the strength of the shaft a bunch...you will have to evaluate that possibility for yourself.

If the pitting is not very deep, this MAY be the best route to go as you will have to reduce the diameter only far enough to remove the pitting, KEEPING IN MIND that you will have to have the diameter correct size for whatever workable seal you can find.

Let us know what you figure out, OK??

[Merccooper]

Thanks for the quick feed back!
I had not thought of the turning it down. I have one that is in worse condition so maybe I'll give it a try on that one (after seeing if I can get a small diameter seal)

[Manisoba]

Help for an amateur

Merccooper, from where the seal sits on the shaft in the picture, is the shaft the same size or smaller all the way to the end on the left side? If it is CR seal makes a sleeve specifically for the application. It's called a speedy sleeve. It a very thin ring of steel that fits snug on the shaft and gives the seal a new wear surface. No machining and no chance of warping due to welding.

[Meltedmetal]

Yes it is feasible. I would probably use bronze with oxy/acetylene cause that is how I am equipped. --Meltedmetal

[Merccooper]

Thanks Manisoba. I was looking into the sleeve. Here in Canada they cost $70 each and I need two (one the drive shaft and one for the prop shaft)

Meltedmetal, Thanks for the input. I have a MIG wire fed welder using flux. Can I use this and if so, what wire would I use? (sorry if I'm not using the right terminology...but I really am an amateur!)


(Oh, as an amateur I promise not to weld anything (trailer hitches) that could endanger others!)

[gnforge]

Help for an amateur

Yep can be done, did two last month. I Tig welded them. One was hard I used 309 SS wire thought it wouldn't absorb as much carbon but still got pretty hard & I had to get carbide cutter to finish. The other one wasn't hard, built it up whole way around & turned down easy. Both shafts were slow speed and seal only holds grease in. Saved both.

[Meltedmetal]

[QUOTE= Meltedmetal, Thanks for the input. I have a MIG wire fed welder using flux. Can I use this and if so, what wire would I use? (sorry if I'm not using the right terminology...but I really am an amateur!)[/QUOTE]

I don't do mig yet so I`m not the person to advise you on the proper wire(I'm still trying to find the time to set some equipment up to mig aluminum) but I don't see why you couldn't do it with mig. It would be better if you could determine what material it is. You can get an idea by grind testing(use a spot that won`t suffer from the mark it leaves). The properties of the sparks give an indication of what material it is. I know I saw a link to a site that explained grind testing somewhere in this forum, might also be called spark testing. Welding it may also bend it so you could have to straighten it post weld. I find alternating weld site can help to reduce deflection. Others may have different ideas. You might want to protect the bearing seat from spatter, if you wrap it with tin and wire it on that should do it. Just don`t weld the tin to the shaft. ou can also get a rough idea of hardness with a decent file, again use an inconsequential site.
Meltedmetal

[Merccooper]

Thanks again Meltedmetal
Here is a video of a spark test. Can anyone suggest the metal type?

http://www.flickr.com/photos/9474584...in/photostream

[dondlhmn]

Kind of hard to tell from the video, but it does not look hardened to me....hardened usually gives tiny little sparks that only show up tiny and bright for a very short distance from the wheel. Video can be very deceiving due to what is called persistence of the video gear.

Another way to get an idea how hard something is would be to try to file it with a good, fairly new file that hasn't been destroyed by the wrong kind of use. PUSH only and do not drag. If the file doesn't bite at all and kind of just slides over the metal without taking a cut, then usually it is hardened. If the file bites pretty easily, I'd bet that the metal being filed is not all that hard, if at all.

[Meltedmetal]

Find info on spark test here:http://www.tpub.com/steelworker1/6.htm I found this in a thread about " how to identify between cast steel and forged steel." If the link doesn't show up search for the thread.--Meltedmetal

[fjk]

As others have said, a) It is possible and b) you really must find out what kind of metal it is as step 1.

That said, you have said that you're a rank amateur. I suggest that you get good at controlling the weld puddle, your heat, and so on, before doing this. Until you're fairly good, you could turn the shaft into so much scrap. You definitely need to be careful and not warp the shaft; that probably means building up the area a little bit at a time on opposite sides (eg, deposit metal at 12:00, 6:00, 1:00, 7:00, etc), and let it cool before moving on to the next bit. Also MIG tends to be fairly fussy about the cleanliness of the base metal ... you might want to clean/grind/etc the area down to bright shiny metal before dragging out the welder. I also would not use fluxcore (which you indicated you would use) but rather MIG (no flux, with shielding gas) as it makes for a cleaner weld, reduced probability of slag inclusions, and so on.

[dondlhmn]

Hey, that spark test page was pretty good. I have always just "sort of" used the sparks or a file to help me figure out what sort of metal I had at hand, but that explains and narrows it down pretty good. I think I'll save that one!

[bababouy]

Another great way to test metal is to use a magnet. I should attach a video but you can try youtube. I would tig weld the shaft, but build a fixture around the shaft to prevent warping.

[Merccooper]

Thanks for everyone's input.
Looks like I have a little more homework before I dive in.
....maybe the best thing is to take it to an expert. If this was the only thing to put money out on then I wouldn't hesitate, but rebuilding this engine has a lot of individual money drops that are adding up.
Homework time!