Boat Lower Unit Repair

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So my buddy gives me a call earlier this week, and asks me "can you tig something for me?" Yea sure what is it?I get to his place, and he shows me. Apparently its known as a "Scag" though I remember it being broken when his father bought this boat over 6 years ago, when we were both in High School. As you can tell the repair that was made previously was not welded well, and had no penetration. So heres a quick pic cronicle of the repair, no weld bead pics since I was running late welding before work, and just sanded it down when it cooled enough after I cleaned up my catchall workbench. Feel free to critique if you must.The pic of the break Another break pic A pic of the "repair" made before. Notice no real pen. in the base metal of the new fin that was welded by the previous welderJust a few pics of the beveling I did on the two pieces, to acieve better pen. I didnt feel the bevel had to be ridiculously consistent for what the job was, and for what it needs to support.
Reply:If you notice in the last two pics the bevel wasnt cobtinuet to the edge of the pieces. I left it like that to keep the piece in the same place as before, since the break still lined up when placed against each other. Once I got the center welded in, I beveled the edges (though I probably didnt need to) and finished it up. I couldnt get this last pic in the last post. Notice the pock marks above where I welded. There was quite a bit of porosity in the metal, on both his previous repair and the casting. He laid a LOT of weld beads over the original repair, he added nearly 1/8th of AL on either side across a 4x4 or larger area.Anyway, enough of the chattering. Heres the final product. Finished off in about 30 secods with a flap wheel. Attached Images
Reply:for a sec my computer wouldn't load up the last pic and thought you left it out. can't hardly tell where the weld was except for a couple pinholes.Last edited by docwelder; 07-19-2014 at 12:37 PM.i.u.o.e. # 15queens, ny and sunny fla
Reply:Did you wrap the gearcase housing with cool wet towels before applying heat to the skeg? There are a few rubber o rings and some seals that do not take to kindly to heat. You might wanna remover the propshaft and replace if you have any reservations about their integrity after your welding.  Seals and o rings are cheap....him replacing the lower unit/outdrive as.a result of infusion would be $800-$3000 ;(Last edited by woodtick007; 07-19-2014 at 03:47 PM.
Reply:That'll work. I've only done one in the past myself but some here have done numerous.Pretty common in the boating world as I've come to learn and many boat shops offer this type of repair in their lineup of services.  Replacement skags can be purchased for welding on when the broken piece can't be retrieved or just use an appropriate piece of aluminum plate and form to shape as needed.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Originally Posted by woodtick007Did you wrap the gearcase housing with cool wet towels before applying heat to the skeg? There are a few rubber o rings and some seals that do not take to kindly to heat. You might wanna remover the propshaft and replace if you have any reservations about their integrity after your welding.  Seals and o rings are cheap....him replacing the lower unit/outdrive as.a result of infusion would be $800-$3000 ;(
Reply:I've repaired quite a few, some weld like new material others like crap.  Not to be an *** but I think its skeg :-).....Mike
Reply:He pronounced it "scag" and when he called me I thought he needed a lawnmower fixed. FAIL lol. yes I kept the lower unit cool, but the whole thing needed rebuilt anyway. He brought it to his shop to reseal the impeller/water pump shaft, as oil was mixing with water. When he was moving it with his lawn tractor it decided to pull him across the yard without any warning, and slid into a slight embankment off his driveway. Seeing it break with almost no force, and seeing how light the weld penetration was, I understood why it broke so easily. He was more than happy with the repair, and I didnt think it turned out so bad myself. Could of been really great if I didnt have to bring the bead down in less than 10 minutes before work!
Reply:Originally Posted by mrmikeyNot to be an *** but I think its skeg :-).....Mike
Reply:In Texas it's s "skaig/skage" no matter how you spell it. "The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Thanks for the backup Sandy. MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:FWIW...often times in repair situations like this I won't pre grind a prep like you did.  I'll  put the pieces back together (using the broke edges as an alignment guide) and put some fairly good tacks on it so it stays in place.  Then using a 3/8 or 1/2" diameter, ball nosed, carbide burr I'll cut in a U-groove prep between the tacks.  Once I get those areas in between the tacks welded up I'll grind those surface tacks off and put a groove in where they were and weld that area up.   That way I end up with 100% penetration all along the joint.   Also, in general I favor making any welds preps on aluminum castings with a carbide burr.   It leaves a nice, clean cut surface to weld to.   Grinding rocks or flap discs tend to leave abrasive grit particles smeared into the surface of the preps that end up interfering with getting the weld in there smoothly and not having a lot of that black trashy stuff left stuck on the surface of the weld.   Plus there's the fact that those non-metallic inclusions that get mixed down into the weld metal lower it's strength.   If you find yourself already working on a lower quality casting that's already got a lot of that non-metallic (trash) in it that interferes with the welding there's no sense of adding more of it to the mix with your weld prep method.   Another trick for dealing with a trashy casting is to go down the joint first with out adding any filler metal just using the torch to melt into both faying surfaces to see how much of that black crap you can melt out and get to float to the surface.   Then go back and cut the prep clean with the burr to get rid of it before putting a good pass in there using filler rod.One more thought.....be careful with using a power wire wheel for inter-pass cleaning to remove build ups of that non-metallic stuff on the surface of the weld.   A power wire wheel will smear that stuff into the surface of the aluminum.   If doesn't come off with light manual wire brushing use the burr to cut it off.Last edited by HT2-4956; 07-20-2014 at 09:52 AM.
Reply:I did. I used a straight grinder with a carbide burr. Didnt take me long. Then washed andscrubbed with Acetone and a SS brush. I do a lot of cast AL intake repairs for a friend who takes broken intakes and repairs them for resale.Like I said above, i ground 90% of the middle with a quick no worries bevel, and used the two ends with "clean breaks" to realign the part. Then after getting a line or two down the middle on both sides I carved out the ends.
Reply:Well duh on my part.  Now that you've said that and I've re-looked at the pictures I can see that the prep was was cut with a burr.   When I told you all that I wasn't sure just how much aluminum casting repair experience you had.   Sounds like we might have some similar experience at working on Al castings.
Reply:Yeah, when I was in high school, they taught us mainly mig, but I was attracted to TIG due to the complexity and diversity it has. Then I finally pulled the trigger on one. Then a co-worker said "can you fix aluminum intakes?" as he proceeded to dump old offenhauser and edelbrock intakes into the bed of my truck with cracks, broken carb bases, the works. It keeps me busy when Im not working on my never ending car project. The piece wasnt terrible to weld, since it had been done before a few years ago, it wasnt filled with crud.
Reply:Goes to show how much I know.  Probably would have spelled/pronounced it correctly if I had done more than one.
Reply:I know of one shop that does thousands of these a year, also fixes props. We happen to have a ton of lakes and lots of those lakes have either deadheads or rocks.
Reply:Originally Posted by mrmikeyLOL, most of the people that brought them in would call it "that thing that hangs down below the blade thing" .......Mike
Reply:turismolover22,If you're looking for more of that kind of work may I suggest you go around your area and let all the motorcycle, boat and hot rod shops, diesel truck repair and equipment rental places that you can do aluminum casting repair.   Also a lot of these cement mixing trucks you see going down the road have a big cast aluminum oil pan on them that I've fixed a few of over the years.   All though it's not cast I've made some decent lunch and beer money off of fixing those aluminum diesel fuel tanks like you see on semis.   RV places are another good source for aluminum repair work.   I've fixed quite a few of those aluminum water heater tanks that people forgot to drain before winter that froze and split.
Reply:Hmm, you may have something there for a few side jobs. But Ill tread lightly. Even in simple mechanical repair jobs, I seemed to find two kinds of people. Ones who want it done yesterday, and ones who want it done for free. And if unexpected or unforseen repairs come up, they get mad.At least with welding I can see exactly what needs done 100% of the time.
Reply:Another good source of potential work is your LWSs and material suppliers.  A lot of people go in those asking if they know of any one that can repair or build things made from aluminum.   Another good promotional idea for your services is to weld up a bunch of workmanship samples (that you've written your name and phone number on or taped a business card to) and hand them out to the kinds of local businesses I've mentioned.    One simple thing I've gotten a lot of mileage out of is these aluminum pen and pencil holders.   I've got these sitting on the front counters of a lot of the local businesses in my area.   Just the other day I got a $100 cash side job from some one having seen one at a place he was in.   Here's some more examples of the kinds of things I've made up (mostly from left overs from other jobs) and handed out.   Never under estimate the power of giving some one a "shinny thing".   At a minimum you'll usually get some "good will" in return for doing it.
Reply:Those pencil holders and cubes are pretty cool looking. From what I can see your welding is spot on man.I know if my friends watched me weld beer cans together, theyd want me to weld two full ones together, and then punch the "bottoms" out for a king size beer.
Reply:turismo,Those 16 oz. Miller Lite cans with the screw on top I've got welded together can be refilled with beer.   I've done that a couple of times, put them in the ice chest with the other beers and taken them to parties.   I've gotten some good entertainment value out of doing that.   Usually before breaking one out I'll ask people if they've seen Miller's new 32 oz. can?   It's kind of a cool party trick to drink one side off, flip it over and start on the other one.   If you sneak shake the can a little bit before unscrewing the top it will hiss and sound just like your cracking a fresh, never before opened beer.   I've got a few people around here fooled into thinking that I actually welded two full beers together.
Reply:I don't know what the agricultural situation is in your area but another thing you can make some money at is fixing aluminum irrigation pipe.   Around here there seems to be a lot of those 4" hand lines that get damaged from having had water left in them that freezes and causes splits.  Plus they get punctures (including bullet holes)  and crushed from being run over with equipment.   Small splits or punctures can normally be sealed with just a bead but the larger ones get a patch piece put on.   I just cut out the crushed areas and spliced another piece in.    The last time I did this the guy brought me 20 40' pieces that were no longer useable and I managed to salvage enough pieces from them to give him back 16 good ones.
Reply:Man I need a bigger shop. Looks like if I ask around I can get a lot of side work going on.turismo,Another good source for work is all your local machine and sheet metal shops.   There's good money to be made from just doing the welded assembly of parts that other people have made.   Another piece of advise that I'd give you would be to get paid in cash when ever possible.   Especially for all repair work or one off items you do for other private individuals (as opposed to doing things for other businesses).   If some one absolutely has to have a receipt so that they can get reimbursed for what they've paid you just write one out on a blank 3 x 5 card.
Reply:Ill keep that in mind. Any dealings I do outside of the 9-5 are almost always cash.