Aluminum boat prop repair?

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I recently bought a used 25 horse outboard motor.  Each blade of the 3 blade prop has a 50 cent piece sized chunk of the prop tip missing.  A new prop is around $100.  I spent $23 to buy the motor (needs new head gasket, thermostat, and water pump).My questions are these...Can a MIG welder with aluminum wire & appropriate shielding gas build back up the missing area?  I know that I'd have to grind away the excess material, build up some more, grind, repeat.I do not have a spool gun.  The gun cable on my Hobart 187 is 10 feet long.  I would have to keep the cable relatively straight while doing this repair.  I'd also have to buy another tank for argon.  Currently I just have a tank of C25.My main area of concern is that I'd spend money on another tank, and then find out that the prop can be repaired properly, or that the aluminum wire won't feed properly through the 10' cable.  In either case, the money spent on the tank would be wasted.  Should I buy the argon tank and try the repair?  If it works, I would have other boat projects that require aluminum welding.  Or should I just buy a new prop?  I also have an O/A setup, but I have zero experience doing anything with aluminum.HH187Harris O/AInfrared thermometerHalf a dozen angle grinders
Reply:If it were me, I'd probably try the O/A with some flux cored brazing rod. Crown sells a aluminum brazing rod that works quite well. Royal 110FCo is the rod I have had good success with. I have built up some pretty large holes in aluminum with it. It does take some practice to use it properly as the melting point of the rod is close to the melting point of the base aluminum. I use a number 3 tip with a slightly carburizing flame with about 4lbs of both O and A on the regulators.
Reply:gonna have to grind it out with a burr but even then might be tricky. You would be better off just buying a new prop but if you want to just dick around and try the brazing rods go for it. Just dont look for a professional repair. You really need TIG and years of experience to do something like this
Reply:mig may work but it will be a PITA  when welding on props the heat will increase as you weld making it tuff to not over heat the hub. tig is the recomended way to repair using O/A will be even tuffer and DONT use the wonder rod, because it will not mix with 4043 or 5356 if you ever take it to get repaired by a promig deposits more filler than needed so a lot of grinding will be needed  (if you would like, ups to me and i can repair for half of the price of new )if you do try keep ,in mind that it will need to be balanced, after repair both in pitch and weightto keep from knocking out lower unit bearings and sealsif you need give us a call 918-207-6938idealarc 250/250 ac-dc tigidealarc 250/250 ac-dc tig #2 used for sticklincoln sp100hh125dual arbor grinder polisher30 yrs of hand tools52 pitch blocks 6p-26prake gauge -pitch gaugeG&D prop repair 918-207-6938Hulbert,okla 74441
Reply:the catch is the props need to be balanced afterwards.      The local prop place to me charges a $80 flat rate for prop repairs..   I think you would be into the repair much more than that with tank and all...Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Buy a new prop or send the old one to Prop Doc.You're definitely "in over your head" on this one.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Originally Posted by SundownIIIBuy a new prop or send the old one to Prop Doc.You're definitely "in over your head" on this one.
Reply:another vote for new or prop doc an unbalanced prop will do alot more then 100 dollars damage to your lower unit350P 30A spool gun cut master 51  syncro 250 other stuff " take a dog off the street and make him prosper and he will not bite you sad the same cannot be said for man" i didnt use punctuation just to piss you off
Reply:Try some Alladin 3-in-1, aka Durafix, HTS-2000, etc etc. It's perfect for dirty garbage like old boat props. Trying to TIG the broken blades will be a nightmare for whoever ends up doing it, especially if the prop spent any time immersed in salt water. I wouldn't even bother MIG welding it, especially not without a spool gun.
Reply:on a $23 motor, with only a quarter sized piece missing, just run it till somethign breaks worse miller syncrowave 250hobart handler 140home made 400 amp engine driven in progress...