Dinged Aluminum Prop Repair

[NA3VY]

My prop on my Suzuki DT25 2 stroke has a small chip and a number of dings. I wonder if the low temp aluminum brazing rods they sell at Harbor Freight could be used to repair the prop edges. I'd add a little metal and using a dremel and a file grind the edges back to the original shape.

 

[RaisedByWolves]

Got a pic?

I’m not real fond of the aluminraze type of rods and especially on something like this.

You have to get those rods close to the melting point of the aluminum and any error with the torch (aluminum does not turn orange when hot) and you will have the blade just fall away without warning.

 

[airshot]

Prop repair is not that expensive, at least not in my area. I have always repaired my own bumps and dings but if chunks are missing, I leave it to the professionals!! Do you have a spare prop?? If not, now would be a good time to buy another good orop abd keep the dinged up prop as a spare.

 

[DaleH]

Never use a metal file on a tin prop … causes problems if welding if ever desired in the future.

Use crocus cloth or metal paper on a hardwood backer. Unless you have a huge gouge with missing material, you’ll never notice any performance loss, just smoothen everything up well!

 

[Randaln]

You can use those little rods..
I call them monkey metal.
They are a pain in the ***.
Everything has to be clean..
And you need to grind
The area to be repaired
At an angle to increase bonding surface area.
You want to use rod as a scrubber
On the sanded /ground area
For two reasons
First to see when props up to temp to accept
The rod and then for a cleaning action..

And be aware that the rod is heavier than alm.
It’s better to just tig it..
Or mig it
Last resort monkey metal..

 

[Randaln]

It is also advisable to use a backer plate
Against but area to be repaired ,have it away
About 1/8” and put extra rod on area to be ground off.
If you try it without backer plate the monkey metal will fall to floor.

 

[thill]

I've used the rods, but typically use my MIG with .030 aluminum wire and a .035 tip and 100% ARGON shielding gas. DEFINITELY use a heat sink underneath. A little hand shovel works pretty good for prop repair. Stack stringer beads for big areas, or just little beans of weld for smaller chips, then touch up with a flap disk.

If it's just small stuff, you can just smooth it out as mentioned above, especially with a 25 HP. Eventually get another prop, if you notice a drop in performance, and keep the current one as a spare.

 

[bbot1967]

I've used the rods, but typically use my MIG with .030 aluminum wire and a .035 tip. DEFINITELY use a heat sink underneath. A little hand shovel works pretty good for prop repair. Stack stringer beads for big areas, or just little beans of weld for smaller chips, then touch up with a flap disk.

If it's just small stuff, you can just smooth it out as mentioned above, especially with a 25 HP. Eventually get another prop, if you notice a drop in performance, and keep the current one as a spare.

I'm surprised MIG was possible. I've always been told TIG is not only the best way but the only way. I've got a TIG welder, she works for Caterpillar and makes it look so easy, but I might have to play around with the idea of MIG on some props I don't really have too much concern over. I've been telling her she should start fixing props and lower units on the side for people or for local dealers. You know, when ya' absolutely need it the same day or next sorta thing.

 

[thill]

I forgot that you need to use 100% shielding gas. Does NOT work without that. Some use a spool gun, but it's not necessary. You need to maintain about a 3/4" standout, or the aluminum may burn back inside your tip, which is a pain.

YouTube Aluminum Mig, and you will see a bunch of videos. That's how I learned. Just remember, if it starts getting too hot, STOP. I find the best way is to work in short, 3-4 second bursts, pause and then resume. Having the heat sink behind is a real life saver when working on thin stuff, like the hull of a boat.