Welding cast aluminum???????/

**B.Mac** · 01-20-2003, 09:10 PM

Two welders today told me that they are not able to weld cast aluminum

I've got a Panther jackplate that the mounting holes have corroded to be oversized and oblong. I wanted the holes either filled in with new material or at least decreased in diameter so I can redrill them to 1/2".
Guys are tellin' me aluminum "absorbs" salt and causes a weak bond.........They can't do it.......
I think it's more like they can't justify "absorbing" enough salt outta my pocket for a simple job?
Is there any truth to this salt mularky?
B.MAC

**Airboater** · 01-20-2003, 09:24 PM

Is there enough room to drill out the oblonged area and insert a steel bushing or sleeve.Just a thought

Paul

**skidoo29** · 01-20-2003, 09:50 PM

although I am not a great welder I have worked with enough guys that know how to do it properly and from what I remember cast aluminum is hard enough to weld properly when it is new never mind something that is aged and has absorbed salt ( it does create a weak bond) feel free to correct me if I am wrong, and I will check with someone tommorrow to see if it can actuallly be done. I am sure someone will give it a try though, even I would if I didn't mind wrecking it. but I am sure that is not an option, the steel sleeve might be an option if you could find someone to bore it in for you. just my .02 cents

**B.Leonard** · 01-20-2003, 09:56 PM

Unless there is an awful lot of material around those holes and even then, I would drill larger an sleeve it. Too much strain on that plate.

I know where I can get a used Bob's 5" cheap if you want it.

-BL

**sho305** · 01-20-2003, 10:02 PM

Never heard of it, but the only salt here is on the roads! I had a skeg heliarced on my Force, the only way to weld aluminum. They say not to do 100mph LUs though, I guess I can see that. Otherwise it would be real easy to drill it out and put a SS or bronze sleeve in the hole(press/cement it in there easy), and if it has a plate or washer on each side it would not matter anyway. Never heard of salt "going into aluminum" except when it corrodes of course. How would you repair anything aluminum on a salt boat then? Aren't motors aluminum?

I would do that, unless you are tight on room it will be strong. If corroded, well I welded plenty of rusty steel stuff on cars here, and it ain't pretty

I imagine it would be the same deal, as the corrosion puts holes in the metal and mostly causes gases in the weld....equals bad welds. Good enough for a tailpipe.

Not sure exactly what you have there, but if the holes are trashed/corroded, and you have no room to make them bigger....you may be able to weld the whole thing on a plate/set of plates for a new mounting surface. They could weld/bolt on to the good aluminum all the way down....if it were the bolts to the hull for example. You could even move the plate up or something then, but you would have added thickness there too. Just an idea?

**Burke Kilgour** · 01-20-2003, 10:12 PM

I'd drill it out fairly big (get rid of corrosion) , machine a aluminum stepped washer to fit into the hole, epoxy prime the mating surfaces then fit the washer into the hole with structural adhesive .
That'd be good for a long long time and you wouldn't have any dissimilar metal corrosion like with a steel bushing.

**skidoo29** · 01-20-2003, 10:13 PM

I might be wrong about the salt but I have seen a guy try to weld a custom snowmobile trailer that was made out of aluminum that was about 10 yrs old and he was having trouble getting a good solid weld because he said that salt had gotten to it. could have just been an excuse though.

**Burke Kilgour** · 01-20-2003, 10:25 PM

Most trailers are made from extruded aluminum (6061) which is extremely susceptible to exfolliation corrosion. Cast isn't much better...............both are extremely hard to weld succesfully when corrosion has started.

**fredsav** · 01-21-2003, 12:23 AM

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**fredsav** · 01-21-2003, 12:24 AM

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**fredsav** · 01-21-2003, 12:25 AM

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**B.Mac** · 01-21-2003, 05:13 AM

That is exactly what I'm talkin' about! I'm on my way up there.
I'm only about 50 hours from you.

Sleeving sounds like the ticket.....these are the four primary mounting holes for a 13" set back. Better know that I know huh?
Thanks for the info guys!!
B.MAC

Bruce is that unit manual or hydraulic? I need a hydraulic.

**gaineso** · 01-21-2003, 05:17 AM

fredsav, that's wrought aluminum which is musch easier to weld than cast. Finer grain and different alloying elements.

BMac, I'd be very leary of welding an aluminum casting. Unless you know what alloy it is and can tell a really experienced GTAW welder so that he/she can pick the proper filler, you're looking for trouble. Also, if there is any evidence of corrosion anywhere near where the weld is to be made there is great potential for problems. I agree with Burke K. That would be one way to go. Also check with your buddy B.Leonard about that Bob's plate. All the beautiful work you've done, you don't want to take chances on something like that.