# How to Aluminum Weld



## Bondo (Dec 8, 2007)

BigJim said:


> I have welded steel and cast iron before but never tried to do any aluminum welding. A few years back I sold my tanks and torches and welding rig so I am needing something that I can aluminum weld with.
> 
> *I won't be doing much at all so I need something small and cheap.* Any suggestions?
> 
> ...


Ayuh,.... Howdy Jim,... Just how much, on what sorta aluminum ya got in mind,....

Patchin' up an ole barge,..??
Weldin' motor castin's,..??
Buildin' stair railin's,..??
Structual,..??
Sheet metal work,..??

As ya know, Welders, 'n Cheap rarely fit well in the same sentence,...

Basic choices for aluminum are the solders, torched down,....
Tig welders, 'n Mig welders,...

The solders I haven't used,...
Tig would be nice for really thin stuff,...
'n of course, I've got a Mig, 'n have posted some stuff I've done with it,...

As for Tips,... Ya can't get aluminum Clean enough,...
Ya want a couple SSteel brushes for yer grinder, that have never been used on any metal, but Aluminum,...
Use that SSteel wire brush to clean the aluminum _Just_ before ya weld it,...
If ya wire brushed it Yesterday, do it again, before ya weld,...


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## joecaption (Nov 30, 2011)

Small amount of welding that needs to be done then far cheaper to take it to a real welding shop and have them do it for you.


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## BigJim (Sep 2, 2008)

Bondo said:


> Ayuh,.... Howdy Jim,... Just how much, on what sorta aluminum ya got in mind,....
> 
> Patchin' up an ole barge,..??
> Weldin' motor castin's,..??
> ...


This should be right down your alley since you are a mod on the Iboats forum. I am going to swap my camper for a pontoon boat and I am paranoid of water in the toons. I want to install a tire like valve stem in each one with a drain plug, just in case I get water in one, that is why I need to know how to weld aluminum. Do you think that is a good idea?


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## BigJim (Sep 2, 2008)

joecaption said:


> Small amount of welding that needs to be done then far cheaper to take it to a real welding shop and have them do it for you.


You are probably right Joe, I just like to learn and do things myself.


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## Fix'n it (Mar 12, 2012)

if i were buying now, i have heard good things about these.
http://www.eastwood.com/tig-welders-eastwood-tig-ac-dc-welder.html

i have a MILLER DYNASTY 200DX. i haven't used it in years 
i didn't have the less expensive options when i was buying.


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## Bondo (Dec 8, 2007)

BigJim said:


> This should be right down your alley since you are a mod on the Iboats forum. I am going to swap my camper for a pontoon boat *and I am paranoid of water in the toons.* I want to install a tire like valve stem in each one with a drain plug, just in case I get water in one, that is why I need to know how to weld aluminum. Do you think that is a good idea?


Ayuh,..... Yer overly paranoid,....

Of the millions of 'toons out there, it's rarely a problem,.....

If weldin' on a 'toon, I could do it with my mig, but a tig would be better suited,....

My Starcraft blew out a chine a few years ago, 'n We fixed it with a mig, but it's painfully slow, as ya gotta spot weld yer beads, bein' such a thin base metal,....

To do what yer thinkin',.....
An aluminum conduit coupler could be cut down, 'n welded in for a drain plug, 'n the other 1/2 used to screw in a schrader valve, though it'd need to be bushed down to fit,...

But again, I think it's unnecessary,....

If the 'toons were torn all to 'ell, 'n this was a major cut-apart, tear-down, rebuild,...
Maybe I'd go the extra mile, 'n add the drain, 'n schrader valve,....
But that would be because I didn't trust my own welds,....:whistling2:


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## BigJim (Sep 2, 2008)

Bondo said:


> Ayuh,..... Yer overly paranoid,....
> 
> Of the millions of 'toons out there, it's rarely a problem,.....
> 
> ...


Thanks Bondo, that makes me feel better, well... kinda. :laughing: At least I won't worry about sinking now, or worry about installing a drain and valve stem. What amazes me is how aluminum can hold up a 115 hp motor on a toon. Hopefully the pontoon won't be in too bad a shape when I get it.

I appreciate all the information fellows, I would still like to learn how to aluminum weld, just for the learning experience.


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## Bondo (Dec 8, 2007)

BigJim said:


> Thanks Bondo, that makes me feel better, well... kinda. :laughing: At least I won't worry about sinking now, or worry about installing a drain and valve stem. What amazes me is how aluminum can hold up a 115 hp motor on a toon. Hopefully the pontoon won't be in too bad a shape when I get it.
> 
> I appreciate all the information fellows,* I would still like to learn how to aluminum weld, just for the learning experience.*


Ayuh,... It's only a thousand miles or so,....

Stop on over, 'n I'll teach ya,.....:thumbsup:


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## BigJim (Sep 2, 2008)

Bondo said:


> Ayuh,... It's only a thousand miles or so,....
> 
> Stop on over, 'n I'll teach ya,.....:thumbsup:


Thanks buddy, I appreciate the offer, don't think my ole truck would make it that far. LOL


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## Bondo (Dec 8, 2007)

Ayuh,... Before I bought the Lincoln welder the size of a small car to weld aluminum,....

I was usin' one of These,.... had 2 of 'em, bought used on ebay,....

I built alota nice stuff outa aluminum with that rig, runnin' on ole dumptruck batteries,...


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## Oso954 (Jun 23, 2012)

Whether you need to worry about water in the pontoons will depend on the construction and condition of the pontoons. The welded construction pontoons are less susceptible to leaks then the riveted ones.

Some builders put threaded plugs on top of the pontoons. Water can be pumped out, siphoned out, etc.

I would be hesitant to put drain plugs into the pontoons bottoms. Any hole below the water line is a potential leak source.

Boats need drain plugs more for rain and spray than for leaks. Hopefully you don't have rain or spray entering your pontoons.

If your pontoons are the sealed type (no plugs) you still might think about holding off on adding plugs until you actually have a water leak. You can spot it by a change in trim, water dripping from the pontoons long after the boat and trailer have dried off, sounds of water sloshing, etc.

The two happiest days in your life are the day you buy a boat, and the day you sell it.


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## Fix'n it (Mar 12, 2012)

Oso954 said:


> The two happiest days in your life are the day you buy a boat, and the day you sell it.


lol

BOAT = Break Out Another Thousand


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## BigJim (Sep 2, 2008)

Oso954 said:


> Whether you need to worry about water in the pontoons will depend on the construction and condition of the pontoons. The welded construction pontoons are less susceptible to leaks then the riveted ones.
> 
> Some builders put threaded plugs on top of the pontoons. Water can be pumped out, siphoned out, etc.
> 
> ...


That is some good information, I hadn't thought about weld vs rivets, that is a real good point. I appreciate it.

Just a thought, could I use a propane torch to keep heating the aluminum while using another torch to do the actual welding? From what I am seeing, one problem is getting the aluminum up to heat and keeping it there with small torches, so if one torch is use to heat and one to actually weld, would that work?

A question, I have a 1985 88hp Johnson, runs great, the only problem I have is I can either get in in forward gear or reverse, not both. The fellow I got it from told me he didn't adjust the shift rod when he changed out the impeller, I tried to adjust the rod when I took the carbs off but it didn't work. Any suggestions?

One more, I have a problem with the electric choke, it seems to work, just not good enough to close all the way to choke it when cold. After it is warm I have no problems.

I know what you mean about buying and selling a boat, they are a very bad investment.


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## Oso954 (Jun 23, 2012)

Jim, I don't think I can help on the shift rod adjustment. Last one I did on a similar sized engine was enough years ago, I can't even be positive of the make, much less the year of the motor. We had to use an adjustment length from the shop manual. 

I would try an online forum similar to this.

http://www.marineengine.com/boat-forum/forumdisplay.php?26-Johnson-Evinrude-Outboard-Forum


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## Bondo (Dec 8, 2007)

> Just a thought, could I use a propane torch to keep heating the aluminum while using another torch to do the actual welding? From what I am seeing, one problem is getting the aluminum up to heat and keeping it there with small torches, so if one torch is use to heat and one to actually weld, would that work?


Ayuh,.... That sounds like yer talkin' 'bout that aluminum solder stuff,.....
As I said, ain't tried it, don't have any faith in the process,....
Got some layin' in a toolbox drawer somewhere,.... 
If I find 'em, I'll gladly send 'em to ya,...

Aluminum is gotta be electrically Welded,.... Mig or Tig,...

That welder I linked above, two 12v batteries, 'n a tank of argon will get ya Weldin',....


> A question, I have a 1985 88hp Johnson, runs great, the only problem I have is I can either get in in forward gear or reverse, not both.


I'm sure somebody in the Johnnyrude forum at iboats would have that Info,...
'n You already know how to get there,....


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## BigJim (Sep 2, 2008)

I will check out the Johnson/Rude forum and see what they have to say. 

I didn't give the soldering and welding enough thought, I will be on the lookout for an electric welder.


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## BigJim (Sep 2, 2008)

Got rid of the camper and now have a 24 foot pontoon boat, I never dreamed it would be so much work to get a pontoon water ready. The floor is in real good shape except the light colored carpet is stained a little but for a fishing rig that will be ok for now.

The trailer is a really good one but had to get new tires right off the bat. The only issues I have with the trailer is the way it is set up for loading. I will be installing a set of 12 foot long carpet covered 2X8s as guides instead of 4 post just sticking up in the air to be easily hit and bend everything out of shape. I will need to brace the 2X8s forward and crisscross brace side to side.
This part is no problem.

I discovered two hairline cracks in the rear section of the two logs. I have called a fellow who does this type of welding so that should take care of that. I wish I could get a small cheap MIG welder and fix the cracks myself. I could also weld the cross braces which will be steel.

The only thing that has me concerned, is the hairline cracks are right at a very stressful point, as that is one main place that the floor cross support rests that holds the 85 hp Johnson up. I couldn't believe that one aluminum support would hold that much weight.

I did reinforce that area because the motor had a lot of bounce, and I mean a lot. There is no way I would have gotten on the water with a motor bouncing like that. I got a stick of 2x2x1/4 inch aluminum angle and bolted it to the cross floor support (I used SS bolts and nuts).

I raised the rear rail up and installed another aluminum angle on top of the cross floor support. Also, one foot back, in front of the motor, I installed another aluminum angle and bolted it to the pod that holds the motor up. By redistributing all that weight to three points on each log, instead of mostly one point, I am comfortable about getting on the water now. There is no bounce at all now.

I could seal the hairline cracks and let it be but I still want that welded to make sure no water can get in the cracks. Below is a picture of the hairline crack, both are exactly the same.

Should I get a small MIG and give it a try myself or just let the fellow who is an expert do it?


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## Bondo (Dec 8, 2007)

Ayuh,.... Whether ya weld it yerself, or have the other guy do it,....

Don't put any sealant in/ on it, as it'll be impossible to remove the sealant for weldin' later,....


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## Fix'n it (Mar 12, 2012)

that crack is longer than what you have marked. have the guy weld it. but before he does, you should learn what good and bad welds look like = don't just trust him. i have seen guys weld for years, and still couldn't do it.
a "cold weld" will look good to the ignorant. but when put into real service will fail.


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## BigJim (Sep 2, 2008)

Thanks Fix, I think I may have already messed up, Bondo said not to put sealant on it and I did. I took the pressure off that spot and placed it in two other places but with a wider area to lessen the PSI pressure, so I am not worried that the crack will widen.

After buying so many smaller things like new tires etc, the funds are getting slim. LOL The fellow wanted $150 just to come out to the house. I know people have to make a living and I probably would charge the same thing in his shoes. I figure if I took the pressure off that spot and then sealed the crack to keep water out, I should be good to go.


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## Fix'n it (Mar 12, 2012)

it probably will crack further. boats can take a pounding. 

the sealant = as you know, anything can be undone. i wouldn't worry there. 

lets see pics from further back.


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## Teevee (Jul 15, 2015)

To best weld aluminum with MIG you'll need decent size welder running at least 220V and a spool gun. using aluminum wire in a regular gun will cause lots of burn back and clog your liner in the gun. MIG welding for aluminum is for 3/16 and thicker. If you can put a 2"-3" plate across the bottom edge of that whole area and up the side too... Stitch weld it and seam sealer after it will be good. No need to preheat aluminum because heat travels so fast in aluminum that by the time you get welding everything will be nice and warm. The cracks are there because of the 90degree joint. Once aluminum starts flexing it cracks and gets real brittle too. Wire brush just before welding for best welding.


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## BigJim (Sep 2, 2008)

Fix, sorry I didn't see your post or i would have responded sooner. It very well could crack further but I hope by getting the pressure off that cracked area it will lessen the chances a little. I transferred the pressure to two other places away from the crack by at least 8 inches at one place and 12 inches away on the other. 

I can not believe that that one narrow stick of channel aluminum could hold the weight of the motor (386 pounds), but it did. I now have 3, 1/4X2X2" angle aluminum running from side to side to transfer the pressure and add extra support for the motor.

Hopefully I can explain, envision a rectangle box with no top or bottom sitting on a pontoon log, there are two, (actually there are many supports like this) one on each side supporting the aluminum channel that supports the motor and the floor. Now envision the aluminum channel that runs from outside rear edge on each box, and runs across to the other side. The channel bowing a little from the weight of the motor is putting pressure on the inside edge and corner of the rectangular boxes. Right on the inside rear corner of the rectangular aluminum box is where the cracks are.

As I said, I took most of the pressure off that inside cracked area and transferred it to the outside rear edge (corner) of the boxes. Also about 12 inches back is another 1/4X2X2 angle aluminum which is helping to support the motor and is also transferring some of the pressure to there.

At this time there just isn't enough funds to buy a welder that can weld aluminum so hopefully this will hold until there is. The way the motor is running there isn't a lot of chance it will get worse right now.LOL But that is another story.


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## mako1 (Jan 7, 2014)

I'll throw my 2 cents in here since I used to weld aluminum all day in a factory .we used a heliarc in those days.
Your pontoon is not the place to start learning how to weld aluminum.there are several ways you can really make a mess of it.the most common are to much heat and you blow a hole thru the metal or to little heat and you get a bad weld with no penetration.


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## Anti-wingnut (Oct 18, 2009)

BigJim said:


> Got rid of the camper and now have a 24 foot pontoon boat, I never dreamed it would be so much work to get a pontoon water ready. The floor is in real good shape except the light colored carpet is stained a little but for a fishing rig that will be ok for now.
> 
> The trailer is a really good one but had to get new tires right off the bat. The only issues I have with the trailer is the way it is set up for loading. I will be installing a set of 12 foot long carpet covered 2X8s as guides instead of 4 post just sticking up in the air to be easily hit and bend everything out of shape. I will need to brace the 2X8s forward and crisscross brace side to side.
> This part is no problem.
> ...


That's going to be a nightmare to correctly repair. You just can't apply weld metal over the crack. I think you are going to have to remove the brake shape, patch the pontoon and the reapply the rake shape with added gussets.


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## BigJim (Sep 2, 2008)

mako1 said:


> I'll throw my 2 cents in here since I used to weld aluminum all day in a factory .we used a heliarc in those days.
> Your pontoon is not the place to start learning how to weld aluminum.there are several ways you can really make a mess of it.the most common are to much heat and you blow a hole thru the metal or to little heat and you get a bad weld with no penetration.


I do agree the boat isn't a place for learning to aluminum weld, I will do some serious practice with similar thickness aluminum. I don't know if I would be good enough to actually repair this.

"That's going to be a nightmare to correctly repair. You just can't apply weld metal over the crack. I think you are going to have to remove the brake shape, patch the pontoon and the reapply the rake shape with added gussets."

Thanks AW, this may be a little more than I want to DIY, hopefully it will hold until I can get the fellow out to weld it. 

I will take some pictures of his before and after welding.

Thanks again fellows I really do appreciate it.


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## concrete_joe (Oct 6, 2014)

if the crack can be backed buy some copper, i might do a grind out of the crack line using a thin blade on a dremel, then back it with copper, then TIG in some new AL using just enough heat to get a liquid seam going. after air cooling i might do some stress relieving by heating with some mapp and let air cool, then lightly grind flat. but it looks like its a tube that needs fixing..... 

1) need to know what type of AL it is
2) only a TIG for this job


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## Mattia.R (Apr 20, 2016)

Aluminium welding requires high amps, so it can't be small and cheap. Best choice would be TIG welder, but it needs to be AC/DC but they are quite expensive.


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## Crazyjake8493 (Sep 26, 2014)

Mattia.R said:


> Aluminium welding requires high amps, so it can't be small and cheap. Best choice would be TIG welder, but it needs to be AC/DC but they are quite expensive.


I've got the AHP Alphatig 200X and works great for aluminum, but it was $700-ish and that's a low end model TIG welder. Still cheaper than a 240V MIG with a spool gun, but not "cheap" for a hobby DIY/homeowner.


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## crash525 (Apr 3, 2013)

Welding aluminum does not need to be heated if your are using mig or tig. Welding on aluminum you need to clean the aluminum oxide off right before welding. Use a purpose cleaner for it. They work best. Iso rubbing alcohol worls ok or use a stainless steel wire brush. Anything else wont work. Any cheap AC/DC mig or tig welder will work. They just need to be sealed not for super strength. Practice on same sized aluminum first because buring throigh on aluminium is not the same as steels. If you inly have a few spots to fix take it to an experienced shop. Cheaper that way and they take the blame if its not done right. 

If you have more questions just reply ive welded alot of aluminum. 

Sent from my Nexus 6P using Tapatalk


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## crash525 (Apr 3, 2013)

BigJim said:


> Thanks Fix, I think I may have already messed up, Bondo said not to put sealant on it and I did. I took the pressure off that spot and placed it in two other places but with a wider area to lessen the PSI pressure, so I am not worried that the crack will widen.
> 
> After buying so many smaller things like new tires etc, the funds are getting slim. LOL The fellow wanted $150 just to come out to the house. I know people have to make a living and I probably would charge the same thing in his shoes. I figure if I took the pressure off that spot and then sealed the crack to keep water out, I should be good to go.


To stop a crack take a small drill bit and drill each end of the crack.

Sent from my Nexus 6P using Tapatalk


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## MarkoG (Jun 25, 2017)

To do a proper aluminum weld I recommend using a proper shielding gas. Oxygen mixture for example and Sulfur hexafluoride is also very recommended. 

You might want to think about using arc welding as well. Some reasons why: 
http://roshmetal.com/advantages-of-arc-welding/

The ease of use and the low price might be the main reasons why. At least the ones I consider when working.


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