Brazing Aluminum Gone Wrong | 14' Gregor Hull Repair **HELP**

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Jan 6, 2019
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Recently purchased a 14' gregor for a great deal with a running 15hp evinrude. After further inspection i found a hairline crack that didn't leak, but im weird and wanted seal it. I mistakenly tried brazing that hairline crack and BLEW a fat whole through the hull using too high of heat, after research there are plenty of products to seal such tiny cracks. RIp. But now im here. After speaking with a local welder with lots of experience in aluminum welding he suggested i patch the hole with another piece of the same aluminum and just rivet and seal it instead of welding. So here are some photos as well as a "mockup" if you will. Nothing has been done yet other than me shaping the patch piece of aluminum to fit the keel.

I have a .025 11x18" aluminum sheet that i want to rivet with aluminum closed end 3/16" rivets w/ washers spaced 1" apart. I want to seal each rivet and fill the cavity between the hull and patch with 3m 5200. The boat with be used in the socal bays and lakes. Note: the aluminum is thin enough to shape with a rubber mallet, lots of elbow grease tho.

Is this the best solution for such a crappy problem? If the hull lasted 3 years, id be stoked ;)
 

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Scott Danforth

Grumpy Vintage Moderator still playing with boats
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take the boat to a competent welder and spend the $50. if you cant find a welder, go to your local radiator repair shop (they weld aluminum)
 

gm280

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Jun 26, 2011
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They actually sell some welding rods for aluminum that you can use with a propane torch and seal that up. While I have never used such rods, that would be a good try to fill in the hole. Also, if you do try to weld it with those rods, place a piece of steel sheet behind it so the filling effort won't go any further. The steel will not weld to the aluminum and help keep the aluminum in place as you fill it in. JMHO
 

harringtondav

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I've done a fair amount of welding structural aluminum. Argon gas shielding is the only workable method. TIG or spool gun MIG. I'm not skilled enough to weld something this thin w/o burning a larger wound.

Perl Scott D, a prop shop is also equipped to weld this.
 

oldrem

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Nov 7, 2013
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They actually sell some welding rods for aluminum that you can use with a propane torch and seal that up. While I have never used such rods, that would be a good try to fill in the hole. Also, if you do try to weld it with those rods, place a piece of steel sheet behind it so the filling effort won't go any further. The steel will not weld to the aluminum and help keep the aluminum in place as you fill it in. JMHO

I tried those. On thin aluminum, even that amount of heat was enough to warp it badly. I will never use them again on a boat.
 

Mad Props

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I agree with Scott Danforth ... If a welder recommended you don't repair the aluminum, then I'd hesitate to call him a welder. Should be a fairly easy fix by a competent welder. Get it fixed right and never worry about it leaking.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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I tried those. On thin aluminum, even that amount of heat was enough to warp it badly. I will never use them again on a boat.

you have to hammer and dolly the warpage out. just like doing body work.

a good welder will leave it ready to paint without needing fairing (putty)
 

oldrem

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you have to hammer and dolly the warpage out. just like doing body work.

a good welder will leave it ready to paint without needing fairing (putty)

Yes, that's what I ended up doing. For the tough stuff I took it to a pro.
 
Joined
Jan 6, 2019
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Thank you all so much for replying! If I were to rivet instead of weld, what gauge aluminum sheet should I use?
 

oldrem

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I think most aluminum boats are 16 gauge, so should be good enough for the patch.
 
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