[Ty1on]

Hello All,

Looking for a little guidance on welding up a crack. I believe this is a crack from a dock impact. Hull thickness based on info from manufacturer is .100" (might be a little thinner due to being on the corner). My research says it is most likely 5052 alum. Plan on using 5356 filler - (I have 5356, 4943, 4043). It is pushed in a little and its hard to get into to push out. I can barely reach the crack on the inside but I will try to clean with some scotch brite and then acetone. It is my boat so any goof up is on me. Looking for any tips? Drill holes at each end of crack, V out the crack some, etc.?

Thanks in advance!
Ty

[Louie1961]

Those cracks may go farther than you suspect or farther than you can detect visually. Go to the weldingtipsandtricks youtube channel and search around. Jody posted a video a while back on how to detect where the ends of the cracks are (I believe he used some sort of dye penetrant). Drilling the ends of the cracks is a great idea, but only once you find the end of the crack for sure. You may want to use a die grinder and a burr to vee or notch out that crack a bit. Also if you are TIG welding it, spend some time running the arc over the crack without filler and without melting the metal, just to get the cleaning action going and boil out any impurities. Good luck!

[cj737]

Clean it well. Use a MAPP torch and heat the crack. The length of it will show up. Drill the ends. Weld it up. If you are doing multiple passes, I like to peen the weld in between to help prevent hot short cracking. Use ample gas and postflow to cool it too.

[Ty1on]

Thanks Louie & CJ737!

Here is the repair. Hit the crack with MAPP torch multiple times to find ends of crack. Drilled 1/8" holes at the ends of crack. Grooved out crack a little with carbide burr. Buffed inside of crack the best I could with scotch brite then acetone wipe on both sides. Ran a little bit of a cleaning pass across crack - not sure I did the best job with that - arc was jumping back a forth from one side of crack to the other and when I tried a little more pedal, the edges were starting melt. Brushed with ss brush and acetone again. Then tacked in 4 places. Made 3 stitches to complete the weld. Went pretty well except at the beginning of each stitch I got a little blow up of black soot but cleared up after 2nd or 3rd dab of filler. Trying to figure this out - contamination but from where? I am low on gas ( around 200 - 300 psi left). Hmmm???

Syncrowave 200, 130 amps, ac bal set to 7, 3/32" cer, 3/32" 5356, #6 standard cup, 15CFH argon.

Hopefully she holds! Open for any critiques.
Thanks again for the help!
Ty

[Louie1961]

Looks good enough to me. Well done.

[cj737]

Looks fine. Black smoot is not uncommon welding on a used pontoon. Lord knows what has soaked into it over time. Plus you can’t really get the backside fully clean from the outside.

[Ty1on]

Thanks again for the guidance!!

Ty

[Mattman06]

The kitty knew you had it under control.

[BugHunter]

If you don't have a really good regulator, low gas will cause all sorts of issues, both on aluminum or DC. I won't get into the theory of it, but some say it's not good. Was true for me before buying new regulators. Now mine runs ok on 75psi.