aluminum

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well this old man met his match this week. from reading this board i knew 1/16th? thick alum. boat would be next to impossible to do with a mig. but thanks to info found here using a large block of copper to back it up got the 12 in. crack mostly "stuck" together so my buddy could fiberglass it to seal it. my hat is off to the people that can pass all the tests to be a real welder. it did stay together after using a rather large hammer
Reply:Fiberglass to seal a crack in an aluminum boat hull??  In the future, if you are ever called on to make a repair like that in a boat hull, and you're not comfortable doing the whole crack with the mig, try using some of the torch-friendly aluminum welding (brazing) rods.  (Muggy Weld is one brand you could try.)  Something about sticking fiberglass to aluminum doesn't sound too good to me.  I hope it holds for you.Miller Syncrowave 350Millermatic 252/ 30A spoolgunMiller Bobcat 225g w/ 3545 spoolgunLincoln PowerArc4000Lincoln 175 Mig  Lincoln 135 Mig Everlast 250EX TigCentury ac/dc 230 amp stickVictor O/AHypertherm 1000 plasma
Reply:it will hold for a little while, then peel due to flexing of the Alum.idealarc 250/250 ac-dc tigidealarc 250/250 ac-dc tig #2 used for sticklincoln sp100hh125dual arbor grinder polisher30 yrs of hand tools52 pitch blocks 6p-26prake gauge -pitch gaugeG&D prop repair 918-207-6938Hulbert,okla 74441
Reply:**** it duck it.I forgot how to change this.
Reply:A panel Beater in a factory near me that I knew came in on Tuesday afternoon and asked if I could do some aluminium welding for him on a cracked Audi front guard.He said one of his blokes had tried but it was too thinUh oh.... I said I didn't like the sound of that , he said it was rooted now and a new guard would take weeks to get in , could I try and if it gets binned ... it gets binned. "It's only a little crack""Ohhh... OK ,  damn it  bring it around"   He had it there  . The guard was real thin 1.6mm max. his man had ground of the paint on the top but not the back then hit it with a Mig  what a mess! Contamination everywhere  I cut it out with snips, ground the paint of the back and tigged on a 3mm 50x50 patch on the back then built up the patch with a Mig  .Gave it to him ... it was ugly real ugly  and said "Oh well your the panel beater ... you do your magic "He looked at the guard , looked at  me burst out laughing and pulled a case of beer out of the Ute . He had his work cut out for him !BrettLast edited by Brett; 08-31-2011 at 09:54 PM.A good guess is better than a bad measurement
Reply:i never thought  about the flexing of aluminum. the little boat is older than my neighbor and really oxidized his going to use if for duck hunting this winter then probably scrap it if it doesnt hold. it should hold my so-called welding has plenty of muscles showing "looks like bird droppings"
Reply:Boats suck. Boats suck worse with a MIG. Fiberglass will never ever hold! Before I started welding my father tried it all to patch the work boats. No matter what like mentioned the flex of the aluminum would make anything and everything peal off. Even soft plyable glues would just simply peal off after time.The problem is if you weld just the crack the aluminum WILL crack next to the weld over time or right down the middle of the weld if it isn't a great weld. The best is to weld the crack then weld a patch over the crack moving the stress points away from the original crack. But the patch itself sometimes creates stress risers and cracks will form along the patch. Over all the years fixing our boats I have had the best luck when the patches are big enough to butt up against existing seams in the boat. Our boats get beat to &*^% though. Maybe a small patch would hold up fine on most boats.Two episodes stick out in my mind of our work boats on bad days. First one was our older (now my fishing boat) boat, fully loaded down, going downstream in the river at WOT. Coming to the landing about 100 feet out we hit a rock with the front of the boat and it stopped dead right there! I thought for sure we were taking on water and we were gonna lose the boat. To my surprise the rock hit perfectly between a rib and the corner seam of the boat where there is a original two layer brace panel welded in. Even with the two .120" panels there was a nice dent left from the rock.Second time was with our new boat flying fast up the river in the dark. The water came down about 3 feet over night and we were heading to a place on the river that we were at day after day before. Come up to a corner in the river and all hell breaks loose! Drove right over a pile of boulders that were sticking out of the water! The boat got airborn I believe twice, tore the lower skeg off the motor, ruined the stainless prop, and bent the prop shaft. No tears in the boat or holes and the outboard was fine to run yet. Scared the crap out of me and the other two guys in the boat! That will wake you up int he morning!The lower unit with the bad skeg went on my fishing boat. Ironically while I was fishing this summer I wasn't paying attention and slowly drove into a rock pile, prop hit a rock, and now the prop shaft that was bent for 7 years or so is strait again!  lolSee, no skeg: