Welding on a galvanized trailer

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I am picking up a flat boat trailer this weekend that is going to be turned into a ocean kayak trailer. The trailer is galvanized. What is the best way to remove the galvanization? Should just grinding it off be enough or should I use muratic acid?Century AC 100 stick (dead but trying to fix it)Everlast PA 160 STHhttp://www.riograndehatters.comhttp://www.texashatcleaners.com
Reply:I used to make biodiesel and the plumbing for the processor should be black pipe.  Couldn't find a ready source so used galvanized and used muriatic to remove it.  Can't remember the acid to water ratio, but the pipe was left overnite (at least 8 hours) soaking in a bath and then the pipes were rinsed.  You won't be able to do that with the trailer and you shouldn't put it on full strength either.  I tried that on a test piece and it was a very violent reaction. Originally Posted by ironmanjayI am picking up a flat boat trailer this weekend that is going to be turned into a ocean kayak trailer. The trailer is galvanized. What is the best way to remove the galvanization? Should just grinding it off be enough or should I use muratic acid?
Reply:I normally use a flap wheel disk on a grinder to clean up around the weld area.  I clean further back on galvanized steel than I do when I'm just removing mill scale.  Using muriatic acid won't hurt.  I'll be interested to see other ideas.GravelThe difference between theory and practice is that in theory there is no difference.
Reply:I spent years building galvanized marine docks. We just ground the galvanizing off with a grinder. For some reason Hobart's Fabshield 21-B gasless flux core works great for welding galvanized material.Don’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:the contractors i've worked with will generally burn it of with an O/A torch.do that out side and upwind with a fan going.after you finish welding on it, repair it with Gal-Viz hot galvinizing sticks.  nothing else really holds up in my experience.here is a weld topped with the Gal-Viz after a year of exposure to salt spray on a bridge deck in town.  good stuff!
Reply:Oh yeah, that stuff is the best!  Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:The American Galvanizers Association (AGA) claims you can weld right over hot dipped galvanizing. I've welded right over electro plated galvanizing many times with good results, but I've never been able to weld over hot dipped galvanizing. They say just turn up your heat and move slower. Allow the galvanizing to melt away before advancing. I tried it but got very porous welds. But maybe you'd have better luck? I was welding on a solid block of cast iron, so maybe it was just too much of a heat sink for this situation.John 3:16(2) Miller Pheonix 456(2) Millermertic 252Dynasty 210DXHobart 210MVPDoringer D350 SA Cold SawScotchman 350LT Cold SawWebb 10x50 MillWebb 15x40 LatheGeka Bendicrop Ironworker
Reply:I repair a lot of cracks in Valmont center pivot irrigation eqipment, Usually a crack next to a bracket thats fillet welded to a 12 ga pipe then hot dipped. I normally use 1/8" 6011C at around 105-115 amps and it burns right in, a quick brush pass then a good fill pass on top of that. Usually very minimal disturbance of the galvanizing too.Last edited by 12V71; 05-23-2014 at 03:34 PM.Reason: Forgot rod size... Duh
Reply:Thanks for the replies! I guess I'll grind it off then follow with a MA wash to clean it. I don't want to take any chances with the fumes. I have a welding respirator and there is a lot of wind down here in Deep South Texas.Century AC 100 stick (dead but trying to fix it)Everlast PA 160 STHhttp://www.riograndehatters.comhttp://www.texashatcleaners.com
Reply:Welding galvanize never bothered me too much, cutting it with a torch would make me sick as a dog. But fine the next day. Just set up a small fan to blow the smoke away from you, and you'll be good to go.Don’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Originally Posted by ironmanjayI am picking up a flat boat trailer this weekend that is going to be turned into a ocean kayak trailer. The trailer is galvanized. What is the best way to remove the galvanization? Should just grinding it off be enough or should I use muratic acid?
Reply:Just for hot dipped galvy I keep a few of the grinding discs designed for aluminum on hand. They won't last long if you go leaning on them on steel but they work great for the hot dipped galvy. Don't clog up near as bad.Again that's just for the hot dipped. Eletro-plate or one of the chromates just about anything works. Nothing there to start with."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Hello ironmanjay, use some WD-40 on your grinding disc/flap wheels/sanding pads, they won't load up nearly so bad, just a quick spray of the wheel after you have triggered the grinder to get the wheel spinning,spray directly onto the contact surface of the wheel. As to the fumes: good ventilation and if you have it available, a good respirator. If you ever get a good dose of the fumes/smoke from working/welding/cutting on galvanized you'll know that it can't be good for you. Good luck and best regards, Allanaevald
Reply:I don't even bother to take it off. I just run the rod ahead slowly, but not welding, for about an inch and drop back and weld until it's close and run up another inch. It's always worked fine for me and I don't have any prep work to slow me down.
Reply:I tested a "new" (to me anyway) method of measuring and fish-mouthing some 2 7/8" diameter galvanized pipe this morning.   Then I welded the pieces all up.   I used Lincoln 5P and my buzzbox (DC+) and burned that galvanized $h!+ away.  The welds didn't look half bad (my own crappy standards as I SUCK at welding small pipe).  I do notice that when I weld through zinc galvanized (I do it a lot because I can get so much of it), that I must travel slower but fast enough not to burn through the parent metal.  I don't hardly grind off the galvanized zinc anymore either, because it just takes too long for what I need to do with certain projects.    I do though as others have mentioned, wear a weldor's "pancake" filtered respirator, stand "up-wind" and use a fan (sometimes) to "suck" away the smoke plume.   I only use a fan if I'm going to be welding a lot of galvanized metal, rather than just a few beads here and there.Lincoln Power Mig 216Lincoln AC/DC-225/125Miller  625 X-Treme PlasmaMiller 211 Forney 95FI-A 301HF 91110Victor Journeyman O/PMilwaukee DaytonMakita  Baileigh NRA Life Member
Reply:Just get a decent respirator and weld through it.  If working with 3M products the pink pancake ones don't filter fumes you want the white charcoal units.
Reply:Originally Posted by 76GMC1500Just get a decent respirator and weld through it.  If working with 3M products the pink pancake ones don't filter fumes you want the white charcoal units.