Welding Galvanized Metals

[RABBITFISH]

I was looking for advice about getting a piece of my trailer welded. It's the rear crossmember, and it has a small section in the middle that's rusted. I am not able to find a replacement part, so I am thinking about getting the piece repaired or cut and welded with a new section or re-inforcement. Has anyone ever done this before and what were the results?

Thanks for any help..

Tommy

[clt_capt]

With proper preparation, welding galvanized steel is just loke welding other steel - with one big exception - the zinc dip is toxic nasty stuff - especially when burned during welding...

Could you cover the area in question with a section of U-Channel and bolt it on instead?

[rarhomes]

If the metal is in good condition - Weld it "no problem". You may want to spray it with cold galv. after it's been welded, it's not as good as hot dipped but it will work.

Capt Rick

[nautiduck]

Rabbit just make sure if you get it welded who ever does the work grinds off the galvinizing where the weld penetration will be. There is some rod that will burn through it but for anything structural its not worth the risk. We used alot of hot galv in our parking deck connections and it HAD to be ground off or it would be rejected meaning if there werent grind marks around the weld it was a no go. If its done right you wont have any issues. Grind the whole area near the weld and cold spray it with a good galv paint after its fixed and check the paint every couple of months.

[rarhomes]

Rabbit just make sure if you get it welded who ever does the work grinds off the galvinizing where the weld penetration will be. There is some rod that will burn through it but for anything structural its not worth the risk. We used alot of hot galv in our parking deck connections and it HAD to be ground off or it would be rejected meaning if there werent grind marks around the weld it was a no go. If its done right you wont have any issues. Grind the whole area near the weld and cold spray it with a good galv paint after its fixed and check the paint every couple of months.

We are talking about a trailer here not a gas or water pipe. The welder will burn all galv off and the weld will be just fine, no grinding nessary. Trust me.

Capt Rick

[nautiduck]

I agree for the most part welding will burn of the hot dip but if its my boat on the trailer Im not taking the chance. I wasnt talking about pipe we built the decks themselves these were plate to plate connection or slug to plate. Ive seen two 6"x6"x3/8" galv plates butt welded together without removing the galv with a weld that was passed by a CWI that when you smack it over a block the weld would fail. Im not arguing with you but inspecting welds was something I did for a living and for something thats going down the road with god knows how much of a boat on it. Grind the galv off.

[Gringo]

Oh strap an E-tec to it and the zinc will fall off on it's own...

[rarhomes]

I agree for the most part welding will burn of the hot dip but if its my boat on the trailer I'm not taking the chance. I wasn't talking about pipe we built the decks themselves these were plate to plate connection or slug to plate. Ive seen two 6"x6"x3/8" galv plates butt welded together without removing the galv with a weld that was passed by a CWI that when you smack it over a block the weld would fail. I'm not arguing with you but inspecting welds was something I did for a living and for something thats going down the road with god knows how much of a boat on it. Grind the galv off.

I don't know your qualifications, but smacking a butt welded plate over a block is not proof of chit. If it's butt welded it needs to be "V" grooved to be 100% certified. If two plates are just butt together and welded, weather it's galvanized (gound or not ground), cold rolled, aluminum, a 3 year old kid can break the weld if it's only welded one side.

I have been welding galvanized steel for nearly 40 years, I have held a 6g welding certification and I have never had a weld break because the galvanized was not ground off..

Capt Rick

[porkhunt]

mate ,ive been a sheetmetalworker/boilermaker for 20 years now and have rebuilt many trailers.cut the rusty beam off with a grinder.weld new one in using a mig welder with gasless wire as that will burn threw the gal.then spray some cold galvanising on the welds.or take the trailer down to your local sheetmetal fabricator and he would not charge to much money to fix it for you.