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  1. #1
    Join Date
    Feb 2012
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    templestowe
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    12

    Default Prep Work for welding Gal Steel

    I'd love to say I'm in the middle of a major project,but I don't believe I've hit the 1/2 way mark just yet.Still coming out of the ground after many years of grunt&toil.I've been carry out some extensive renovation works which has involved a s##t load of heavy steel beams.Anyways to cut to the chase the bulk of it is galvanised.So my question to the experts out there is, can I simplify the prep work for arc welding by applying say, hydrochloric acid or something of the equivalent to help strip back the gal to bare metal.Your input would be greatly appreciated.
    capt'n.

  2. #2
    Join Date
    Jan 2004
    Location
    Mackay North Qld
    Posts
    6,446

    Default

    Its pretty straight forward to skim the angle grinder over the to be welded areas and then weld.

    Etch prime over the weld and bobs your uncle.

    Given your doing lots of welding on galvanizing, I would offer a major caution.If you are in any way have any chest complaints, this stuff can can kill you.

    Asthmatics especially.If you work on it I would advise a respirator and a fume removal system or at the very least a big fan behind you to blow away the fumes.

    People will tell you tales about drinking milk , but that is BS I worked for Cyclone for a while welding gates and my lungs suffered. Stick will do well on the work , but mig is not as good.
    Be safe

    Grahame

  3. #3
    Join Date
    Feb 2012
    Location
    templestowe
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    12

    Default

    Thanks for the words of wisdom Grahame.Galvanised poisoning is right up there.I've found that the galvanising on the 100x100 posts has been pretty light on and grinds off easily but the galvanising on the 200x135 pfc's has been a lot deeper and takes a fair bit of effort to grind back to bare metal. Don't mean to sound like a dumbkoff but can you elaborate on etch prime
    capt'n

  4. #4
    Join Date
    Jan 2004
    Location
    Mackay North Qld
    Posts
    6,446

    Default

    Etch prime is a zinc rich paint which has a base which etches into the bare metal.Its about the next best thing to use other than galvanising.

    It is dearer than normal paint but as corrosion protection it is tops. I generally etch prime and then paint my steel projects. Generally I am short of time so I use spray cans.

    This explains etch primer pretty well.

    Etch Primers - what are they?

    Grahame

  5. #5
    Join Date
    Jun 2010
    Location
    Canberra
    Posts
    1,322

    Default

    My understanding is that etch primers are designed for better adhesion to "slippery" surfaces, such as the Duragal coating, but aren't by definition "zinc rich". While some may be, in my experience while most are grey, that's just a pigment rather than zinc, and don't provide the same degree of galvanic protection as a "cold gal" type product.

  6. #6
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,945

    Default

    Rather than using a grinding disc to take of the galvanising try using a very coarse sanding disc it won't clog up as quickly, especially on hot dipped galvanized items ie. boat trailers etc.
    Cold galvanising paints are more efficient, if painted on about 2mm thick (according to instructions on the can) 3mm is equal to hot dipped galvanizing.
    Kryn

  7. #7
    Join Date
    Dec 2010
    Location
    NINGI Qld Australia
    Age
    68
    Posts
    208

    Default

    Yes +1 get it all off the area to be welded and some. I would much rather have to repaint a bigger area then suffer being poisoned again. I did as an apprentice about 40 years ago before I knew the dangers and the dumb ##### tradesmen I was working under left me there to get poisoned. Gave me the Oxy set, showed me some galv steel pit covers they wanted cut and then all left the unventilated room. It's a wonder I didn't die in there. I know I was off work for a few days feeling like I was dying. Should have sued them for negligence and damages. Who knows what the long term effects are, My lungs aren't very good and I have never smoked.
    Still angry about it in case you haven't picked up on that..

    Cold galv primer seems good stuff but needs a sealer or top coat of something over it to give lasting results.
    Even after grinding or better sanding it all off it often leaves some residue from the disc so I agree too that the stick welding is the go and allows for fanning any fumes away.

    Look after yourself.

  8. #8
    Join Date
    Sep 2010
    Location
    Lebrina
    Posts
    1,910

    Default

    I am glad that many people have really hammered home the health considerations of welding galvanised products. Nobody has yet mentioned the masks that can be worn under a standard welding shield, either a disposable type or a replaceable filter type that are designed for welding fumes. For many years I welded a lot of galv product and would always use these masks. The welding process was mostly CO2 shielded mig, (the only gas for galv as far as I'm concerned). It is imperative to be clean shaven for full protection, but even with a beard, these masks do make a difference.
    Welding galv without protection WILL kill you pure and simple.

  9. #9
    Join Date
    Jul 2012
    Location
    Newcastle
    Posts
    9

    Default metal fume fever

    The health issues with gall should be taken seriously. I welded it for quite a while with out any major effect, though at the end of the day if if you took a really deep breath you could feel a tickle and i would cough. After some months i think that whatever poisions you builds up in your body and a small exposure will make you sick. Some time after the exposure (3 ,4 hours or so you go into a bad fever realy bad shivers and can't get warm. The reaction is like what you see in the movies with drug addicts who can't drugs. By morning you ar ok,ready to go to work and start all over.
    If you look up some of safety gear suppliers (protector or welding supply comp) you can find the filters you need, i think it is a P2 ?

  10. #10
    Join Date
    Sep 2010
    Location
    Lebrina
    Posts
    1,910

    Default

    Quote Originally Posted by Kevin-R View Post
    The health issues with gall should be taken seriously. I welded it for quite a while with out any major effect, though at the end of the day if if you took a really deep breath you could feel a tickle and i would cough. After some months i think that whatever poisions you builds up in your body and a small exposure will make you sick. Some time after the exposure (3 ,4 hours or so you go into a bad fever realy bad shivers and can't get warm. The reaction is like what you see in the movies with drug addicts who can't drugs.
    Ah, Metal Fume Fever, how I remember thee
    The worst of all is when welding components in a production situation where the fumes become really concentrated with lovely white fluff floating through the air. I have had reactions in the past that would make a detoxing junkie proud. Those were the days when OHS was nowhere near as well promoted and masks were an exorbitant luxury - in the eyes of the person not doing the work.
    Let us not overlook the fact that fumes in general can build up in an enclosed environment when welding other metals.
    The saying that "you never see an old boilermaker" was coined for a reason. Thankfully those days should now be behind us.

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