I have had a serious run of work where every thing has been coated in galvanizing. I tell you if a person needs to appreciate the simpler things in life, like clean steel spend a couple weeks working on that stuff. After grinding and heating with the torch to remove it it still welds like s&%$. What I have found though is it sure has improved my skills as far as welding on clean mild steel as the puddle is just that much easyer to see and it seems as there is all kinds of time to blend in the edges on the uphand verticles. What I was wondering though is apart from grinding it or melting it off with a torch does anyone know of any other method for removeing it from the weld area. I found a root pass with 6010 help to burn alot of it out but still feel that the contamination to the weld was still there. Is there any written procedures for working with it ? What would be the long term affects to the weld haveing been contaminated with it? As I am sure it won't be the last time I have to look at the stuff How does it relate as far as code is conserned?
The long term effect I would worry the most about is YOUR HEALTH from inhaling the fumes. It is probably not practical for the job You were doing, but the zink can be eaten off with acid, viniger wil do it slowly, muriatic quickly.
if you are in d1.1 or aisc be careful with filler metal strength,as far as any hints, avoid at all cost. grinding is bad for your lungs,burning it out is bad for your nervous system.
what is it that you're welding. is it maintenance? ive found a long arc 6010 gets rid of most of it on structural. but depending on what your welding it may not be an option. i find when i try to grind it away that if i push it away from the weld it seems to be a bit better but it is so "slippery" that there is always some left over. would be nice to know if any one does have a better way of getting rid of zinc. also is there any sort of non destructive testing on the weld. i would be interested in how that would come out.
darren
Hello darren, a while back I posted a "tricks of the trade" on grinding galvanized prior to welding, you could do a search for this one or I suggest using WD 40 on the grinding wheel while grinding, it will help to prevent the loading of the wheel. Truly, grinding the coating off is the only real way to not have an issue with it. I feel your pain as well as anyone elses when having to weld on parts that have already been galvanized. Regards, Allan
All work was done for structural purposes and as far as I know they are not doing any type of NDT. The health thing is always a concern Dave I always wear a full face resperator when grinding welding etc.
For respirators, what do you use that fits under your shield? I've been using a disposable respirator by 3M #8514. Just looking for any alternatives, because our cartridge type respirators will not fit under the shield.
Hello John, I have a respirator that I use when I'm welding on galvanized, I don't have it handy right now to see who the manufacturer is or the model number of it, but it is an under-hood model that has hoses that go up over each side of your head and the cartridges attach to the ends and you thread your belt through them to hold them in place behind your back. The great thing about this set-up is that you are drawing the air from behind you and not at the point of the source. Regards, Allan
Hello again John, I was on the North website and located a couple of items that you might want to check out. They list a 7700 series half-mask that can be fitted with a BP1002 backpack adapter, this is the type of respirator I was talking about in my first response. You should be able to get the cartridges for this that would best protect against zinc fumes. Good luck. Allan
Thanks for digging into that for me, I'll have to look it up and get some more info to pass on to the higher ups here. I like for our people to be well protected.
I love choking and feeling lik shi** at the end of the day..............
John I use the same kind that Allan has mentioned douple hose that go over the shoulder and the cartridges hang on your back. Mine is made by "North-Model# 7700-30L" they come in small,medium and large so as you can imagine they are not one size fits all. I belief 3M also makes a similiar unit. The north is a comfortable piece of gear to wear. Have not worn the 3M so cannot comment on it's comfort. hope that helps.
By dschlotz 
Date 07-27-2007 11:19
Edited 08-29-2007 11:25
We do a lot of galvanized plate welding. With hot dipped we chip off the surface with a flat sharp chisel and grind with Flexovit honeycomb wheels. Galvanized pipe like for handrail we do no prep other than cut and fit. We weld plate with E71T-8. We weld handrail pipe and up to 1/8" plate with E71T-GS. Both are a little challenging compared to uncoated steel. The galvi handrail is very easy and the weld is beautiful, almost no clean up. We run the E71T-GS .035 at 130 Amps 20 volts.
If you want more particulars email me.
Dennis
By cwf07
Date 07-30-2007 00:44
Edited 07-30-2007 00:51
I know about the bad galvanizing if you inhale too much you get too feeling like you got the flu , I weld alot of galvanizing on bridges. I used the respirator mask but on the hot days it feels like you can't catch your breath, so I got a Hornell hood & respirator pack it works alot better but its takes a little bit to get use too with the pack on your back but it filters out all the smoke. and on welding it I just cut the heat up a little and burn threw it. 6010 works the best for me but here in ga. the DOT want let us welder use but a 7018.
