Hector Lopez, asked us how to weld galvanized steel. Here is his question: Galvanized to Stainless Tungsten? What kind of tungsten should I use for tig welding galvanized to stainless steel?
Here are some answers that welders who are on our mailing list contributed:
Not A Good Idea:
First, it's not a good idea to tig weld galvanized steel. The galvanized layer can be removed by grinding down to the bare metal, but if you miss any, it will make the welding difficult. For mild steel to stainless, I would use 2% thoriated or ceriated electrodes. Stevel Bleile
I agree with everything already said. If you have no other option than using tig, then use the tungsten type already mentioned and ensure you are using the correct filler wire as these metals are dis-similar. I've used 309L Mo many times with no problems other than ones already mentioned - the joy of tig welding galvanized steel I'm afraid.
One further tip I offer is to use the narrowest necked ceramic you have at hand, this will reduce the amount of molten zinc that can damage your gas lens. As already said, use extraction clean as much as possible and expect a lot to have to sharpen your tungsten frequently.
Fume Fever by: Bobhdus
Galvanized coating will spit and sputter and ruin your tungsten really quick. Stick or mig is better process to use rather than choosing to tig weld galvanized steel. Remove galvanic layer when possible, but know that you just lost your corrosion protection.
Always use fume extraction and removal for any welding. Sounds weird but I always heard you should drink milk if you get a sweet taste in your mouth after welding galvanized steel. It helps reduce the effects of exposure (fume fever), but I don't if this works or not.
Welding Galvanized Metal Is Too Risky:
Galvanized metal has a coating of lead and tin when you heat that, TOXIC gases are created. You risk Metal fever, or the Zinc Shakes when you weld galvanized steel.
There are not specific symptoms but the most common ones are fever, flue like symptoms, chills, nausea, headache, fatigue, muscle aches, joint pains, shortness of breath, chest pain, and some cough.
It is also reported that
you'll get a metallic taste or a sweet taste. You also may get a dry
throat or it may feel irritated and you may get 'horse'.
If you get a more severe dose of this you might feel burning, shock, you can't pee, you may collapse, you may get convulsions, you may feel shortness of breath, and you may get yellow eyes, skin, or a rash. You may also start throwing up, have diarrhea, and get low blood pressure.
Any of the above symptoms should be treated right away by a doctor.
It is reported that that symptoms of flu should disappear in 1 or 2 days. It will take more like 4 or more days to feel a full recovery.
Welding galvanized metal is dangerous because zinc oxide is released into the air as the metal melts. Good ventilation is required. If the galvanized is not burned off prior to welding then a poor weld will be the result. I use an acetylene torch to burn off galvanized prior to welding and utilize a fan to blow away the zinc oxide fumes.