Quote:
Originally Posted by artdutra04
Don't weld it.
You can get zinc poisoning from the fumes.
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Quote:
Originally Posted by DonRotolo
I repeat: Do not weld it.
...snip...
On a robot, some steel can be useful, but often it can be too heavy.
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I always cringe when new people are jumped on for spreading misinformation... but I feel that this is a time for learning as well.
You can weld galvanized steel with no issues as long as you use proper equipment. You do not get zinc poisoning from the fumes. However, you should have adequate ventilation (read as borderline too much ventilation) and proper equipment (i.e. respirator) to avoid zinc oxide irritation which is similar to an allergic reaction that results in what is known as "metal fume fever." It is greatly unpleasant and has symptoms like the common flu. Fever, chills, awful headaches, and other not so fun issues commonly arise. These symptoms will be horribly uncomfortable, but generally clear up in 6-10 hours. If zinc oxide was so bad, we probably wouldn't rub it all over our bodies every summer. Most cases of major problems from welding galvanized steel are generally related to people who develop pneumonia or already have a weak respiratory or immune system, or where a person was so engulfed in fumes that the building was evacuated for visibility issues due to burning coatings of to prep for welding operations.
If what was said above was true, then stainless steel should really never be welded because it releases chromium. And that stuff is a carcinogen, damages your kidneys, and will kill you if you are exposed to it for too long.
I'm not advocating that every team go out and use galvanized steel on their robot and weld away, but making it sound like the world will end if you do is over the top a bit. In fact, to avoid any issues that could arise, it's probably smart to try to avoid it. The discomfort you will feel if you aren't right about your ventilation isn't worth the end result. Also, in the process of burning off the zinc coating, you will contaminate your weld resulting in a weak bead when using the most common welding alloys and shielding gases.
Steel also is heavy, but you generally can use a lot less of it than aluminum. To get the same strength you need thicker or more aluminum than you would steel.
This company has a pretty good explanation of what I'm getting at. To say that you should always use aluminum is like saying you should only ever turn right in a car because it is easier. We have found that in using steel for a frame: it is stiffer, lighter or equal in weight (because we use less material), smaller in volume, and if it gets bent somehow we just bend it back.