I MADE IT AT TECH SHOP. www.techshop.ws Lets say that you have a piece of metal that is either galvanized or has some other type of coating that you need removed in order to weld do body work with fiberglass or bondo or whatever. Here are some ways to do it .First the best and safest way to not damage the material would probubly be aircraft paint stripper but the messiest, second would be to sandblast or media blast the piece of metal, then would be to sand with an orbital sander or hand sand with a block, finally if you have alot of material to remove like bondo etc you can use what i call the "blue disk" or the "black disk" which is a nylon sponge looking attachment that goes onto a angle grinder that abrasive enough to take off a lot of hard material like bondo or fiberglass but is not abrasive enough to damage metal but can heat up thin metal and warp it.
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Step 1: Media Blasting
now it turns that this piece of m
etal is plated on one side the brown side is galvanized. the white side is some sort of other plating. now this would probably be the best way to strip the metal because you don't get the off gas of burning the galvanized blasting. however this plating is so hard to strip it that it will take a while and you do have to be patient. now we are going to continue hitting the metal with the media until it turns into a finish like in the picture above. then you know with a little cleaning with BIODEGRADABLE CLEANER you should be ready to coat with paint weld or whatever.
Step 2: Black Disk
this disk fits on a angle grinder and I believe it is made out of nylon and a abrasive resin to hold it together. this disk is pretty special because it is not abrasive enough to destroy the metal but it will destroy about everything else. now the bad part when you are working on thin metal like this 20 gauge steel it will build up heat very quickly and warp out or burn this thin steel as you can see in the picture with the darker metal. but it will make quick work of the coating and is a great thing to use to clean up a potential weld area.
Step 3: Stripping Metal With Orbital Sander
now we can also strip metal with a orbital sandbar with a 60 grit hook and sand. you can also use a d8 sandbar that will make heaven quicker work of stripping the metal. so this option is best for this 20 gauge steel. I did this panel in about 5 minutes and it turned out super clean and ready to weld or paint and no warping or damage to the metal.