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Sandblasted metal and welding

G_arc

New member
Joined
Nov 7, 2025
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I keep reading that welding on sandblasted surfaces is a bad idea because the embedded silica causes porosity and weak welds. Makes sense but what I can't find a clear answer on is whether you can actually clean the sandblasted metal enough to make it weldable again, or if once it's been sandblasted it's just permanently contaminated.
Like, if I grind down the surface with a flap disc or wire wheel it really aggressively, does that get the embedded media out? or is it in there too deep to practically remove?

Also, are there blasting medias that remove rust and paint but don't cause welding issues? I've heard walnut shells and soda blasting mentioned as alternatives, but not sure if those are actually safe to weld over or if they cause their own problems

Thanks for your replies in advance
 
yeah, welding on surfaces sandblasted with silica sand is a bad idea because the embedded silica can cause significant porosity and weak welds, and this contamination is difficult to remove completely
but, the contamination isn't really permanent, bcs the affected metal can be removed, and there are alternative blasting media that are safe for surfaces that will be welded
 
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