cleaning steel for welding

sadisticiron

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hey guys. does anyone know of anything else that strips the scale off of hot rolled and removes surface rust on cold rolled other the acid. same as with the coating on DOM
 

scottm

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I use a wire cup wheel in a hand grinder and scotchbrite for surface rust. For DOM weld zones, emory strips work well. You can clean weld zones on HR with a grinder or sanding disk, but cleaning big areas just sucks and is more trouble than its worth. Cutting Edge Mfg uses cold rolled sheet exclusively up to the max availavle thickness of .134" (sometimes you can find .156"). 3/16 and 1/4 thick steel is readily available descaled, called Hot Rolled Pickled and Oiled, abbreviated HRPO or P&O. 3/8 and larger is only available in HR, except in bar form, but then only up to about 6 inches wide.
 

BajaFand

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Find someone to sandblast it for you, or a wire wheel on a bench grinder works okay for getting HR scale off. The best thing is to try to avoid working with HR material all together, it's worth the extra money to get nice cold rolled or even pickled material. With those you can just scrub it with a Scotchbrite pad for a couple minutes then spray it off with brake cleaner or laquor thinner.
 

Dezertpilot

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I dont work in or use shop equipment but what about those belt sander dealios?
 

L&LMotorsports

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I have a 6X48 belt sander with a scocthbrite pad and it is excellent for prepping cr stuff but just does not getthe job done on the hr scale. You would need to prep with like an 80 grit 4 1/2 flap wheel first. The belt or disk sander does not work well on the scale since the hr stuff is not perfect and you will end up with low spots with scale.
 

scottm

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Cool, thanks dw - What waterjet shop do you run?
 

atomicjoe23

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Careful with sandblasting and welding. . .make sure that you are using a blasting media that will not introduce contaminants into the weld or make sure that there isn't any blasting media embedded in the base metal. . .your welds will end up contaminated and will be the starting point/catalyst for cracking and porosity. . .
 

Twisted Minis

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Careful with sandblasting and welding. . .make sure that you are using a blasting media that will not introduce contaminants into the weld or make sure that there isn't any blasting media embedded in the base metal. . .your welds will end up contaminated and will be the starting point/catalyst for cracking and porosity. . .

What would you recommend as a blasting material? I usually use a 3M Fast Strip to clean HR, but I am curious if I can start blasting small parts. I currently have aluminum oxide in the blaster. I would probably still hit it with the 3M disc after wards.
 

BajaFand

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Just out of curiosity, what happens if you dont clean DOM tubing before welding? Is it that big of a deal?

The big thing about cleaning the material before welding how good it welds when it is clean and penetration. When you leave it uncleaned there can be impurities in the scale that covers it and it will not usually weld very nice. The other thing is it's just another layer of junk you have to penetrate through before the pure material. So it can inhibit penetration.
 
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