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A quick way to remove scale


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I'm not sure if any of you have ever tried this, but I've found that sand blasting works darn well at removing scale. I'm working on a project for a friend that involved a hammered finish. I have usually ground, sanded...etc the scale layer off of a piece when I was done with the forge. This isn't a great option in this case since it would remove some of the concave "defect" left from the ball peen hammer. I went at it with a soda blaster and was very disappointed with the result, but when I sand blasted it I was happy to see a nice dull finish free of scale. I'm not sure how well this would work for a piece that is to be highly polished, but it sure does remove the scale fast.


So, if you're looking for an easier way...this might be it. I'm sure a lot of folks don't have a sand blaster, but small units suitable for knives...etc) can be had at a pretty reasonable price. You can get a cheap spot blaster for about $20 and a 50# bag of blasting media for around $8. It might not be for everyone, but it's something to consider.



Have you ever thought about the life of steel? It's interesting to think that you can control the fate of a piece of metal.

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Thanks for the tip. You can also pickle it in vinegar if you don't want the blasting texture.

Ben Potter Bladesmith



It's not that I would trade my lot

Or any other man's,

Nor that I will be ashamed

Of my work torn hands-


For I have chosen the path I tread

Knowing it would be steep,

And I will take the joys thereof

And the consequences reap.

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Does the sand blaster also take off cold flux that is stuck to a billet? Scale I can deal with. Grinding the black, glass-like patches of cold flux off of billets between welds is the bane of my existence.


"It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood, who strives valiantly; who errs and comes short again and again; because there is not effort without error and shortcomings; but who does actually strive to do the deed; who knows the great enthusiasm, the great devotion, who spends himself in a worthy cause, who at the best knows in the end the triumph of high achievement and who at the worst, if he fails, at least he fails while daring greatly." -- Theodore Roosevelt


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Cold flux is just about the hardest thing to remove but aluminium oxide will get it of eventually. I know a lot of people grind clean between welds but unless I am doing something very complex or has a lot of time invested in it, I just cut, fold, reflux and weld with normal layer stuff.



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I keep a few spray bottles of water around the forge and anvil to keep parts "cool" and to spray down the face of the anvil. It does break up and remove some of the scale while forging.


I didn't have this piece laying in the puddle of flux that now resides in the bottom of my forge, but i did manage to get some the black glass like stuff on the blade in a few spots. It didn't come off as easily as the scale did, but it did come off. I'm guessing that a grinder would make faster work of it, but then you have the course scratches to file out. What I like about the media blasting is that you're left with clean metal just as it came out of the forge.


There is still plenty of trial and error with this, I'm sure, but so far it seems promising.


Mick, thanks for the tip on the glass beads. I'll give it a try.


For what it's worth, don't both with soda blasting. I soda blast a fair bit when I'm rebuilding outboard engines (a lot of aluminum parts) and started there. I created a lot of white dust, but the scale was not impressed. With "Black Diamond" blasting sand (found at Northern Tool) the scale just disappeared.

Have you ever thought about the life of steel? It's interesting to think that you can control the fate of a piece of metal.

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One thing to keep in mind is that blasting media hitting with enough force to remove scale may be embedding itself into the surface, too. A welder brought that to my attention some time ago- he hated seeing bead blasted stuff come in. Steel shot does not have the same problem. In fact, it's not as messy or sensitive to air pressure but it can rust. I don't know about the walnut shell media or the other types in use now, but the steel shot has my vote in this dry climate.


The steel shot method is also known as "shot peening" and is said to relieve some surface stress

Edited by brian458666
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