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How do I get rid of this scale on my blade?


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This is my 5th attempt at a knife shaped object. On my previous attempts Ive had a hard time grinding off all the scale. And have uneven hammer blows that really make it difficult. Any words of advice and help would be greatly appreciated! Thanks!

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A soak in vinegar will remove the scale and make finishing go a little faster. Forge scale can be hard on your files and sandpaper (while hand sanding), but if you're using a flap disk or a belt grinder it really shouldn't take much to get through without the extra step of removing it.

The hammer marks on the other hand, those are usually easiest to get rid of at the anvil with light planishing blows at a lower temperature depending on how deep they are. Otherwise you just have to grind the whole face down.

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Ditto on hammer control to minimize dings, and you should also brush your piece frequently to remove scale during forging. Once it's out of the forge, a going over the surface with a knotted wire cup brush in an angle grinder (using all appropriate safety measures!) is a good way to remove scale while preserving the forged finish if you're doing brut de forge. Otherwise, a flap disc or a grinding wheel in the angle grinder will remove any scale and the outer layer of decarburized steel and leave your blade ready for further shaping and finishing. As Frazer notes, this isn't really necessary if you're using a belt grinder.

Note that vinegar soaks do take time, while angle grinding is a lot faster. That can affect your work schedule, depending on how much time you have available.

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Another ditto on hammer control. And use a hand wire brush after taking it out of the fire and again after forging. Builds good habits.

Never forget,,, iron is cheap, learning is expensive. 

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Keep the face of the anvil clean too; brush the scale off it every time the metal goes back into the forge!

I have a friend who used to sandblast the scale off large blades.  I used to soak the piece overnight in household vinegar---the entire piece needs to be immersed or a line will etch where the air/vinegar border it.  Then wash it with a scrub brush under running water.  I use the hose bib outside.

Good fire control can help; if you are using a gaser, can you make it a bit more reducing?  (WARNING reducing means more CO is produced so VENTILATION!!!) If you are using solid fuel; are you putting too much air into the fire?  (Often a problem with electric blowers. or not deep enough fire.)

Not leaving your piece in the forge too long helps as well.  If you need to go do something take the piece out!  (Or shut down the forge.)

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36 minutes ago, anvil said:

use a hand wire brush after taking it out of the fire and again after forging. Builds good habits.

 One way to help build those habits is to keep the brush somewhere easy to reach, so you're not losing seconds to trying to find it every time. Mine hangs off my anvil stand under the horn, where I can grab it easily with my hammer hand. 

 

 

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An overnight soak in household vinegar followed by a wirebrush scrubbing should take care of the scale.

Light hammering on a semi hot blade is called planishing. It will remove some, many or all hammer marks left from forging. Planishing is done when the blade has lost it's glow and it turning black. 

An angle grinder is the fastest and worst way of removing scale and hammer marks, particularly for a beginner. It does nothing to improve your skills/technique and you might get used to using one at the expense of becoming a skilled blacksmith. 

Have a little patience, you'll get there.

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Awesome thanks to everyone for the words of wisdom! I appreciate it!!

11 hours ago, ThomasPowers said:

Good fire control can help; if you are using a gaser, can you make it a bit more reducing?  (WARNING reducing means more CO is produced so VENTILATION!!!) If you are using solid fuel; are you putting too much air into the fire?  (Often a problem with electric blowers. or not deep enough fire.)

Not leaving your piece in the forge too long helps as well.  If you need to go do something take the piece out!  (Or shut down the forge.)

I’m using a gasser but how would I reduce it? Sorry I’m new to all this. I’m using a majestic forge 2 burner. 

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Determine if it's burning lean, neutral or rich and then adjust the amount of air into the burner. I have no idea what those burners look like; Some burners have a built in adjustment, others you can vary fuel input and a lot you stick a piece of ducktape to cover a bit of the air intake.

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