to Brush or not to brush

[Francis Trez Cole]

I pose the question Why do you use a wire brush in the forging process?

[Steve Shimanek]

To reduce scale?

[Sheltowee]

Exactly, and when punching or chiseling the scale can obscure your lines or due to texture cause an errant line to be made. Crusty ole Carbon.

[billyO]

To reduce scale?

 

Exactly.  Scale will leave pockmarks in your work as you hammer the scale into the soft, hot metal. 

[BlackKnight0739]

To get rid of the oxides (scale) and prevent inclusions; the oxides are harder than the metal being forged (and not just because they are cooler either) and can seriously mess with my work.

 

So the short answer is because I appreciate the technical aspect of it and not just the aesthetics lol

[Ric Furrer]

not always wire brush..though a twisted cup brush on an angle grinder does remove most of the scale faster than you can with a hand brush.

With some die work one can plan so an upsetting blow or two causes most of the scale to fall on its own. On longer pieces one can simply bend it by bouncing on the floor or in a big swing and slam on the anvil...the resulting bending will cause most of the scale of fall.

I am sure we have all seen this when twisting a bar..most all the thick scale falls off.

 

Scale can add to the texture of a bar, but it will not do you favors when die forming or if the work requires grinding later. On some work I have to allow for up to a light 1/8" of overage to guarantee cleanup and get below any decarb.

 

Thee are some good forge coatings out there that prevent scale and add lubricant to the forging. An article here shows some of the benefit:

http://www.forgemag.com/articles/print/84248-protective-coatings-increase-material-yield-and-reduce-costs

 

Ric

[Francis Trez Cole]

I have seen a few smiths never pick up a brush. First is waste time and heat. As soon as you hit a piece of metal from the fire the scale flies off. Second any scale on the bottom side of the work will just pulverize and become a dust. Third Looking back at old blacksmithing books never mention using a wire brush in the forging process to remove scale.

[anvil]

interesting no one has mentioned that the simple act of wire brushing by hand develops a very silky, matte appearing finish. that's my primary reason, beyond scale removal for hand wire brushing at around a red temp. this is particularly effective during my finishing heats.

I also use a farriers rasp with the end rounded and sharpened to aid both finish texture and scale removal.

[Daniel S]

I use it to remove scale and keep the piece smooth as I forge.  Some of the first advise that I ever got from an experienced smith was that it can make the difference between something people will buy or not buy.  I also use it to clean off my anvil as I'm forging for the same reason.

[george m.]

It depends on what I am making.  If it is something that will have a black "natural" surface I generally don't brush.  If I intend a smooth or polished surface I am scrupulous about brushing off scale.  Sometimes I brush and not brush on different parts of the same piece.

[HWooldridge]

I used to brush between heats but eventually stopped because I felt it was a waste of heat and time.  If the stock is above scale temperature, the scale will continue to form as the piece is worked.  It may be worthwhile brushing below a scale heat if you want a shiny scale finish but just as easy to sand blast the surface when the piece is cool.

 

I'm sure most folks have seen large industrial forgings that are worked under a hammer or press; the scale continues to pop off every time the piece is struck or pressed.  As Ric stated, a substantial allowance for material loss due to scale must be made by the manufacturer if the part has to be produced to a specific dimension.

[jeremy k]

wire brushing can be good in some cases - although if forging at the right temp you are below scaling but can still forge what you need with out the need for a brush.

[bigfootnampa]

Personally I do not mind a bit of scale on my work.  I DO dislike having big chunks of coal clinging to the work surfaces as I bring it to the anvil though!  I often have to scrape that off.  I usually do just forge through the scale and rarely encounter any problems with that practice.  I think that gas forges tend to produce more scale... I use a coal forge.

[rockstar.esq]

I watched a bladesmith doing a demonstration where he dipped his hammer into a water bucket and wet down his anvil before bringing the stock out of the forge.  The first hit made a loud pop that blew the scale off the work.

 

It seemed to work for him but I'm not sure it's really applicable for operations beyond thin flat stock.

[Francis Trez Cole]

Personally I do not mind a bit of scale on my work.  I DO dislike having big chunks of coal clinging to the work surfaces as I bring it to the anvil

Bigfootnampa if you have coal sticking to you metal it is in the conversion stage from green coal to coke. and the tars and impurities are what are causing the coal to stick to your metal.

Rockstar I have seen that my self Japanese sword makes use that method to refine there blades 5 minutes in the forge can save you a half hour with the file

[TechnicusJoe]

I hardly use to brush, now that I have a good brush, for me, it makes a noticable difference. Though, it has to be a good brush.

What is a good brush? Not a wire brush, brushing with a wire brush to remove scale, hot just before forging, is a waste of time as it won't remove a lot.
A good one is a farrier's brush or a butcher's block brush, with those (spring steel I have heard?) flat "wires".
These remove a lot in one stroke. The scale and dirt from the fire is gone, won't get forged into the surface and you can see your material a lot better while forging. Thus your forging gets cleaner.

For example, look at the farrier's, good farriers brush before forging to get a good view at what they are forging. And it keeps the material clean(er) than

if it were taken straight out of fire.

In short: if you have a good brush. Yes, brush.
If you don't have a good brush and only like a wire brush, I won't bother because it doesn't work good enough for me to spend time on and lose heat.

My 2 cents.

[Frank Turley]

The last few heats on a piece can be at a low cherry to blood to near black with the worker running the hammer over the piece with light blows. He or she leaves a small finishing allowance. Water on the anvil is an old aid to help pop scale by thermal shock. I was taught to use water on the anvil with a wet flatter, but a wet hammer on a wet anvil works well. I've heard that the Japanese call it "washing the blade." In the olden days, they didn't have wire brushes nor is it likely they hot rasped, this latter observed by Peter Ross. One way to use scale and its absence to advantage is to make a center punch mark that you wish to find at a bright free-scaling heat. The hot piece can be wiped on the edge of the anvil or a straight edge can be moved across the face of the work. This removes scale except for the little dark spot within your center punch mark.

[arkie]

<snip>.... One way to use scale and its absence to advantage is to make a center punch mark that you wish to find at a bright free-scaling heat. The hot piece can be wiped on the edge of the anvil or a straight edge can be moved across the face of the work. This removes scale except for the little dark spot within your center punch mark.

 

Frank, that is a great tip.  Thanks for mentioning it.  :)

 

I'm always losing my punch marks at yellow and orange heat and have to wait until the piece goes to red to see it, then the piece is almost too cool to work.  Will try it tomorrow!! 

[Pat Roy]

I agree with Technicus Joe on the butcher block brush and thank you Frank Turley for the tip.

[Francis Trez Cole]

Joe I use both brushes they sit on a hook in the shop. I use them to brush the scale off my anvil.

I have taken a class with Peter Ross he rarely ever uses a wire brush.

I have also worked with smiths who brush 5-6 times every time they take metal out of the fire.

the effort and results becomes obvious when you see the work being preformed.

Jeremy So true Keeping you metal in the proper place in the fire to reducing oxidizing in the first place.

Frank thank your for you insite.

[SReynolds]

Lets see your wire brush

 

LOL

[SJS]

I have been rereading some of my BS library, and in "Just An Idea" by L. H. Stanley, there are several notes about wire brushing the work to produce clean high quality finished work, he also mentions scale adding to the clinker. and I notice that a lot of the guys doing hand made hammers and forged to finished tools spend some time with the wire brush to get the best finish.  I think like a lot of "good" ideas it doesn't seem absolutely necessary, but that if you develop the discipline you production rate may go down but the finish and the appeal of your work will go up. I wire brush some, and would like to be more disciplined about using the technique to improve the finished texture of my work.  When I first started forging my best friend taught me I should ring the anvil ever second or third hit...  It didn't seem necessary and I lost the habit, now I am older and it seems to make life easier on my hammer arm??? Good practice in principle for most people, but may not be profitable, or palatable to their temperament to some other people???

 

I find if I try and work too many pieces in the gas forge, and so I have to crank down the pressure, then I tend to get a more tenacious scale which I really have to work to get rid of and not mark up my surface too badly. But I like to stay busy;-)

[FieryFurnace]

I have seen a few smiths never pick up a brush. First is waste time and heat. As soon as you hit a piece of metal from the fire the scale flies off. Second any scale on the bottom side of the work will just pulverize and become a dust. Third Looking back at old blacksmithing books never mention using a wire brush in the forging process to remove scale.

 

 

I'm coming in late in the conversation, but try grinding and polishing a hammer that was forged without brushing and one that has been made with brushing. 

 

I've done both, and I always brush. 

 

In normal, every day forging operations, I'll brush at the end or maybe on the last few heats. 

 

The finish on a hammer that has been brushed before forging is far better than one that was not brushed. This does not mean that one must always brush in every forging operation for the best finish. 

It just means that I, working in my shop, with my tools, obtain a better finish on hammers, when using a brush. 

[basher]

I rarely brush. just to remove slag from the fire. I do sometimes wet forge . and occasionally dip the piece in water quickly and then brush.

 steam is often used in industry to blow the scale prior to rolling.

 I tend to wire brush with a cup brush on a grinder after the forging is done.

[allessence]

I use a wire brush,  Also use a butcher block brush with the carbon steel bristles.. Also use a farriers rasp with the end ground down to a wood chisel profile.. Also use water on the anvil  and sometime use a wire brush on a grinder.. 

 

It really all depends of the operation at hand.. If doing lots of forge welding on heavier cross sections i have a tendency to use the butch brush or the rasp's chisel end to scrape off the accumulated flux after the weld is solid but before the final finish heats which if the flux was left on will create dents from the thick coatings.

 

If you take an orange heat to remove the flux it certainly comes off easier and sometimes you have to take a higher heat to remove it but at that point the wire brush works just as well.    Once removed then the wire brush is usually adequate to clean up at the end.. 

 

If making hardware (thumb latches) usually there is no reason to wire brush till the end as a clean up measure...  I have also found it really depends on the amount of metal moved during each heat and forging process.. 

 

Cleaning of the anvil can be just as important.. And this gets scraped of residue and scale as need be..