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Daniel chapa

Borax/flux

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Borax melts and keeps oxygen away from the hot metal. This helps prevent a layer of oxide, commonly known as scale, from forming on the surface of the metal. It's used during forge welding, scale prevents the weld from taking. 

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When I forge in my charcoal forge I get a lot of scale. I tried scraping the metal with a stainless steel brush and this helped some but I still got quite a bit of scale. I the tried sanding the metal to a shine and then forging and using the brush and results where better but still what I thought was a lot of scale. If I use the borax will it decrease the amount of scale more?

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Yes, but just beware that when you hit a hot piece of metal covered in melted Borax, it will splatter. Be sure you're wearing an apron and eye protection. A better way to deal with scale is to get a heavy wire brush and scrap the metal hard while it's still red hot, the scale will pop off easier. And when the forging is done just keep brushing hard to keep scale formation down. If you can, invest in a good angle grinder and wire wheels for it. After the piece has cooled this can pull scale off in moments. 

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Daniel, scale build up during heating is caused by a high ratio of oxygen to fuel in the fire. Where in the fire are you placing the steel while you heat it? 

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To go along with what Brian is saying, go buy a butcher block brush with a handle.  You can get them online for like 10 bucks, and they are awesome for removing scale while forging.

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Scale is iron oxide.  It happens when oxygen combines with iron, which it does fast when it's hot.  If there is too much air blowing into the forge, it creates an oxidizing atmosphere which makes heavier scale.  If you put the steel too close to the air inlet the same thing happens.  That's what Joshua was asking.  I know

you're using a shop vac for a blower, so I suspect you're going to have too much scale no matter what.  Borax is only for forge welding.  Using it during regular forging is just going to make a mess.  

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I do put my metal like almost on top of the inlets. And yes I use the shop vac but the tuyere is horizontal with the main opening blowing outside the fire, and I have a few holes drilled facing up to blow into the fire. That's still too much?

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Apparently so.  To get a reducing fire with charcoal you need around five or six inches of charcoal between the inlets and the steel, and another inch or two on top of the steel.  The idea is to burn all the available oxygen before it gets to the steel, and to have a layer on top that keeps it from getting in that way.

Don't get me wrong, you will always have scale forming no matter what since you have to take the steel out of the fire at some point.  A deep fire with the steel near the top will lessen the amount quite a bit, though.

The more I hear about this style of forge the less I like them.  Cheap and easy, yes, but they sound more trouble than they're worth.  For charcoal a traditional side-blown fire is usually best.  There's usually a good reason something is considered traditional, after all!

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I'm glad I asked. With your guys help I realize my problem I thought putting my steel at the hottest point was best but nope that's worst. I've been putting my steel under all my charcoal, like right on top of the inlets.  I want to redesign my forge now, but I'm gonna try putting my steel more centered first 

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Thank you Alan, you understood exactly where I was going with my question and I think we found the root cause.

Daniel, before you make major mods to the forge, do some testing to see what needs to be modified. First, try simply using a bigger pile of charcoal and getting the work piece more centered as Alan suggested. If that doesn't help, make a few mods to the blower/air supply situation. You could try either a mechanical adjustment or an electrical one. The electrical one is simply using a potentiometer (dimmer switch) between the shop vac and the electrical supply. This will lower the voltage and slow down the blower. It may also burn up the shop vac! Somewhere on the forum is a thread with some suggestions on how to do this without destroying the shop vac motor, but I cannot remember where. The mechanical adjustment would be done by taking the vac hose and inserting it into the long part of a plumbing pipe Tee fitting. on the other end of the long part, put a valve (gate or ball valve). Pipe out of the valve into the tuyere. Presto, you have a way to control the air flow without messing with the electrical parts. You can increase or decrease the amount of air by operating the valve.

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I'm gonna make a DC squirrel cage blower for sure and switch to that. But I'm not ready for that yet. I have to get the vacuum fan blade and the pvc. I won't make any forge changes till I try these two things first.

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