Bent Slag Tool

I just made a new slagging tool. I have found myself needing to have the shank of my prior straight shanked slag tool more or less vertical as I pull slag out of my crucible. That is OK outside the blazing furnace. But most of my slagging is done with the crucible in the furnace as the melt proceeds. And with the furnace full-on, the heat on my gloved hand and on my body standing close to the furnace quickly becomes uncmfortable. So, I put a bend in the shank of one of my slagging tools. That (pitiful) tool was obviously made of stuck together scrap. But here are some pics.

I'd be interested to know what other folks are using.

Denis

 

You can see porositymaster's skimming tool at 2:14 in this video.



Apparently it is just a piece of flat rectangular steel bar stock.

I have copied this, as shown below, and used a fairly heavy piece of stock.
During my last iron melt, it tended to accumulate a large amount of solidified slag on it, and I think porositymaster used a steel block to strike the end of his skimmer on after each skim to break off the adhered slag.

I broke the slag off of my skimmer with a hammer after it was cooled, and the slag does not stick to the steel and will break off cleanly.

When the melt is at or near pour temperature, you can actually melt the end off of a skimming tool, which was surprising to me when it first happened since I assumed that the melting point of steel was much higher than the pour temperature of iron.

So a flat rectangular bar stock skimmer can have a new end bent on it if necessary.
I am going to grind the end of my skimmer round to conform to the interior of the crucible.
I think I am also going to shorten the foot by about 1/3 to help it pierce the slag, and maybe angle it down slightly for the same reason.

Two tools my be better; ie: a piece of straight rebar to punch through the slag and begin to break it up, and then the golf-club skimmer to pull the slag out.

I am going to lengthen my skimmer considerably, and it is about 30" long now.

I also have a piece of tempered plate glass that I use to peer into the furnace, as a heat shield, and that helps deflect the hot blast.

And I have some powdered limestone, and I am going to try that just before I begin skimming, since it is suppose to help break up the slag.
I am not sure if the limestone will attack the crucible or not.
The slag definitely corrodes the crucible.

I am going to add a piece of scrap steel next to the furnace to be used a mass to strike the skimmer on, to break off slag.

I noticed that one person (I think superdave) dips his skimmer into a bucket of water to cool it.
The skimmer would need to be dried and preheated if this is done.

And I am going to make at least there skimmers, so that if one overheats or gets clogged, I can use the others.

 

And I noticed that porositymaster's skimmer does not seem to be very long, and he does a lot of skimming, so I am guessing that his combustion air is as low as possible.

I have dialed in a 3 gal/hr flow rate, and will be adjusting the combustion air to suit that fuel flow, so hopefully that will minimize the hot air blast coming out the lid opening.

 

I am also using 3 gal per hour. [ To do so with my .75 nozzle I am using a 7-10 PSI fuel pump and about 30 pounds compressed air for atomization. I have to add only a fairly small amount of additional combustion air as the atomizing air seems to provide most of what's needed for a good burn. ] Seems like a whole lot of heat to me. I have shrunk several leather gloves due to overheating.

I have burned off the end of my skimmer. But then I just weld on a new blade. I like having a sort of cup shape to my skimmer as it seems to hold a good bit of slag and I can lift it out without dropping it (most of the time). I might try one of you "putter" shapes too. In my hands no one shape seems to do it all. I have several. For the final skimming a light thinner skimmer seems more agile.

Denis

 

I think you may be on to something there; have a range of skimmers with different functions, ie: pulling out the initial slag buildup, pulling out light slag buildups, final skim, etc.

I made up a stirring stick that consisted of a 1/2" graphite rod attached to the end of a metal rod, and I used this to stir in the ferrosilicon, since the graphite will stand up to a lot of heat.
I had a little trouble with the attachment of the graphite rod to the steel shaft, and need to work on that.

As far as leather gloves, they don't last very long in the vicinity of molten iron or the top of an operating furnace.
I have resorted to using slip-on heat shields that aluminized pads used for welding.
These add considerably more heat resistance, and save a lot of gloves.
They are similar to this item:
https://www.northerntool.com/shop/tools/product_200579799_200579799

For smaller melts, I hand-pour the iron, and I like my right hand within 4" of the crucible for good pour control.
The only way to get your gloved hand within 4" of a hot crucible is to use a metal heat shield, and so that is what I added to my pouring shank.

For large melts, I use a pouring cart, but prefer hand-pouring on the smaller melts.

 

My only skimmer is a handle of 3/4" water pipe with a 1/8" flat steel end that is shaped like an ellipse to match the inner curve of the crucible. It's designed to scrape the inside of the crucible to loosen crud on the crucible below the surface of the metal and allow it to float for skimming. It works fine to skim off the surface but is useless to scrape the crucible and looking at my friend, Pete's skimmer: it's identical 1/8" mild steel but shaped like the letter J. That allows you to keep the handle close to vertical for large radius curves and lean it over for tight radius curves at the bottom of the crucible. He has a separate skimmer for the surface of the metal.

 

Something else I thought of but forgot to mention is welding a sheet metal shield onto the shimmer shaft, right in front of where the gloved hand would go.
This works well with my pouring shank, and so I think would work well with a skimmer too.

 

Good idea, PatJ.

I have used a shield on the skimmer shaft. It is not welded on, but has a sort of bracket the I place between my lower hand and the skimmer shaft. That way, I can sue the same shield on any of the skimmers on either end (some are double ended) and as far up or down the shaft as circumstances warrant. Makes a big positive difference and super simple to make. I am hoping the bent shaft will obviate the need for such---pretty sure it will protect both my hand and my put my body back a foot or two from the open furnace. I'll still use the others, but for the heavy skimming, the bent shaft should be my go-to. I plan to pour either tomorrow or Sunday. Tell you more then.

Denis

 

Yesterday I had an opportunity to use my bent-shaft skimmer. I much prefer using it to my straight shaft skimmers. I was able to skim my crucible late in the melt (very hot furnace and iron) holding the skimmer with my bare hands since they could be off to the side, not above, the furnace. And it was possible to lift half-fist sized blobs of slag out of the crucible with it. A light straight skimmer is nice for the very final skim as it can be more easily trailed around the rim of the molten iron. But, in the future, the heavy lifting at my foundry will be done with a bent-shaft.

Denis