A lot of interesting observations, but I am not any closer to knowing what is happening on the top of my melt. With only a couple of tries, I have not yet found any bad things with ignoring what is happening on the surface and just drain the pot. I think I will try it a few more times and see if anything bad becomes obvious. As of right now, it seems like it is better than Marvelux, boric acid, and ordinary fluxing.
Talk to me about what forms on the top of the melt...
- Thread starter Harry O-1
- Start date
RicinYakima
High Steppes of Eastern Washington
Harry, You would not be adding tin with solder, by any chance. Like the resin or acid core stuff?
Yakima: No resin or acid core solder directly into the pot. I did have a lot of that stuff and smelted it outside with an old pot (not the one I am currently using for casting). It was pretty ugly, but after the melt was cleaned up, it works well. I cast it into 0.690" round balls to make it easy to add to the mixture. When I run out of the solder, I have about 15lbs of solid 50-50 solder bars and after that, a few pounds of pure tin. I will undoubtedly be casting them into balls, too.
Rick: My experience with Marvelux and boric acid is that they are quite a bit different in action, but both fall short of what I am looking for. The Marvelux worked much like beeswax for fluxing, but without any smoke. It was easy to break up and scoop out when done fluxing. The boric acid does nothing for fluxing. It starts as a powder, but melts into a form of glass to protect the top of the melt. It is easy to stick something into the melt, twist it, and take out most of the molten glass when it is time to recharge the pot.
However, where the both are the same are when they stick to the sides (and both of them do), building up layer on top of layer of insulation. Not good for running a hot pot. I have removed both from the inside of the pot with a coarse file, but it is not nice work.
Rick: My experience with Marvelux and boric acid is that they are quite a bit different in action, but both fall short of what I am looking for. The Marvelux worked much like beeswax for fluxing, but without any smoke. It was easy to break up and scoop out when done fluxing. The boric acid does nothing for fluxing. It starts as a powder, but melts into a form of glass to protect the top of the melt. It is easy to stick something into the melt, twist it, and take out most of the molten glass when it is time to recharge the pot.
However, where the both are the same are when they stick to the sides (and both of them do), building up layer on top of layer of insulation. Not good for running a hot pot. I have removed both from the inside of the pot with a coarse file, but it is not nice work.
Don't take my word for it, here is a cut & paste from the book "From Ingot To Target" by Glen E. Fryxell. Chapter 4, Fluxing.
From Ingot To Target
Some of the commercial fluxes on the market today contain boric acid, borax, or other borate containing materials (e.g. Marvelux). These materials are fluxes in the true definition of the term since they melt to form a borate glass which entrains any oxidized materials and extracts these contaminants into the molten glass phase. These fluxes have the significant advantage of being smoke-free and odorless. They are also extremely effective at removing contaminants. This is because the borate anion binds all metal cations and extracts them into the molten borate glass. Unfortunately, this includes any oxidized tin, and so the alloy is depleted of this valuable component. The borate fluxes do nothing to reduce the oxidized tin, nor do they protect the melt from further oxidation. You’ll note that this behavior is exactly opposite to that of the waxes, described above.
Underlining is mine. In addition (not mentioned here) is that the borax is extremely hydroscopic. Anything that comes into contact with it will suck up moisture (including humidity in the air) like a sponge. Anyone wishing to use it should use extreme caution when placing spoons, ladles etc. back into the melt.
Edit to add: No, borax does not work like beeswax or any other wax when fluxing. I highly recommend reading the entire chapter. Actually I highly recommend reading the entire book but this thread is on fluxing and what forms on top of the melt. The link is in this post.
From Ingot To Target
Some of the commercial fluxes on the market today contain boric acid, borax, or other borate containing materials (e.g. Marvelux). These materials are fluxes in the true definition of the term since they melt to form a borate glass which entrains any oxidized materials and extracts these contaminants into the molten glass phase. These fluxes have the significant advantage of being smoke-free and odorless. They are also extremely effective at removing contaminants. This is because the borate anion binds all metal cations and extracts them into the molten borate glass. Unfortunately, this includes any oxidized tin, and so the alloy is depleted of this valuable component. The borate fluxes do nothing to reduce the oxidized tin, nor do they protect the melt from further oxidation. You’ll note that this behavior is exactly opposite to that of the waxes, described above.
Underlining is mine. In addition (not mentioned here) is that the borax is extremely hydroscopic. Anything that comes into contact with it will suck up moisture (including humidity in the air) like a sponge. Anyone wishing to use it should use extreme caution when placing spoons, ladles etc. back into the melt.
Edit to add: No, borax does not work like beeswax or any other wax when fluxing. I highly recommend reading the entire chapter. Actually I highly recommend reading the entire book but this thread is on fluxing and what forms on top of the melt. The link is in this post.
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Yeah, decades ago I also used it. Used it for several years in fact, why did I use it? Because at the time I didn't know any better. Not only the rust but it would take a stiff round wire brush on a drill motor to grind the stuff out of the pot. Was so bad one time I considered throwing away the Pro-Melt rather than deal with it but I eventually got it out.
Aside from all that and the rust it DOES remove tin from your melt. Use it if ya like it but I learned my lesson. The hard way.
Warren4570
Active Member
Initially i was getting some blackish crap floating around as well.. fluxed using candle wax or beeswax lighting it up once it smoked. I too will use a section of hardwood dowel or bamboo to stir .... maybe only the first third of the melt... and will clean the valve rod and scrape sides with a stainless spoon. It all worked well but then I decided to really clean to pot out .... drained it ... lapped the valve in the bottom the the spout for better fit ... wiped it out with isopropanol... the ran a brass wire wheel the diameter of the pot through ot with my drill... cleaned again with Iso and blew/wiped the dust out.
Seems to be much better now... mind you that was out of a new lee 20 and it was probably production oils and rust prevention products in the pot cooking out.
It's much better now
And yes Glen's ingot to target is a great solid read.
Seems to be much better now... mind you that was out of a new lee 20 and it was probably production oils and rust prevention products in the pot cooking out.
It's much better now
And yes Glen's ingot to target is a great solid read.
Warren4570
Active Member
Still doesn't answer the original post but
Another thing I noticed too
Melted some culls that I rejected after lubing, back in the pot and got some heavy blackish scum on the surface .. some had the carnuba red type lube and some the original felix lube recipe (love that stuff)
However in that case I believe it was the oils and possibly some of the waxes ie carnuba that were the cause of that.
Another thing I noticed too
Melted some culls that I rejected after lubing, back in the pot and got some heavy blackish scum on the surface .. some had the carnuba red type lube and some the original felix lube recipe (love that stuff)
However in that case I believe it was the oils and possibly some of the waxes ie carnuba that were the cause of that.
Ian
Notorious member
Ivory soap will make a very black scum layer. I use a lot of soap in my lubes and even FWFL will cause it if enough gets in there. It's harmless but yucky. I don't use much Carnauba Red so I can't comment on that. Carnauba wax melts/burns very clean and has a distinct, rich, sweet smell to it.
Warren4570
Active Member
That would explain what happened in one of my experiences then too