I'd like to use some 15% phos copper shot to de-oxidize pure copper scrap and would like to know what dosage is used commercially for this purpose. Apparently it works by forming phosphorous pentoxide the gets skimmed off in the slag and leaves very little phosphorous behind in the metal: 0.02% for C12200 copper. For a recent melt I used 20 grams of phos copper shot into 10Kg for 0.2% dosage and ended up with a fluid copper that poured some successful castings. I later realized that I should have had some way to plunge the phos copper into the melt rather that pelt it at the surface where it instantly melted and probably had less effect. So I'd appreciate any advice about using the stuff especially with pure copper. I understand too much will cause porosity in castings.
I have used 15% phos copper shot many times and added it to the surface of the metal and it works well. When I melted fine copper wire a lot more than usual had to be added because fine copper wire oxidizes badly. The copper was used to make tin bronze. If you are pouring high conductivity castings 15% phos copper shot is a bad choice as even in small amounts it lowers the conductivity. I think boron is used instead. A long time ago I was given some railway bearing bushes to make more bushes and the result was a real mess. These bushes are made from phos bronze and will seep into the sand a long way just like water will seep into sand.
Belmont has everything you will need https://www.belmontmetals.com/product-category/deoxidizers-and-degasifiers/
I was also melting scrap wire so it was getting that oxidation effect so I consolidated it into a lump with a steel bar to help it melt. There's no doubt it needed the deoxidizing I'd read that phosphorous deoxidized copper C12200 is 85% the conductivity of oxygen free copper but fortunately I'm not using it for electrical purposes. I'd heard that bushes made with high phosphor content are made porous to retain oil for lubrication. Thanks I had a look at their datasheet but could not find much info about ballpark dosage. Tonight I was able to get hold of a copy of Foseco's Foundryman's Manual 9th edition" and found a page on deoxidizing copper where they pour some test slugs and look for relative contraction on cooling. I did get some contraction on the casting feeder so it looks like it was successfully deoxidized but still could have been over dosed.
Mark, here is another place to get phos copper C.I.G sells 20% phos copper brazing rod. I was given some rods years ago so I would mark it with a texta to the length which was the amount I needed to add. I just plunged it in to the melt. In the end I ran out of those rods and got a decent amount of phos copper shot from a foundry closing down sale.
I'll definitely keep an eye out for the brazing rods in case I find some for a good price. I was able to get a kilo of 15% shot from a foundry metals merchant at a good price and had to drown it in paraffin to keep moisture from it.
your dose for degasser per navy foundry manual page 260 2 ounce of 15 percent Phos copper /100lbs of melt V/r HT1
I have a copy of that manual, it's time I started to actually read it.... So if I work that dosage back into metric I should have used 12.35 grams for 10 kilos of copper instead of the 20 grams I did use (60% overdose). At least I was in the ballpark dosage and tossing it on top of the melt instead of plunging probably vaporized some too. For my non electrical purposes that should be fine.
I recently bought some foundry items that came from a school. Included were some various fluxes. Phosphor copper shot. Instructions on the box.
A little bigger image and an online OCR: COPPER DEOXIDIZER - E-102 PHOSPHOR COPPER SHOT USED FOR TIN BRONZE AND COPPER Used at end of melt, after drawing crucible from furnace, just prior to the pouring. Plunge to bottom of melt. Deoxidizer for all copper and copper alloys. Removes oxygen oxides and increases fluidity of melt. One ounce treats one hundred pound melt. A number 50 crucible holds 150 lbs of copper or brass. (Crucible size x3). KEEP DRY TO PREVENT THE POSSIBILITY OF AN EXPLOSION! https://www.onlineocr.net/ (got it about 95% correct)
I sectioned the sprue and parts of the runner for analysis, the sprue is 1" dia. and 3" deep, the runner is 1.25" wide and 0.5" deep. The shrink hole in the sprue is 70mm/2.75" deep, the copper either side of it has shrink defects but the end at the bottom and the runner is sound where I cut it off the casting and then sanded it smooth to look for defects.
