New to spruing

Discussion in 'Lost wax casting' started by LJLundgren, Jul 25, 2020.

  1. Jason

    Jason Gold

    Ya know I bought a few hundred of those little drums from BG and they work okay, but last about 1/10th as long as the dremel brand ones do. I'm thinking they aren't worth the money savings. I spend wayyy too much time changing them out every 5minutes of use. My garage floor is littered with them! I can blast through 20 of those little things in an hr. They must use some cheap rice glue to stick the abrasive to them. Whatever the stuff is, it's weak at best. If I buy a little box of 5 dremel drums in the blister pack, I'll have them for 2 months.
  2. OMM

    OMM Silver

    I agree and disagree. Experimenting with garbage is fun and cheap. The crucible at $100ish is nothing and if the fuel is nothing.... I encourage experiment on.

    I just poured my first aluminum bronze casting and it was crap. I can melt scrap copper no problem into a ingot. Copper melting so far is ok.... But, when I drop the aluminum in it seems to boil and then settle down. I find I need to pour within two or three minutes.
    Last edited: Jul 30, 2020
  3. I think the softer bronzes are around 80/100 where brass is 100/100.
    You know the phenolic glue used on abrasive wheels goes off with time and weakens?. A retired boilermaker in my home state sliced open his jugular with a 5" grinder wheel, turns out the grinder disc dated back to when he retired and years later when he gunned the grinder and the wheel exploded. He had the presence of mine to hold his hand over the wound and they had to get the emergency rescue chopper to take him to hospital. I think in Europe they are required to put an expiry date on grinder discs and wheels.
  4. Jammer

    Jammer Silver Banner Member

    OMM, It's much easier to melt the aluminum and then add copper a little at a time as you increase the temperature. The copper melts into aluminum like sugar.
    OMM likes this.
  5. rocco

    rocco Silver

    That is my experience as well. One of my very first metal casting projects was a watercooled heat sink, my intention was to embed copper tube coil inside a large block of cast aluminum. It was a total failure, I found out the hard way that copper is highly soluble in molten aluminum, the tube had completely disappeared.
  6. Peedee

    Peedee Silver

    Mark, yes we do have use by dates on disks now, I think it's a shelf life of around 5 years from manufacture.

    Agree with Jammer and Rocco, dissolve the copper into the molten Al.
  7. Petee716

    Petee716 Silver Banner Member

    I've found the same is true with sandpaper. I made the same mistake with Ace brand paper. Within 3 or 4 strokes I knew the score. On metal or wood I only buy 3M. The stuff with the poly backing is worth the money.

  8. Zapins

    Zapins Silver

    Depends on the brand/batch. The flap wheels seem to gunk up or loose effectiveness quickly. at least with drums you just switch them out and have tons of spares for the same price. I feel like I go through more drums but get more sanding done with them than flap wheels.
  9. Jason

    Jason Gold

    Zap, you do know you can refresh grinding flap wheels right? I use the corner of a brick.
    OMM likes this.
  10. LJLundgren

    LJLundgren Copper

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  11. Jason

    Jason Gold

    not seeing any date on these.. 8bucks for 5 discs. that's a deal

    unless this is it?
  12. OMM

    OMM Silver

    I just use a pedestal grinder.
  13. LJLundgren

    LJLundgren Copper

    Tried casting the piece today. I thought I had enough bronze by eyeballing it. I didn’t weight it. Aaaand I didn’t have enough. I measured the edges and it was about 1/4” but the bottom was way thicker than I thought it would be. Next time I’ll have it though.

    Attached Files:

  14. Jason

    Jason Gold

    Wax weight times 10 should keep you outta trouble. Be sure to weigh the entire completed wax.... That means sprues and cup too.
  15. Tobho Mott

    Tobho Mott Silver Banner Member

    Too bad, betcha get it next time though.

    On the bright side though, now you can just melt the whole thing down and try again instead of having to figure out how to cut that sprue off! :D


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