I did these about twenty years ago (in school.) They came out awful. I've no idea why, and no one else in class - instructor included - did either.
Why were they never cut apart? And what are they? Yes the surface finish sucks. Could have been metal temp too hot, investment not mixed correctly or organics still present and not fully burned out. I will say if you overheat investment it can cause some weird stuff.
They were some fittings I was trying to make for a computer water cooling setup - to achieve maximum noise reduction. (Twenty years ago, that meant 90+ percent home-made.) They were some kind of bronze. I think I might have added some silver. Cut apart - to look for porosity? Or cut off the sprues and pouring basin? Were I to do them now, I'd sand-cast them - in Petrobond if possible, green sand if needed. And yes, I do plan to send money to Mifco for an 8 inch thermocouple. I'm tired of guesswork when knowing is possible. Thanks.
Probably want another A4 for "trinket/silicon bronze," then. (Even if I doubt I'll be doing much that way, outside of gifts and occasional trades/sales.)
Question: was cleaning the last few days, and happened upon some silicon bronze wire/Tig rod. The stuff looked almighty copperish color. Is the regular kind like this when it is cast? If so, then I'm moving up the Lancaster money as much as I can, espeially after learning the stuff isn't near as awful to machine as I thought. (As per machinist handbook.)
Your tig wire was probably more gold when it was new. Hit it with a scotch brite pad and I bet it shines up like new. The TIG wire I've been using is a dead nuts match for the sil-bronze I've been casting. After a repair, I've polished to a high shine and you can't tell where the weld was!
I never realized how red silicon bronze is until I put an ingot of everdur (r) next to some aluminum bronze (l). The red isn't as obvious once you cut into it, but it's much less yellow than the Al bronze. Jeff
That sectioned ingot looks enough like a pre-1983 Dead-Lincoln (cent) to suit me. Does it look that way when it's cast? If so, it might be a near-Godsend for us people with breathing troubles - no fumes. Does it get sorta reddish-brown - again, like a Dead-Lincoln cent - when it sits for a year or two?
