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+--- Thread: First try at melting metal (/thread-92.html)
RE: First try at melting metal - stevec - 09-16-2012
Good
RE: First try at melting metal - Rickabilly - 09-16-2012
Actually from my Blast Furnace experience, I can say that too much air is a bad thing for temperature, as in a Blast Furnace the air is preheated in stoves, if the stoves are not sufficiently heated a cold blast can freeze a blast furnace, Apparently in a coke or charcoal forge you need just enough air to react with the available surface area of red hot coals, any more air serves only to cool the furnace by dilution,
The correct process apparently is to use some form of temperature measuring device and start "Blasting" with a small flow rate of air, wait until the temp stabilizes, then slowly increase air flow until the temperature starts to drop, at this point you have a maximum air flow setting, that should not be exceeded and a rough idea of how much heat is available at what "Blast rate"
RE: First try at melting metal - stevec - 09-16-2012
If the leaf blower, which I imagine is a universal "brush" type motor, it's output could be controlled by a variable transformer or even a light dimmer switch (don't say I said that!)
RE: First try at melting metal - Rickabilly - 09-16-2012
Often the easy way to regulate flow when using a centrifugal blower is by use of a butterfly valve, as RPM vs flowrate curves are far from linear and with little back pressure just plain difficult to manage, but, with a correctly sized butterfly; a closed butterfly is closed and at half open the flow is around half of full flow and open is full flow.
Regards
Rick
RE: First try at melting metal - pamrick - 09-30-2012
I never thought of "too much" air. It does make sense though. I use a hairdryer sourced from the scrap heap. My wife determines when a dryer has outlived its usefulness and it goes to the shop to be 'repurposed'. It seems a simple slide gate would work as well.
RE: First try at melting metal - SnailPowered - 09-30-2012
I made a particle separator when I was in Jr. High using a shop vac and some PVC pipe and we used a sliding gate. It worked to the point that we were able to confidently separate some pretty closely weighted objects. I don't remember what we got down to but I was amazed at how well it worked. We stole the idea from the place that my dad worked that used big fancy versions for separating paint chips from a plastic blasting media.
RE: First try at melting metal - dallen - 09-30-2012
variac and a shop vac motor and a couple other bits will get you there up to cast iron.
http://youtu.be/Z9DeZUrj0H8
RE: First try at melting metal - sasquatch - 09-30-2012
Very good first try, i dream of having all sorts of brass castings to machine, i can think of all kinds of nice shiney things to make.
Thanks for posting this, very interesting.
RE: First try at melting metal - big job - 10-01-2012
This has been on my mind a long time, I have pails of brass swarf that I have always
wanted to put back on the shelf.
RE: First try at melting metal - SnailPowered - 10-01-2012
I have a buddy who's dad was short on ingot molds so he went to all of the local antique stores and bought up all of the cast iron cornbread molds he could find. He uses them for lead ingots but I don't see why they couldn't be used for brass as well.
