This idea was starting to merit it's own thread given Rob, Philip, and Dave's contributions. So as not to derail Will's question/discussion I moved it over here.
Casting aluminum can be done cheaply. I've cast random blobs using soup cans for crucibles, a wash tub filled with clay insulation, a leaf blower and lump charcoal. backyardmetalcasting.com has a wealth of information including designs. Propane and air work well, oil and forced air work well too but have a tendency to make smoke during startup and if they blow out. I have a set of needle drills I bought from hobby lobby for $15 so we could make our own propane burner. People have reported decent results using MIG gas tips for oil burners. Getting greensand shouldn't be too hard. We can buy petrobond stuff or make a few(10-15) pounds of wet sand while we test the waters. This will definitely need to be done out of doors. We will also need to put down -dry- sand around the furnace and pouring area. In the event of a spill hot aluminum can cause explosive spalling of concrete sending concrete fragments and molten aluminum in every direction, a bad thing(TM). As Dave pointed out clay and especially graphite crucibles require specific care if we want them to last. You need to bake out the moisture immediately before each use and ensure they cool slowly in the furnace.Not filling them during the initial melt stages allows the aluminum to shift and expand without stressing them. Lastly handle them with care to avoid breakage. The best kinds of aluminum to cast are extruded items like lawn chairs, car rims, window frames, sliding doors, etc. Beverage cans work well enough for art pieces and learning to cast but those allows are optimized for cold working and forming into cans. The lid and body are actually two different allows. Using Steel for crucibles and ingot forms is ok, but it's best kept in mind that a portion of the iron does dissolve into the aluminum slowly changing it's properties. As does sand casting except silicon instead of iron, so if the end use has tight mechanical tolerances it's best to use the least handled material possible. Chips are nice if that's all you can get but their high surface area means you get more dross in the melt even if you don't add them to an empty crucible. The bigger the starting material the less dross and losses to adsorption you'll get. I've got a few of the Gingery and Lindsay Books on aluminum casting I'll bring to tonight's meeting so you can look them over Philip. As a side note, why not just use steel plate machined to shape for your triggers? Should be something do able with a bandsaw and some creative dremeling. regards, Andrew L On Tue, May 27, 2014 at 4:05 PM, dave walton <walton.d...@gmail.com> wrote: > We have a local source of mixed aluminum shavings (several alloys - mostly > 6061) coming from a CNC machine for ~$0.50/lb. They tend to still be a bit > damp from the spray jets. You have to dry them, then add to an existing > pool of molten aluminum. They will oxidize and turn to dust if you try > heating them on their own. > I can hook you up with our source, but I suspect you can find something > closer. > > > On Tue, May 27, 2014 at 1:32 PM, Philip P. Patnode <ppatn...@gmail.com>wrote: > >> Rob, >> >> A 10min search on The Google using the search term "aluminum casting" >> resulted in many videos showing how to do it easily and cheaply. >> >> One tutorial showed it could be done using two steel cans, a hair dryer >> set on "cold", and charcoal briquettes. >> >> No need to have a class - just look at the videos and try some >> experiments in your backyard. >> >> BTW, how much aluminum do you have in you horde? Any square or circular >> tubing? I might be interested in buying some of it from you. >> >> Philip >> >> >> On Tue, May 27, 2014 at 1:17 PM, Robert Rybicki <rob...@robertrybicki.com >> > wrote: >> >>> Using oil sounds neato! I for one would be very interested in learning >>> how to do this. Maybe we can have a class or something? I have aluminum I >>> have been hoarding away. >>> >>> Rob >>> >>> Sent from my iPhone >>> >>> On May 27, 2014, at 6:46 AM, dave walton <walton.d...@gmail.com> wrote: >>> >>> We use regular old propane at Maker's Alliance. Works fine. >>> Any extra gets poured into muffin tins from Walmart for easy melting >>> next time. >>> We have used crucibles as a container for melting, but they break after >>> a few uses and if you don't watch the heat, they melt too. >>> Cast iron works okay - preferably old thick stuff. Not cheap Chinese >>> imports. >>> I've read about groups using waste oil and waste vegetable oil as a fuel >>> source. They recommend using a siphon nozzle: >>> http://www.amazon.com/Delavan-Siphon-Nozzle-30609-30609-9/dp/B00EO5IE3C >>> If you go that route you will need an adapter - Delavan 17147 or 17136 , >>> some plumbing, and an air source. >>> >>> >>> >>> On Tue, May 27, 2014 at 9:03 AM, Devin Wolfe < >>> de...@midnight30products.com> wrote: >>> >>>> Not effectively. We would need a oxy-acetylene, MAP, or a Oxy-propane >>>> torch set up. Then we would need sand for mold making, and we would have to >>>> make some mold boxes. If your making small parts you can use MAP gas from >>>> the hardware store, but if the parts get bigger, or you want to make a lot >>>> of them, it is far more cost effective to buy big bottles of oxy-acetylene >>>> or oxy-propane. >>>> On May 27, 2014 8:44 AM, "Philip P. Patnode" <ppatn...@gmail.com> >>>> wrote: >>>> >>>>> Related, but off on a tangent here - >>>>> >>>>> Does SH have the equipment to make small aluminum castings, not larger >>>>> than say 4in x 4in x 4in ? >>>>> >>>>> >>>>>
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