Cool tidbit. Same reason I like my leather belt drive engine lathe, it’ll slip before destroying crap. I don’t make stuff from wood if I can avoid it (hereditary metal guy) so the peach tree prunings go in the smoker.
3 Likes
Shapeways has provided aluminum printing for years. Dunno why this article is even news.
because AlSi10Mg isn’t high strength.
4 Likes
I haven’t done much metal casting, but worked over a decade as a plastic injection mold maker. I have some interest in it, as I already have a heat treat oven, but have heard home casting comes out much better if you set up some sort of centrifugal mechanism?
And vegetation contains a lot of silica, why wood working and tree cutting tools dull so quickly.
2 Likes
Depends on the detail and how thin your parts are. I worked with a guy who was making elaborate lattice butterfly wings that needed the pressure of centrifical force to get the metal all the way through. But plain old lost wax sand casting has been done for thousands of years.
2 Likes
Based on my very small amount of experience and very long familiarity with the concepts, I think your mold material (oilsand/greensand or whatever) has the most effect on the detail quality of the final piece.
Most of the goldsmiths and jewelry makers I know use a centrifugal rig, and some people I know who cast small parts do also. But once whatever you are casting is past a certain size (not expert enough to know what size that is, sorry, I’ll randomly guess half a pound of metal) you can just make a tall pouring sprue and vent riser, and the weight of the metal itself will press the gasses out of the mold. Since most of your shrinkage will occur down the center of the sprue, which will eventually be cut off and recycled, having it be heavy is also useful for keeping shrinkage from reaching the cast object.
Aluminum is really very easy to cast. Bronze is way, way harder, a quantum level harder. But don’t use my ghetto aluminum casting as any sort of model for what to do! It was an expedient way for me to quickly and cheaply make a part I couldn’t purchase, and note that I cast four hoping to get at least one I could use, and I broke a lot of the rules (including the one about not casting in the rain).
2 Likes
Maybe to do well, but I cast a bronze belt buckle open face in green sand in my basement when I was 15. Came out pretty good, I just silver soldered on a loop for the belt and a tooth to grab the hole.
3 Likes
Yeah I was mostly interested in bronze, or some other alloy applicable to knife fittings.
Real 9/1 copper/tin bronze, not the 7/3 copper/zinc brass that modern machinists and architects often incorrectly call bronze? You can do aluminum standing on your head, then. 
1 Like
Brass is excellent for that, and a lot cheaper and easier to find than real bronze-age style bronze.
Watch out for founder’s ague, in any case!
1 Like
Why don’t you mix your alloy then if it’s hard to find? Honestly, that’s what I did back then, but since I didn’t have any pure tin I just threw in some solder with the copper! It was probably 50-50 lead/tin. Metallurgy smetallurgy, I just wanted to melt some shit with a torch! At least now I know about proper ventilation when I’m casting lead fishing jigs.
1 Like
I’ll be making my own bronze, I’ve got a silicon carbide crucible that’ll hold 15 lbs, and about 50 lb of scrap copper. I’m going to buy tin pellets from Amazon unless I find a better source. I have a small fume hood and a cast iron gas blower scrounged from the breakup of DuPont’s engineering design labs, and a big ol’ ohmite variac to control the blower.
But first I need to finish sewing these hats, finish rebuilding the front porch, teach myself to weld so I can rebuild the collection cart on my tractor towed electric leaf sucker, harvest the black walnuts, split a cord of firewood… 
1 Like
1 Like
I’m familiar with the phenomena. Honestly though, welding is easy, doing it well is what’s hard. I’m not sure it’s possible to learn to do it well without working a production job. When I do small jobs I manage to finally get it right by the time I’m finished but the first part of the job looks like hell.
Have you seen the Easywelder MIG spool gun that can run off 2 car batteries? I’ve used it for many years even though now I have a buzz box I can use with a stick or hook it up to the spool gun. It does a pretty decent job on aluminum, the reason I originally got it.
1 Like
Find someone who can tutor you. @Urbanacus is absolutely right; welding isn’t that hard, doing it well is the tricky part. It helps a lot (and saves a lot of time and prevents a lot of frustration) if someone can show you not only the how-to, but also the little tricks and cheats that go with it. Most people who are good at something like to pass on their experiences; that whole master-apprentice thing didn’t just pop up out of nowhere.
Also, re list of unfinished and list of unstarted projects… don’t even ask…
1 Like
Sounds exactly like me doing historical plastering! By the time I’m done I’m an expert, then I won’t do it for a couple of years and lose the “touch”. If it’s highly visible work sometimes I go back and rip out the first bit, do it over.
Part of the reason I haven’t developed mad welding skills is that my buddy Pedro the Cruel is an expert welder and has a buzz box in his truck. He has carefully explained how to use my $20 yard sale stick welder, but I need to practice on my own now and learn the muscle skill… especially since Pedro has a lot on his plate right now, even more than me.
I’m probably unusual in that I’ve forge welded and pattern-welded with a hammer but never stick, wire or torch welded. I’m very good at plumbing and electrical soldering, too. 
1 Like
Do you mean the repair work I describe as “sculpting walls flat”? Or do you have the rarefied skill of actually floating a plaster wall over lath?
I can do it to any level of authenticity desired, including 3-coat plaster over split lath with horsehair in the browncoat. So far I have managed to avoid slaking any lime. 
My house is a hodgepodge conversion of an 18th or 19th century water-powered factory, built in large part from recycled materials, including an early 18th century house moved from elsewhere and integrated into the structure. It has every kind of plumbing and every kind of plastering that I know of. We have plaster over compressed sugar cane waste, expanded metal lath, unpapered gypsum board 2" thick, traditional 3-coat, you name it, it’s there somewhere, of highly variable quality.
This is the most randomly wandering thread in a long time!
4 Likes
Very impressive! I have an assortment of wall construction in my 3 >100 yo properties too, but when things are decayed beyond patching and skimming I end up tearing it out for drywall. I can’t be precious, these are rentals. That expanded metal is a huge PITA, if there was convection behind it, it completely rusts out, and demoing it, with the ca 1950 cement rather than plaster on it, is a bear. Another place has such thin horsehair plaster that it’s often unsalvageable. I mean all coats being 1/4" total!! Weird because the place is otherwise solidly built.
1 Like
I’m an engineer and generally a fan of designing parts with ease of manufacturability in mind, but there’s still a lot of times at my job when I’ve found 3D printing to make sense. For example, I’ve designed some parts for a medium size fleet of vehicles that could theoretically be injection-molded (requiring expensive tooling) or CNC milled (requiring a machine operator to fixture and re-position the parts multiple times), but we found that printing them from ABS was the most cost effective production method for the quantity we were dealing with.
Also, some designs such as Moog’s line of “highly integrated smart actuators” for robotics allow for assemblies that, due to internal fluid channnels that would not be possible through other techniques, are lighter and have fewer parts than a traditional actuator assembly and doesn’t require a bunch a little hydraulic lines and fittings that could leak. Fewer parts and less assembly time actually saves money.
5 Likes
