The casting ended up with a poor surface finish. I haven't worked out the main cause of this. It may be related to pouring temperature or venting.
For small things like this I think it would be interesting to try building a small electric furnace.
People I meet via the Omaha Maker Group often ask me what it is that I make. I try to avoid the “Everything” answer, popularized by Jason Uher, but it seems to be sort of the truth. Due to a renewed interest [by people who aren't me] in things that I’m making, I’m trying to do a better job of actually driving these projects to completion, and maybe even doing a slightly better job than I otherwise might. I’m also trying to do more projects that are more “grand” in scale (for example, building a power supply, instead of a really neat custom connector; Not that either of those are really grand, in the big picture). Below is one of these projects.
After lots of fiddling with desklamps and bounce cards every time I want to take a decent macro photo, I’d finally had it. I started looking into buying a ring-flash accessory for my digital camera, but found them to be alternatingly pretty expensive or in the realm of “I could build that”. So I did. Read on for the details and a few more photos.
I determined early on that I didn’t want or need a flash-tube-based solution (like the one built by Patrick), which is a reflective ring illuminated by a standard photo flash. I didn’t want to spend the money for a fancy “automatic” external flash, and didn’t want the headaches and setup associated with a cheap manual flash.
I did some initial research on running an LED illuminator on the camera’s hot-shoe trigger, but decided that it really wasn’t needed, as LEDs can just be turned on and off and don’t need to be “fired” like a xenon flash. My illuminator is powered by a simple pack of 4 AA batteries (ideally NIZN for the extra .3V).
The illuminator itself is just 8 banks of 14 (112 total) white LEDs soldered to a piece of perf-board and a connector for power. To make it run on 6 volts nicely (and to give me more input voltage range), I wired both halves of the LED array in parallel and then the two banks in series. I could have just put the banks themselves in parallel (and run the array on 3ish volts), but that would put my total current draw at over 800ma, which I opted to avoid.
I found a pretty neat online schematic designer, so I whipped up a schematic, in case you can’t picture what I’m saying:
From a physical standpoint, the LEDs are just soldered to the perfboard and surface-wired on the back side. I’m a bit embarrassed by my soldering job, so I won’t be posting any photos of that here. I cut the hole in the center of the board with a few forstner bits, and finished it out with a sanding drum in a Dremel. I plan on gluing a 58mm filter ring [generously donated by Don] to the back side of the board so that it can attach to my S5′s filter adapter. I’ll probably just Velcro the battery pack to the side of the camera, as this rig is mostly for use on a tripod.
One problem I have come across is the convergence pattern on the LEDs. At distances less than about 8″, there’s a bit of a dim spot at the center of the frame. This should be correctable with some sort of diffuser and a bit of tweaking of the LEDs angle.
As for the LEDs, they were ordered from Tayda Electronics for $8 shipped ($0.04 each, plus $2 shipping). At 3.1ish volts per bank, I’m under-volting them just a bit, but they seem plenty bright.
Below is a few more pictures of the light, plus a photo of another project, demonstrating the dim spot. More photos of the device will follow, as soon as I get it into a more final form.
Kevin was kind enough to bring down his nice crucible after I brought my furnace body in. It is just barely small enough to fit in with about 1/2″ clearance on either side.
I may try to increase this slightly, as the sides aren’t exactly perfectly circular anyway. Im just not sure how to ream it out without destroying it.
So I spent an hour or so making a tool for the upcoming alum smelting sessions. I came up with a nice set of tongs that fit right around the body of the crucible. It is just barely small enough to fit between it and the sides of the furnace, and sometimes need a bit of finageling to get it in, or out. But all in all it works pretty well.
I loaded it up with a bunch of alum scraps we have, as tightly packed as I could make them, and the tongs seem to hold it just fine.
I was finally able to get my medium size furnace moved out of the shed, and into the Makery. This was used at my previous residence to melt aluminum with a waist oil burner that was scratch built. I have a feeling that it will be converted to a propane, or propane/oil hybrid burner here at the space.
This is the inlet port that it cast right into the side. It takes a 1.5″ OD pipe and locks it into place with a small bolt tapped into the side.
A nice view of the inside, where there is a small plinth block to keep the crucible off the bottom, and the burner inlet with the venturi tip installed.
It has a chamber about 7.5″ Diameter and 8.5″ depth.
Who said bomb? Not me. Not you. Its just smoke, people.
Dave gives a great fireworks related demonstration, just in time for the 4th of July. If you ever need to send smoke signals, here’s how:
OMG doesn’t recommend you go out and do this on your own without experience and safety equipment. /disclaimer
I’ve decided to take the plunge.
Lacking basic cooking skills for much of my bachelor life, it occurs that rather than thinking of the endeavor to procure tasty food as a time consuming chore, I should think of it as an opportunity to experiment in a chemistry lab. To that end, I’ve recently fallen in love with and purchased a Sous Vide setup.
Now, I realize its not very “Maker” of me, but I did purchase (instead of make) a very precise temperature controller, the Sous Vide Magic. For this project, the maker bit is in the cooking, not the constructing of the device. So there.
The Sous Vide Magic marries up nicely to a dumb (no fancy electronics) rice cooker, in this case a $30 10 cup Black and Decker. The temp controller allows the user to set the temperature and time, then controls the electric output to the cooker to control the temperature. A highly accurate temp sensor sits in the water bath filling the cooker.
To this bath the scientist must add a vacuum sealed plastic bag. If you’re not familiar with sous vide, this should set off alarms, but never fear: we’re cooking at low temperatures for long periods of time. The plastic won’t melt. Additionally, I’m using vacuum seal-able ziploc bags, which contain no BPA to leach into my food and turn me into a woman (BPA acts as a synthetic estrogen in the body). Bases covered.
We must vacuum seal the food (sous vide is vacuum in French, so I hear) in order to both fully expose it to the water bath on all sides, and of course, the food you wish to cook is kept in the bag so as to keep it from being soggy in the water. Simple enough.
The first experiment was a simple “Patio” steak. I cooked it at 140F for 90 minutes. The steak came out medium, tender, and quite juicy, as all its original juices remained in the plastic bag. The added benefit was a minimum of mess, as I simply threw out the bag when finished. The seasoning (simple black pepper), though minimal, seemed to be amplified. In the future, I would consider cooking for even longer, as this particular cut can be gristled and this would tenderize it more. Also, I plan to buy a creme brule’ torch so I can sear the outside of the steak briefly before serving next time. Moderate success!
Next test: Sous Vide coffee. Stay tuned.