Formaplode: Lab Notebook

Index : Summary : Background : Design : Materials : Processing
Results : Further Development : Lab Notebook : Bibliography : 3.082

Files:

Presentations in Microsoft PowerPoint format: Presentation 1, Presentation 2, Presentation 3, Presentation from April 10, 2003, Presentation from April 24, 2003,
Final Presentation - May 15, 2003 ;
Pressure Vessel Spreadsheet in Microsoft Excel and OpenOffice formats;

Images: Final Part, Large Clamps, Hemispherical Cavity 1, Inside the front door of the Magneform, The first set of parts we bought, Electromagnetic forming coils, Hemispherical Cavity 2, The Magneform Machine, and many other images, as yet unsorted.

Entries:

5/14/2003 : 5/6/2003 : 4/29/2003 : 4/24/2003 : 4/14/2003 : 4/9/2003 : 4/5/2003 : 4/3/2003 : 3/25/2003 : 3/19/2003 : 3/13/2003 : 3/11/2003 : 3/10/2003 : 3/9/2003 : 3/6/2003 : 3/4/2003 : 2/27/2003 : 2/26/2003 : 2/25/2003 : 2/24/2003 : 2/23/2003

Wednesday, May 14, 2003 : On Thurdsay, May 8, a few more workpieces were fired in free expansion, proving the new electrodes effective in preventing unwanted arcing, and post-casting processing continued on the die. Measurements were conducted on more of the samples that had already been fired, and it was calculated that some workpieces achieved true effective strains of 0.6 (60%) without failure.

On Friday, May 9, 2003, two aluminum workpieces were fired with the finished die. The "I" of the "MIT" on the inside of the die made a good impression on the workpiece, but substantial wrinkling was seen on the workpieces. Where the workpieces had contacted the die, they had picked up it's texture, demonstrating an effect called 'coining', which we had been anticipating.

On Tuesday, May 13, 2003, two aluminum and two copper workpieces were fired with die, and the addition of a vacuum pump removing the air from the die. The 0.040" thick aluminum sample filled the die almost completely, taking clear impressions of all three letters of "MIT". A 0.050" aluminum sample and the two copper samples did not come out quite as well, but show interesting results nonetheless. The electrical characteristics appear to have been consistent for all of the firings since the installation of the newest high-voltage electrode, although it appears that we are only getting 483 Joules through our system.

Tuesday, May 6, 2003 : On Wednesday, April 30, time was spent preparing the final dies for casting with bronze. At it's most strained, one of 0.32" thick samples from Tuesday's tests showed in-plane x and y component engineering strains of 0.35.

On Thursday, May 1, two more electrohydraulic tests were conducted. For these tests, a rubber pad had been placed on the platen of the laboratory press, to isolate the vessel from the press electrically, and a wire had been attached between the low-voltage electrode and the pipe plug for that electrode, to make sure that even without the grounding path of the lab press, there would still be a path for any charge left on the vessel to dissipate. However, both tests on Friday produced bright flashes and loud noises outside the vessel, indicating a larger amount of energy was being lost to arcing than before. The workpieces used in these tests were annealed sheets of 0.625" thick 5052 aluminum, and they still showed noticeable deformation, despite the loss of energy outside the pressure vessel. The deformation in these samples was very slight, however, compared to the the thinner samples tested on Tuesday.

On Tuesday, May 6, more workpieces were prepared, and plans for our final presentation and poster were discussed. A new high-voltage electrode was prepared in the Edgerton Student Shop, and the system was fired once, using a 1/16" thick annealed aluminum workpiece that had already been fired once. The firing went quietly, without the loud external arcing of the previous tests, a small spark did appear somewhere on the front of the pressure vessel during firing.The deflection of this workpiece was noticeably increased after firing, but a preliminary look at the data recorded by the LabView software indicated that much less current passed through the branch of the electrical system with our vessel than in previous tests.

Tuesday, April 29, 2003 : On Friday, April 25, we fired the magneform with our system in parallel with the work coil. We used a thin brass bridging wire (which came from Don Galler's EDM setup) Our workpiece was an 8" square of 0.021" thick 110 Copper Alloy, as received from McMaster (unannealed), which we spraypainted with a grid and labeled sample Cu-A. We photocopied the grid on the workpiece at copytech. We filled the pressure vessel with tap water, and clamped the system in the lab press to a load of 12,500 lbs. We put a Diet Coke can in the work coil of the Magneform, set the Operating Level Knob on the Magneform to "100", and fired the machine. The crushing of the can made a loud pop typical of what we've heard before, and we didn't notice any additional sounds from the pressure vessel. When we took the system apart, the copper workpiece was noticeably bulged, with a little more than 3/8" or 9mm (no accurate meaasurement was taken) deflection at the center. The bulging was not completely symmetrical. One vinyl tubing sleeve that had been added to the electrode assembly for extra insulation was burnt and distorted; the other vinyl sleeve has not been found, and was presumably blown off that electrode upon firing. Some signs of melting from an arc are visible on the electrodes, so we clearly lost some energy to that arcing.

Over the weekend, the new aluminum workpieces were annealed, and on Monday, April 28, the new copper workpieces were annealed as well. New teflon sleeves were made at the Edgerton Student Shop, which leave only a short length of each electrode exposed outside the pressure vessel. These new sleeves should increase the air gap between copper and steel on the outside of the vessel enough to eliminate arcing of the type seen on Friday.

On Tuesday, April 29, we conducted more electrohydraulic tests, and obtained measurements of the current and voltage across our system as the Magneform fires. On our last firing, on Tuesday, these measurements were recorded with LabView software, which makes the data easy to transfer into a spreadsheet for analysis. The data from the last test on Tuesday show that about 3.6 kilojoules of energy was dissipated in our system, and that the total energy discharged by the Magneform in that firing should have been about 4.7 kilojoules. Despite the new teflon sleeves, some sparking was seen outside the vessel, so the energy dissipated through our system was not dissipated entirely between the electrodes. The electrohydraulic explosion in Tuesday's test was powerful enough to stretch the workpiece (a 0.032" thick sheet of annealed 5052 aluminum) a considerable distance and rupture it.

Thursday, April 24, 2003 : It's been a long time since the last update to this notebook, and a lot has happened. More details will be filled in soon. The small capacitor bank was tested and proved to be insufficient, the Magneform was troubleshot, understood, and eventually made to work pretty well. On Friday, we plan to conduct our first electrohydraulic test with the Magneform tomorrow. Our system will be in paralell with a work coil in the Magneform, to protect the dump resistors in the Magneform. Die casting will happen next week.

Monday, April 14, 2003 : Last Thursday, Corrine delivered our 5th presentation, which was at least as long as the last one from our group. (In general, the groups seem to have more to present as the semester goes on). After the presentation, we obtained some wire to connect Dave Bono's capacitor bank to the electrodes on our pressure vessel, and all the remaining machining operations were completed, with the exception of pushing the pins into the copper electrodes.

On Monday, Corrine got two of our 5052 Aluminum workpieces into an over for annealing, and they will be ready to use tomorrow. Ike borrowed (it will be returned) a few pounds of sand from the East Campus volleyball court, and later went to the Edgerton shop to put the pins into the rods. There was some difficulty with the pins at first, but Toby was able to figure out a good way to push them in, and it turned out to be possible (though a little tricky) to assemble and disassemble to the electrode assemblies in the pressure vessel itself, which allows all parts to be removed if necessary (We had previously been concerened that once the pins were in place in the electrodes, the electrode assemblies would be impossible to remove without cutting them. Ike brought the vessel to 8-003, and carefully raised the top platen of the Carver Lab Press from 5 and 7/16" above the bottom platen to 10 and 7/8" above the bottom platen. (To make sure the top platen remained level, it was important to mark one face of the each of the eight nuts that fix the top platen in place, and to count the number of times each nut was turned)This is a little taller than the entire pressure vessel-workpiece-die system, but we may want to raise the top platen a little bit more to make it easier to move the parts of the system in and out from between the platens.

As of this writing, it seems we only need three things to be able to fire tomorrow: water (available from the tap in 8-003); a bridging wire (which we can get from Dave Bono's lab down the hall, if not elsewhere; and a workpiece, which will be done annealing before class on Tuesday.

Wednesday, April 9, 2003 : On Monday, Ike met with Dave Bono in the afternoon to work on troubleshooting the Magneform. Dave had identified an old damaged switch in the Magneform which seemed to be causing the Magneform to blow the fuse on the wall circuit, and had connected a variac to the Magneform to allow for testing the machine with lower voltages so that the problematic components could be more easily identified. The bad switch was replaced, but the schematics for that segment of the machine could not be located in the regular manual. Work was stymied until Ike found a supplement to the manual in another envelope, but by that time both Ike and Dave had other obligations to attend to.

On Tuesday, the new stainless steel pipe plugs arrived from McMaster, as well as pins and washers. Corrine worked on the remaining machining operations at the Edgerton shop while Rachel and Hao worked on the gaskets and the stenciling for the workpieces. Hao had talked to Joe Parse, and on Tuesday the 3D-printer in 8-003 was printing one of our dies. Also, some dies from Z Corp should finally be arriving soon. Ike went to talk to Dave Bono about the Magneform.

Dave Bono turned out to be busy with another project Tuesday afternoon, but was able to spare 10 minutes in discussion before the person he was helping arrived. Ike had talked to Jorge Feuchtwanger that day before talking to Dave Bono, and Jorge pointed out a capacitor bank in that lab that had been assembled from some old capacitors that had been lying arround another lab's storage. Ike was surprised that there had been an source of information about capacitor banks that had managed to go untapped during the initial search, and asked Dave about the possibility of assembling another such device. At this point, Dave learned that Formaplode's project is not electromagnetic forming (what the Magneform was designed for), but rather electrohydraulic forming, and furthermore that the Magneform machine is going to someone else when Formaplode is done with it. Dave offered Ike the use of a smaller capacitor bank he happened to have mounted in an equipment rack in his lab. This new capacitor bank holds roughly 0.2 Farads at 100V, for an energy of about 1kJ.

This is a drastic change in plans, but this new capacitor bank has the advantages of being ready to use and known to be working, and also has a connector to hook it up to an oscilloscope to measure the characteristics of it's discharge. The disadvantages are that it has a much lower maximum energy than the magneform and operates at a much lower voltage than the Magneform or the voltagese reported in the literature we've studied. In the literature, thinner bridging wires are generally considered to be more efficient for converting electrical energy into a hyrdaulic shockwave, but at a lower voltage, we may find different behavior. We still anticipate achieving a permanent and measureable deformation in our workpiece, but as before, we don't know how much of a deformation.

A small list of discrete machining operations remain before the pressure vessel is complete, and work will continue on these operations Wednesday night. We anticipate being able to conduct an electrohydraulic test very soon, but probably not on Thursday.

Saturday, April 5, 2003 : Corrine sent a detailed update talking about several topics: A list of new parts for the pressure vessel ordered from McMaster, some pressure calculations for part of the electrode assembly, further research into theoretical explanations high-velocity metal-forming phenomena, and research into determining whether our vessel qualifies as a leak-before-break design.

Thursday, April 3, 2003 : Several updates for this week; on Tuesday Corinne, Hao, and Ike went to the Edgerton Student Shop and continued to work on the coles for the electrodes in the pressure vessel. (Rachel is traveling this week) Toby had finished drilling and tapping one of the holes the week before spring break, and the second hole was drilled and tapped on Tuesday. Some uncertainty remains as to the necessary of depth of the hole for the pipe plugs that hold in the teflon insulation sleeves, to enage a sufficient number of threads in the hole. By design, if anything other than the workpiece fails under the pressure of the explosion in the forming process, we'd prefer it to be the teflon insulation (the pressure vessel is the most difficult to replace, and if the pipe plugs fail, the threads in the holes of the pressure vessel could be irepparably damaged. Therefore, the threads of the pipe plugs should be strong enough that the teflon fails under the pressure of the explosion first, if at all). Currently, each hole for the pipe plugs in the pressure vessel is drilled to a differrent depth. We're working to determine how much load a given turn of the thread should withstand, but have had difficulty locating the correct fomula for the calculations. One alternative may be to fabricate some test pieces and simply empirically test the loads at which they fail.

On Wednesday, Hao and Ike went to the Edgerton Shop at various times to work on teflon insulation with Toby. Presently, the teflon insulation is a too long to expose the intended 3" distance between the electrodes, and still have room for the pin and washer in front of the Teflon. We also decided to get a 5" length of 6" I.D. 8" O.D. 6061 Aluminum pipe from the Central Machine Shop's stock, to use for clamping the workpiece to the pressure vessel without having to use a die.

On Thursday, the group split up: Corrine ordered parts and investigated the failure mode of the pin and washer that will keep the copper electrodes from sliding out through the teflon insulation under pressure; Hao continued to work on getting a 3D printed model of our die that we can cast from, and also worked on the gaskets for the vessel and the grid pattern we will stencil on the workpiece to take strain measurements from, and Ike picked up the Aluminum pipe from the Central Machine shop and took it to the Edgerton Shop, where it will stay until we've drilled at least one hole through the wall of it, for air to escape through, or to pull a low vacuum through.

Regarding the Magneform: between the efforts of MIT Facilities personnel, and Dave Bono, the machine has been furnished with a power cord. According to Dave Bono, however, as soon as the power switch to the machine was turned on, the fuse on the breaker supplying the machine with power immediately blew. The cause of this is unknown and not immediately obvious, and Dave Bono plans to troubleshoot the machine by applying only a small voltage to it from a large variac (preventing it from blowing the fuse) and probing the machine to isolate whatever component was malfunctioning and causing the short circuit-like behavior.

Tuesday, March 25, 2003 : Last Thursday, Hao delivered our 4th presentation (which is not yet available on this site). Our presentation was long, as was the presentation of Team 3: Aeropure, and afterwards we spentsome time in discussions with the teaching staff of 3.082. Toby Bashaw informed us that he'd made good progress on the machining operations Wednesday. When we were done with the discussions, we found out there was a small amount of flooding in the basement area of building 8 where we and other groups had been working, and it was too late to get any further machining done.

Over spring break, we hope to further improve the website, and to continue to search for information regarding the behavior of metals at high strain rates in general, and the behavior of our workpiece material (5052 Aluminum) specifically.

Wednesday, March 19, 2003 : Yesterday, some small replacement parts (indicator lightbulbs and a pushbutton switch) for the Magneform had not yet arrived, and the electrical work to connect power to the machine had not been done yet. The whole team discussed the design of the system briefly, and then moved the pressure vessel from the Central Machine Shop to the Edgerton Student Machine Shop, where we'd arranged to meet Toby Bashaw to perform several machining operations. Corrine, Ike, and Rachel stayed there to watch and help with the machining, while Hao went to 8-003 to continue work on the design of the dies.

At the Edgerton Student Machine Shop, several pieces were cut from the 3/16" copper rod for electrodes, and from the 1/2" teflon rode for the insulation. 5/16" holes were drilled in two pipe plugs to allow the electrodes to pass through with a layer of teflon isolating them from the vessel and the pipe plugs all the way through. Holes to attach the bridging wire were drilled in the electrodes, and one of the holes that an electrode will enter the pressure vessel through was started, but could not be finished yesterday, due to difficulties relating to the dimensions of the vessel, the vertical range of the milling machine, and the lengths of the available chucks, drills, and end mills. Toby kindly offered to finish those holes on Wednesday, using borrowed tools from the Central Machine Shop, and ordering some tools (on our group's budget, of course) to tap the holes for the pipe plugs.

After finishing any machining operations for the day, Corrine and Ike spent a little while talking to an as-yet-unknown individual at the machine shop about the design of our electrodes. To prevent the electrodes from sliding through their teflon insulation under pressure, we realized we could put a 1/16" hardened steel pin through the electrode, with a washer of mild or stainless steel behind it, and that that would be enough to fix the electrode relative to the teflon in the outward direction. The plan to use the pipe plugs to keep the teflon from sliding out of the holes in the vessel is unchanged so far, but we'll do some calculations to make sure we're unlikely to extrude liquefied teflon out of the pipe plugs when we fire the device.

With respect to die design, given the availability of the 6" I.D. 8" O.D. Aluminum pipe at the Central Machine Shop, and the difficulty of 3D-printing large diameter round parts, we will probably move to a design where the die is a plug that sits in the 6" I.D. pipe. The dies could be printed and ready to cast the week after spring break (next week).

Thursday, March 13, 2003 : Today while Rachel and Hao drove to a Home Depot store to pick up pipe plugs, spray paint for stenciling a pattern onto our workpieces, and some fast-but-not-too-fast-curing epoxy, Ike and Corrine walked around MIT following up various leads and connections in the search for an electrician to inspect the Magneform and help us make sure it is working normally before we attempt to use it for our device. Referred by Toby Bashaw, they eventually found Dave Bono, who is employed by Course 3, and is quite confident in his ability to understand the Magneform and troubleshoot it. He very graciously offered to read the Operator's and Maintenance Manuals for the Magneform over the weekend, and to help us test it next week. He removed the back panel from the Magneform, just to check for any visible signs of damage to the capacitor bank, but fortunately everything in the back of the machine looked very clean, practically pristine. Since so far all the visible parts of the machine look good, the easiest way to test it will be to load it with one of the magnetic forming coils that came with it, and to simply run through the operation (and if necessary, troubleshooting) procedures outlined in the manuals. We will still probably need to go through MIT Facilities to get the right power cord and plug for the machine, even if the 220VAC single phase power the machine requires is nothing complicated.

We've scheduled time with Toby Bashaw for machining on Tuesday. Time permitting, we will machine: holes in the pressure vessel for the electrodes, the electrodes themselves, the teflon sleeves for the electrodes, the pipe plugs which we'll adapt to use to hold the teflon sleeves in place, and an adapter to connect the terminals of the Magneform to the electrodes of our apparatus. (We can base the design for this adapter of the terminals of one of the coils that came with the Magneform.)

If the electrical work can be done quickly, and the machine goes as quickly as it should, we could conceivably be firing the device on Thursday, albeit without a die, since it's unlikely we'll be able to cast a die any earlier than Thursday next week. Without a die, we'd need something for clamping the workpiece around the rim of the pressure vessel. As mentioned in the last entry, the Central Machine Shop has 6"ID 8"OD aluminum 6061 pipe, which would fit our pressure vessel very nicely. A 4" length of this pipe would leave plenty of room for our workpiece to deform.

For the time being, we've decided to forgo ordering the clamps (since McMaster ships quickly) in favor of using the Laboratory Press.

Tuesday, March 11, 2003 : Hao drove out to pick up the free section of 10" inside-diameter steel pipe we had arranged when we were still planning to cast an epoxy pressure vessel. Meanwhile, at MIT, Ike, Rachel, and Corrine talked with a number of people about the next steps in our project. Specifically, they talked with Don Galler in the welding lab about borrowing clamps to hold our system together, and picked up a few pieces of scrap sheet steel we might use for workpieces. They photographed the Magneform machine, and then Corrinne went to confer with Chris and Yet-Ming about purchasing clamps. While she did that, Rachel and Ike went to the Central Machine Shop and photographed the pressure vessel. They found that the Shop has a number of large clamps that the Shop would be happy to lend us. They were unable to determine, however, how much load those clamps are safe for. They also found that the Shop had a 6" I.D., 8" O.D. pipe made of 6061 Aluminum, which we could cut a piece from to use to distribute the force of whatever clamping method we use over the workpiece, in lieu of a die, if we're having trouble making our dies. Later, Ike and Corrine talked to Joe Parse about design issues for the teflon-insulated electrodes, and noticed that the laboratory press in 8-003 might be usable for clamping the system together, since it appeared to have a pressing force of up to 50,000 lbs.

Added a design page for the electrodes, fixed errors and updated the pressure vessel page, and updated the materials page; hopefully, we'll have pictures soon as well.

Monday, March 10, 2003 : Hao reports progress on die design. Toby Bashaw says the easiest way for us to cast the dies will be from wax molds by way of 3D printing done complimentarily at Z Corp. The casting can be done the foundry at MIT.

The pressure vessel looks good, and took the Central Machine Shop 4 hours, so the cost will be well within the acceptable range. We'll pick it up from them on Tuesday, March 11, 2003.

Sunday, March 9, 2003 : Updated Design and Materials pages

On Friday, Ike took the bus out to AMTI at 176 Waltham Street, Watertown, MA, where the MagnaForm machine was located. It turned out that the machine was actually called a "Magneform". The Magneform was loaded into a large, old van with a forklift, and wooden blocks were inserted under the frame of the Machine to get it off it's casters, to prevent it from moving around. Ike then drove back to MIT from Watertown, which was a little bit of an adventure, but ultimately pretty easy. Unloading the Magneform at the Building 3 loading dock was a little difficult, but not too bad. From there, Ike pushed the machine down the basement of the Infinite Corridor to 8-006, where we plan to store and use the machine until we give it up to it's eventual owner at the end of the semester. Finally Ike drove the van back to AMTI, and took the bus back to MIT. The Magneform, a machine designed for electromagnetic forming, fortunately came with an Operator's Manual and Maintenance Manual, so as long as none of the major components are broken, it should be easy to get the machine working. The machine will need to be thoroughly inspected for damage, and perhaps cleaned for dust, before we run through the operational tests described in the manuals. Our biggest fear at this point is that we will find that the capacitors have leaked and would need to be replaced.

Regarding pressure vessel design and fabrication, on Tuesday, March 4, we decided that we needed to look into making a thick-walled steel pressure vessel, since a suitable epoxy seemed impossible to get in a reasonable timeframe, and even then the strongest vessel we could make might not have been strong enough. We checked with the Central Machine Shop about this, and found that they had a 6" diameter cylinder of cold-rolled steel, which would have been suitable for a 4" diameter hemispherical pressure vessel, as well as a much larger, ~11.5" diameter cylinder that could have been used for a 6" diameter hemispherical pressure vessel. The costs for the ingots and for machining them at the Central Machine Shop seemed reasonable, but as mentioned in an earlier entry, we were able to get a 8" diameter by 8" long cylinder of medium-carbon steel (AISI 1045). The Central Machine Shop finished the machining operation (to put a 3" radius hemisphere in it, after cutting the cylinder down to 5" long) on Friday afternoon, and we haven't picked up the finished part yet. The next step in pressure vessel fabrication is to drill the holes for the copper rod electrodes, which we plan to electrically isolate from the vessel itself with solid teflon. Additionally, we haven't yet solved the problem of how we'll clamp together the vessel, the workpiece, and the die. On Thursday, March 7, we also picked up 8 pieces of 8" square, 1/16" thick plates of aluminum (Aluminum alloy 5052) from the Central Machine Shop, which we will use for our workpieces, after we anneal and water-quench them.

(The entire saga of the Magneform, in brief: The capacitor bank search was proving difficult and not very fruitful when Ike saw the "MagnaForm prototype" mentioned in a posting to the list reuse@mit.edu. Ike attempted to claim the machine for the group, but another claimant had already 'won' the item. Ike asked to contact the claimant, to try to arrange for use of the machine. The claimant was very agreeable to the machine being used at MIT, provided that Ike and the rest of the team sign an agreement release the claimant from any responsibility for injury or damages resulting from the use of the machine, and that his 16-year-old son get to watch when we attempt our electrohydraulic forming. Ike briefly inspected the Magneform on Monday, March 3, met with the claimant on Tuesday and signed the agreement (which as of this writing has only been signed by Ike, the rest of the group should sign Tuesday), and on Friday, Ike brought the machine to MIT)

Sunday, March 9, 2003, addendum : "It just keeps getting more overdesigned." Upon the realization that annealed 5052 Aluminum has a tensile yield strength of 13,000 psi, not 28,000 psi (that's it's ultimate tensile strength), the pressure vessel should be about 50 times stronger than a small aluminum workpiece.

Thursday, March 6, 2003 :
Today was our third presentation, done by Corinne and availiable in Powerpoint format:Presentation 3 - 3/6/03.We took the billet of steel that was generously donated to us by the Timken company in Ohio (thanks to Hao for making the request to Timken) to the Central Machine Shop to have a hemisphere bored into it and have it leveled and cut down to shape. This procedure will be begun tomorrow morning and should be finished by the end of this week. In association with this, we wrote a proposal for this procedure to submit to the Prof. Chiang and Prof. Schuh, as it cost a bit more money than is typical. That is availiable in MS Word Format: proposal.doc.

The search for a way to clamp the apparatus together re-begins. We did a few calculations and figured out that we would need to use ~30-40 of the bolts which we purchased from Home Depot in order to attain the kind of clamping we want. Since the planned size of steel plate is only 1 foot by 1 foot, this is clearly not feasible. So the search begins for bolts which are stronger or for clamps which will work.

We spent some time discussing the casting of our mold with Toby Bashaw. In addition, we tried to call the Edgerton Machine Shop in search of a lower priced alternative steel plate. There was no answer, so we sent email. We purchased some aluminum blanks at the Central Machine shop, which was very exciting. But the most exciting part of our day was definitely traveling the basements of MIT with a 133 lb chunk of metal on a roll-ey chair.

Tuesday, March 4, 2003 : Spreadsheets updated: in Excel and StarOffice format. There's a fair amount of other news to catch up on, which will be added to this entry later (re: getting the magnaform, pressure vessel design and fabrication, and other things). **Edit** News is caught up on in the Sunday, March 9, 2003 entry.

Thursday, February 27, 2003 :
Corinne talked to the epoxy man (Kevin Rudolph). We have decided to go with the CLR 1069/CLH 6930 by Crosslink Technology Inc. from the Rudolph Brothers in Ohio. This epoxy is specifically designed for casting masses larger than 3 kg. It also cures at room temperature and in thicknesses up to 3 inches. We calculated that we need approximately 7 liters of epoxy per pressure vessel. We plan to purchase enough for two pressure vessels, in case our first attempt does not work out. This works out to a purchase of about 3.6 gallons of epoxy.

We called several pipe companies and ended up with a 10 inch interior diameter from Marmon/Keystone in Southhampton, MA. They are willing to give us a 1 foot tall section of a pipe for the low-low price of $150.

Capacitor bank search proves fruitful. The person who claimed the Magnaform machine posted to reuse from Watertown has given us permission to use the machine for the duration of our project. The problem that we have is that it is unknown if the machine is in perfect working order or not. In addition, we have to get the machine to Maine after we are finished with it.

Wednesday, February 26, late : Spreadsheet of some pressure vessel calculations available in Excel and StarOffice format.

Tuesday, February 25, 2003, 4pm : Corinne and Hao went to a junkyard in Lawrence, MA to try and locate a steel pipe for the exterior of the pressure vessel as well as purchasing some plastic vacuum tubing, nuts, bolts, and other small assembly materials from Home Depot. Ike and Rachel went to the Central Machine Shop in the basement of building 36 to find ~10 inch square steel plates, sheet rubber for gaskets, sheet metal blanks for the workpieces, and thick copper wire for the electrodes. We found that the plates, rubber and wire were items that would need to be ordered, most likely from McMaster-Carr. We were also shown a numer of different diametered pipes in steel and aluminum, which might be useful in the pressure vessel construction if the junkyard route proves to be unfruitful. We spoke to Peter Morley, supervisor of the Shop, and picked up the gazing spheres that we plan on casting our pressure vessel from. We're storing them in 13-5016 in one of the cabinets.
The junkyard route, as we feared, was not fruitful; the place they planned to go to (Tom Barillo's) went out of business, so they only made it to Home Depot.

In addition, Rachel found equations for use in thick-walled pressure vessel calculations in High Pressure Vessels by D.M. Fryer and J.F. Harvey, pp 34-61.

Tuesday, February 25, 2003 : Ike does some general updating and adds rudimentary safety design calculations to the design page, realizing in the process that they're really not the appropriate calculations to be doing, but retaining confidence in the safety of the design, which he believes can be shown to be safe through more appropriate calculations.

Monday, February 24, 2003 : Corrine reports in with some design information: 

Last week we decided that an epoxy would be the best choice of material for 
our pressure vessel for a few reasons:
-no stock part (after a bit of looking, we decided it would be easier to 
make our own than to try to convert some part of another apparatus)
-electrical insulation (don't have to worry about the electrodes arcing to 
the side of the vessel
-ease of processing (having something machined would take considerably 
longer than it takes epoxy to set and we can cast it exactly as we want)
-insertion of electrodes (we will drill holes into the epoxy to allow for 
insertion of the copper electrodes and expect that we can use epoxy to make 
a secure bond between the electrodes and the vessel wall

So we began a search for epoxy... We decided that our epoxy would need the 
following requirements:
-not be metal-filled
-be able to set without a vaccuum
-be castable in large batches
-be able to set even at thicknesses up to 3"
-have a relatively high yield strength

After talking to Toby and Chris, we had a few leads.  We called Polytek (C) 
and Buehler (C), but neither had suitable products for our needs.  We 
emailed several companies in the Thomas Register to fan out our search a 
bit.  Crosslink Technologies (C) has gotten back to us and they believe 
they have a product for us.  We hope to get this ordered early this week.

We also decided that we should cast into a steel pipe to add some safety to 
our system.  It will put the epoxy into compression instead of tension 
during the explosion.  It should also contain the epoxy in the case of a 
catastrophic failure.  Toby suggested a personal contact in Lawrence, MA 
where we should be able to find some pipe scraps, so we plan to go there on 
Tuesday to find a pipe with a 10" inner diameter pipe and cut it to ~6" long.

Sunday, February 23, 2003, ~3PM : Begin serious work on Formaplode's webpage. Our first two presentations are available, in Microsoft PowerPoint format: Presentation 1 - 2/13/03, Presentation 2 - 2/20/03.

Prior to this update, members of the team have been working on various aspects of the project, including:




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