Harvesting Aluminum Flake From Paint?

Richard Nakka recently added a page to his site about harvesting aluminum flake from paint. Actually, there are several new additions to the igniter page that I found intersting. I'll defer to Richard's page about the usefulness of flake aluminum as a thermic agent for igniters and the harvesting details.

I haven't had much time to devote to rocketry lately, but this technique seemed so simple and the cost was so minimal that I decided to give it a try. One thing that I noticed was that the lip on the paint can made it difficult to get all of the slurry out of the can and it was difficult to determine how deeply to insert the siphon. Too deep and you just sipon out the actual aluminum. I ended up transferring the slurry to a baby food jar for the 2nd acetone wash. Not only was it easier to get the slurry out of that container, but being clear glass I was easily able to see when the aluminum had settled. It was also easier to see the placement of the turkey baster used to siphon out the acetone ensuring that a minimal amount of aluminum was siphoned out. I ended up with a yield of 34 grams from a half pint of Rustoleum 7715 aluminum paint which is easily enough for 50-75 igniters.

Amateur Icelandic Rocketry (AIR)

Magnus Gudnason and Smari Freyr Smarason of AIR recently static tested the two motors intended for a two stage project to be launced later this year. Some preliminary test results can be seen on their forum. I think that this could be one of the best "sugar" powered launches to date, definitely one to keep an eye on.

Old Launch Photos and Stuff

Going through some old photos and rocket related things recently, I came across some photos from 2002. At that time two of the largest motors that I had were designed around two inch diameter "washing machine standpipe" that I found at Home Depot. I decided to try these pipes at the time because they seemed to be very good quality, good/consistent weld, and dimensionally consistent. They also have a thin (0.035") wall thickness which makes for a very lightweight casing. I designed two motors that utilized this casing material. Both motors used identical casings, bulkheads, and closures, but one was designed to use a single unrestricted grain and the other a single restricted grain. The differences in the nozzles are shown in the drawing above. I was concerned about the low initial thrust of the motor that used the single restricted grain and tried to reduce the weight of the nozzle for that motor as much as possible. In the end both motors ended up weighing nearly the same (1.75 lbs). I static tested the unrestricted motor and the numbers correlated closely to the design. Ultimately both motors flew numerous times at the RRS. They were simple to prepare on site (due in part to the fact that each needed only a single grain and that the motor was used as the casting mould). The motors proved to be durable, consistent, and fun to fly.

In the first photo you can see the casing with its nice shiny zinc coating. It is not that shiny from Home Depot, but the finish didn't take much time. Unfortunately the zinc blistered after the initial firing, so the coating was removed with a quick dip in muriatic acid. The 5th photo shows Peter and I taking the rocket out to the launch tower. The 6th photo shows (from left to right) Greg Coleman, myself, Kevin Koch, and Alan Hoyt lifting the launch tower into position. The 7th photo is Kevin, myself, and Alan. The orange and black aeroshell flew a total of five times at the RRS on three different motors. I made it from three inch diameter heavy walled cardboard tube that Kevin found in a dumpster. The fins were cut from quarter inch plywood and were epoxied on to the tube and reinforced with a layer of heavy fiberglass. The nose cone was turned from a block of pine. Eventually, it became too small for the new motors that I was making and was retired. It was always difficult to adjust the tower for it correctly since it had three fins and the tower at the RRS is built for a four fin rocket.

Photos 6-10 were all taken by Tony Richards.

Camera Rocket Recovery Photos

I recently ran across a couple of photos that I hadn't seen before (here and here) of the rocket I launched in April 2007. I found the photos on the Mojave Desert Advanced Rocket Society website located here. I recognize a couple of folks in the web site's photo section from motor classes that I recently participated in including the MDARS president Kevin Metzler. The photos of my rocket were taken by Dave Allday.

Side by Side Comparison

I fired two motors this past Saturday. One was an AP based motor and the other was a KNO3 based motor. Both motors were of approximately the same total impulse, but it wasn't really a fair comparison. The KNO3 motor used Xylitol for the fuel. I first heard about this sugar on Scott Fintels web site, and it was available at the local Whole Foods store. It has a low melting point and casts very nicely, the problem was that the grains took a long time to cure, weeks in fact. Anyhow, the propellant in the AP motor is fully characterized and the propellant in the KNO3 motor not so much. The side by side comparison is still interesting to watch though.

Composite motor class

I took part in a composite motor class this past weekend. The class was taught by Dave Reese and was conducted at the Friends of Amateur Rocketry site. The class was a lot of fun and full of lots of useful information. Dave is currently a student a USC and I'm sure that he is very busy but despite this he did a great job organizing and conducing the class. The motor that we prepped propellant for was based on standard high powered rocketry hardware of which I have none, so I made some hardware based on drawings that I found on the Loki Research website. The hardware worked really well; I like the simplicity of the Loki design. Here is a video of the class motor that I static tested, I didn't have any instrumentation partly because I didn't want to risk any equipment on untested hardware and a propellant that I don't have much experience with, but mostly because I've been so busy lately that I just didn't have time to get anything together in time. The design/propellant is pretty well characterized though. The thrust produced should have been in the neighborhood of 90lbs with and Isp of around 185-190.






The Paul Breeds of Unreasonable Rocket were also at the site. Paul senior was flying an RC helicopter loaded with telemetry to gain information for their Lunar Lander Challenge quest.

Composite Propellant Class

Later this month I'll be participating in a composite propellant class at the FAR site. The class is being taught by Dave Reese. Dave's a student at USC and was involved with this awesome project flown at the RRS some time ago. Photo by James Davidson.





Here is a picture of some of the 38mm hardware that I made myself for the class. I only had to buy the tubing. I bought enough for three casings for under $30. I had enough "scrap" pieces laying around for the bulkheads and nozzles.