Kim didn’t show up on time and was some place other than her house because of some dispute with her roommate or her roommate’s boyfriend or the seven cats or some such thing.  We couldn’t even find her.  She left her cell phone in our living room so we couldn’t call her.  This was very much unlike Kim and I was worried about her.  James had spent the night and of course Xenia was there so the three of us picked up Sara and left nearly 40 minutes later than we planned.  I asked Barb to keep calling people and asking about Kim.  Kim called about 12 minutes later.  She was very apologetic. Someone had borrowed the cell phone she had borrowed to use an alarm.  It was in another room and no one heard it go off or had turned it off.  I told her to just meet us there.  We arrived on site and found the ground wet and very soft.  I nearly got stuck going through the wrong part of the creek on the way to the Taj Mahal. The creek was completely dry five weeks ago.  We starting setting up.  Xenia and Sara pounded the stakes in the ground.  James and I setting up to make explosives.  Kim showed up still in her pajamas.  She hadn’t even gone to the bathroom yet this morning and she had her toothbrush and toothpaste with her.  She and I went to my parents place to get ten gallons of gasoline for the fireballs and we both used the bathroom.  Dad wanted to show me the new tractor and so I lost another five minutes there.  We got back to the Taj Mahal and still had more setup to do.  It probably took another 30 minutes before we actually started making targets.  We are at least an hour behind what I had planned.  Kim forgot to take her medicine and had to walk back to her car and walk back out again, we were probably 20 minutes without her.  Once she came back however she really cranked out the targets.  If it hadn’t been for her we would have been very, very late getting the targets done.  As it was we were about 20 minutes later than what I had told Dave.

I did the shooters meeting while Kim took Xenia and Sara to my parents place then came back to blow the air horn for the ceasefires.  Xenia and Sara had homework to do and had their jobs completed.  Dave and ten others set up and started shooting.  After ten or fifteen shots a boomer detonated.  It wasn’t as powerful as I expected.  People started saying they were hitting them without getting a detonation.  I was worried.  Something wasn’t right.  We called a ceasefire and James, Kim, and I examined the targets.  There was a problem.  They were getting solid hits without detonations.  A closer examination showed why.  We took apart each target, while crouched in the mud, fixed the problem and remounted the box on the stakes.  The wasn’t something Kim or James had done wrong while packaging the material.  They did it exactly as I had told them.  It was one of those things you never would have thought of until you did the tests.  Moving the targets 300 yards and a few hours in the space time continuum had screwed us.  I’m so incredibly glad we did this real world test three weeks before the big event. We only had 50 targets we needed to rework while 11 people were waiting on us rather than 600+.targets while there was 100 people waiting.  The boomers started going boom.  Frequently there would be ‘smoke’ (water vapor actually and powdered lime) from multiple boomers in the air at once.  They eventually stopped shooting about 15:30.  They said all the targets were gone.  James, Kim, and I started setting up the fireball targets.  There were still several targets left.  Some completely untouched. This is tyipcal.  It’s tough to see everything from 375 yards away.  Dave and his gang drove across the bridge and walked out to the target line. They lined up about 25 yards from the berm and I ignited 11 flares behind the 11 gallons of gas behind the 11 reactive targets.  If you look closely in this picture (click on the picture to get a hires version) you can see the flares.  In this next picture the hot spots have grown some:

The second guy from the right is dodging some material that came back his way.  Kim said she got hit with some dirt.  Everytime we have shot stuff up close she gets hit with something.  Always before it was a prill of ammonium nitrate.  No AN prill this time but at least she has her 100% hit record intact.  There were lots of big grins on the people’s faces when they left.  A couple of them signed up for the event on May 1.

The complete photo album of the adventure is here.  Click on the pictures to get a larger version.

Ry showed up as we were almost comletely done with clean up.  He was delivering some Tannerite.  We did some very quick tests and found it was no more senstive to impact than our mix and couldn’t really tell it apart in terms of power.  It’s far, far more expensive however.  It’s a binary explosive and can be shipped via UPS so it’s a great product for a lot of people but it’s not a market I want to get into with our mix which has four ingredients.  Ry’s alternator light came on just as we were about to leave at 18:00 and he still had 8 hours of driving ahead of him as he has to go back to Redmond and Microsoft tonight.  He figured he could make it to Moscow on his battery and figure out things there.  I brought the kids back to a nice meal Barb had prepared for us.

I’m tired and it’s been a long day.  Enjoy the pictures and start planning a Boomershoot for your future.

The most labor intensive portions of Boomershoot is the building of the reactive targets.  Each year we learn more and improve things for the next year.  One of the things that has been a pain has been the pouring of “Fuel 0“ into a small measuring cup.  A couple weeks ago I spotted this the store (click for a bigger picture):

I picked one up at the store today along with the little stand which it is setting on.  This will allow us to dispense the fuel easier, cleaner, and faster than before.

A few days ago I purchased 50 pounds of “Fuel 2”.  I only expect to use about 35 pounds but it was cheaper to buy 50 pounds than to buy 40 pounds (so I make sure I don’t run out) in the next size smaller package.  It came in a paper sack which I was certain would draw moisture and fall apart during storage.  I bought the plastic containers pictured below, transferred it into the containers, and managed to clean up the kitchen (it’s rather messy stuff) before Barb got home (click on the picture for a larger view).

I’ve got my eye on some more kitchen appliances to speed some other aspects of the process up from last year.  Boomershoot 2005, over 600 targets, over 1000 pounds of high explosives.  It should be a snap this year.

Executive summary:

Ry, his kids, and I spent the day testing reactive target mixtures in two different types of target containers. We discovered the target bodies we used for the first time last year were part of our problem with failures to detonate. Those problematic target bodies will not be used for Boomershoot 2005. We also found modifications to our procedures and to our mix to make the mixture more sensitive. With the new mix and the new target bodies but with small sample sizes we got 100% detonations with .22 caliber bullets (CCI Stingers) going about 1420 fps at the target. We got 100% failure to detonate with a target velocity of 1170 fps which means the targets are safe to handle. We did not do sufficient tests to determine the actual threshold for reliable detonation but do not expect it to be much if any below 1400 fps. The new mix has a lot more “punch” to it that the old mix and there is a very noticeable flash.

High level view of Boomershoot reactive targets:

The chemistry of our shoot.

History of Boomershoot reactive targets:

Explosive Experiments.

In 2003 we changed to a new type of fuel that cut the costs considerably and make things more sensitive at the same time. Since that time we have kept the fuels proprietary. The mixes listed on the web page work and are “good enough” for most purposes but our later mixes give us an edge in some areas. Yesterday was spent testing new fuels, a couple of catalysts, and the target containers.

Boomershoot reactive target innovation:

Almost all of our innovation to make the mix sensitive enough to detonate (not ignite, that is something completely different) and yet safe enough to handle has been with changing the amount of potassium chlorate and using different types of fuels. This has been an ongoing learning experience.  I have purchased probably twenty books and spent countless hours learning about explosives and the detonation mechanisms.  Then a friend (usually Ry) and I would test my latest hypothesis on how to make the mix better.  Most attempts were disappointments.  Only occasionally would we have something that worked better than what we had used before.  For the last three years we used the same components in the same proporitions with only an involuntary change in the grade of the AN we received from our supplier.  Yesterday was the first time we had a significant advance in a long time.

Yesterdays experiments:

Yesterday we took four new fuels with us but only had time to test three of them and only two in enough detail to be confident we found the “sweet spot” in the proportions. The two fuels insufficiently tested looked to be poor performers on paper and we probably won’t investigate those anytime soon unless the storage tests being done turn out very poorly.

We use two different oxidizers in our reactive targets. Ammonium Nitrate (AN) is the main ingredient and Potassium Chlorate (PC) is used to increase the sensitivity. These chemicals are mixed with a fuel to create an bullet sensitive mix.

The fuels we used will be called:

• Fuel 0–the liquid fuel we have been using since 2003.
• Fuel 1–new solid fuel which looked the best on paper but is a little difficult to find and slightly more expensive than some others.
• Fuel 2–new solid fuel which looked second best on paper, is very easy to obtain and is cheap.
• Fuel 3–new solid fuel which looked poor on paper but is commonly used in the fireworks industry, is easy to obtain and is moderately priced.

As many people know the discovery of Penicillin was an accident. And so it was yesterday for us. One of the changes we adapted was because I made a mistake on the very first batch. From a chemistry and common sense point of view we should grind the AN. We buy it in prilled form (spheres about 0.1″ to 0.13“ in diameter) with a very thin coating which protects it from moisture. But what we have found in the past is that either it didn’t make any difference (Boomershoot 2001, 2002) or better performance was achieved with only some of it ground. In 2003 our supplier of AN had fertilizer grade material instead of the usual explosive grade material. It sort of went “POP” instead of “BOOM!!”. We tried grinding the AN and it made a better boom but wasn’t sensitive enough. We ground half of the AN to get a compromise. Since then we have had the best results when half the AN was prilled and half was ground. Yesterday the first batch was made entirely with ground AN. Whoops! Well, rather than just burn it (our disposal method) we decided to box it up and test it. We found that with the present fuels having all the AN ground made a huge positive difference in sensitivity. Another accident was that we used just a small amount of Fuel 0 “to keep the dust down”. It turned out the presence of Fuel 0 was crucial to detonation. Without it there was no detonation even with a .223 at close range.

We ended up making 13 batches of reactive target mix. Each of the batches made from two to four targets depending on the size of the target and volume of fuel we used. Except when we intentionally left out Fuel 0 and only used Fuel 1 we could detonate everything with the .223 at 12 yards. The high velocity .22LR got at least partial detonation on most mixes. By observing the points at which we would start having failures to detonate we could bracket the acceptable limits of the proportions of the fuels.

We explored the limits of Fuel 0 and found that we had been using too much in previous years for optimum detonation sensitivity. We explored those limits and found the optimum proportion for maximum sensitivity. The power was a little lacking but the detonation was very reliable. We then adjusted the proportions of Fuel 1 for optimal sensitivity with the previously determined amount of Fuel 0. Fuel 2 was explored in a similar manner to Fuel 1. At the optimal levels of either Fuel 1 or Fuel 2 we could not distinguish a difference in performance between the two. Both would detonate in the new target bodies with the .22LR at velocities of about 1420 fps. And both would generate a significant flash upon detonation with a much better “punch” to the chest than mixes of previous years. Since Fuel 2 is cheaper and easier to obtain we decided it was preferable.

We tried optimal mixes of both Fuel 1 and Fuel 2 in the 6″ target bodies from last year. We could only get rare detonations with the .22LR at velocities of about 1540 fps. The target bodies were creating an effective loss in velocity of something well over 120 fps with the 32 grain .22LR bullets! The .223 would detonate them every time at these short ranges.

With the Fuel 2 mix we added Catalyst 1 and tried it again in the 6″ target body. We got one detonation out of four with velocities of 1540 fps. Not good enough.

We were in the process of trying Catalyst 2 when we had a big scare. I mixed the fuels with the AN and then added Catalyst 2. Within about five seconds there was a very strong smell of ammonia and I turned off the mixer and took the mixing bowl outside. There was no apparent heating or visible problems with the mixture but the smell was still very obvious. I dumped the mix on the burn pile for later disposal without ever adding the PC.

Next we tried Fuel 3 combined with Fuel 0 in the 6″ target bodies. Zero out of three detonations with 1540 fps .22LR. The time was 1700 and Ry and the kids had to leave. I stayed to make one more batch of the optimal Fuel 2 mix in the new target bodies for storage tests, cleaned up, and then came home later.

Next week Barb and I will go back and test the stored product for sensitivity and then a couple weeks after that we will test again.

I just got a call from Stephanie, who does the publicity for Boomershoot.  She received a postcard from Dave Barry declining the invite to Boomershoot 2005.  He has a fundraiser he is attending that weekend but would like to be invited to Boomershoot 2006.

She did have news that someone else of very high status will probably attend.  Details will have to wait until things are confirmed.

For the first time this year I had trouble going to sleep and staying asleep due to the Boomershoot. Even now my stomach is tied in knots. There aren’t really any big obstacles to overcome. Things are a little behind but we have a plan to take care of that. Everything is looking pretty good. Even the weather isn’t too awfully bad. Probably one of the best weather forecasts ever for a Boomershoot. I think part of the problem is that I’m not working on it. Tomorrow I start and don’t stop until it’s done.

When I had the pickup this morning I picked up the last of the crates for storing explosives.  36 of them.  The magazine will hold 72 and I already had the rest.

I received 1000 plastic disposable aprons via UPS yesterday.  I found two different sources for them.  One source had a minimum quantity of 1000.  The other source I could by in single quantity.  I wanted about 50 or so, but for the price of 100 from the single quantity source I could by 1000 from the other place.  I got the 1000.  When we are mixing the explosives I want to keep certain chemicals off of people’s clothes.  The potassium chlorate in partcular is a very strong oxidizer.  If it were to get mixed in the fibers of someone’s clothes and they could burn up like a match head, a fire extinguish would be almost useless against such a fire because the potassium chlorage supplies the oxygen.  And with lots of cheap aprons workers shouldn’t be too hesitant to throw one away and put on a new one if it gets torn or something.

Boomershoot 2004.  A ton of explosives.  Fun beyond measure.  And most of all I want it to be safe for everyone.

http://www.boomershoot.org/2004/blast.htm

I had a big flood of entries in Boomershoot 2004 last week.  Probably a record in terms of dollars, but not in number of entries.  I’m past the breakeven point for the actual event expenses now and can start paying off some of the loan for the Taj Mahal (http://www.boomershoot.org/TajMahal/Magazine.htm).

Yesterday Ry tested out a new mix someone emailed to me.  It comes close to meeting our needs and has some big advantages.  We probably can tweak it enough to work for us and still retain the advantages.