Topband: 'Spud Gun'

Thu Mar 18 21:11:00 PDT 2010

I don't want this to become an OT thread for Top Band, most people 
here have fine antennae for 160M but some of us are antennae 
challenged and make the best of our circumstances.

What I did was use the March 09 QST article as a base for the Spud 
Gun and I did what I innately do & tried to improve on what was 
described. I rarely... leave well enough alone...

So I uploaded some photos to my website so you can see what I have 
described. Here goes:

http://doctorgary.net/spud1.jpg
In this photo I am showing the relationship of the valve and barrel 
of my spud vs the one in QST. The one in QST is on the top and does 
not have the trigger attached. I removed it as I want to drill out 
the internal access hole and then epoxy the brass fitting in it, the 
threads just don't match what the trigger needs. It was intact, I 
needed a more permanent fixture and haven't put it in because I 
prefer the larger gun. 

I figured having a bore the size of the valve would do better than 
having a valve that acted as a reducer. I have an adapter to allow me 
to use the smaller barrel on the large valve and it is much, much 
more powerful than using the smaller valve.

I wrapped the large one in tape out of my innate paranoia that should 
a defect allow the pressure tank to explode, the duct tape would 
prevent shrapnel. I did fill this with well over 100 psi while 
covered in a sandbag and it holds pressure beautifully.

http://doctorgary.net/spud2.jpg
In this view you see the business end of the smaller valve. You can 
see the larger opening, this is where the air trigger goes into. 
Actually, the ideal place would be where the small 4 sided thumb-
screw is located but it is too small to be useful. The larger 
circular opening is where the solenoid came from.

If you feel the need to use the smaller sprinkler valve assembly, 
bore out the inner hole more than it comes with. You will need to 
remove the brass fitting inside, it was designed to mate with the 
rubber gasket of the solenoid and reduces the air inflow when you 
fire the device & this will reduce the power it offers. ( the brass 
fitting is already removed in the photo)

http://doctorgary.net/spud3.jpg
The larger valve beside the one in QST. I could have taken  a more 
inclusive photo but you saw the comparative difference in spud1. You 
see the orientation and placement of the air gun trigger. I paid like 
6-8 bucks for this air trigger at Advance Auto.

I paid $14 for the smaller valve locally at a lawn service wholesaler 
in the area. I paid something like $30 for the larger one on ebay.

Where this was placed was at the pressure adjustment valve. I removed 
the plastic bottom and drilled it out on a drill press to give me 
maximum air inflow so as to allow the maximum FPS the projectile will 
travel. 

http://doctorgary.net/spud4.jpg
A macro of the trigger mount and the opening where the solenoid used 
to be. You will see the white inside the old solenoid mount, that was 
baking soda I filled it with and then put crazy glue on top of it. 
This allows instantaneous cementing of the baking soda to the plastic 
and seals off that area 100% which is needed to allow the trigger to 
work where it is now placed.

I thought it might be more powerful to use a larger tank but since 
this works perfectly to send a larger projectile than a tennis ball 
or smaller PVC "Spud", I didn't need a larger tank which would have 
required more pumping to fill. So you'll see both tanks are about the 
same size.

Again, the spud this shoots is about one pound and the monofilament 
is 30 pounds. The spud will not likely get caught in branches and 
will fall to the ground. The 30 pound monofilament will not easily 
break when pulling the antenna wire up.

IF you have a single tree to simply get over, anything will do but if 
you want to get that projectile through a forest canopy and shoot it 
through a small window above with accuracy, this is the cats A... to 
do so.

Also, I have a 10 gauge goose gun, it has a very long barrel, much 
longer than any other shotgun I have. That longer barrel gives a much 
better range and far more accuracy than a shorter barrel. I made my 
barrel longer based on that reason. IF accuracy is necessary, use a 
longer barrel, if again, it is a tall tree to get over and there is 
no small window of sky to get the wire through, a shorter barrel like 
the kit mentioned earlier will surely be fine.

At around 90 pounds of pressure, it takes 12 seconds after firing for 
the spud un-attached to the monofilament to hit the ground.

This will do the job...

And will drop that deer...
:)

Gary
KA1J
> ========================
> 
> Message: 3
> Date: Wed, 17 Mar 2010 22:07:37 -0300
> From: "Mike & Coreen Smith" <ve9aa at nbnet.nb.ca>
> Subject: Re: Topband: suitable wire for top loading wires?-spud gun
> 
> I'd love to see plans for that Spud Gun, Gary (or anyone)/.....I've been
> using a fishing rod for years but it's not entirely accurate and I've been
> "caught up" in the tops of trees more than once.  I usually try to use some
> rocks taped to the end of my monofilament in case I have to yank and break
> it free.......then the rock drops to the ground.  A spud gun sounds like the
> bees-knees.
> (and I could harmlessly target practice on the hoards of deer in the back
> field when not working on antennas! ;-) J/K ) Mike ve9aa .
> ,,,SNIP...
> I forget which month that Spud Gun was explained in QST, it was 1-2 years
> ago. I made one just like in the magazine but then I fiddled with the valve
> and made it a bit better. I then ordered a larger valve from Ebay. Either
> would work but I wanted a heavy duty version that would be sure to do
> anything I would ever ask of it. Minus the monofilament, that sucker would
> take down a deer at 300'...
> 
> 73,
> Gary
> KA1J
> 
> 
> 
> ===
> If anyone is interested, here's a spud gun -- I call it a "Squirrel Cannon"
> -- that I put together, borrowing from the best features of several designs.
> The unique feature about this design is that it uses a single, 10' piece of
> PVC. I've had a number of locals use this design with a lot of success.
> 
> http://www.ws6x.com/ws6x_files/squirrel.html
> 
> 
> Enjoy,
> 
> Jim, WS6X
> 
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
> 