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Biulding the Perfect Sabots

Posted: Sat Feb 23, 2008 11:29 am
by Jared Haehnel
So here’s the perfect sabot round for any spud gun. Well any large bore spud gun. Its reusable and you don’t have to walk a hundred yards to retrieve it.

So here what you do. You buy a sheet of blue board. You know the foam insulation that they wrap around your foundation. Its perfect for sabots since it lightweight easy to manipulate and for what it is its pretty rugged stuff. So I have a three-inch barrel that I love to lob soda cans out of. This is how I made a sabot for that barrel. However the same technique can easily be adapted to suit a wide verity of ammunition and replace any tape or wading around the object. One sabot would take about ten minutes to make and easily could be mass-produced.

The sabot is made of layers blue board. You go out and buy a hole saw for your drill the same diameter as your barrel and cut several plug out of the sheet of blue board. For a can I use two inch thick blue board and cut out three plugs. Then you glue them together in a stack. You can use a variety of glues for this but they make a glue especially for blue board. The stuff I use comes in a caulking tube and is (pl200) basically a solvent weld similar to PVC. I’m sure epoxy would also do well This gives you a stack roughly six inches high. Then I have a second hole saw around two and a half-inches in diameter. I like to make it look neat so I use a drill press and cut the hole down through the slug leaving an half inch ring around the out side and a full two inches on the bottom. The can doesn’t quite fit so I sand the in side out with a dremel until the can slips in neatly.

The last two steps are great fun. (blue dust all over ) The first one is to sand the out side with fine grit sandpaper so it gives a very smooth finish to slip down the barrel very nicely. Because of the very light weight of the foam and smooth texture your basically reducing friction inside the barrel which would lead to increase muzzle velocities of the projectile. The last step is to cut the sabot in half so when you launch it falls away from the can or what ever object you fit it to. It wouldn’t be much of a sabot if it stuck with the can the two, three hundreds or however far he can goes can flies. Not to mention who wants to walk that far. That and it would seriously affect the velocity of the object (‘nough said?)

Vola! You’ve got you first spud gun sabot that is reusable. I would suggest two things. One: If you use it in a hybrid or combustion you place tin tape or at least duck tape on the bottom of the sabot or your going to melt the foam away to nothing. It will, in a heavy launch, make a mess of your barrel. Two: It might be easier for some to cut the holes in the plugs before assembling them in to the sabot. That way you are sure you don’t cut through the bottom on accident. If you’ve got a small barrel you can get a small hole saw and a sheet of one inch thick insulation and it make great wading.

The sabots are nearly indestructible. I say nearly because I am sure some one could find away. And when they do wear out its usually because they get too loose in the bore. If they break and yes some times it happens thought I’m not sure why probably because of rough handling on my part you can easily repair them with the glue and a bit of extra foam. So that’s it sorry its such a long post but its worth it.

I know this should probably be in the how to post but its also ammunition I was divided on which I should stick it into. If it needs to be moved please feel free

Posted: Wed Mar 19, 2008 11:46 am
by rcman50166
I feel bad for Jared. He spent all this time to write this great tutorial just so no one would post. It's ok because I am here armed with a question. Does this design allow for dart shaped rounds? More specifically, a nail that's the size of a railroad tie. It's very heavy and I'm not sure if this type of construction could support the forces that would be upon it.

Posted: Wed Mar 19, 2008 12:40 pm
by SpudBlaster15
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Posted: Wed Mar 19, 2008 2:49 pm
by fireman565
rcman50166 wrote:I feel bad for Jared. He spent all this time to write this great tutorial just so no one would post. It's ok because I am here armed with a question. Does this design allow for dart shaped rounds? More specifically, a nail that's the size of a railroad tie. It's very heavy and I'm not sure if this type of construction could support the forces that would be upon it.
It might with aluminum or duct tape. Maybe cut out two circles the size of the inside diameter of the sabot. Stick them together. If the sabot is split vertically in half, glue the circle of tape to one side of the bottom of the sabot. The tape should be strong enough to support the railroad spike. If that's not enough support, sandwich a piece of 1/16" thick plastic sheet between the two pieces of tape.

Posted: Thu Mar 20, 2008 7:23 am
by Jared Haehnel
Blue board is pretty sturdy stuff... so yes I would say it probably would hold up. I've used the same design for pretty heavy objects. Probably my heaviest was a full soda can which weighs pretty near a pound. Shot it out of a light weight pneumatic at 135 psi and I was able to reuse the sabot just fine.

Really all your doing it building a cup that wraps around the object with a solid base of blue board. All the pressure will be on the rear of the sabot. This get a bit more tricky to do with smaller barrels and the blue board may not hold up if you trim the walls down too thin. I'd say anything less then a 1/4 inch and it may not hold up so well. On the bright side they are cheap and relatively easy to repair if they break.

Edit: As an example of Blues board rigidness I have seen it used for a toilet seat in an out house. The guy cut out the pattern with a jig saw and sanded it down to fit. No more frosted buns in the winter 8). It was instantly warm when you sat on it.

Posted: Thu Mar 20, 2008 12:49 pm
by rcman50166
So, how man layers of blue board should be beneath a .5" x 18'' iron nail? It's very heavy and fins protrude from it. My design, based off of your idea, has 2 layers of the foam. I have a diagram. I'll attach it when I get home. Proxies can't upload images.

Posted: Thu Mar 20, 2008 1:07 pm
by Jared Haehnel
Thats quite the dart.... 8)
How thick of foam are you using? How much PSI is the gun going to be charged with?
Most cases I would say a layer of two inch think foam would work fine. The force of the air is going to exert a constant pressure on the object no matter what the weight of the object is. This is true in pneumatics any way. In hybrids and combustions its a bit different as the weight of the object will increase the pressure the combustion creates as it takes longer for the object to move down the barrel.
Are you forming a cup around the object? Or are you using the foam as wadding?
I'll look forward to seeing your diagram
8)

P.s thanks for the interest in the idea :)

Posted: Thu Mar 20, 2008 1:11 pm
by rcman50166
It's a combustion, and I want to use the two inch like you suggested. But if hardware stores sell thicker sheets, I'll use that. I'm using the sheets to form a piston behind it and a sabot over it. I may possibly attach them together to make a single sabot.

Posted: Thu Mar 20, 2008 1:50 pm
by fireman565
rcman50166 wrote:But if hardware stores sell thicker sheets, I'll use that.
I was only able to find 1/2" thick blue board at our local Lowe's. That just means 4 times the cutting... :lol: Of course that maybe a regional thing though. Two inches thick, wow... :shock:

Posted: Thu Mar 20, 2008 2:12 pm
by Jared Haehnel
A single sabot has the advantage that you don't have to go look for four individual pieces... but it won't matter at all if you use on or two. Just preference

Since its a combustion I would suggest putting tin tape on the rear of the sabot. It will help to prevent the foam from melting.

Depending on the object you launch you may be able to get by with 1/2 or an inch. The two inch allowed me to make a cup for a wide assortment of objects. Mainly a soda can full of soda. But I've used it for paint ball buck shot, easter eggs, hard boiled eggs, jelly beans, certain small rodents (kidding) and what ever else one might shoot out of a 4inch barrel with a three inch sabot. The design is very flexible and can be easily adapted to the materials available and the object being launched.

Posted: Thu Mar 20, 2008 3:12 pm
by rcman50166
Here's that diagram that I was talking about. It's more or less to scale too. However if 1/2 in board is the biggest they sell at Home Depot, (which is where I was planning to go) I may have to reconsider the design. That is a lot of cutting...

Posted: Thu Mar 20, 2008 3:59 pm
by Jared Haehnel
That will work just fine...I think it must be a location thing because most hardware store where I am sells at least one inch. 1 1/2 inch isn't uncommon either.

I haven't done this before but you might try streamlining the sabot a bit...it should still separate just fine but you might gain a bit...

Another thought... you can probably get by with only a few sheets of blue board in front of the fins. The brunt of the force will be taken up by the rear and the sheets in front just serve to hold the object centered in the barrel. As log as the rear has a pretty good seal all the front end does and make sure the object stays centered in the barrel...

When you get it all done could you post a vid... I've been meaning to make one but its just to dang cold right now...

Posted: Thu Mar 20, 2008 4:42 pm
by rcman50166
It's supposed to be cold when I fire this Saturday, but that doesn't stop me. I'll post a vid. It'll probably also be in the Spud Showdown thread also. However I may just make a seperate video to get the best angle of the sabot. Kinda wish I had a high speed camera. :( Oh well we'll just have to depend on that one frame where you can see the sabot in action.

Posted: Thu Mar 20, 2008 7:09 pm
by Jared Haehnel
I don't have the time or the camera to get everthing to set up like it really should be to do it any justice. So I look forward to it. Good luck 8)

Posted: Thu Mar 20, 2008 7:46 pm
by Carlman
rcman50166 wrote:It's supposed to be cold when I fire this Saturday, but that doesn't stop me. I'll post a vid. It'll probably also be in the Spud Showdown thread also.
or did you mean the spud gun accidents thread :D