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Author Topic: Percussion Cap Hulls  (Read 1216 times)

Offline ofitg

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Percussion Cap Hulls
« on: Sun,PM,18,49 »
Since the Tap-O-Cap is no longer on the market, I've been experimenting with alternative ways to manufacture percussion cap hulls. Some of you old-timers might remember the Mattel Vac-U-Form which was marketed to kids 50 years ago - if you can scrounge up one of these old machines from eBay or some other source, you can fabricate serviceable hulls from milk jug plastic.



The Vac-U-Form has an electric "oven" on one end, and a moulding platform on the other end. You clamp a 3" x 3.5" sheet of plastic in a carriage and swing the carriage over to the oven...... after 10 minutes or so, the plastic gets hot enough to mould, then you swing the carriage over to the moulding platform and operate a manual vacuum pump to suck the plastic down over a mould.
At first I had trouble getting the plastic hot enough, but a couple of mods to the oven improved the efficiency - I cut a thin strip of sheet aluminum, 0.4" x 13.25", and bent it into a rectangle to block the air vents around the sides of the oven - I also cut a 3.2" x 3.9" piece of aluminum plate and put a wooden handle on one side to serve as a lid for the top of the oven (and hold in the heat).

My mould is a piece of perforated steel plate with four 8-32 x 1/2" machine screws sticking through it. The plastic moulds itself over the ends of the screws, so it's necessary to unscrew the screws from the plastic when everything cools down.     



I use a a dog's toenail clippers to snip off the little plastic "peaks", and then I trim them to the correct length with small scissors.



The molded-in screw threads mean these little plastic hulls are internally ribbed. These little hulls fit perfectly on my Uberti's nipples.

I've seen guys from Australia and South Africa posting on different forums, those guys would give their eye teeth for a Tap-O-Cap! I hope our laws in the U.S. never get that bad, but it's nice to know that there's more than one way to skin a cat.
 
Apache Proverb - It is better to have less thunder in the mouth, and more lightning in the hand.

Offline jack404

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Re: Percussion Cap Hulls
« Reply #1 on: Thu,AM,04,51 »
mate,  this too is a ripper idea ,  a adaptive genius  you are !!  i've not seen one of these eh..  this has LOTS a great uses for ammo and such    cheers eh

with the screws  , make em shorter  ....

lowering the height will thicken the walls and you'll be able to double the amount of screw heads  per sheet  as they wont be so strained  and risk tearing and not forming correctly

Offline ofitg

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Re: Percussion Cap Hulls
« Reply #2 on: Thu,AM,09,00 »
Jack, that makes sense. Thanks for the great input, I'll give it a try!
Apache Proverb - It is better to have less thunder in the mouth, and more lightning in the hand.

Offline jack404

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Re: Percussion Cap Hulls
« Reply #3 on: Thu,PM,19,06 »
try all the original 12 holes in that sheet but at only 2mm  or so more than you need to allow the clippers to work ( or adjust height so its a one snip operation each time to cut off and get the right length )

i found one ( many actually ) on ebay ;)

Offline washbuster

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Re: Percussion Cap Hulls
« Reply #4 on: Tue,PM,17,28 »
What and how are you loading these plastic hulls.How well does the plastic do ,does it clogg the nipples?

Offline ofitg

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Re: Percussion Cap Hulls
« Reply #5 on: Tue,PM,18,00 »
I was using a potassium-chlorate-based primer mixture to load these things. No problem with clogging up the nipples. The plastic skirts generally spilt lengthwise upon firing, very similar to what a metal hull usually does.
Apache Proverb - It is better to have less thunder in the mouth, and more lightning in the hand.

Online mustangpalmer.58

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Re: Percussion Cap Hulls
« Reply #6 on: Tue,PM,23,32 »
 *rockin^ Good Karma on ya for this one!
"Stand your ground. Don't fire unless fired upon, but if they mean to have a war, let it begin here."