Black Powder Piston Capsule Test

Conducted by: Jack A (484-502-8924), Claire J

Location: Blast Chamber

Date: 05/02/23

Time: 1830-2030

 

Safety Precautions:

  • All participants must wear safety glasses.

  • Range safety officer must audibly countdown before the test and ensure that everyone is paying attention.

  • Test articles should not fragment into sharp, hard pieces during the test sequence.  This is ensured by eliminating any unfastened materials within the body sections, and limiting the amount of pyrotechnic charge used.

  • The SO should inspect all test articles prior to initiating the piston test.

  • Appropriate PPE will be used when installing the charge prior to the test (i.e. safety goggles and nitrile gloves). There will never be skin contact with the charge

  • If a misfire occurs:  wait at least 60 seconds and disconnect the battery (or use an alternative method to disable the testing mechanism) before allowing anyone to approach the test article.

  • Strict 25 foot keep-out zone must be established, which all test participants must obey. Members should ensure that no bystanders are present. The SO must ensure that no one is in the expected path of the projectile regardless of distance from the test articles. Mark of the test area (such as with caution tape) or otherwise guard entrances from bystanders.

  • All debris must be cleared out of the blast chamber when the test is complete.

  • Call MIT Police 617-253-1212 to report an emergency. 

  • Email Anthony Zolnik about blast chamber usage and receive approval or confirmation. 

    NOTE: Because there is no smoke or venting of fumes, members and the SO do not need to contact police before testing; however, it is required we reach out to at least one facilities manager (Anthony). 

Goals:

  • Evaluate the performance of two new designs for black powder capsules

Materials:

Tools:

  • 2 adjustable crescent wrenches

  • Gloves

  • Alligator clips

  • Bricks/sandbags/weights

  • Vacuum chamber & pump

  • Safety glasses 

  • Close toed shoes

  • A very long wire

  • Multimeter

  • 9V battery

  • Scale

  • Hydrostatic Testing Manifold
  • Hydrostatic pump
  • Bucket of water

Hardware:

  • 4 pistons

  • 2 Brass NPT Plugs with two holes

  • 2 Brass NPT Plugs with one hole

  • 8 Brass NPT Reducing Adapters
  • 8 Burst Disk Washers

  • 4 1/4-20 screws

Consumables:

  • Black powder (.4 g per capsule)

  • 5 minute epoxy

  • 16 e-matches

Procedures:

Check-offs:

  • Fit check

  • Reserve the blast chamber

Black powder capsule integration procedure (24 hours before):

  • Insert two ematches into the hole in each brass plug
  • Fill the gaps of the brass plugs with epoxy
  • Wait for adhesive to dry

Hydrostatic Testing Procedure:

  • Wrap each brass plug in at least 3 wraps of teflon tape
  • Screw each plug into the hydrostatic testing manifold until tight
  • Wrap each 1/4-20 screw in teflon tape
  • Screw all but one 1/4-20 screw into the hydrostatic testing manifold
  • Wrap the hydrostatic testing pump's screw end in teflon tape
  • Screw the tube end into the 1/4 NPT hole in the hydrostatic testing manifold
  • Put the inlet and outlet tubes from the hydrostatic pump in the bucket of water
  • Ensure the fluid is routed into the hydrostatic testing manifold
  • Operate the pump until water spills out of the one remaining hole in the hydrostatic testing manifold
  • Screw the remaining 1/4-20 screw into the hydrostatic testing manifold until tight
  • Operate the pump until the pressure gauge reads 1000 psi
  • Check for any leaks in the brass plugs
  • Release pressure in the hydrostatic testing manifold
  • De-integrate the testing set-up and clean up
  • If no leaks are present, proceed to the rest of the procedure (ensure the brass plugs are dry before adding black powder)

Piston Integration Procedures: 

  • Using a 1/4 inch torque wrench, ensure that the bolts holding the piston together are tight (100 inch-pounds of torque). If the bolts are loose, the piston will lose pressure as it extends. (torque wrench adapter in piston box)

  • Use multimeter to check continuity of e-matches (should be about 1.0-1.4 ohms) and twist the wires to short it. Two people should visually confirm that it is shorted. 

  • Everyone put on safety glasses. From now on, everyone within the vicinity of the pyrotechnics must wear safety glasses.

  • Measure out 0.4 g of black powder and pour it into each brass plug, holding over a weigh boat to catch any fallout. This should be close to filling the plug and may overflow slightly.

  • Wrap the brass plugs with three wraps of Teflon tape.  

  • Insert one burst disk washer into each reducing adapter

  • Screw the powder-filled plug carefully into the reducing adapter (hopefully until it bottoms out on the washer)
  • Check for leaking black powder

  • Compress the piston completely!

  • Screw the capsule into the piston NPT hole.

  • Test the piston by pulling up rod for 5 secs and checking that it is sealed

  • Log e-matches

Black Powder Capsule Testing Procedures:

  • Perform integration according to the Piston Integration Procedures above.

  • Run wires from outside to inside the blast chamber. Make sure that the wires are shorted on the outside of the blast chamber. On the inside, unshort the e-match leads and connect it to the wires.

  • Place the piston in the vacuum chamber (firebolt-fitting assembly pointing down).

  • Clamp the piston between two bricks. 

  • Put the lid on the chamber and turn on the vacuum pump until pressure level reaches 0 psi. 

  • Only after exiting the chamber and closing the door, perform a countdown and connect the outside wires to a voltage source (battery).

  • In the event of a misfire, disconnect the battery and wait at least 60 seconds before allowing anyone to enter the chamber/approach the test article.

  • After firing, wait at least 60 seconds before entering the blast chamber.

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