Ebay with Metal Bulk Plates - Wildman

[Zeke Johnson]

I received an electronics bay from Wildman Rocketry. It is a very basic kit, 1 32mm fiberglass coupler and two bulk plates (See Pictures).

I have never worked with metal bulk plates before. I was wondering if I could get some ideas on how to pass the electrical signal from my altimeter inside the ebay to the BP charge outside the ebay.

If it were non-conductive material, such as fiberglass or wood, I would just put 2 screws through the plate. Wire the altimeter to the screws inside, then wire the Black Powder capsule leads to the other end of the screws outside the ebay.

Since the plates are conductive metal, this method will not work.

I could just pass a pair of 22 awg insulated wire through a small hole in the metal plate, but then I risk a short due to vibration.

I asked Tim, but he din't offer any suggestions. He just offered to swap them for fiberglass plates.

Keep in mind this is pretty small. This is a coupler that goes inside a 32mm airframe.

Here are the photos:

Wildman-32mm-Ebay-2

• Zeke Johnson
• Feb 20, 2020

Wildman 32mm eBay with Metal Bulk Plates

Wildman-32mm-Ebay-1

• Zeke Johnson
• Feb 20, 2020

Wildman 32mm eBay with Metal Bulk Plates

Any suggestions will be greatly appreciated.

Zeke

 

[NateB]

I used the screw insulators from Binder Design through the aluminum bulkhead plate on my Punisher. The 3/16 one was the right size for my kit and I used it with the charge wells with integrated terminal blocks. You could use something similar to protect whatever screws you would use in a wood or fiberglass bulkhead like you described.

https://binderdesign.com/store/page28.html

You could also use a Well Nut or even just a hole with the e-match lead attached directly to your altimeter and secured with some putty. Given you have a small e-bay, I'd probably just drill a small hole and keep vibration and gasses out of the ebay with the putty.

 

[DaveW6DPS]

I use binding posts designed or mounting in a metal cabinet. I have a couple of Wildman ebays with them. I also use the same basic type for wood or fiberglass.

This is about mounting the Big Red Bee, but shows the binding posts: https://rocstock.org/learn/advanced/mounting-a-big-red-bee-gps-tracker/

 

[David Schwantz]

Easy way would be to just countersink your holes.

 

[Speaknoevil]

Drill your holes, pass the wires through and use hot glue to seal the hole and protect against shorts. If that is too ghetto for you, then try these: https://www.lowes.com/pd/Hillman-15-Count-6-32-x-1-2-in-Rubber-Standard-SAE-Well-Nuts/4189131

 

[markg]

I use terminal blocks. I drill the holes to match the legs on the blocks, then solder on the wires and wrap them in heat shrink tubing. I put a JST connector on the other end of the wire for the connection to the altimeter. I use a little bit of epoxy on the terminal block to keep it in place. I cover them in masking tape to protect them from BP residue after everything is connected. You can get these cheap from aliexpress.

cheers

 

[Brent]

Dam how did they cut the OD on those bulk plates a chisel? That is some terrible chatter.

 

[Rob702Martinez]

Dog house rocketry has a set up for this. You could also make your own with nylon standoffs, washers etc. Drill to fit a standoff put washers to insulate, put the metal screw through that.

 

[Wallace]

Easiest/most cost effective solution would be to simply take Tim up on his glass plates offer. Seems to me like everything else has to many potential issues/difficulties/costs/problems. In my mind, a couple of rock solid screws (as you've stated) as terminals and done is by far the best solution. There is a reason G-10 or phenolic, not aluminum is used for circuit boards and or potentially conductive areas.

 

[djs]

Drill your holes, pass the wires through and use hot glue to seal the hole and protect against shorts.

I do the same, but use sticky tack/poster tack to plug the holes.

 

[Zeke Johnson]

Easiest/most cost effective solution would be to simply take Tim up on his glass plates offer. Seems to me like everything else has to many potential issues/difficulties/costs/problems. In my mind, a couple of rock solid screws (as you've stated) as terminals and done is by far the best solution. There is a reason G-10 or phenolic, not aluminum is used for circuit boards and or potentially conductive areas.

I think I like this suggestion the best. If there were more room to work with, I could experiment with different ways to insulate wires from the conductive plates.

This is a pretty small area. The pass through holes would need to be over sized to allow for the additional insulation material.

I think I will swap these out the the fiber glass plates and use my proven method of simple screw terminals.

 

[jd2cylman]

Drill your holes, pass the wires through and use hot glue to seal the hole and protect against shorts. If that is too ghetto for you, then try these: https://www.lowes.com/pd/Hillman-15-Count-6-32-x-1-2-in-Rubber-Standard-SAE-Well-Nuts/4189131

I do the same, but use sticky tack/poster tack to plug the holes.

That's what I do also, except I use a single layer of 1" masking tape. Has held up to multiple 7 gram charges so far. Never any soot in the AV bay interiors. Switch if you want, but the wires aren't going to be moving in the hole, especially long enough to wear through the insulation. Drill the holes, chamfer each side, and pass the wires through. Tape or sticky tack or hot glue over the holes. Boom. Done. No terminal blocks to get crudded up.

 

[Speaknoevil]

Adrian, 7 gram charges, OMG!

 

[ep29030]

I would solder wires to terminal blocks, then put 1-2 layers of shrink tubing on wires to insulate through the bulkhead. Should work fine.

 

[jd2cylman]

Adrian, 7 gram charges, OMG!

Well, it was a 8" tube x 36" long, so there was some volume there... Actually, main was 6.5 and back up was 7.5 now that I think about it.
But the single layer of tape held against the pressure fine...