Tip: DIY Penetration Kit For Under $10!

[9GT]

I couldn't bear the thought of spending $57 for a 3/4" firewall penetration kit so I did some digging around on the internet. I found these on Amazon in a variety of sizes and quantities. Two for $7.85, and free shipping with my Prime membership: https://www.amazon.com/uxcell-Diamet...ld+Neck+Flange . 2" X 1/2" stainless steel washers from my favorite hardware store at .45 cents each. They work as a backer on the cabin side of the firewall. Just drill out the 1/2" hole to 3/4" with a good Unibit and deburr, then match drill the mounting holes, or drill new ones to suit. I had a foot of 1" I.D. silicone fire-sleeve leftover from another project and have a tube of 3M 200 Fire Stop sealant to seal up the firewall on hand. Add a couple SS worm clamps and your good to go. The flanges have a drilled hole in side of the tube for a set screw but the sealant, worm clamp, and overlaying fire sleeve will take care of that. I have a TIG so will probably weld the holes closed though I do not thing it is necessary. So here I have 2 nice stainless steel firewall penetration kits for about $5.00 each.
[IMG]DSC01987 by David C, on Flickr[/IMG]
[IMG]DSC01988 by David C, on Flickr[/IMG]

[Mike S]

Ah........the joy of experimental aviation

[wirejock]

Excellent. Not too far away so I'm ordering a few. Thanks for the tip.

[160kt]

I’m curious what alloy of Stainless these flanges are made from? Could you put a magnet on one and see if it sticks at all? I like to keep magnetics to a minimum in front of the compass.
Thanks

[rv8ch]

I used this method with my first engine, and it was very good. For a flange and tube, I used stainless steel bathroom safety grab bars.

http://www.aeroelectric.com/articles.../firewall.html

For the second engine, I purchased the well-known kits, since I needed much smaller penetrations.

http://www.aircraftspruce.com/catalo...ration_kit.php

I've seen many methods on RVs and certified aircraft that I wouldn't feel comfortable with, like just a hole with a dab of RTV to "protect" the wires, plastic snap bushing with RTV, rubber grommet with nothing else, and even the rubber grommet with the stainless steel cover, but these aircraft seem to have been signed off and fly. ?\_(ツ)_/?

[Electrogunner]

I literallly just installed my stainless steel shower rod holders last week. Glad to see I?m not the only thrifty one in the bunch. I just could not spend $60/ea on them. I did cut mine down to the set screw though.

[hgerhardt]

Another nice way is to take a steel AN bulkhead fitting and bore out the hole on a lathe. You can also turn down the OD and remove the threads everywhere except where the nut needs to go to lighten it.

[Ethanol1]

You must of bought the last ones.

https://www.amazon.com/uxcell-Diamet...ld+Neck+Flange

[kentlik]

Originally Posted by Ethanol1

You must of bought the last ones.

https://www.amazon.com/uxcell-Diamet...ld+Neck+Flange

https://www.amazon.com/gp/product/B0...8BJ6JWOC&psc=1

Here are similar items.

[Av8torTom]

They remind me of SS marine rail fittings. These might be on the heavy side, but offer a choice of angles.

http://www.go2marine.com/product/675...ss-steel.html?