Electrical penetration of the firewall
Posted: Tue Oct 30, 2018 2:45 pm
by Bryan Cotton
Hey all,
Been planning my next firewall penetration. I noticed that some of you (like Ryan’s Waiex) have a firesleeve hose clamped to something that screws on the firewall. Is this a made or bought part? How big of a hole did you need?
Thanks!
Re: Electrical penetration of the firewall
Posted: Tue Oct 30, 2018 5:03 pm
by Bryan Cotton
I just found them at Spruce. I think I’ll make my own.
Re: Electrical penetration of the firewall
Posted: Tue Oct 30, 2018 6:50 pm
by peter anson
Hi Bryan, I used several small Mil-spec connectors https://en.wikipedia.org/wiki/U.S._Military_connector_specifications
You can get them with solder terminals so don’t have to buy expensive crimping tools. Can be fabulously expensive but my guess is that it may be possible to buy used or surplus ones. They are entirely reliable. The ones I used have only 6 connections per plug so wiring was pretty simple.
Peter
Re: Electrical penetration of the firewall
Posted: Tue Oct 30, 2018 7:18 pm
by Rynoth
Bryan Cotton wrote:Hey all,
Been planning my next firewall penetration. I noticed that some of you (like Ryan’s Waiex) have a firesleeve hose clamped to something that screws on the firewall. Is this a made or bought part? How big of a hole did you need?
Thanks!
Mine was this kit from ACS:
https://www.aircraftspruce.com/catalog/ … kkey=33137
The fitting was just a simple stainless steel plate with a hole in it, with a stainless steel ring welded onto it to give the sleeve something to hose-clamp to. It wouldn’t be difficult to make if you knew what you were doing. Mine was a 1-inch hole, which was enough room for all of my electrical wires.
Re: Electrical penetration of the firewall
Posted: Wed Oct 31, 2018 2:54 pm
by Jim1342
Tony Bingelis offers an inexpensive homemade penetration which is published on the EAA website.
https://www.eaa.org/en/eaa/aviation-com … et-shields
Electrical penetration of the firewall
Posted: Wed Oct 31, 2018 9:28 pm
by n307tw
I agree with Ryan. I used the 1 inch kit. Yeah it’s kind of expensive but one hole and all the wires go through it and it looks neater and professional. I’m not done yet but I attached some pics of my progress so you can see what I mean. Hope this helps.
-Tim
Sent from my iPhone using Tapatalk
Re: Electrical penetration of the firewall
Posted: Wed Oct 31, 2018 10:07 pm
by Bryan Cotton
Thanks guys! I have the Bingeles books and had seen that shield before. I did poorly forming them with the stainless I had on hand, and where do you get asbestos washers? I will probably make one like the Spruce offerings out of 4130 to match my leftover fire sleeve.
Re: Electrical penetration of the firewall
Posted: Thu Nov 01, 2018 1:49 am
by woodmw
Could you cut some round disks out of fire sleeve to use in place of the asbestos washers?
Re: Electrical penetration of the firewall
Posted: Thu Nov 01, 2018 6:35 am
by Bryan Cotton
woodmw wrote:Could you cut some round disks out of fire sleeve to use in place of the asbestos washers?
That is a great idea!
Re: Electrical penetration of the firewall
Posted: Thu Nov 01, 2018 8:59 am
by 9GT
These are a great low cost solution for firewall penetrations. Buy a foot of appropriate fire sleeve and a couple clamps and you have a professional looking fire barrier to the cabin. https://www.amazon.com/uxcell-Diameter-Silver-Stainless-Flange/dp/B00E1HEGTO . When you have all your wires run through, don’t forget to stuff the penetration with some 3M Fire Barrier 2000 sealant: https://www.aircraftspruce.com/catalog/ … kkey=13950 , then worm clamps, one holding the fire sleeve on the flange, the other over the end of the fire sleeve where the wires exit into the engine compartment. Don’t fool yourself into thinking you could use high temperature RTV instead of the expensive 2000 sealant. There is no comparison in actual testing results.
Re: Electrical penetration of the firewall
Posted: Thu Nov 01, 2018 9:50 am
by Bryan Cotton
Thanks David! I just placed an order for that part.
Re: Electrical penetration of the firewall
Posted: Mon Dec 03, 2018 11:32 pm
by Bryan Cotton
Here is my cheap penetration installed. I have enough spare firesleeve to seal it up.
Inside:
Re: Electrical penetration of the firewall
Posted: Tue Dec 04, 2018 8:29 am
by Bryan Cotton
One thing I forgot to mention - if you put the fitting in like I did, it protects the wires from the edge of the firewall. I was going to install it like in Ryan’s picture and then I had an epiphany.
Re: Electrical penetration of the firewall
Posted: Tue Dec 04, 2018 11:03 am
by Rynoth
Bryan Cotton wrote:One thing I forgot to mention - if you put the fitting in like I did, it protects the wires from the edge of the firewall. I was going to install it like in Ryan’s picture and then I had an epiphany.
I like your solution!
For what it’s worth, in the ACS kit installation, the wires are protected from any firewall/metal edge contact by wrapping the wires in some of the fireproof sleeve passed through the fitting itself. Besides protecting the wires from chafing, I assume this also helps to make a better fireproof seal on the engine-compartment side (more meat for the full sleeve to clamp onto.) It was done by taking the sleeve and cutting down the middle of it lengthwise to make it a smaller diameter to stick through the opening. You might consider using the same method even in your install. Here’s some pics:
You can see in the bottom picture that the outer sleeve is wrapped around the inner sleeve which is wrapped around the wires.
Re: Electrical penetration of the firewall
Posted: Tue Dec 04, 2018 1:01 pm
by Bryan Cotton
Ryan,
I will do that, thanks.
Re: Electrical penetration of the firewall
Posted: Fri Mar 29, 2019 1:28 pm
by n307tw
Bryan,
That looks great, just found out I have to make another penetration in my firewall for all the sensors for the Aerovee Turbo. Garmin doesn’t approve of their engine monitor being installed in the engine compartment so I have to bring all those wires into the cabin. I will be doing the cheaper option for this penetration on this one for sure. Both your and Ryan’s came out great.
-Tim
Re: Electrical penetration of the firewall
Posted: Fri Mar 29, 2019 7:05 pm
by GordonTurner
That’s a lot of orange. Bryan, what was your favorite color again?
Gordon
Re: Electrical penetration of the firewall
Posted: Sat Mar 30, 2019 9:57 am
by GordonTurner
Hi Bryan
Question about your fire wall seeling. It appears you are seeling both the engine side and the cockpit side of each fastener with rtv. I’m sure the protocol for firewalls is spelled out somewhere, do you happen to have an informative but still readable source?
Thanks, Gordon
Re: Electrical penetration of the firewall
Posted: Sat Mar 30, 2019 1:33 pm
by Rynoth
Hi Gordon, I assume you’re referring to my pictures above. I actually only did one side of most fasteners, it’s just that I didn’t seal the nutplates until they were installed and only really had access from the inside of the firewall since the attached accessories were in the way. Didn’t follow any real guidance other than just trying to make sure every hole I made in the firewall was made airtight with sealant.
And yes, I like orange. It was a big tube of sealant and I have fat fingers.
Re: Electrical penetration of the firewall
Posted: Sat Mar 30, 2019 3:10 pm
by GordonTurner
Ok. Thanks for all the info, more to think about as I creep up on the firewall forward part of the project.