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rvtach

Joined: 28 Jan 2008
Posts: 26
Location: Tucson, AZ

Posted: Mon Jan 28, 2008 3:42 pm Post subject: Firewall penetration

Hi-



Working on making firewall penetrations and making them fireproof. I'm using steel eyeballs for engine control cables and a stainless heater valve. I'm expecting to have a single penetration for electrical wiring and for engine sensors etc near the battery box. 



I like Bob's modified grab handle method for a fireproof penetration but it's larger and bulkier than I need. And it's probably not a good use of my $time$ to try to come up with a less expensive alternative to the SafeAir 1 stainless fire wall pass through system; it's only $50. But it's $50! I came across a plumbing fitting in the "swamp cooler" section of my local plumbing supply today and it just might be a $3.50 alternative. I have posted some photos at http://picasaweb.google.com/rvtach/FirewallPassthrough that show the hardware. 



It comes threaded internally for 1/2" NPT. I removed the threads by running a 7/8" drill through it. The whole thing fits snugly through a 1" hole and is secured by a threaded nut which would need to be secured with some thread locker.  I would use firesleeve and hose clamps like Bob's grab handle or the SafeAir 1 product. There's just over 1/2" to clamp the sleeve to which is a little short but should be adequate.



So, can any of you guys think of any problems with this method? Maybe I shouldn't use brass hardware against the s/s firewall? Brass melts to easily? Anything? Appreciate any help at all here.

_________________
Jim McChesney
Tucson, AZ
RV-7A Flying

RV10 4JF

Joined: 30 Nov 2007
Posts: 7

Posted: Mon Jan 28, 2008 4:54 pm Post subject: Re: Firewall penetration

Hello,



Tony Bingelis wrote an article on making pass-thru fittings. They are similar to those used on Cessnas except that they are one piece where as the Cessna fittings are two piece. They are oval in shape, SS with fire retardant material surrounding your pass-thru item. You make them out of stainless steel using sockets or pipe as the forming die. They are attached to the firewall with 2 screws. You drill a hole to fit your pass-thru item. You can make them as large or small as you like. You just have to find the right die.



I will see if I can find the article and maybe I can post some pictures or a poorly drawn facsimile.



BTW, in case of an engine fire, you want these fittings to provide some protection so you really need something good.



JF

Dale Ensing

Joined: 11 Jan 2006
Posts: 571
Location: Aero Plantation Weddington NC

Posted: Mon Jan 28, 2008 5:34 pm Post subject: Firewall penetration

Be aware of possible impact on engine sensor data if sensor leads are too 

close to high current (fat) wires.

Dale Ensing



---

_________________
Dale Ensing
RV-6A
Aero Plantation
Weddington NC

ceengland(at)bellsouth.ne
Guest

Posted: Mon Jan 28, 2008 7:21 pm Post subject: Firewall penetration

rvtach wrote:

 	  Quote: 	
		   

 

 Hi-

 

 Working on making firewall penetrations and making them fireproof. I'm using steel eyeballs for engine control cables and a stainless heater valve. I'm expecting to have a single penetration for electrical wiring and for engine sensors etc near the battery box. 

 

 I like Bob's modified grab handle method for a fireproof penetration but it's larger and bulkier than I need. And it's probably not a good use of my $time$ to try to come up with a less expensive alternative to the SafeAir 1 stainless fire wall pass through system; it's only $50. But it's $50! I came across a plumbing fitting in the "swamp cooler" section of my local plumbing supply today and it just might be a $3.50 alternative. I have posted some photos at http://picasaweb.google.com/rvtach/FirewallPassthrough that show the hardware. 

 

 It comes threaded internally for 1/2" NPT. I removed the threads by running a 7/8" drill through it. The whole thing fits snugly through a 1" hole and is secured by a threaded nut which would need to be secured with some thread locker.  I would use firesleeve and hose clamps like Bob's grab handle or the SafeAir 1 product. There's just over 1/2" to clamp the sleeve to which is a little short but should be adequate.

 

 So, can any of you guys think of any problems with this method? Maybe I shouldn't use brass hardware against the s/s firewall? Brass melts to easily? Anything? Appreciate any help at all here.

 

 --------

 Jim McChesney

 Tucson, AZ

 RV-7A Finishing Kit


	


Is it a brass fitting? If so, it will melt at a lower temp than 

stainless, but so will the aluminum rivets & angles (and the copper wire 

going through it will, too). You might be able to find the same fitting 

in stainless from a food supply grade plumbing supplier.



You just have to weigh risk/benefit/expense.



My personal opinion is that there's much more risk from the heater 

penetration, even with stainless parts, than with any penetration 

carrying solid wires or steel cables. If you look at the air gap around 

the flapper valve on the heater penetration, the total area of the gap 

is effectively a gaping hole, compared to a wire penetration filled with 

wire & fire suppressing caulk.



Charlie

echristley(at)nc.rr.com
Guest

Posted: Mon Jan 28, 2008 7:53 pm Post subject: Firewall penetration

rvtach wrote:

 	  Quote: 	
		   So, can any of you guys think of any problems with this method? Maybe I shouldn't use brass hardware against the s/s firewall? Brass melts to easily? Anything? Appreciate any help at all here.

   

A big contributor to the elbow fitting's effectiveness is the elbow.  
	


The fire would have to turn a corner.  You loose that with a straight 

through fitting.



It should be fairly easy to find a stainless elbow that would do the 

same thing.  You might have to got up to $10 to get one though 8*)

klehman(at)albedo.net
Guest

Posted: Tue Jan 29, 2008 4:45 am Post subject: Firewall penetration

It is not difficult to make a stainless guillotine valve right on the 

firewall. A pull cable pulls a plate over the firewall hole to block it 

and control the heat. In case things distort in a fire, I have it set to 

pull closed. It is on the cabin side of the FW. Perhaps not as good a 

solution for those who have to dump excess manifold heat but excellant 

for water heat and for fire blocking.

Ken



snip

 	  Quote: 	
		   My personal opinion is that there's much more risk from the heater 

 penetration, even with stainless parts, than with any penetration 

 carrying solid wires or steel cables. If you look at the air gap around 

 the flapper valve on the heater penetration, the total area of the gap 

 is effectively a gaping hole, compared to a wire penetration filled with 

 wire & fire suppressing caulk.

 

 Charlie

RV10 4JF

Joined: 30 Nov 2007
Posts: 7

Posted: Tue Jan 29, 2008 6:34 am Post subject: Re: Firewall penetration

I found the article that I mentioned on the EAA  builders site. 



http://members.eaa.org/home/homebuilders/building/firewall/How%20to%20Make%20Firewall%20Grommet%20Shields.html#TopOfPage

Check this out and see if it will work for you.

JF

david.nelson(at)pobox.com
Guest

Posted: Tue Jan 29, 2008 8:14 am Post subject: Firewall penetration

Hi Jim,



Clever idea.  I presume it's brass so it's corrosion resistant even though

you drilled out the threads.



I saw a clever use of EMT tubing set screw connectors (ie steel electrical

conduit tubing).  You can see a picture here (search for 'set-screw'):



http://www.alliedtube.com/electrical-raceways/conduit/emt-connectors-couplings.asp



The builder had notched out the set screw.  Personally, I think I'd leave

the set screw hole (and toss the set screw) and make sure the inside of

coupling was free of any burrs, etc.  The set screw hole is slightly

raised thus providing a little bit of a "barb" to keep any clamps and fire

sleeve from backing out.



The connectors are available in a variety of nominal sizes from 1/2",

3/4", 1", 1-1/4", 1-1/2", all the way up to 4".  Any hardware store (at

least in the US) would have the smaller sizes.



I would also think about using some .032 sheet behind the locking nut

rather than have the nut gouge the firewall.



Regards,

          /\/elson

          Austin, TX

          RV-7A - Canopy frame

~~  Lately my memory seems to be like a steel trap .... without any spring.  ~~



On Mon, 28 Jan 2008, rvtach wrote:



 	  Quote: 	
		   



 Hi-



 Working on making firewall penetrations and making them fireproof. I'm using steel eyeballs for engine control cables and a stainless heater valve. I'm expecting to have a single penetration for electrical wiring and for engine sensors etc near the battery box.



 I like Bob's modified grab handle method for a fireproof penetration but it's larger and bulkier than I need. And it's probably not a good use of my $time$ to try to come up with a less expensive alternative to the SafeAir 1 stainless fire wall pass through system; it's only $50. But it's $50! I came across a plumbing fitting in the "swamp cooler" section of my local plumbing supply today and it just might be a $3.50 alternative. I have posted some photos at http://picasaweb.google.com/rvtach/FirewallPassthrough that show the hardware.



 It comes threaded internally for 1/2" NPT. I removed the threads by running a 7/8" drill through it. The whole thing fits snugly through a 1" hole and is secured by a threaded nut which would need to be secured with some thread locker.  I would use firesleeve and hose clamps like Bob's grab handle or the SafeAir 1 product. There's just over 1/2" to clamp the sleeve to which is a little short but should be adequate.



 So, can any of you guys think of any problems with this method? Maybe I shouldn't use brass hardware against the s/s firewall? Brass melts to easily? Anything? Appreciate any help at all here.



 --------

 Jim McChesney

 Tucson, AZ

 RV-7A Finishing Kit





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=160931#160931

rvtach

Joined: 28 Jan 2008
Posts: 26
Location: Tucson, AZ

Posted: Tue Jan 29, 2008 9:26 am Post subject: Re: Firewall penetration

 	  david.nelson(at)pobox.com wrote: 	
		  Hi Jim,



Clever idea.  I presume it's brass so it's corrosion resistant even though

you drilled out the threads.



	
[/quote]



Yup. It is solid brass. Any opinions if brass is adequate fire protection in this application?



 	  Quote: 	
		  Be aware of possible impact on engine sensor data if sensor leads are too 

close to high current (fat) wires. 

Dale Ensing 

	




Hadn't thought of this. I had planned on running my main bus and e-bus feed lines through this pass through (along with all engine sensors). No really fat wires (like starter or B-lead) but would there be enough current here for me to need to make a separate penetration to keep these wires separate?



Really appreciate all the input so far. If I actually do need to make 2 more penetrations then maybe this is worthwhile ($7 vs $100).



Thanks,

_________________
Jim McChesney
Tucson, AZ
RV-7A Flying

ericparlow(at)hotmail.com
Guest

Posted: Wed Jan 30, 2008 7:05 am Post subject: Firewall penetration

We used a similar fitting but it has a barbed extension to clamp flexible conduit over it.

$2.50 ea in Lowes Aviation dept.

See photos attached

 

We used 4 of theses on our RV-10 mounted in the firewall center recess.

The wires pass thru the bulkhead fitting with a connector on either side.

The wires are wrapped in fire sleeve similar to the SafeAir design.

After the pass-thrus are in the firewall the FWF side connectors are mounted on to the back side of a SS plate which covers the recess.

 

Eric Parlow

RV-10, 40014

N104EP



 	  Quote: 	
		   Date: Tue, 29 Jan 2008 10:10:07 -0600

 From: david.nelson(at)pobox.com

 To: aeroelectric-list(at)matronics.com

 Subject: Re: Firewall penetration

 

 --> AeroElectric-List message posted by: 'David E. Nelson' <david.nelson(at)pobox.com>

 

 Hi Jim,

 

 Clever idea. I presume it's brass so it's corrosion resistant even though

 you drilled out the threads.

 

 I saw a clever use of EMT tubing set screw connectors (ie steel electrical

 conduit tubing). You can see a picture here (search for 'set-screw'):

 

 http://www.alliedtube.com/electrical-raceways/conduit/emt-connectors-couplings.asp

 

 The builder had notched out the set screw. Personally, I think I'd leave

 the set screw hole (and toss the set screw) and make sure the inside of

 coupling was free of any burrs, etc. The set screw hole is slightly

 raised thus providing a little bit of a 'barb' to keep any clamps and fire

 sleeve from backing out.

 

 The connectors are available in a variety of nominal sizes from 1/2',

 3/4', 1', 1-1/4', 1-1/2', all the way up to 4'. Any hardware store (at

 least in the US) would have the smaller sizes.

 

 I would also think about using some .032 sheet behind the locking nut

 rather than have the nut gouge the firewall.

 

 Regards,

 /\/elson

 Austin, TX

 RV-7A - Canopy frame

 

 

 ~~ Lately my memory seems to be like a steel trap .... without any spring. ~~

 

 On Mon, 28 Jan 2008, rvtach wrote:

 

 > --> AeroElectric-List message posted by: 'rvtach' <rvtach(at)msn.com>

 >

 > Hi-

 >

 > Working on making firewall penetrations and making them fireproof. I'm using steel eyeballs for engine control cables and a stainless heater valve. I'm expecting to have a single penetration for electrical wiring and for engine sensors etc near the battery box.

 >

 > I like Bob's modified grab handle method for a fireproof penetration but it's larger and bulkier than I need. And it's probably not a good use of my $time$ to try to come up with a less expensive alternative to the SafeAir 1 stainless fire wall pass through system; it's only $50. But it's $50! I came across a plumbing fitting in the 'swamp cooler' section of my local plumbing supply today and it just might be a $3.50 alternative. I have posted some photos at http://picasaweb.google.com/rvtach/FirewallPassthrough that show the hardware.

 >

 > It comes threaded internally for 1/2' NPT. I removed the threads by running a 7/8' drill through it. The whole thing fits snugly through a 1' hole and is secured by a threaded nut which would need to be secured with some thread locker. I would use firesleeve and hose clamps like Bob's grab handle or the SafeAir 1 product. There's just over 1/2' to clamp the sleeve to which is a little short but should be adequate.

 >

 > So, can any of you guys think of any problems with this method? Maybe I shouldn't use brass hardware against the s/s firewall? Brass melts to easily? Anything? Appreciate any help at all here.

 >

 > --------

 > Jim McChesney

 > Tucson, AZ

 > RV-7A Finishing Kit

 >

 >

 >

 >

 > Read this topic online here:

 >

 > http://forums.matronics.com/viewtopic.php?p=160931#160931

 >

 >

 >

 >

 >

 >

 >

 >

===========

klehman(at)albedo.net
Guest

Posted: Thu Jan 31, 2008 9:25 am Post subject: Firewall penetration

FWIW I ran everything including starter fat wire through the same 

opening which is a hardware store steel towel rack/grab bar elbow. It 

really doesn't matter if an engine sensor is misreading a bit during 

cranking. At idle on the ground I can hear a bit of electronic ignition 

noise from one ignition. No alternator noise at all so I'd do it again. 

I don't have mags.

Ken

 	  Quote: 	
		   

 

> Be aware of possible impact on engine sensor data if sensor leads are too 

> close to high current (fat) wires. 

> Dale Ensing 

>

 

 

 Hadn't thought of this. I had planned on running my main bus and e-bus feed lines through this pass through (along with all engine sensors). No really fat wires (like starter or B-lead) but would there be enough current here for me to need to make a separate penetration to keep these wires separate?

 

 Really appreciate all the input so far. If I actually do need to make 2 more penetrations then maybe this is worthwhile ($7 vs $100).

 

 Thanks,

 

 --------

 Jim McChesney

 Tucson, AZ

 RV-7A Finishing Kit

Bill Schlatterer

Joined: 09 Jan 2006
Posts: 195

Posted: Thu Jan 31, 2008 5:42 pm Post subject: Firewall penetration

Just FWIW, I posted a similar firewall penetration a couple years ago using

the cheap pot metal electrical connectors shown in the attachment.  I was

cautioned to AVOID any of the fittings that were made of cast steel

compounds (gray looking pot metal material) because they would actually burn

very well under modest flame.  Was told to ONLY use the steel tube/forged

fittings which were much more expensive but would not burn.



I did not put a torch on them to find out but thought I might mention it.

Pictures of the rejected fittings attached.



Just what I was told on this list back then. 



Bill S

7a

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Joemotis(at)aol.com
Guest

Posted: Thu Jan 31, 2008 6:07 pm Post subject: Firewall penetration

Those connectors are made from ZAMAC and have a melting point of around 750  degrees. You can melt them in a saucepan on a gas cooktop.

  

 Joe Motis

  

 Do not archive



Start the year off right.  Easy ways to stay in shape in the new year. 

  [quote][b]

longg(at)pjm.com
Guest

Posted: Fri Feb 01, 2008 1:37 pm Post subject: Firewall penetration

I understand the experimental mentality and all, but this crap is so

cheap-o. Are we left to salvaging conduit fittings from electrical

contractors? I have tons of these things in coffee cans in my basement

if anyone really wants to use them.



These clamps are right at home running conduit to my air-conditioner,

but if you do a risk analysis of using them on the firewall with your

family sitting behind them, what value would you place on buying

something actually made for the firewall for a few dollars more? 



 

--

mkimball(at)gci.net
Guest

Posted: Fri Feb 01, 2008 2:35 pm Post subject: Firewall penetration

Anybody have a web link to the proper penetration fittings?



Mike



--

stevea(at)svpal.org
Guest

Posted: Fri Feb 01, 2008 3:34 pm Post subject: Firewall penetration

These are what I installed.  Buy direct from EPM or get them through 

Aircraft Spruce.

http://www.epm-avcorp.com/tubeseal.html



The idea here is to buy time to shut off the fuel and get the airplane 

on the ground in the event of an in flight engine fire.  Aluminum, 

plastic, brass, and zinc/aluminum (conduit fittings) will fail 

catastrophically well below the temperature at which gasoline burns.  

Steel (stainless or non-stainless) will withstand that temperature much 

longer, allowing for a better chance at surviving the situation.



It is called a "firewall" for a reason.



Steve A

RV-6A

Mike Kimball wrote:

 	  Quote: 	
		   



 Anybody have a web link to the proper penetration fittings?



 Mike

Bret Smith

Joined: 09 Jan 2006
Posts: 178
Location: Mineral Bluff, GA

Posted: Fri Feb 01, 2008 3:38 pm Post subject: Firewall penetration

Mike,



Here is one example.  Hopefully this discussion will shake out some other

"less expensive" options.



 http://www.epm-avcorp.com/tubeseal.html

Bret Smith

RV-9A N16BL

Blue Ridge, Ga

www.FlightInnovations.com



--

_________________
Bret Smith
RV-9A (Emp)

Terry Watson

Joined: 09 Jan 2006
Posts: 290
Location: Seattle, WA USA

Posted: Fri Feb 01, 2008 4:06 pm Post subject: Firewall penetration

This is what I used and I like them. I bought the middle size, hoping that

two of them would be big enough and that it would be cheaper than the bigger

ones. Hindsight says that the biggest ones would have been better for me.



Terry

RV-8A

Wiring

--

Mark Phillips in TN

Joined: 10 Jan 2006
Posts: 431
Location: Columbia, TN

Posted: Fri Feb 01, 2008 6:34 pm Post subject: Firewall penetration

In a message dated 02/01/2008 3:40:03 PM Central Standard Time, longg(at)pjm.com writes:

  	  Quote: 	
		  I understand the experimental mentality and all, but this crap is so

cheap-o. Are we left to salvaging conduit fittings from electrical

contractors? 	


 OK folks- I've been watching this pass-thru stuff for quite a while now (years, in fact) and while building my plane, solved the issue to my satisfaction with the following:

  

 http://websites.expercraft.com/n51pw/index.php?q=log_entry&log_id=5006

  

 http://websites.expercraft.com/n51pw/index.php?q=log_entry&log_id=5007

  

 http://websites.expercraft.com/n51pw/index.php?q=log_entry&log_id=5517

  

 For use by a fellow builder, I've had additional copies of this made in the size shown and slightly larger to accomodate fatter/more wires, and the extra parts I had cut have been hanging on the wall of my shop for some time, looking for a home.  I had no intention of "marketing" this, but if there is any interest, I'd gladly send what I have to those interested, provided my costs were covered.  I have theorized some improvements and might even consider going into production if y'all think it would be useful.  I could provide fotos of the newer installation to those interested.

  

 It ain't rocket science, it just works...

  

 From The PossumWorks in TN,

 Mark Phillips, RV-6A N51PW "Mojo" (she's a good girl!)

 http://websites.expercraft.com/n51pw/



Who's never won?  Biggest Grammy Award surprises of all time on AOL Music.

  [quote][b]

_________________
From The PossumWorks...

Allen Fulmer

Joined: 10 Jan 2006
Posts: 79
Location: Alexander City, AL

Posted: Fri Feb 01, 2008 7:58 pm Post subject: Firewall penetration

For some reason this link hasn't worked for the last few days from

Vansairforce.net but I have just recently bought one of their stainless

firewall penetrations.  They only have 1/4", 1/2" and 3/4" i.d. versions.

Kind of pricey but will certainly do the job.



Also just ordered a similar 0.90 i.d. firewall penetration from SafeAir1 at

http://www.safeair1.com/index.htm.



Allen Fulmer

RV7 Wiring and plumbing



[quote]>>--

_________________
RV7 QB Fuselage
Eggenfellner H6 on orde
N808AF reserved
Alexander City, AL

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