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-   -   Firewall Foil Advice (https://vansairforce.net/community/showthread.php?t=167547)

rvanstory 01-07-2019 06:47 AM

Firewall Foil Advice
 
Planning to use Dan H's information to install Fiberfrax on firewall. Seemed really straightforward until ordering supplies on ACS. They don't seem to sell stainless foil in 24" width??? After trying to find an answer on vendors, found MANY options listed on forum and now I'm stuck in analysis paralysis. Need some questions answered to get "unstuck".
1. Thicknesses listed is from .002"-.010". If I want minimum "wrinkling" and a smoother finish, is thicker better?

2. Does outer sheet need to be stainless? Can it be aluminum?

3. What specific vendor and product would you recommend? I found options on McMaster Carr, but thicker (.008-.010) higher grade SS is often limited to narrower (2") sheets.

4. Some have even suggested HD Reynolds wrap. Can you really get by with Reynolds wrap from local store?
Thanks in advance for help!

Reflex 01-07-2019 07:01 AM

Ditto.

Randy, glad you asked....just getting into this now. Looking forward to responses.

AdamB 01-07-2019 07:13 AM

I purchased the 970J 1/8" x 24" Fiberfrax
and also Ordered McCaster Carr 3254K92 for the foil.
That is .002" x 24"

My plan is to have 2 sections cover my firewall with some overlap.
Either a vertical overlap down the middle or horizontal overlap.

I also ordered some SS pop rivets to secure the overlap area to the firewall.

As you can probably tell, I have yet to install this, but is what I've seen a couple of others do, so that's what I went with.

F1Boss 01-07-2019 07:44 AM

An easier potion
 
https://www.koolmat.com/heat-resista...ts-protection/

Order: #04248 ZERO CLEARANCE / PSA

Install on the fwd side of the firewall.
Does a great job of keeping heat off your feet, and there is some noise attenuation. Touching the cowling IMMEDIATELY after shutting down - the cowl is at ambient temp around the exh pipe areas.

Works more or less the same as the Fiberfrax/SS sheet, but this stuff is cut, peel, and stick. Best to add some of their aluminum duct tape too - both products are the stickiest things I have run across - except Gorilla Tape.

The Zero Clearance sheet is about $80 -have a very sharp pair of scissors to cut the stuff.

I have not tried the silicon sheet they recommend for aviation. I could not come up with a glue to hold it on.

PM me if you want a picture of an installation.

DanH 01-07-2019 09:17 AM

Quote:

Originally Posted by rvanstory (Post 1314783)
Thicknesses listed is from .002"-.010". If I want minimum "wrinkling" and a smoother finish, is thicker better?

Yes, but 0.010" is exactly five times heavier, and provides no additional fire resistance.

Quote:

2. Does outer sheet need to be stainless? Can it be aluminum?
Aluminum will work as a top sheet only if the insulation is intended for comfort purposes during normal operation. It will immediately melt given an engine compartment fire, and fire protection will degrade rapidly from there.

Quote:

Originally Posted by AdamB (Post 1314788)
My plan is to have 2 sections cover my firewall with some overlap. Either a vertical overlap down the middle or horizontal overlap.

Make the overlap vertical. Seal it with a high quality aluminum duct tape. The tape will melt given a fire, unsealing the seam, and allowing the outgassing fiberfrax binder to escape into the engine compartment where it is harmless. The vertical seam puts some of the overlap down near the cowl exit, where the heat will be high. The SS overlap will continue to provide fire protection.





Quote:

Originally Posted by F1Boss (Post 1314802)
https://www.koolmat.com/heat-resista...ts-protection/

Install on the fwd side of the firewall.[/b][/i] Does a great job of keeping heat off your feet, and there is some noise attenuation.

I've used this and similar on low and slow airplanes, where my interest is ordinary thermal comfort during normal operations, but not fire protection. It's not going to be very useful given an FAA-standard fire (2000 for 15 minutes, not 12 seconds with a Bunsen burner), but it looks nice and will keep the cockpit cooler.


rocketbob 01-07-2019 09:37 AM

I used this stuff on my Rocket. No overlap required.

https://www.amazon.com/gp/product/B0...UEKDZ4IY&psc=1

To Dan's point I took a sample and had a propane torch on it for about 5 minutes to no effect. Other than the foil disintegrating, the fiberglass stayed perfectly intact.

DanH 01-07-2019 10:18 AM

Quote:

Originally Posted by rocketbob (Post 1314849)
I used this stuff on my Rocket. No overlap required.

https://www.amazon.com/gp/product/B0...UEKDZ4IY&psc=1

To Dan's point I took a sample and had a propane torch on it for about 5 minutes to no effect. Other than the foil disintegrating, the fiberglass stayed perfectly intact.

That is what you see on the Kitfox firewall in the previous photo.

Melt point of fiberglass fabric is fairly high (2100F ballpark, IIRC), but the rate of heat transfer will go up dramatically when the aluminum foil cover sheet melts away at about 1100F. The cover foil is both reflector and hot gas barrier.

cdeerinck 01-07-2019 10:46 AM

Penetrations
 
Hey guys, dummy question here. Do you put this on before you make penetrations and install items, or afterward?

David Paule 01-07-2019 11:23 AM

And how do you handle the penetrations?

Put a spacer under them?

Let them squeeze the Fiberfrax?

Or something else?

Dave

David Paule 01-07-2019 11:29 AM

I'm using .005 titanium foil from Titanium Goat, an outdoor equipment vendor. It comes in up to 16" widths, and if you need their 20" wide foil, that's .008 inches thick.

It's not hard to work but compared to the thin stainless, there's a weight penalty. Since I've never worked with the thin stainless foil I can't offer a direct comparison.

Dave


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