Fiberglass For Firewall

BBShark

BBShark

Garage Monkey
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I had to cut a corner of the footwell out of my car for header clearance. I'm thinking that I will have 1/2 inch clearance between the glassed in cutout of the footwell and the header.

Is conventional glass fiber with epoxy heat resistant (enough for this)?
 
Just did a quick check of some of my tables - and the max I see for "run-of-the-mill" Epoxy is around 200 degrees F.

McMaster sells some sheet (already laid-up) that is Flame retardant and good to 140F.

Specialist resins go up in heat range - and so does cost.

From FiberGlast:
#3300/3330 High Temp Tooling Epoxy can be used with #1096 High Temp Epoxy Surface Coat. When used together, High Temp Epoxy Resin and High Temp Epoxy Surface Coat can create tough, durable, heat resistant tools.

Mix Ratio (by weight) – 100:22
Pot Life @ 77°F – 150-180 minutes
Color – Amber
Maximum Service Temperature – 350ºF

$150 a quart...
Click to expand...
There is a detailed post cure needed and may not be too practical.

A piece of sheet metal with a Jet-Hot Coating?

Sounds like an interesting challenge. Not much help there - Good Luck!

Cheers - Jim
 
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I have successfully used DEI Floor and Tunnel shield. It has a metal outside, a heat resistant material on the inside, and is sticky backed. It is less than .25 inch thick and molds fairly well.

Pappy
 
I could do something like vette427sbc did. That material looks like foil.

I stole his pic
45bfb1a171966f.jpg
 
Here are photos of the heat shield I referred to above. I covered the whole thing with the gold reflective, then I added the DEI Tunnel Shield to the bottom half (closest to the exhaust). The Vipers have a lot of trouble melting the plastic fuse box, especially when driven hard on track. I have had no issues since adding the shielding. The bottom part of the shield is .75 inch from the exhaust manifold.

Viper Heat Shield 1.jpg

Viper Heat Shield 4.jpg
 
I will give the DEI Tunnel Shield a go. Here is a picture of the footwell cutout I need to clearance.

45c03c037080a5.jpg
 
I called West Systems about the resistance of fiberglass to heat from the headers and was told that 1/2" clearance would be OK. The tech guy I talked to has a 71 Corvette. He did tell me that I should use epoxy resin (to bond to the polyester floorpan) and woven fiberglass mat. I will also use the DEI tunnel insulation.

After checking the underbody clearance with the completed chassis, turns out I will have to cut out the top of the tunnel to clear the taller Tremec transmission anyway. So that is another area that I will have to insulate. Planning on an aluminum cover there.

Might be easier to cut out the whole tunnel!
 
I ended up buying the DEI tunnel shield. When it came I noticed there isn't an adhesive backing. DEI sells a spray adhesive but it is "rated" at a max 160 degrees. Probably OK in the tunnel but not 1/2" away from the header.

Anybody know any high temp spray? Maybe epoxy it on?
 
Got a link for the one you bought? I did the DEI tunnel shield in my.... tunnel, and it had an adhesive backing. Not anything I would trust to keep it affixed by itself though. I also mechanically fastened mine using the factory clips and starter cable studs.
lmore2855.jpg
 
BBShark said:
I ended up buying the DEI tunnel shield. When it came I noticed there isn't an adhesive backing. DEI sells a spray adhesive but it is "rated" at a max 160 degrees. Probably OK in the tunnel but not 1/2" away from the header.

Anybody know any high temp spray? Maybe epoxy it on?
Click to expand...

I have a piece of DEI tunnel shield in my hand. It has an adhesive backing and a thin plastic film you have to peel off. Their add says the adhesive is good to 450 degrees. I also use their heat tape around the edges to keep moisture from soaking into the shield material.

Pappy
 
This is what I bought:

Design Engineering (DEI) 050506 Heat Shield Material
This Design Engineering (DEI) Heat Shield Material is made of 10 mil aluminum bonded to a layer of high temperature resistant glass fiber and withstands temperature up to 1,750 degree Fahrenheit.


Never saw that it didn't have adhesive backing until I received it. Searching around looks like I should have ordered DEI 050502
 
I used the DEI heat shield. Nice stuff, conformed well to the cutouts I had to make to clear the headers. Ended up cutting a pretty good chunk of the passenger side floor but not to bad on the drivers side. Thats a good thing because the gas pedal is right above.

45d3ee4f8d27fc.jpg

Next is cutting out the top of the tunnel to clear the transmission.
 
69427 said:
Just trying to keep up here. What transmission are you planning to use?
Click to expand...

I am using a Tremec TKO500. The footwell clearance was the result of my desire to keep the header collectors even with the bottom of the oil pan (for no other reason than I don't like the look of headers hanging down under the car).
 
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