Coroplast near exhaust and engine clearance - need advice please.

[Cd]

Can Coroplast rest directly against the bottom of the engine and transmission ?
It would press upwards on the oil pan, as well as the transmission.
I know you need 2 - 3 " clearance around the exhaust pipe.
I plan to add a center section of sheet metal (steel roof
flashing ) that will touch the exhaust pipe.
Is this metal coated with anything that could catch fire ?

Do you need extra clearance near the cat. converter ?

My exhaust pipe hangs quite low.
It will be enclosed by a steel dryer pipe.
Since the entre underside will be sealed, it's going to trap pockets of heat.

I plan to perforate the metal and add reverse ducts to expel the heat, but I'm still concerned about it being trapped and what it would do to the Coroplast.

How would heat from the exhaust pipe transfer across a steel shield that extends around 2" ?
I ask, because the gas tank is directly behind it.
I would imagine that heat could transfer though the metal and cause an explosion if touching the gas tank.
Rather than have the steel shield cover the pipe and rest on the top of the gas tank, I plan to have it hover over it ( have a small gap in other words.
There would be a Coroplast cover over the gas tank that will be shaped to re-attach the airflow.

How does aluminum react to heat, vesus steel ?
The Coroplast will be screwed to aluminum transition strips that will loop on top of the exhaust pipe.
( The exhaust pipe will have the transition strip resting directly on it )


I'm enclosing my entire underbody on my 1993 Civic hatch.
Just like Basjoos - in fact this will be a sort of AeroCivic Lite, or AeroCivic Jr.
I plan to copy what he did, but with a few modifications.

I wish he was still active on the forum.

Any advice is appreciated folks !

[Cd]

Coroplast melting point : 162 degrees.

That's really low.

I noticed modern engines have plastic covers on them.
After looking it up, some of these plastics can withstand 600 degree heat.

But if I cover the engine areas with metal, and then attach the metal to Coroplast, will the heat transfer through the metal ?

[freebeard]

Yes. How much? Dunno.

Coroplast melting point : 162 degrees.

https://www.coroplast.com › resources › health-and-safety-aspects
Health and Safety Aspects - Coroplast®
Until the sheet reaches a temperature of approximately 600 degrees F, it will not release flammable - low molecular weight hydrocarbons. Should a fire occur, any available fire extinguisher may be used. In a limited fire situation dry chemical powder extinguishers have proven very successful.

https://christinedemerchant.com › coroplast-scoring-cutting-gluing.html
Scoring, Folding, Cutting and Glueing Coroplast - Christine DeMerchant
When the Coroplast is scored it gets crushed on the score line and this makes it easier to fold in that spot. There are scoring tools out there but you can easily use a screen inserting tool sold to replace damaged window screens. ... Information on Coroplast resin used Melting point (324F or 162C), Density etc. Corplast specification Page They ...

This makes it sound like melting and burning are two different things. Maybe Coroplast is not fit for purpose? Maybe butt the two materials instead of layering them?

[Cd]

"While Coroplast® will burn, it does not have a flash point or an uncontrollable flame spread rate like some acrylics or styrene."

And what of heat transfer on that heat shield I mentioned ? I plan to use aluminum sheeting.

Edit - scratch that.

So I assumed that aluminum had less of a heat transfer rate than steel. Whuups.

[freebeard]

Coroplasst is for prototyping.

www.nudo.com/resources/p22_product_data.pdf

Polymetal is laminated aluminum skins on a thermoplastic core. It has a Class A fire rating for whatever that's worth.

[aerohead]

Dr. Teddy Woll of Daimler-Benz, in 2014, wrote that the entire exhaust system of an internal combustion vehicle could be thermally insulated to facilitate enclosing the entire length of the underbody.
One would need to use commercial/industrial insulation products as Knauf provides.
They're not a 'retail' product that a 'civilian' can walk into a store and purchase.
With a 'business card' they might let you through the door.
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Short of that, you might be able to just rely on metal heat-shields/ multiple heat shields as you may see above and below catalytic converters.
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American ICBM missile silos use sixteen concentric metal heat shields around the missiles to stabilize temperatures. The company in Dallas that I used to work for was a contractor to the Pentagon for working around technology like that.
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You need about a half-inch air-gap between shields. And some can be attached to the upper face of the coroplast if you can't do hangers from the exhaust system above.
I was able to use 1/8-inch thick Luan door skin on the Spindletop CIVIC CRX by doing this.
I don't see why the coroplast would be a problem.

[freebeard]

One would need to use commercial/industrial insulation products as Knauf provides.
They're not a 'retail' product that a 'civilian' can walk into a store and purchase.

It's sold by the package, not linear feet.

https://www.oreillyauto.com › shop › b › performance › safety-equipment › exhaust-heat-shields---wraps › 8753c8a475cb
Exhaust Heat Shields & Wraps
Mr. Gasket Heat Tape - 6323. Part #: 6323 Line: MRG. 90 Day Limited Warranty. Width (in): 1-1/2 Inch. Overall Length (in): ... Design Engineering Tan Glass Fiber Exhaust Wrap - 010104. Part #: 010104 Line: DES. 1 Year Limited Warranty. Compare. Design Engineering Tan Glass Fiber Exhaust Wrap - 010105 ...

https://www.jegs.com › c › Exhaust-Systems_Heat-Shields-Insulation-Header-Wrap › 10261 › 10002 › -1
Exhaust Heat Shields, Tape and Heat Wrap for Headers
Adding heat shield wrap, tape, and insulation under the hood is a great way to increase cooling and protection for your vehicle's exhaust and electrical systems. JEGS offers a wide selection of exhaust heat shields, tape, and header wrap from top manufacturers such as DEI, Thermo Tec, Vibrant Performance, Dynamat, JEGS, and others

[Cd]

Great ideas guys !
I hadn't thought of header wrap.
Great idea - but way past my miserly budget.
Today, I switched the aluminum HVAC ducting for steel.
I also got a 24" x 36" piece of steel sheet to use for hot areas. I will likely need a second sheet.
I was given two 24" x 36" pieces of aluminum that I planned to use for the skid plate / belly pan, but they are heavy guage, and as crazy as this sounds, I passed on using them because of the weight.
I have built a skid plate / pan in the past using thin aluminum flashing. It is very loud when the car is at idle due to vibration; so this may be a challenge.
I'll try and update this thread with pictures of my progress tomorrow so that I can get y'alls advice on what you see that I-m doing wrong.