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1,016 Posts
Discussion Starter · #1 ·

First I would like to state that the information presented in this thread is from
Classes I have attend with I-CAR
(Inter-Industry Conference On Auto Collision Repair) on "AUTOMOTIVE FOAMS".

About I-CAR
Formed by the collision industry in 1979, I-CAR is an international, not-for-profit training organization.
All I-CAR activities and resources focus on helping the industry achieve a high level of technical training.
The I-CAR Vision for the industry is that:
The I-CAR vision is that every person in the collision industry, current and future,
has the necessary knowledge and skills relevant to their position to achieve a complete and safe repair.
I-CAR develops and delivers technical training programs to professionals in all areas of the collision industry. In addition, I-CAR provides a communication forum for anyone interested in proper collision repair. I-CAR's primary funding is derived from student tuition and services. This assures that I-CAR can remain unbiased in developing programs and services on an industry-wide basis.

You do not have to be a member or employee of a collision repair facility or bodyshop
to attend one of their classes. If interested check out the web site for a class near you.
Classes cover all topics of autobody repair. I-CAR even has some vehicle specific classes which include
Collision Repair Overview for the 2006 Chevrolet CORVETTE Z06.

This thread is just a sampling of what a class will cover. I have edited it quite a bit as
to only cover what info would be useful to the C3 owner. I will keep the info as close
To the same format as I received it.


Foam is used in vehicles to:
• Reduce noise, vibration, and harshness (NVH)
NVH may be caused by vehicle design, texture
of the driving surface, or air passing along the
• Repair water leaks.
• Stiffen the body structure and help control twisting
and flexing of the vehicle.
• Provide collision energy management.
• Provide additional crash protection for occupant safety.


The chemistry of foam used for collision repair is similar to the
material chemistry used by vehicle makers.

These include:
• Structural foam being epoxy based.
• NVH foam typically being urethane based.
If urethane-based material is opened and resealed,
the self life of the material will be shorter than
unopened material.
• Materials being closed cell.

Some product makers list the product chemistry on the material label.

Collision repair foams are typically flow-grade, two-part materials that
Are dispensed and allowed to flow into where they expand and cure.


Sound dampening material:

• Does not expand like a two-part foam. Although commonly called foam,
sound dampening material is more like sealant and low-grade adhesive for
use between parts.
* Can be used as an adhesive to attach existing NVH foam to replacement panels.
• Is designed to be applied to small gaps.
• Has little or no expansion.
• Has a longer work time than traditional two-part expanding foam.
• Is usually black
• Looks like windshield urethane because it is usually the same color and has no visible cell structure.
• Has a smooth surface texture when dispensed.
• Has limited compression.
• Is flexible.
• May require a special mixing tip.
• Is not designed to be used in applications where cavities require filling.


• To reattach original foam that is being reinstalled. Some of these applications
Include reattaching the foam between a door skin and an intrusion beam, or roof
skin and roof bows.
• Between the quarter panel and the fuel-fill pocket.
• To fill small gaps, up to 13mm (1/2”)


• Low strength, with a high compression rate.
• Extremely flexible, and does not permanently deform when compressed.
• Typically black, but depending on the product maker, may be charcoal or white.
• Able to expand up to 10 times its liquid volume.
• Combustible when heated to a high temperature. When heated above 300* C (575*F), the material will melt.
• Typically urethane based.
• Has a short foam time. This time may range from a few seconds up to about 20 seconds.
• Has no structural enhancement capablilites.
• Commonly referred to as anti-flutter foam.
• Has a visible cell structure.

Some uses for flexible foam include controlling panel flutter, absorbing and controlling sound,
and blocking air movement, sealing out dust and repairing water leaks because the material dose not
absorb water and seals tight to the surrounding area.
Another use includes filling large voids.
NVH foam is not designed to affect the structural integrity of a vehicle.


* Is packaged under many different names. These include semi-rigid, pillar, and
rigid foam.
• Is more rigid than flexible foam.
• Will permanently deform when compressed.
• Has a limited compression rate before it permanently deforms.
• Such as pillar foam, has an extended foam time. This allows the foam to flow down into the parts before expanding.
• May expand up to 10 times its non-expanded volume.
• Provides limited chassis reinforcement.
• Is not a replacement material for structural foam.
• Typically has a visible cell structure.

Commonly used for…..

• NVH control, such as absorbing sound, blocking air, and helping control
movement of body parts and panels.
• Cushioning adjacent parts.

Rigid foam must NEVER be considered a replacement material for structural foam.

Though not used for structural enhancement or to change crash characteristics, rigid foam may be used to stiffen the vehicle structure to minimize twisting and flexing.


• Is stronger than rigid foam.
• Is not flexible. Structural foam is a hard material that is prone to cracking rather than deforming.
• Is a hard plastic-like material and is highly dense.
• Has the appearance of an adhesive when dispensed due to its cell structure and surface appearance.
• Is a heavy-bodied, two-part flow-grade material.
• Has a minimal expansion rate. The expansion rate is so minimal that it is not a factor when determining how much material should be installed.
• Increases strength and adds less weight than if additional steel were used.
• Is offered by only a limited number of suppliers.
• Is used to structurally enhance a vehicle. These changes will affect the crash characteristics.
• Is used on full-frame torque box areas. (such as the 2003 Ford Crown Victoria)
• Is combustible and will begin to melt and produce toxic fumes when heated above 204*C (400*F).

Structural foam is not a material that should be used for noise control. Using structural foam for NVH control may actually create problems rather than fix them. This is because the foam has the ability to transfer or amplify sound.

SAFETY: Wear protective eye ware, gloves and a respirator when working with foams.
NOTE: When cured foams get hot enough to melt, they generate toxic chemicals, including
carbon monoxide and cyanide gas.


• Ensure areas that will receive foam are clean and dry.
• Prime all bare metal areas to reduce chance of corrosion. When priming, apply an epoxy or urethane primer. If acid-etch primers are used, they must be fully cured before foam is applied. Because structural foam is epoxy based, the use of an epoxy primer is recommended under any structural foam.
• Cleaning areas for foam installation is similar to cleaning for refinishing.
• The first step is to use a water-based cleaner. Water-based cleaners WILL NOT remove contaminants that are solvent-based.
• The second cleaning step is to use a solvent-based cleaner. Solvent-based cleaners WILL NOT remove water-based contaminants.
• After cleaning, prime bare metal areas.


Structural and Rigid Comparison

Foam Samples

Expansion Rates

Making Dams

Methods of Application


I hope everyone finds this informative and useful.
I edited the info that pertained mostly to uni-body cars, otherwise this post would have been many, many times larger. :D
If you would like to attend an I-CAR class check out the web site under training and search for your area.
There is a fee to attend and you will be tested at the end of the course.

Whew!..:thud: .....that's a lot of typing :buhbye:

5,916 Posts
So, with all your experience, would you inject foam into the vette frame rails for strength? Think it would help? Would it add side impact protection? Would Viagra be better?

738 Posts
Good info, thanks for posting all that, the videos were especially helpfull. I don't know about filling the frame rails, but I can a lot of application in the body and birdcage.

1,016 Posts
Discussion Starter · #6 ·
So, with all your experience, would you inject foam into the vette frame rails for strength? Think it would help? Would it add side impact protection? Would Viagra be better?
I believe if it were used in the same manner that Ford uses it on the Crown Vic
there would be some benefit, That is in the Torque Box areas cause this is where
your flex actually occurs.
(provided you were able to properly prep the insides of the rails before installation).

Filling the rail completely would become rather expensive. Remember the
Structural Foam has almost no expansion. I don't think making it as rigid
as a Sherman Tank would be good, especially for a Daily Driver.
I'm no engineer so I try to follow the examples from the manufactures.

If you do wish to install any of the mentioned foams a spray gun pictured
below is what you would need to prime the inside of the rails.
This one is made by SATA and sprays the material in a circular fan pattern.
The hose is for accessing the inside of rails, hinge pillars, even birdcages.


2,366 Posts
I'll fill mine if you let me borrow the tools to do it. I'll pay for the foam though ;)

The structural foam doesn't expand very much?

How much weight would it add?

And how much would it cost to do those 4 locations.

My car is up on a lift so it would be easy to do right now.

1,016 Posts
Discussion Starter · #10 ·
How many tubes would I need?
That.........I could not tell you :huh:

I have yet to do a C3 frame...........if it is within your budget, experiment with it
and give us all an update. It will be a good while before I get to that point with
my car.

1,016 Posts
Discussion Starter · #12 ·
Have you been up close to it? Does it weight a lot? How much does it expand?
Check out the video link in my first post to see an example of expansion.
I have never put any in a cup like shown in the video to get any idea as
to weight vs volume.

Sorry I can't be more specific but the only time I play with this stuff is on
a "as needed" basis. I do plan to use some of the other type foams on my
C3 when I get that point but right now I have many projects ahead of the
vette. :(

Premium Member
17,444 Posts
This product info sheet indicates it expands 20 to 50 % So I think it is
going to be real pricey to do the full frame

LORD Fusor® 1908 Structural Foam
LORD Fusor® 1908 structural foam can be used for structural
enhancement, stiffness and sound/vibration dampening
of rails, pillars, supports and frames.
Structural foam products must be used only in the structural
and non-structural applications as specified by the
automotive OEM.

1. Preheat LORD Fusor 1908 structural foam to 100-
150°F (38-66°C) using heat lamp, heat gun or by
standing the cartridge in hot water.
Note: If more than one cartridge is required to fi ll the
cavity, make sure a suffi cient number of cartridges is
preheated. Use caution, as large masses of material will
create heat during cure and the surface temperature may
exceed 177°F (80°C).

2. Cover holes or cavities of the part to be fi lled with

3. Insert cartridge into the dispensing gun.
Note: Use of the LORD 304X pneumatic dispensing gun
is recommended for best application.

4. Squeeze out a small amount of product from each
side to level the plungers. Attach the mixing tip and
dispense a small amount of material to verify that the
foam is evenly mixed and the color is consistent.

5. Insert tip into cavity and fi ll. The structural foam will
expand 20-50% when preheated in the cartridge at
100-150°F (38-66°C).
Note: The product requires a minimum mass of 200 cc to
cure rapidly and expand to its maximum potential.

6. Allow LORD 1908 structural foam to cure 24 hours
before applying load.
Technical Data
Work (Expansion) Time, minutes
@ 70°F (21°C) 15
@ 100-120°F (38-49°C) 7-8
Full Cure Strength, hours @ 70°F (21°C) 24
Handling Strength (Full Expansion), minutes
@ 70°F (21°C) 30
Lap Shear Strength, psi (MPa) 725 (5)
Compression Strength, psi (MPa)
@ 77°F (25°C) 3046 (21)
Compression Modulus, psi (MPa) 145,038 (1000)
Cautionary Information
Before using this or any LORD product, refer to the Material
Safety Data Sheet (MSDS) and label for safe use and
handling instructions.
For industrial/commercial use only. Must be applied by
trained personnel only. Not to be used in household
applications. Not for consumer use.
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