Expandable Foam Usage

[de Noir 0]

I wonder if anyone here tried filling closed box sections (sills for example) of theirs 205s with two-component axpandable foam, normally used in civil engineering and construction?

 

This would be great load-bearing and shell stiffness enhancement.

Not to mention how lightweight actually it is. Benefits are huge.

 

I read topics on other forums about this method, being a standard procedure for many trackday cars.

Tho, people who did this upgrade claim expandable foam as very humidity-attracting and therefore not exactly suitable for road cars, because of possible rust issues...

 

 

So guys, any experience, comments and suggestions?

Someone did it already?

[d-9 0]

http://www.talkaudio.co.uk/vbb/showthread.php?t=57729

 

on expanding foam for sound deadening purposes, some of it might be helpful

[de Noir 0]

EDIT: Let me correct line above, not humidity attracting, but foam will, allegedly, hold the moisture in unwanted places. My bad, wrote this all wrong.

 

@d-9: unfortunately, I see just first 5 lines of this expandable-foam-guide on talk audio?

[boombang 2]

Surely a good spray of WD-40 to disperse all water, followed by some heavy duty grease / waxoyl would seal it up?

 

Then fill with expanding foam.

 

Only two issues I can see - expanding foam could contain water, and often needs water sprayed on to cure.

 

Other issue is it expands a lot - I sprayed into a panel before and it poured out. Felt lucky it wasn't a more enclosed gap as it would've bent it!

[engine killer 5]

a copy of article from autospeed.com.

 

 

 

Foams

 

Foams seem to be the latest innovation used throughout the vehicle for the ultimate benefit of the occupants. Foam materials used during vehicle repairs are typically two-part materials that can change in state and shape after they are dispensed.

 

NVH Foam Categories

 

Some of the first foam materials were used for NVH control. NVH foam materials are currently broken into four categories: sound-dampening material, flexible, rigid-type, and structural. Rigid-type foam is broken into three sub-categories.

 

Sound-dampening material is an NVH foam used for covering or sealing small openings that are easily accessible, and for reattaching existing foam. This is a two-part product that is black, heavy bodied, and non-expanding, much like windshield urethane or seam sealer when compared to common two-part expanding NVH foam.

 

Another NVH material is flexible foam. Flexible foam is soft, compressible, and returns to its original shape without retaining permanent deformation.

 

Rigid-type foam is the NVH material that currently has three sub-categories. These sub-categories include rigid, semi-rigid, and pillar foam.

 

Each material has distinct characteristics as an NVH control product. Rigid foam reacts differently than flexible foam when compressed. Rigid materials have a much lower compression rate when a force is applied and may remain permanently deformed when the force is removed. The main difference between rigid and semi-rigid is the strength of the material. Pillar foams are typically rigid foams with unique foam times and flow rates. This allows them to be used in situations where foam placement is difficult.

 

The latest material introduced to the foam family is referred to as structural foam. Structural foam is used for stiffening parts of a vehicle chassis/body and for increasing occupant protection in the event of a collision.

 

Foam Replacement Considerations

 

Along with identifying the material originally used in the vehicle, there are other considerations that affect installing replacement foam. These include determining the amount of material to be installed, how to get the material to a specific location, and how to get the foam to adhere in a specific location. Expansion rate, viscosity, and foam time are among the variables that must be considered.

 

The expansion rate of a foam product is typically given as a maximum amount. Products may have expansion rates listed as "up to ten times." The actual expansion rate of the foam may change based on many variables, some of which technicians can control. To determine how much material should be installed in a part, the volume of the void to be filled should be calculated. After determining the volume of the void, and matching that to the approximate expansion rate of the material being used, the proper amount of two-part foam can be determined.

 

Knowing the viscosity and foam time of different foams can be helpful when determining how to place the foam in specific areas. Sometimes, due to location and access, it is difficult to hold foam in specific areas. When this is the case, dams can be used. Depending on where the dam is to be placed, it can be installed either before or after parts are assembled. There are many different acceptable materials that can be used as dams. The most important consideration for using a dam is determining its ability to retain moisture. Do not use materials that have the ability to retain moisture.

 

Conclusion

 

Overall, there are six different classifications of foam, along with a variety of application techniques that may be required for positioning the material. Choosing the correct replacement material is important, as is using the proper amount of foam and properly filling the specific area.

[mattmk1 0]

You'd really want to use intumescent foam as this is fire proof, but is slightly more costly.

[888rmb 6]

I know Ford were doing this back in the 70s in the sills of mk1/mk2 Escorts to stiffen them up. The only downside I can see is the possibility of water retention, but if its for a track day car that isn't used every day then I don't see you've got much to loose.

[de Noir 0]

I have read on a Malaysian car forum about specific car-usage designed product, named AUTOFOAM, manufacturer German WURTH, but strangely haven't found it anywhere on Wurth's web site.

There also exists certain 2c-foam by DOW chemicals, but downside is that it is supplied only in barrels.

 

I found a supplier overhere who sells naval stuff, we're in negotiations on what type of 2c-PU foam would be the best solution for chasis-stiffening purposes...

 

Product names and availability on various markets are real nightmare.

[dee205 3]

How about some MicroFill...

Lightweight volcanic rock used for packing around chimney flu's! Doesn't retain water too.

Shoot it in with a Scutch gun.

 

[t16ryan 1]

When i worked for rover that was used as a warranty item on the 200s 400s and 600s where the rear quarters creaked, there warranty fix was remove rear trim and fill half a can each side, better warranty rover fix advised by rover when tyre well fills with water on 800s and 600s instead of curing the leak there fix was drill a small hole at the bottom of the tyre well, NO WONDER THEY WENT BUST

But the expandable foam is good stuff cant see there being a problem using it

[kyepan 291]

where could you spray it on a 205?

[de Noir 0]

You could apply expanding foam into sills and rear-quarter bottom for sure.

I havent inspected it thoroughly yet, but kick panel bottom and lower part of B pillar also seems possible and worth doing for structural reinforcement.

 

Having in mind split seam on B-post discussion of old, welding the 205 shell like described in topic + filling the sills and lower B-pillar with expanding foam would further stiffen the structure and fix/eliminate 205's chasis weak spot.