Our Foam Seal

We use open cell foam to seal our doors.  Most factory open cell foam is a polyester based foam that is biodegradable, which is why it comes apart and blows out of the vents.  Our foam is a synthetic polyether based foam that is not biodegradable and therefore will not deteriorate like the original foam. A common question that we get here is “Why don’t you use closed cell foam like the other guys?” The simple answer is, we’d love to, but we have yet to find closed cell foam that will perform satisfactorily in an HVAC box. There are a few requirements that foam must meet in order to be acceptable for use on our replacement doors:

  • The durometer or “squishiness” of the foam must be soft enough to sufficiently seal the box. The plastic housings have a very loose tolerance for what can be considered “flat.” We’ve had boxes here that have had as much as 1/4 inch gap on the sealing surface when the door was closed.  The foam must be able to compress completely on the high side in order fully seal on the low side. Most closed cell foams are too hard to seal properly.
  • The foam must be durable enough to withstand the extreme heat and extreme cold that an automobile will experience. The air conditioner evaporator will produce air temperature around 40 degrees F and the heater will produce around 200 degrees F. Don’t forget the interior temp when the car sits outside in the summer sun all day in Arizona or all night in a North Dakota winter. Very few types of foam can withstand this kind of abuse.
  • The foam must be American made.  We pride ourselves with an American made product produced by American workers.  We will not lower our standards by using a cheaper foreign made foam to increase our profit.  

      We are continuously testing new types of foam in order to provide you with the highest quality products available.  If we ever find closed cell foam that meets all of these requirements, we will start using it to seal our doors.  So far, every type of closed cell foam we have tested has failed on one or more of the requirements. The open cell foam we currently use passes all of these tests and will not deteriorate like the OEM foam does.  You will not be disappointed in the performance of our products.