October 11, 2018

The Ultimate Guide to Weatherstripping

Sound familiar?

As a rubber manufacturer for the Auto, RV and Marine industries, we have technical terms we use to describe our products. This guide is to help beginners and pros alike to decipher the types of parts we offer and their application. In this post, we will explain:

  • What is Weatherstripping
  • How is Weatherstripping Applied
  • What is the Difference Between Auto, RV and Marine Weatherstripping
  • Basic Weatherstripping Terminology

What is Weatherstripping?

Defined, weatherstripping is a strip of rubber or other material used to seal the edges of a door or window against the cold; however, weatherstripping has a variety of applications and protects you from more than a chilly breeze.

Weatherstripping is an essential tool that guards your investment from mold, dust, dirt, grime, draft and pests, and keeps your air conditioning/heat inside.

The weatherstripping and rubber parts we produce here at Steele are manufactured from EPDM rubber. EPDM (Ethylene Propylene Diene Monomer) was developed in the 1960s to meet the increasing demand for innovation in manufacturing. EPDM essentially mirrors the physical properties of natural rubber and adds the important function of UV resistance.



Due to its extreme weather, UV, and Ozone resistance, EPDM is the perfect weatherstripping compound to produce all of our parts out of. We also back all of our parts with a 100% satisfaction guarantee.

How is Weatherstripping Applied?


There are multiple ways to apply weatherstripping from glue-on, push-on and adhesive backed strips. Not every application will work for all projects so it’s important to consider your project’s unique needs before purchasing a weatherstrip.

What is the difference between Auto, RV and Marine Weatherstripping?

Here’s the skinny:

  • Automotive seals are determined by the make, model & year of your car
  • RV seals are what we coined “universal” as they have a variety of applications
  • Marine seals are exactly like the RV seals except they are tested for longevity and durability for fresh and saltwater

Looking for more information?

Automotive weatherstripping is determined by your car’s unique make, model and year. This is both convenient and inconvenient at times. How so? Depending on the type of car you have, you might not find what you’re looking for. This typically means that no one else has asked for that seal, or that there isn’t a high enough demand to produce those parts. If you’re looking for a kit, or all the seals for your particular make and model car, you can use a parts finder like the one of the Steele Rubber site. For example, say I’m looking for the seals for a 1969 Camaro Hardtop.

SRP website screenshot

However, if you search for a car and you can’t find what you’re looking for, we recommend reaching out to us on our contact page. If we can’t produce what you need, we reach out to other companies in the industry to help you find what you’re looking for.


RV weatherstrippping is, what we call, universal. These seals are categorized based off of the seals’ typical location on the RV. For example, compartment doors, air conditioners, windows, slide outs, and hatches. Just because a seal is located in one category, doesn’t mean you can’t use it in another application.


On the marine website you will find boat specific parts and a variety of the same parts you see on the RV site. The main characteristic that distinguishes marine parts from the RV parts is that these seals are tested to withstand fresh and saltwater conditions.

Basic Weatherstripping Terminology

Example Gasket

Gasket – A shaped piece or ring of rubber that fills the space between 2 or more surfaces, generally to prevent leaks. A gasket typically fills the space between the glass and metal channel of the RV.

Example Edge Trim

Edge Trim – Designed to cover rough edges. Used around doors and other applications that require a cover for an edge.

Example Insert Trim

Insert Trim Insert trim rubber is the perfect replacement to the original vinyl seal. Most vinyl tends to crack and let water in the track which causes mildew. Dense rubber insert trim is manufactured with UV resistant compounds and will look great for years to come. It is designed to fit & lock in the metal track found on many RV and Toy Haulers.

Example T-Rubber

T-Rubber – These seals can be used in just about any application where rubber is held in place with a track or channel. Many RV screen doors and shower doors utilize T-rubber seals.

Example Push-On Seal

Push-On – Refers to the type of application. These seals are designed to stop leaks, drafts, reduce noise and ensure a secure fit. The bulbs consist of a high quality, weather resistant rubber mated to a flexible push-on edge trim that has an integrated steel core. The result is a long lasting seal that is easy to install and requires no glue or adhesive to stay on.

Example Peel-N-Stick Seal

Peel-N-Stick – Another type of seal application. These seals are adhesive backed which offers quick and easy installation. The 3M adhesive tape, used on our Peel-N-Stick parts, is superior to other adhesive products in that it makes for a durable, quick and easy installation.

Example Sponge Rubber Seal

Sponge Rubber – There are 2 types of sponge rubber, closed cell and open cell. EPDM rubber seals are typically closed cell sponge rubber. These seals are flexible, weather and UV resistant and can withstand pressure for long periods of time without losing their shape. Sponge rubber can be molded or extruded. Closed cell is ideal because it also does not absorb water like open cell designs. Our sponge rubber is closed cell. This is achieved by a salt-bath curing process.

Example Dense Rubber Seal

Dense Rubber – This rubber can be extruded or molded and is cured using intense heat to achieve a solid structure. These seals feature greater resistance to impacts, abrasion and wear. This type of rubber is commonly found in window applications, and as a replacement for vinyl or plastic seals.

Example of an Extrusion

Extrusion – The extrusion process, as explained on our facility tours, is just like pushing Play-Doh through a toy mold. Dies (the shape we want the extrusion to be) are placed at the beginning of the extruder. Then, the proprietary EPDM rubber compound is forced through that die and “cured” to keep its shape. Dense rubber cures with dry heat, while sponge rubber extrusions are sent through a molten salt bath that makes the rubber expand into the squishy rubber we all know and love.

Machining one of our molds

Mold – Our rubber molds are carefully crafted out of metal by computer controlled cutting machines to very exact dimensions. Each mold requires a specific amount of rubber to form each part. The rubber is either placed or mechanically injected under heated pressure into the mold and placed in a heat press to cure to take and hold shape.

If you need help finding the right weatherstrip for your project, or need help installing a part, assistance is available with one of our Product Specialists over the phone (800-230-6752) and on Live Chat.

*For additional help check out our How To series on YouTube!

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