How to Splice Sponge & Dense Weatherstripping
When you need an extrusion made into a ring or one piece unit, it is best to have the splice molded. This will give the best seal and have maximum strength at the joint. However, when molding is not an option you can splice instead. There are a few general rules to follow.
1. It’s simple, your cut ends need to be straight.
If you put the ends together, all edges should match. Best tool to cut both sponge and dense rubber? A utility cutter. The ends need to be clean cut and free of all debris. If needed, clean with an alcohol pad. I found that for the best results, join them using Loctite Super Bonder 495. It is formulated for rubber-to-rubber bonding. You should be able to find this at any hardware store that carries Loctite products or from the Steele Rubber Products site.
2. Have a flat surface to work on.
After cutting your weatherstrip, remember to test it for a profile match before proceeding. Like all other adhesives, the less adhesive you use the better hold it has, especially with this Super Bonder. It works just like a “Super Glue”. It is clear in color and will stick your fingers together, just like “Super Glue”. However, it will clean up using nail polish remover. Working on a flat surface makes the process of cutting and gluing easier.
3. Put a small amount of glue on just one side of the splice joint.
With a paper clip wire, spread the adhesive evenly over the surface, making sure it is covering the edges. If there is too much adhesive, it will not hold well. Carefully match the edges from one side to the other. Apply pressure from both ends to the splice. For dense rubber, apply greater force. Hold for about 90 seconds. At this point you should have a good strong bond. If there are any parts not adhered, apply a light amount with the paper clip to the void and apply pressure again. If the joint was done properly, you should be able to pull on it without it failing. To ensure that the rubber will make a water tight seal when used as glass channel, apply a clear optical sealant between the glass and the rubber at the joint. The clear auto sealer should be available at any auto parts store.
Just remember, straight clean cuts that match and use the right adhesive for the job. Take your time and you should be happy with the outcome.
Steele not only has all the products you need but all the knowledge you need to get the job done right, too. If you have questions about Rubber Parts or Weatherstripping on your Classic Car, Truck, Hot Rod or even your boat, trailer or RV, feel free to reach out to us! You can call us at 800-650-4482, contact us through our website or comment on this post and we’ll get you answers as quickly as possible. Check out our YouTube channel for our full library of how-to/installation videos.
Steele Rubber Products, located in Denver, NC, is a manufacturer and seller of high-quality rubber parts and weatherstripping products for classic and vintage automobiles, hot rods, RVs and Boats. Steele offers more than 12,000 parts for cars and trucks as well as a large line of universal weatherstripping and rubber parts to be used on any project. Established in 1958, Steele is a trusted name in the automotive restoration industry.