Failing weatherstripping adhesive is annoying, and it can be hard to fix if you don’t know what you’re doing. Once it gives way, seals can peel off, letting air and water in while interfering with the movement of doors and windows. If you simply apply new sealant, or try to fix the problem with an all-purpose glue, the weatherstrip will fail almost immediately. Most of these failures come down to a lack of preparation. To get the adhesive to work, you need clean surfaces on both the seal and the part it attaches to. Here’s what you need to know to effectively and safely remove old weatherstripping adhesive.
What Makes Weatherstripping Adhesive Unique, and Why Does it Fail?
Weatherstripping glue is a high-strength epoxy designed to maintain a tight, waterproof seal in all weather conditions. It’s used to secure rubber and foam weatherstrips around doors and windows in your home and in your car.
Unlike other all weather adhesives like Gorilla Glue and Super Glue, this epoxy requires little to no clamping force to create a tight, waterproof bond. It also remains flexible through temperature extremes, so it can withstand the movement, vibration and friction exerted by driving and outdoor exposure. In some cases, companies also market their weatherstrip glues as gasket adhesive, since both glues have to withstand similar conditions.
While vehicles and doors use a coating of epoxy to bond rubber weatherstripping to surfaces, most window seals are made from foam tape or rubber with a pre-applied adhesive backing. Even if the weatherstripping is still in good shape, this glue will eventually harden and turn brittle. Once this happens, the rubber or foam separates from the surface, creating a leak.
Signs that Your Weatherstripping Adhesive is Failing
There are four main symptoms of failing epoxy:
- Wind noise has gotten noticeably louder around the edges of the opening.
- Light is visible around the edges of doors and windows, even though the weatherstrip is in good shape.
- The weatherstripping doesn’t stay in place, causing interference when opening and closing doors and windows.
- There are signs of water leaks, resulting in mold, wet carpets or pooling water on floors.
Think you have a water leak, but don’t want to wait on rain to check? Use a garden hose to push water around the seals. This makes it easier to pinpoint the leak and fix the adhesive.
Removing the Weatherstripping
Before you remove the dried out glue, you need to remove the weatherstripping that it’s supposed to keep in place. Most seals are held on by a combination of glue and fasteners.
Car seals may have screws and trim pieces to hold down the ends, while the rubber itself often has molded-in studs that push into holes on the body panel. If you’re having trouble pulling these studs out of the panel, use a plastic pry bar. It will give you the leverage you need without marring the paint.
Home door gaskets are usually nailed into place. Nails in rubber and metal can be pulled out with a standard nail puller, although it may be easier to pry out the weatherstrip or trim piece, then remove the nails. To lift wooden frames and trim pieces without damaging them, use a wide putty knife to support the pry bar as you pull up on the trim.
When removing nails from wood trim, you want to push the nail through the piece. You can do this by grabbing hold of the nail with a pair of nippers or pliers. Use the tool’s leverage against the board to pull the nail through the board. It sounds counter-intuitive, but this leaves a small, smooth hole that’s easy to fill. If you pull the same nail out of the front of the trim piece, you’ll probably damaging the face, leaving a jagged hole.
Window weatherstripping can be removed by peeling up an edge with a putty knife, then gently pulling the rubber gasket away from the surface. While rubber seals usually stay in one piece, you may need to pull foam off in several pieces. Any remaining foam sealer can be removed with the epoxy.
Removing Old Glue
Now that you have access to the adhesive, you can go to work removing it. The glue flows into microscopic pores and imperfections on the surfaces of the weatherstrip and the door or window. That means you can’t use physical methods alone to remove the glue without damaging the surfaces it’s on. Instead, you’ll need to use a combination of chemicals, heat and elbow grease to get a clean surface.
Even dried out glue will soften with increased temperatures. Using this to your advantage can make cleanup easier. If it’s warm out, let your car sit outside, or work on your house in the afternoon. The added heat will make the glue easier to peel off.
You can also try applying heat directly to the epoxy. Warming up the adhesive with a heat gun or a hairdryer will make it softer and easier to scrape off. If you’re using a heat gun with multiple settings, stick to a temperature around 300°F. This is warm enough to get the adhesive to flow without melting it into the surface you’re cleaning.
A scraper or putty knife made of rubber or plastic can scrape off glue without harming the paint underneath. For tight spaces, you can try using a flathead screwdriver. Wrap tape around the tip to prevent direct metal-to-metal contact.
The most effective way to remove weatherstripping glue is with chemicals that break down the epoxy into different materials that can be wiped away. While there are several chemical solutions that will work, not all of them are safe to use on all surfaces.
Adhesive removers mix with the adhesive, turning it into a new substance that is less sticky and easier to wipe up. While usually safe, there’s one caveat: most of these chemicals are designed to work with cured paint. If you apply them to a fresh paint job, they can remove the top paint layers. Avoid these products if you’re fixing a weatherstrip installation shortly after painting your vehicle.
It’s important to take safety measures for yourself and the surface you’re working on. Make sure you’re in a well-ventilated area, and wear nitrile gloves to protect your hands. Use a natural bristle brush to apply the remover. Synthetic brushes may react with the solvents in the cleaner, dissolving as you wipe down surfaces.
While there’s no doubt that adhesive cleaner is the best solvent to use on your vehicle, you might not be able to run down to your local parts store and pick up the latest 3M product. However, there are alternatives. Water displacers like WD-40 may work, depending on the glue formulation. Like specially-formulated cleaners, these chemicals can bond to the adhesive for quick removal. Paint damage is unlikely, but they do leave an oily residue that must be removed before applying fresh glue.
Acetone should not be used to remove weather stripping, even though it’s effective at dissolving adhesives. While it removes the glue, it also removes and softens the paint underneath. Acetone also strips oils, resins and stains from wood, and it can bleach or break down plastic.
White vinegar is less aggressive than other cleaners, and it is generally safe to use on wood and plastic. However, it can damage vehicle paint, leaving the surface looking cloudy. If you choose to go this route, soak paper towels in vinegar and press them against the adhesive for a few minutes. This gives the acid time to break down the glue.
Preparing for Fresh Adhesive
To get a strong bond, both the weatherstrip and the surface it attaches to must be clean. This requires a two step cleaning process.
First, remove any oily residue. You can use dish soap and water on home surfaces, while an all-purpose cleaner is the safest option for car paint. A microfiber towel won’t scratch sensitive surfaces, but a regular towel or sponge works fine on unpainted wood and plastic. Use higher detergent concentrations for heavy oil buildup, like you might get from using WD-40 to remove old glue. If you’re reusing the weatherstripping, don’t forget to clean its mating surfaces before applying fresh adhesive.
Follow this up with a wipe down using isopropyl alcohol or “paint prep,” a cleaner used to clean cars before painting. Apply these cleaners with a lint-free towel to prevent threads from interfering with the glue. If you’re using new weatherstripping that doesn’t have built-in epoxy, be sure to clean it, too. Residue left over from manufacturing can cause problems with adhesion.
Addressing Common Sealing Problems
Are you having trouble getting a good seal after you’ve glued everything back into place? While it’s easy to blame leftover epoxy, your problems may be caused by something else. Here’s what you should look for if your seal won’t stay in place.
Check the instructions on your glue. While it may look like a silicone sealer, weatherstripping epoxy is actually a contact cement. That means you need to apply the glue to both the surface and the weatherstrip, and allow it to dry for a few minutes before installation. You only need a thin layer of glue to form a strong bond. Put down a thick bead, and the glue will never fully dry. For the best results, lay down a thin bead and spread it out with a putty knife. You can use painter’s tape to limit the spread of the glue so it only goes directly over the mating surface. When properly cured, the glue should have no trouble holding the weatherstripping in place, even if it wants to curve after being wadded up in its original packaging.
Curing times for glues vary, depending on the formulation and local weather conditions. While the weatherstripping may seem fixed in place, it can take 24 hours or more for the glue to fully set. Don’t disturb the weatherstripping until this time has passed.
For the best results, start applying the weatherstripping in the area exposed to the most moisture. On car doors, trunk lids and hatches, start at the bottom center and work your way up. On house windows and doors, start at the bottom edge for vertical weatherstrips, and one of the corners for horizontal strips.
Rubber gaskets and weatherstrips will shrink a little after application. If the weatherstripping is cut to fit, leave a little extra on the end to compensate for this shrinkage. After a few days, check the condition of the weatherstripping and cut away any excess.Again, try to get the best seal around areas exposed to the most moisture. The cut ends should be up high and away from edges.
Still have air passing under the bottom of an exterior door? If you’re installing a new door sweep, you need to get the thickness just right to seal the door without dragging against the ground. If the sweep is too long, you can trim it down with a hacksaw. The rubber flap on the sweep should only compress slightly with the door shut. If it drags, it will have trouble sealing. After a while, the sweep will peel off of the door.
A misaligned hinge can prevent you from getting a good seal across the door. If you see light on one end, the door needs to be leveled. On car doors, the hinges and door strikers can be repositioned once the mounting bolts are loosened. Using spacers can help you get the door into the right position. You can also support the end of the door with a floor jack and a wood spacer. This lets you adjust the height and tighten the hinges with the door open.
House doors start to sag because most of the weight is on the top hinge. Remove the hinge pin and prop up the door so it’s level. From here, you can use a hammer to bend back the holes for the pin, until they line up with each other. Once you reinsert the pin, the door should stay level.
Remember that the point of gluing weatherstripping is to create an unbroken bond between the weatherstrip and the surface it attaches to. If the weatherstrip slides or peels off, you need to start over again, cleaning and gluing the surfaces to get the best seal possible.
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