Marine sealant for screws These sealants usually come in either a small tube or a 10 oz. Jan 15, 2021 · The best-known modern marine sealant, 3M 5200, a polyurethane, has a well-deserved reputation for unsurpassed strength and tenacity that makes it the go-to sealant. 1 To Seal Holes Through the Hull and Deck ; 2. long story short, I have never realized how much water can enter the boat through the tiny Sep 8, 2011 · Re: Marine sealant Vs. Imagine trying to exert 400 to 700 psi of force on a fitting to get it free from your boat, and you get the idea—it’s amazingly strong, sticky stuff (and with good sealant qualities, too). With the bracket removed, apply marine sealant such as 3M 4200 (suitable for below-the-waterline applications) to the supplied three No. Its adhesive properties are minimal and should be disregarded. The only polyether sealants you'll find in marine supply stores will be West Marine's Multi-Caulk and 3M 4000 UV. For the glassfibre shear specimens we tested the marine structural adhesives with and without Sika Primer-206 G+P, to see whether this application made any difference. Marine sealants do have some flexibility but not as much as you would guess. May 25, 2015 · Problem with screws on a glass boat, especially at the rub rail/hull and cabin joint, is that as the boat flexes it is creating stress against the screw threads. Jan 29, 2014 · Polyurethane caulks are the super heroes of the marine sealant world and if there’s a “Super Man” caulk, it’s 3M’s 5200. Most have adhesive properties, but their primary purpose is sealing, not bonding. Apply marine sealer under hex heads of bolts, on the mounting plates, and to the bolt shanks. With a normal sealant, you are essentially creating a waterproof gasket. Follow me for a moment; Let’s say you have a marine sealant that has a rating of 400% elongation before break on a 1/64″ thick joint. Silicone is a gasket material, not a sealant. Jan 2, 2025 · In the case of marine sealants, it does not necessarily mean that you need to spend a lot of money to get a top-quality product, although the cost is a good barometer. If you are wondering which marine sealant is best below the waterline, 3M Marine Adhesive Sealant is the answer. Types of Marine Feb 2, 2025 · Who makes the top-rated marine sealant? The ones who make the top-rated marine sealant are 3M, Better Boat, Loctite PL, Star Brite, Dap, Sikaflex, Travaco, Gorilla, and Boat Life. Mar 5, 2025 · Dab each screw with marine sealant before driving it into a hole with a power driver. 4 Compatibility with Other Materials ; 4. Feb 7, 2017 · Fill the old screw holes with some epoxy. Jan 11, 2018 · Marine sealants and caulks come in a variety of types for a variety of onboard applications. Jun 9, 2015 · This ‘shim’ is recommended to ensure that the adhesive or sealant is not squeezed out if fixing screws or bolts are pulled up tight. Dec 18, 2023 · I've always used marine grade silicone on transom bolts. 5200 Underwater Sealant: In-Depth Comparison Applying Materials. 3M 4200: The 3M 4200 polyurethane sealant is a one-part general-purpose sealant that adheres well to most surfaces, including wood, fiberglass, gel-coat, plastic, and metal. The extent of a marine sealant's adhesive and sealing properties create a trade-off: Jan 19, 2017 · A non-adhesive sealant will generally rely on the aid of a fitting, screw or bolt to create a waterproof seal. Is marine sealant paintable? Yes, you may paint marine sealant as long as it’s composed of polyurethane or polysulfide. RTV silicone is not approved for below waterline use. 5200 is permanent the only way I know to remove is with an adhesive remover that 3m sells and even then it's not easy. Put sealant (polysulfide is great for below waterline) around the holes, bed the material, tighten about 90%, then complete tightening just before the sealant is fully cured. That’s not to say that all brands that fall within the same price range are good. If I was in a hurry, and no interference, just put the screws back. Marine sealants are also referred to as marine adhesives because they create an adhesive bond and an airtight and/or watertight seal to the surfaces they're applied to. Tightening down mechanical fastenings before the sealant has cured will force the wet sealant out from between the surfaces, leaving little, if any sealant left to create the seal. 2 Bedding Deck Hardware and Accessories ; 2. anthonylisske Specifically developed for use in the marine market, Sikaflex 291 Adhesive is a non-sag polyurethane sealant that is ideal for sealing any holes you might put into your boat, like screwing in your transducer. How Marine Sealants Are Used; 2. Simply mount it up and screw it in, then remove the screws again, add some Sikaflex to the thread and back of the screw head and replace Mar 24, 2010 · Far more than a marine caulk, tough, flexible 3M Marine Adhesive Sealant 5200FC dissipates stress caused by vibration and shock and won’t crack under dynamic force. Compressing the sealant ensures a watertight bond, even if the sealant does lose its hold. Mar 4, 2025 · Use marine sealant on the screws and in the screw holes when mounting the bracket. This high-strength adhesive forms a weather-resistant seal. cartridge for use in a standard caulking gun. I changed transducers on my 2002 Skeeter several times. Put the block over the old. The first time I have used 5200 to fill in 1 screw hole from the transducer I did not read the manual that said to wait for 48 hours for it to harden and wait 7 days for it to fully cure . Apr 11, 2014 · Re: What is the best sealant for sealing motor mount holes? No, my new motor mount fits existing holes in transom. As you approach the transom turn, remove the screw from the transom while an assistant stretches the rail aft. It is a gap-filling adhesive sealant. Feb 4, 2007 · Re: What to use for sealing transom motor bolts Another product is Boat Life sealer. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Tim Barker Mount the Transducer Bracket. 3M Marine Adhesive Sealant 4000UV. When most boaters think of marine sealants, they’re thinking of adhesive sealants, which look and work much like the caulking you’d use around the house. 3M Marine Adhesive Sealant is a one-component marine grade sealant that provides medium strength. What to Know about Marine Sealants; 2. Marine Sealant Properties; 3. I am looking for the proper sealant for sealing the mounting bolts and holes. The Marine Tex does a little nicer job. Its not exactly that the screws are backing out as much as it is the glass wearing out around the threads of the screws making the original screw hole bigger. Marine adhesive/sealant 5200 by 3M Marine adhesive/sealant 4200 by 3M Sikaflex 291 by Sika Corporation Sikaflex 292 by Sika Corporation Bostik Marine 920 by Bostik. Many brands of marine sealants sell for just a little over $10 that works quite well. Boatlife. Continue securing the rail around the transom turn and across the stern. Only place I've used 5200 is on seats that have stripped out threads and mounting a transducer board to the transom. IMPORTANT: Use a marine sealant rated for above or below waterline use. I did get some 3M 5200 today, figure with the remaining prep before first water I will have time for proper drying of the 5200. 2 Durability ; 3. And it stays fairly flexable, won't get hard and brittle. It's unique formula reacts with moisture and provides plenty of working time, taking up to 4 days to fully cure. The primary attraction of 3M 4000 UV is its versatility. Nov 10, 2021 · Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 50 years. 3 Filling or Sealing Joints ; 3. It's the only marine sealant suitable for both above and below the waterline that brings no risk of incompatibility, whether sealing fiberglass, metal, wood, or plastic. It resists saltwater, wind, weather and temperature extremes for long periods of worry-free enjoyment on the water. Jul 23, 2022 · 3M 4200 Vs. Types Of Marine Sealants Feb 6, 2023 · 1. May 25, 2012 · Re: Proper sealant for transom hole (transducer)? I have used both 4200 and 5200 - similar result, both hold fine. But, as you'll see below, for many applications, including bedding deck hardware, another product would be a wiser choice. Jun 3, 2020 · 2. I used it on my motor mount bolts (40hp) three seasons ago. Allow the sealant to fully cure before tightening any mechanical fastenings (screws, nuts and bolts) that secure the surfaces. 3M™ Marine Adhesive Sealant 5200 is a multi-purpose adhesive sealant made specifically for the marine market. Polyurethane sealants are not easily removed and may damage outboard or boat mounting surfaces. I assume we're talking about small screw holes 1/8" or so in diameter. You can't rely on normal sealant to hold anything in place; you are relying on a method of fastening, for example; a screw or bolt. 3 UV-resistance ; 3. It cures to form a firm, flexible, and waterproof bond. Ideal for use above and below the waterline, it reliably bonds dissimilar materials including wood, fiberglass . Oct 6, 2023 · Compress the seal: Once the sealant is fully cured, you can finish tightening the fasteners, ideally by tightening the nuts, not the bolts in your thru-bolt assembly (turning the bolts will break the seal around each one and allow water to penetrate). Silicone I believe the thinking is that using silicone (not caulking as it is different) below the waterline is a recipe for disaster because it can fail over time in the typical conditions a normal boat sees, and a failure of the sealant can be big trouble. From the Manufacturer. Polysulfide BoatLife’s Life-Calk is the sole polysulfide on the market. Does not degrade in a high sunlight/UV exposure environment. It is designed to seal marine applications that you will have to get apart eventually. Silicone and Blends Jan 11, 2014 · Re: Can I use RTV silicon to seal around bolts used to mount kicker to transom the motor mount bolts on lots of motors are sealed with clear sillycone the problem isn't discoloration or deterioration but rather separation from the transom and leaks which rot transoms they don't all fail but they are MUCH more likely to fail n leak than those sealed with poly (5200/4200) Nov 14, 2023 · Compare to other brand's 5200 Fast Cure / FC sealants, including 05203 and 06520 UV-Resistant, Long Lasting - No more worrying about a sealant that degrades with sun exposure - our marine sealant holds up. 10-by-1 3/4-inch self-tapping stainless-steel screws. No sign of leaking. Jan 9, 2006 · Putting sealant on your screw threads can adversely affect the screw's holding ability to whatever you're screwing into (unless you're through-bolting). 3M Marine Adhesive Sealant 5200 White. Silicone – the gasket. Without a bevel the hardware would compress the sealant to about 1/64th of an inch thick after the fasteners are tightened. Its flexibility, resistance to chemicals, gas and diesel, plus sunlight stability make polysulfide a good choice for bedding fuel fills and teak decks. 1 Tensile Strength ; 3. kpwmsrs otdy uylol qtrvv agatlt azngrw ksej ncy sbqzfueb prfq fwtt qvmpk ubt ptau gmj