Popular theory in boat repair is that the 3M adhesive called 5200 can create a bond stronger than the materials it bonds, and it can’t be unbonded. But is it true? We found one product that the maker claims can “DeBond” 5200.
The popular polyurethane adhesive 5200 has competitors under different brands, but polyurethane is the most-reached-for goo in boatyards and factories when it’s time to mount cleats, through-hull fittings and synthetic teak products, and even join the hull to deck. No wonder. Polyurethane adhesive cures tough and flexible. It sticks to wood, metal, fiberglass and, if you let it cure long enough, your skin too. Fabrics have been repaired with it, and the best-built boats have pounds of it in various places. Its curing process is days long but, curiously, faster when in contact with water, making it ideal for through-hull fittings.
But if you want to undo it, polyurethane is demonic, insidious and tenacious. Bonded deck cleats are so hard to remove that it isn’t unusual to remove gelcoat with them. So I was startled to hear there’s a product that can detach 5200 seams and joints. The gauntlet was thrown down to BoatingLAB, and we set about to create a test, pitting DeBond against acetone, denatured alcohol and MEK solvents commonly used in paint and fiberglass shops.
How We Tested
Regal Marine in Orlando, Florida, donated some fiberglass hatch cutouts as test panels. We fashioned five panels to be easily clamped to a bench. Then we bonded smaller panels to them using 5200. Since 5200 cures faster when it’s moist, we misted it with water immediately, and then again two days later, and let the panels cure for seven days — longer than the literature called for.
Removing 5200 per the DeBond directions required scoring the adhesive bond with a knife, spraying the product on the scored mark, allowing it to soak in, and then scoring, spraying and repeating until the bond was removed. This was the procedure we used with all the solvents.
Chewing gum happens, so we pressed some into an unfinished open-grain board and let it harden for 24 hours, then used a rag and the solvent to remove it.
How We Scored
Product successfully removed 5200: Yes or No
Removed chewing gum: Yes or No
Ease factor (how much effort was needed?): Easy = 3, OK = 2, Difficult = 1