Amazing GOOP 5400040 Coat-It Waterproof Epoxy Sealer & Protector - 2 lb Kit, Dark Gray

I bought this to try and seal a 1963 StarCraft aluminum fishing boat. I noticed water collecting in the boat but was unsure where it was coming from. I decided to buy 2 sets of this but only used 1 with a bit left over. It sealed both side joints, the entire keel, all the bottom rivets, and around the seam on the transom. All I did to prep was power wash the bottom, but the boat had been completely stripped of all paint prior to this sealing. After letting it dry I was very pleased with the durability of the product, and then put 2 coats of bottom paint on the boat. When it went back in the water there were no leaks! I’ve left the boat in the water for several days now and it’s still completely dry! Warning, you cannot send back unused product because it’s flammable. They can ship it but you cannot send it back. Fortunately I was able to sell the unused set I bought to a friend. Overall extremely happy with the finished product on a 59 year old boat.

Great stuff for the bottom of my boat.

I needed an acid resistant coating for the inside of a plywood battery box I built to hold flooded lead acid batteries. I'm happy with the results I achieved. I will definitely consider using this product again. A couple of caveats and notes about usage: The biggest problem I had was evenly coating the walls of the box. The epoxy on the walls flowed downward with gravity. As a result, the floor ended up with extra material, and the thickness of the coating is markedly reduced at higher positions along each wall. Enough coating remains even at the top of the walls to preclude the need for a second coat. But a different strategy is required to do a really nice job. Perhaps it is doing each wall separately, or perhaps it is applying multiple very thin coats. I'm not sure, but before I try coating vertical surfaces again I'll want to do some more reading, or experimentation. Based on my experiences, I believe the working and cure times for this epoxy are conservative, that is perhaps actual times are longer than published times. The second issue I had was with bubbling. I experienced some bubbles breaking the surface of the coating on the walls of the battery box, leaving some pock marks in the coating. These imperfections aren't terribly obvious, and for my needs they don't matter. If I wanted a quality finish, I would have been disappointed, done some sanding, and tried a second coat. By comparison, however, the floor turned out great -- no bubbles there, only some variation in thickness due to the aforementioned flows from the walls. I'm not sure if the bubbles were caused by the method of application, or the mixing. Because the floor of the box turned out so nicely, I tend to think its probably the former. Adhesion to plywood is excellent, and I didn't really do much to prepare the surface beyond wiping it down with a damp cloth beforehand to remove any loose particulates. I had drilled a couple of 7/8" holes in the back wall of the box for venting prior to coating. The coating pooled at the bottom of the holes (the plywood is 3/4" thick), so they were no longer round. I used a hole saw after cure to fix that problem. The bond between wood and epoxy is excellent -- the epoxy did not chip or split away from the wood as I drilled it. One last point: the estimated coverage seems right on if not slightly better than published.

I was looking for something to coat the bottom of my boat so stop the leak this is the best thing I found will buy again

I bought this stuff to bring back on old Jon boat to life. I used it on all of the rivet heads and seams on the outside of the boat. It was a little tricky at first because I wasn't expecting the consistency to be the way it was. I found that an epoxy roller was not very effective. To me, using my fingers with nitrile gloves worked the best to spread this stuff where you need it to go. Have a plan because your working time is limited. I drizzled it over the seams and rivet lines, then used my fingers to work it into all crevasses. Dries nicely takes paint. Happy with the results!

Re Do 14' Jon Boat. Wire brushed down whole boat, (wire brush on 4 1/2" disc grinder ) cleaned around all rivets, and did as what is told next. Cut two $0.50 cent brushes 1'' long. put little can into big one, stir 4-5 min poured into alu pie pan, paint on boat rivets. 11 hr. later hard as a rock, took out of garage, and put on four saw horse's so not to buckle boat. filled with water, let set for 2hr. no leaks. drained, back in garage. hand sand to rough up the gloss so it will take paint. blow down boat, wash down after with water. let dry and paint, 1957 Sea King look like new boat, good as new, Monkey Ward would be proud of me, (dam i is me.) I did not paint the whole bottom of boat with Goop, just all the rivets bottom and sides. Had wife help brush on she good girl, keep her another 47 years. (Did not use whole can I mixed.) Ordered two sets of Goop, well i got a spare now. Lot of work for old boat, but the proof is in the pudding. would use this stuff again in a heart beat. you cain't go wrong with dis stuff. ay. bill

Product came damaged. Leaked in the box. When i tried to use it for blocking some small weep leaks in fiberglass it did not work. Not sure if the open exposure or the long cure time, it all needs to be sanded off and clearly did not work. Maybe on upside down boat poured on by the gallon but brushed and rolled did not work for me.

A must have for aluminum boats. Coating the inside of the floor or outside. Works wells and seals all pin holes for good.