3M 20124 All Purpose Fiberglass Resin, 1 Gallon

If you really need great adhesion to smoother surfaces, I'd suggest epoxy resin. But if you can rough-up the surfaces, are working over old fiberglass or previous layers, this stuff is great. Measure the hardener carefully and adjust the quantity to your application. I mix 4-6 oz resin with 8-9 drops hardener at 80-90 degrees F and it begins to gel in about 15 minutes. I'm building water tanks for a RV van project. I'm using this resin with cloth and mat to attach and seal FRP sheets.

I works like it supposed to and easy to use

Easy to use, great product.

I used this product on kid's bath tub around drain area, after applying product i sand just as instructions said. Then replaced the plumbing for the drain and no more leaks. A big thumbs up for this product.

I bought the kit to repair the floor in my fiberglass T.T. where a leak caused water damage and decayed the wood. I spent about a hour preparing the repair spot. I bought a second fiberglass mat to make sure I have enough to finish the job. The repair area is about 15in x 5in. in a crescent shape with a fiberglass lips on the shell that needs to be filled in. After cutting 3/4 of the included mat into smaller pieces and a few of the woven mat, I started the first layer. About 6-7 mixed layers of of resin then laying the mat in to fit and fill out the hole. Take your time preparing for the repair and plan it out, read the instructions. Follow the instructions on how to mix the resin and activator. (For first time users) I've used this multiple times over the decades, lessons learned are above. A few of the times I have tried to shortcut the process it's not worth it.

I bought and used this product the same day. Waiting a full day before sanding and it was hard but tacky ruined my sandpaper so I waited another full 24 hours and same result. Now my canoe is sticking to everything I can't sand it to paint it. I'm very disappointed in this product I wish I didn't waist the money on it. I don't know what to do with it now.

I tried using 3M Fiberglass Resin (20122) to repair a cracked hard-sided suitcase. It never cured – not even with a 2X dose of hardener. Now I've got a sticky gooey mess to deal with – possibly unrepairable. This could be due to the product sitting on my shelf for a year or two – unopened, and in an air conditioned indoor closet. However, I DID inspect the can for an expiration date – and found none. Likewise, I checked the hardener – nope – no date. I scoured the 3M website for anything on shelf life - nada. The umpteen page MSDS sheet- nein. I thought to myself “3M is always top quality stuff – if there's no shelf life info, it must still be good”. My bad. SHAME ON YOU 3M for not providing shelf life info or use-before date - especially on a product with apparently short shelf live. This experience has re-calibrated my thinking about 3M. I used to hold them in the highest regard as an ultra-reliable source of professional materials. From here on out, I'll be looking for better options.

A heavy gallon can of resin was loose in a cardboard box and was damaged in shipping and leaked dangerous contents

I've bought and use around six gallons of this fiberglass resin to make two bumpers and started on a center console. Your gallon resin works incredibly well, but I only needed about a quarter to finish the console that I'm working on, but this stuff is garbage. I applied it with the correct mixture of resin to hardener and it didn't come close to setting after 2 hours. Next I mixed twice the amount of hardener, waited and it still did not set. Now I have to buy a gallon for a quarts worth of work and also lost a whole day. My question is why are the two sizes different resin? I never would of bought it if I knew that. Next question asks if I would recommend this product, my answer would be that I would recommend the gallon size to everyone, but not the quart size.

Followed the instructions on the can...and it won't harden. Mixed exactly 8 oz with 80 drops of harder, mixed and used a paint brush to cover my outdoor town clock...now I have a goo finish. Paint brush harded but not the clock finish....