J-B Weld Liquid Hardener, 1 pt, Clear to Amber, Can

Had an old set of windows in a very old house. House not worth all new windows due to other problems. Sills were rotted and water would just go down the cracks and fester. Wood was punky or soft and wouldn't keep any paint. Used a similar (but two part) epoxy product in Alaska before and it worked great. Thought I'd try this one part product. I will never go back to a two part system. This product penetrated the compromised wood quite deep down and solidified it. The next day I was able to putty the cracks and low spots and the putty stayed in place tightly. When using an electric dual action sander the putty did not loosen at all. After painting you couldn't tell they were ever damaged. CAUTIONS: Wait till the wood is completely dry. Remove any loose chunks and dust. I used light pressure with a wire brush and vacuumed the debris. In poor weather tarp the area and use an electric hair dryer or heat gun to dry surface quickly. Put putty on after this product, not before. USE GLOVES. Some people could be allergic to uncured product. Also use safety glasses if you are using air to blow out the debris. I prefer to vacuum the debris up instead of blowing them away. Also if the area below the window is one you don't want to leave a permanent unsightly stain on shield the area from drips. Don't pour on thick, often one wet coat will do it. A brush is recommended to get deep penetration into the cracks. One bottle will usually take care of two 36" inch sills or several smaller patches. If in doubt, buy two. If you don't have enough to completely fix a bad spot don't use it at all until you have enough product. Otherwise you will semi-seal up the surface and the new product will not penetrate the surface. I left the patches to dry overnight but if the surface is hard and not tacky after 2-3 hours you could lightly sand if needed and putty could be applied. Don't use heat to accelerate the drying process in the first hour or the penetration will not be as deep. A hair dryer will speed up the process though if the wood was good and dry before treating it with the j-b weld product. Acetone will clean up any dripping but also could affect the finish of the surface you are trying to clean, so the best technique is to mask as needed and watch for drips for the first 5 or 10 minutes. A throw away brush is what I recommend. After trying to clean up a brush I used with this stuff I spent more on acetone than the cost of the brush, let alone the time. Have fun and be prepared to be amazed.

this works great.

This worked like magic. I used it on the somewhat rotten wood then filled it with putty and painted the wood. It saved the fence and saved a lot of money.

Worked great on my barn door. Really happy with the results.

I wasn't convinced this could do the job, but I was happily surprised. Worked great on the wood rot on my railing. It was a two by four, and it had rotted out because of what must have been a split in the wood and a hard working carpenter bee. It made the wood hard enough, with several coats, so that it would accommodate these various wood screws (see pic). I think it created a great base for the wood putty as well. Remember, the first few coats will take longer to penetrate and dry, after that, it goes pretty fast. Took eight coats, but it did the job. Also, a little goes a long way. I almost have a full bottle left. Should be sufficient for any project. It's a buy.