Which Exterior Glue?

Bob, I'm gonna build a thing that's gonna live outside. Ok. You're offering me three choices of exterior glue. That is correct. How do I know which one to use? So, again, advantages, disadvantages uh to the glue. Um If you are gluing wood that is high in moisture content, anything above 17% moisture like pressure treated lumber that was treated last week. And I bought it today and it like that is, weighs £11 billion and is dring wet. So you cannot use a water based adhesive because the water base adhesive will not dry between two pieces of what wood and so in that particular case, you're, you're pretty much forced to use a polyurethane glue. One that is, you know, chemically reactive, polyurethane wants moisture to help it. And if your, if your wood is above 17% moisture content, you do not have this water on it. There's plenty of water in the wood to, to get that to react. But that line in the sand is 17%. That's important. I think like because k dried stuff is like six or 8% supposed to be or should be. So if somebody is choosing to use polyurethane glue on K dried wood that really is a percent. They need to add water, they need to spritz a little moisture in order to get it if, if it, if it's on the dryer side, so I digressed a little. So if, if the wood's dripping wet and it's gonna live outside when it's done, polyurethane glue is your Huckleberry and, and note caution when using wet wood is that that wood is not going to be the same shape. It's going to be after it dries. So just using wet wood for your construction projects is not always a good idea, but sometimes you're forced into it. Ok. So then we've got two and three and I think when I stop me, when I go astray, water resistant waterproof. Uh That is correct. Now, the difference is, is type 12 will pass a type two. an test which is where you take ply um soak them in water, fully dry, soak them in water. Then you do that um three times and the test is that the ply cannot have come apart. Um A lot of people robust but some people say, well, it's just soaking and drying, soaking and drying. Well, you got to understand that as a ply, those plies are moving in this direction. So there's a lot of force put on the wood. Uh type on three will pass what is a type one test which is a similar test, same type of place. But you, one is better than two, like it's kind of reversed. Yeah. Yeah. 11 is harder to pass, harder to pass. So the type one test you take the same place but you boil it in water, then you fully dry it, you boil it again and then you pull them apart and there has to be a certain amount of strength versus wood failure, right? And so in a lot of cases, I always ask when I do my presentations, um you know, let me see, uh raise your hand, uh who's boiling their furniture. So in, in a lot of cases, it's not that important that it passes, say an ac type one or type two for exterior for usage. One of the benefits though for type 13 is that it will give you longer working time and that longer working time. In most cases, in some people's minds will be, well, this glue is better because I used, I've had failures with type 12, but not that the failure was because the glue is bad is because they took a little bit too long to put it together. It was very, very fast setting and three is a little more forgiving. In that particular case, either of them since they have been developed and used for, we have never had a customer send in a project that had fallen apart uh due to the glue. And in every case that people have sent us stuff. We have seen wood fiber in, in the uh in the glue lines. And so basically the wood has fallen apart. Um Cutting boards are a huge application for both of these glues. What about FDA food choice? That whole aspect as it affects or in regard to um both of them are all FDA approved for indirect food contact, which is what a cutting board is now. Uh not for direct food storage, which is say I make a cask and I wanna, you know, brew some beer in it. That's not um that would be direct food contact. So a a anything where food is temporarily stored on, on, on the project is fine. Um Again, if you're making a cutting board and it may see a dishwasher cycle, that's probably one of the few times where boiling water would be an issue and type on three would be superior. In that particular case, either one of these really is gonna work for a planter or an Adirondack chair or like outdoor furniture in general, either one's gonna be a good choice but the I I love this for its work. It's open time. Um That's the big advantage it has there. And one of the disadvantages say a polyurethane or really the C A glues which, which tend to get more brittle um living outside that wood is expanding and contracting, right? And so if your glue does not also expand and contract, uh you can get a lot of force on the wood fibers which can over time cause them to tear apart and fail. Um Whereas the type on two and three have been designed to be flexible. If you've ever put a film of that down, it does flex and, and actually when it gets wet, it does soften, which allows the, how do you say the glue lines to not put as much force on the wood as the wood gets wet and as wood gets wet, it also weakens. And so in that particular case, these are perfectly designed for, for those exterior projects. Is, is there any reason why I the woodworker couldn't simply stick with type on three for all my projects? Like I, I guess somebody, for some people, they don't want an inventory original and three, they're sometimes doing outdoor projects. So what? And I say sure, just, I mean, if you want to put cabinets together with that, you can, there's no negative and I use type on three all the time for my and that's my go to for, for everything. Um Now there is probably a price difference if I'm not mistaken on there. And that could be uh one of the issues. But again, the glue is not going to be as costly as, as, as the wood that you're gonna be purchasing in. Cool, helps you narrow your focus when you're picking the right glue for your next outdoor project. Thank you.