There are a handful of topics and questions that pop up pretty regularly in the woodworking world. Most commonly: should I or shouldn’t I add glue to pocket hole joints? If you ask a room full of woodworkers you’ll probably get answers that fall on both sides of the fence. We decided to do a little experiment. Now we know that we didn’t take a hugely scientific approach to this, but it provides some results that are interesting.
The Experiment
We made up two pocket hole joints. One with glue in it, one without (The specific glue used was Titebond Quick and Thick). With one leg of the joint held in a vise, we yanked on the other leg, looking for a fracture. One measure was; how much force does it take to break the joint. The other was; what exactly does the joint look like after it’s been broken.
The Results
Well, we’re not going to give away the results of our experiment here. You’ll have to watch the video. But we can say you’re going to want to incorporate the results into your projects.
Applications for Pocket Hole Joints
There are so many places you can use pocket hole joints and screws. This is a such a versatile way of putting wood together. While most of us probably use it for face frames, or similar applications, pocket hole joinery can be used in lots of other applications.
Also Important…
Choosing the right joint for your project is important, and choosing the right glue is important too. Have a look at 4 Types of Glue You Can Stick With to make sure you’re using the best glue for your projects.
So how strong does a stile and rail joint really have to be? You’re never going to be counter pressure on the joint and it will be secured to a cabinet box. So while glue makes it a stronger joint why does it need to be?
The joint will be pretty strong without glue, and much stronger with glue. I find the minimal incremental investment of time and materials to be worth the added insurance, but it’s entirely possible that I would have never had a joint fail even without glue.
-Paul
Woodworkers Guild of America
Noted that you did not use Kreg pocket hole screws. Kergs have a much larger washer head than the screws you used. Bet they would take a lot more force to pull out of the pocket.
A glued pocket hole joint which has cured is almost as strong without the screws as with. If it is a frame that will be glued and nailed to a carcass glue won’t matter.
I watched your video regarding glue and pocket hole screws however, I was wondering how important you think it is to glue pocket holes where lateral force either forwards or backwards or even side to side is absent such as in the case of carcass construction? I do agree with your admission that adding glue like you showed in the pocket holes in your test is a good idea and something I would likely do in future projects where your example is applicable. Thanks for the tip!
Hi Anthony. It’s a judgment call on that. I always apply glue to pocket hole joinery irrespective of the application, because the incremental time and cost is modest and the increased strength is substantial. But, if the joint isn’t stressed, then the increased strength isn’t going to provide any benefit.
Thanks
Paul-Woodworkers Guild of America
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Thanks
Jean-Woodworkers Guild of America Video Membership
Here’s the thing… maybe you don’t need glue for pocket hole plywood casework, but I’m here to tell you I’d never assemble pocket hole face frames without it. Not because it’s adding any great amount of structural strength – it obviously won’t – it’s an endgrain joint. But what it DOES do – and I’ve done 100s of these with and without so I know what I’m talking about – it does help to keep that joint from twisting and moving seasonally. It adds just enough resistance to a 2″ wide joint to help stabilize it through seasonal changes – and therefore it WILL – not maybe – look better after 5-10 years than a face-frame that wasn’t glued. I don’t use pocket holes very much period – but when I need to do face-frames quickly they can be a useful tool -but after seeing how the seasons impact them I’ll always glue them. The $.10 it costs and 5 seconds it takes is simply a non-issue when you want something to look good year after year.
Very much agreed!!!!!!!!!
How about we just use actual joinery? I get the speed of these pocket hole things, but I’ll never make something with them or buy anything made this way. I might as well go to ikea.
Thanks, I’ve wondered about this issue. I truely enjoy pocket hole joinery where appropriate, and knowing that Titebond will truely strengthen this joint is quite reassuring.
Hmmmmm. Who knew. Guess I’m gett’n the glue out next time.
Hi George,
First, your videos and classes are great. Thanks so much for the work you do.
I can agree that the face frame joints are stronger with glue. The question is does the joint need the extra strength. I am a novice woodworker and it seems to me that most woodworking professionals showing how to do things on the web overly focus on joint strength. I recognize joint strength is important but when is a joint design good enough for its purpose. Same thing for clamping pressure. How much do you really need to create a strong joint?
Hi Jeff. I don’t know exactly the difference in force that is necessary to break a glued vs. non-glued pocket hole joint. I always apply glue to pocket hole joints. It’s quick and inexpensive, so I view it as a cheap form of insurance.
Thanks
Paul-Woodworkers Guild of America
What I do on my pocket joints on my face frames is , before actually assembling I put a coat of glue just on the end grain and let soak in then glue both end grain and edge grain then assemble with the screws. Just make certain you are right thou it will not come apart very easily.
I use tight bond 2 and three just not at the same time.
Curious: you are showing the TiteBond, no drip, fast drying glue, was that the glue you used on this experiment?
Hi Gary. Yes it is what he used, but you can use your regular wood glue for gluing pocket hole joints.
Thanks
Paul-Woodworkers Guild of America
I do general maintenance at an apartment complex.
Part of my jobs consist of replacing kitchen faucets. The easiest way I have found to get my large frame under the sink is to remove the center stile of the cabinet face. They are attached with pocket screws. The joints were not glued when originally produced. If they had been glued I would not have been able to remove the stile to get under there to do any of the jobs that old apartments need done.
So glue does have its uses but sometimes it doesn’t.
I concur with George. I built a number of cabinets for our home 11 years ago and used pocket hole joinery and glue. On one cabinet face frame, I accidentally assembled the face frame in a mirror image which was incorrect. I discovered this after I had assembled the unit and it had set for approximately 10 minutes. I removed the screws and attempted to remove the rail from the stile and it would not budge. Eventually I got it to come apart but it ruined the wood surface on the joint on both pieces of wood. Glue does increase the strength of the joint. To help make the glue joint better. I apply a light layer of glue to the end grain first, let it sit until it feels, dry (about 30 seconds), and then apply another layer of glue to the end joint. This helps prevent too much glue from being absorbed into the end grain and thus making it a much stronger joint.
I’ve built hundreds of pieces of furniture using pocket screws. Every test I’ve seen is just like this, one “L” shaped joint. My house is nailed together and if the same test was done in the same manner, I would expect it would have fallen over, but it hasn’t. Why? Cabinets and furniture are much like houses, they contain many joints creating an overall sturdy structure. I agree that adhesive adds strength, but I don’t believe necessary. For me, if I’m going to use glue, it will be for a mortise and tenon joint.
I think that over time, with the wood expanding and contracting there is potential for eventual loosening. Whereas a glued joint will be more permanent.
Watched your experiment with glue&pocket screws in face frame joints. I’m pretty sure no cabinet will ever be subjected to this amount of lateral stress. I cannot see any added value in the time and glue added to these joints.
Can’t wait to see your glue-less pocket hole face frames in 5-10 yrs. They’ll still be together – but they’ll be looking rough. Guaranteed. Are we all in so big a hurry we can’t take 5 seconds to glue a joint?
Of course it’s stronger with the glue. Glue adds something to the joint, and doesn’t take away any strength from the pocket hole screws. It might be debatable how much extra strength but there has to be more with the glue.
Depends on how strong the joint needs to be. I can’t see needing it on a face frame, but on a rail to leg joint on a table, itnis probably worth it. Not every joint needs to have maximum strength.
The one thing about gluing end grain, yes the end grain absorbs most of the glue before it sets up not giving the full benefit of the gluing process. The better thing to do if you don’t mind taking more assembly time is to spread a thin coat of glue over the end grain first and let it set up sealing the end grain. Once the glue sets up 20 – 30 minutes you can then apply additional glue to the end grain assemble and clamp. End result will give strngth to the joint.
I’m building a changing room for my employer using pocket holes and I’ve been scouring the internet for whether or not I should use glue and NO ONE ELSE has had this idea. I will definitely be using this technique. Thanks!
Not all glue is the same, do you think tight bond 3 would give the same result
Yes