Wood gets slippery when glue is applied to it and sometimes trying to tame a wet slippery wood glue up can be messy and frustrating. The best way to tackle this problem is to assume every glue up will be slippery ... and almost all of them are, and prepare the wood in advance to prevent it from sliding out of place on you with several techniques.
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The first thing to think about in helping to prevent slipper glue-ups is ... What is my margin of error? that means, do you have any extra wood on your glue up that is going to need to be cut off later and where exactly is that wood. Once you know this you can use any one of a few different anti-slip ideas ...
I don't have anyone technique I prefer, it really depends on what I am gluing up and where the extra material, if any is located but one of the first I ever used was simply pre-dripping a very small hole through the top board only, of what I was gluing, just larger enough to accommodate a small finishing nail.
Then I coated my boards and before clamping, I carefully aligned my wood, then hammered the finishing nails into the lower board, but not all the way because I wanted to be able to pull the nails out later. All I needed was for the nails to stop the wood from moving as I applied the clamps ... and presto, it worked like a dream.
Sometimes I get ahead of myself when I am gluing and find that I am already applying glue and I forgot to think about how I will prevent the boards from sliding around. For those moments another clamp at right angles to my main clamping will almost always do the trick. I like to use those little quick release one-handed clamps for that and they are easy on and easy off and once the boards are clamped in the main bar clamps I can take off the positioning clamps and use them on the next glue-up if I need ...
One of my favorite anti slip tools is my 23 gauge pinner. I have rarely used that pinner for anything except glue-ups, it is quick and easy and those times when I am into a production mode like making multiple doors or windows, the 23 gauge pinner is quick and easy and repeatable to use. I don't even have to worry about the pins that are embedded in the wood if I happen to hit one with my sliding mitre or table saw, the thin wire that makes up 23 gauge pins is often not even noticeable when it goes through a blade ... do NOT allow 18 or 16 or larger pins to go through your table or sliding mitre saws, there is a good chance those much thicker brads will at least chip a tooth on your blade ...
One technique I like that hides it'self is using a very small nail, like a picture framing nail, drive one into each end of your board but leave the head about 1/4" above the surface of your wood, then nip the head of that tiny nail off with side cutters. Now when you plant your other glue-up board on top those trimmed nails, they will grab the wood firmly and the more you apply clamp pressure the harder they will grab the wood and keep it firmly attached from moving.
This last technique I have never seen anyone else use ... not saying there aren't some out there who use it, I just have never seen it, and that is to use good quality staples in the ends of the wood to prevent glue slippage. It works amazingly well, is cost effective and you can pull the staples out after with pliers. I have used this a few times and it works great each time ... staples in the end grain, but be aware, they need to be sufficiently long stapes, like at least 1/2 inch and the need to be seated so that they hold the wood. I will usually use 3 or more staples for this and they work just great !!
Check out the TacWise Stapler on Amazon
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Copyright Colin Knecht