Gluing up large panels
Posted on July 13, 2015
I double up a lot of 3/4 material for my speaker baffles, tops and bottoms. And when I laminate my curved shells I am spreading glue on two surfaces about 2′ x 5′ on average depending on the speaker. That’s a lot of glue to get spread and get clamped up in less than 20 minutes. I only use Titebond III for anything wood to wood, and 20 minutes is about the max open time. So I had to find a way to spread a lot of glue fast with out making a mess. I use what we call a peanut roller. The Shed resistant woven type you would use to roll paint. I use the 4″ size for smooth or semi rough surfaces depending on material. Home Depot # 373856 or 381886 or something comparable. I just keep a 6″ x6″ x3″ Tupperware filled with glue and lightly dip right into that, not even using a roller grid. Spread the glue fast and even on both surfaces like you would paint, and come back and lap up any excess. I always go back over the first surface real quick. Then just throw the roller in a bucket of water. It can stay there for a week or more to use again. Just whip it out in the yard, pad it almost dry with a paper towel and roll again! I keep the same roller like this for months. One of the beauty’s of this method !
Now for the clamping. For panels 12″ x 12″ and larger we use whats called in the trades, clamping cauls. Basically a thick piece of wood a little longer than your glue up. Like a 2×4 that’s bowed slightly in the middle so that when there is one on top and bottom of your workpiece and clamped at the ends it will apply pressure in the middle of your piece. I spread them out about every 12 to 18 inches if possible.So if your making a 24″ x 48″ piece, you should use 6 long cauls [3 top and 3 bottom] or 8 shorter cauls about 16″ apart. Always try to position your clamps so that they are putting pressure inside the perimeter of your work piece.
Here’s where I differ from most folks. I use 2″ x 2″ x 1/4″ thick aluminum for my cauls in varying lengths. If I think the project is slightly bowing the aluminum, I will put about 3 or 4 pieces of blue tape in the middle. Just 2″ or 3″ long. Blue tape is about .004″ thick. I know aluminum is pricey, but if you use it a lot like I do it’s worth it. I can get 24 feet of this stuff for about 160$. And most local suppliers will cut it for free.
With this method you can make very flat panels any thickness you want. And certainly stronger than anything you can buy. I hope this helps and don’t be afraid to call with any questions. Yea I know I gotta get the picture thing going.
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