Pulling Surface Joints Tight
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Links to gadgets that can make this sometmes-frustrating issue a breeze. February 8, 2005
Question
We design and build wine cellars, often with a work surface. We make this out of 3/4 ply with a veneer. I'm looking for ideas on how to pull two adjoining sheets together tightly. The issues are:
1. We must pre-finish the tops since they are often being installed in new (unheated) construction and finishing in place is a bear.
2. Because there is racking in place under the work surface, it is almost impossible to get to the underside to insert anything to pull them together.
We currently run a full length spline between the adjoining sheets, but the only way we've found (not really satisfactory) is putting wedges in the far ends to push the joints together.
Forum Responses
(Cabinetmaking Forum)
From contributor B:
Can you insert some biscuits to keep things aligned and pull the pieces together with pocket screws? I'm thinking you might be able to tip the top enough to screw them together. Clamping sheets together is hard, but let the biscuits line them up for you.
From contributor J:
Depending how smooth the surface of your tops are, you could use those sheet glass vacuum handles. Put them on both sides and clamp them to close the joint. Check out www.monumenttoolworks.com. They have a solid surface seam clamp system.
From the original questioner:
Thanks for the hints. I'm writing the vacuum guys this morning. It might be a long shot since I'm not sure how hard this will be on the existing finish.
Contributor B, we already use a spline the full length of the joint, and nope... wish we could. We can't tip up the surfaces (some are 8' long) to get to pocket screws.
Re: Need ideas on pulling surface joints tight
Bob Yankovich 11/30
From contributor O:
You might want to check out the INVIS system (www.swissinvis.com).
From contributor D:
To go a bit in another direction, you may try to work a design in the veneers on the top that will accommodate a slight v-joint. This v-joint will not only be visible at the joints, but also at other points where veneers change direction or are isolated by stringing, solids, or other top elements. May be an opportunity to stand out in the crowd.
As to pulling together any two parts, I like the vacuum pods. Pinske Edge sends me a nice catalog with all the info. I'd bet they have a website real handy.
From the original questioner:
Contributor O, you're a lifesaver for an old guy with no memory left. I knew I'd seen this system at IWF a few years back but could not for the life of me remember the name. Now... just hope they don't want a house mortgage to get it.
From contributor M:
What contributor J is referring to is Paraligns. They have a rubber gasket (O-ring actually) and use vacuum to hold. They are used primarily for solid surface. They also align the top edges, making a flat joint. They have precision linear bearing to make this happen. The manufacturer says that you can use this for wood. I would think that if the top is finished, you should have no problem at all. You might want to consider using Pinske's wavy bit in conjunction with this.
I saw the INVIS system. It looks like you will need space for the dowels that extend past the edge of the material. Can you join these as you lay them flat? How strong are these things? How much pull do they have?
From contributor U:
I use two sets of Penski suction clamps primarily for SS, but I've used 'em with laminate and finished wood too. Handy little items... But you got me on how to secure the tops once pulled tight if you can't get underneath.
From the original questioner:
Thanks for all the suggestions. I looked at the INVIS system and am not quite ready to spend $900 for something we would use only occasionally. It's looking like the suction clamps might be the only alternative so far. Once the joints are pulled tight, we do have places to secure the surfaces from underneath... just not near the joint itself. Still pondering.
From contributor S:
Could the Fast Cap countertop bolts be made to work? You may have to add a filler to get enough thickness.
From contributor A:
If this is completely captured by walls, can't you scribe everything to fit, then fold up at joints and glue, then drop back down into place?
From contributor R:
Raise the counters up on blocks so you can get underneath and use the regular bolt joiners.
I have seen a fellow use temporary wood pieces on the bottom, using inexpensive hot melt to hold them onto the two pieces. He then uses a more suitable glue for gluing the two pieces together. After the joint is completed and main glue is dried, the hot melt wood is knocked off (heating a little beforehand will help the hot melt let go). I have also seen where two small blocks are hot-melted onto each piece and then these temporary blocks are used to anchor the clamps. The blocks are removed later. This block technique is used for Corian around here when joining small sections into a continuous top. I have seen it used many times.
From contributor K:
This is coming from a finisher, mind you, but what you're asking for is the use of drawbolts that fit into a routed out area under tops. These routed spaces are done using jigs to keep uniform and square. All the draw bolts are threaded bolts with wing type nuts that secure and pull tops together when wrenching down.
From the original questioner:
Thanks to all for their comments. Feedback like this is what makes this forum such a great resource.
We are coming down to either using the vacuum pods or using temporary screwed on cleats on the bottom that we can reach with clamps. The joint line inevitably comes right over a racking section, so we cannot use the normal draw bolt concept underneath.
Where it fits, we try to use a piece of contrasting wood at the joint line to at least help disguise the joint.
