Tame tricky clamp-ups

Dry fit

Note: Before tackling a difficult clamp-up, walk through it first without glue (known as a "dry fit"). This exercise tells you whether you have enough clamps of the right type and size, which parts need more work to fit, and if you need any additional help or accessories. Plus, the dry fit familiarizes you with the assembly process before you find yourself racing against the glue's setup time.

Beat the bulk

Large assemblies, such as casework and cabinetry, require loads of clamps, and big ones at that. To apply pressure to areas beyond the reach of the clamp's jaws, extend their reach with cauls (below), or use a heavy object instead (center center). If you don't have enough clamps to complete a glue-up, try making just a few clamps do the same job (third below).

2 boards on table
On wide panels, use clamping cauls -- shaped slightly thicker in the middle than at the edges -- to help distribute pressure evenly across the panel.

Red toolbox on boards
If you don't have a long enough caul, utilize something heavy, such as a toolbox, to apply pressure in the middle of a field.

2 photo together, clamping them together
To get more from a limited number of clamps, we glued in half of this bookcase's shelves, and after they dried, reused the clamps to install the remaining shelves.

Tackle it with tape

Flexible, disposable, and adjustable, painter's tape—available at most home centers—excels at holding small parts securely. Use it when an assembly lacks adequate clamping area, has an unusual shape that makes it difficult to get clamps in place without creating a crisscrossed mess (below), or is too delicate for clamps (second below).

Blue tape with wooden pieces on it
Align mitered box sides tip-to-tip on a long strip of painter's tape; then, roll up the assembly for tightly clamped joints.

Blue tape holding up side of box
On delicate clamp-ups where the weight of the clamp could collapse the assembly, painter's tape offers a light but firm grip.

Overcome odd clamp-ups

When you can't clamp directly across a joint, such as in the assembly shown at the top of page 18, insert spacers between the legs to equalize the clamping pressure along the assembly's length. When cutting tapered parts, save the offcuts (below) to use as cauls. If you find yourself regularly building un-square projects, purchase a band clamp (second below)—it greatly reduces the hassle of those clamp-ups.

Squaring up taper parts
Fit the offcuts of tapered legs against the legs they were cut from to re-create parallel clamping surfaces. In some cases, you may be able to first assemble the parts when square, and then taper them afterward.

Orange band around triangle piece
For clamping jobs with out-of- the-ordinary corners, a band clamp applies even pressure to all joints. Many come with corner blocks to prevent crushed corners and keep glue squeeze-out off the strap.

More Resources

  • Watch clamping and sanding tricks for perfectly flat panels at woodmagazine.com/clampflat.
  • Find nine more clamping tips at woodmagazine.com/clamptips.
  • Check out our favorite clamps and clamping accessories at woodmagazine.com/clampreviews.

 

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