Quick Tips — Questions & Answers 3

Prevention is best cure for glue squeeze-out

Q: When making mortise-and-tenon joints, glue squeeze-out gives me trouble. If I wipe it off with a wet sponge, some of the glue gets into the wood pores and shows up under a finish. If I wait until the squeeze-out dries and scrape it off, I damage the surface. How can I avoid this problem?

A: Think prevention rather than cure. The best way to deal with glue squeeze-out is to keep it from occurring. Here’s how:

First, don’t over-apply the glue. A thin coat on the mortise walls and tenon cheeks is all you need. There’s no reason to apply glue to the end-grain surfaces, such as the tip or shoulders of the tenon, or their mating surfaces.

Second, remove excess glue as you are putting the joint together. When you insert the tenon into the mortise, stop two-thirds or three-quarters of the way home. You’ll see a “roll” of glue on each cheek. That’s the excess glue that would squeeze out if you pushed the joint all the way together.

Take a clean, dry glue brush and wipe away the glue roll, cleaning the brush on a rag between wipes. Now push the joint all the way home. If you do it right, there will be no squeeze-out at all, but there will be plenty of glue left in the joint, where it needs to be.

Apply the glue. Use a brush and apply it on face grain only—the mortise walls and the cheeks of the tenon.

Remove the roll. Insert the tenon partway into the mortise, until the glue forms a “roll” on the tenon cheek. Remove this excess glue with a clean brush. Keep a paper towel close at hand to clean the brush.

Clamp up a clean joint. When the joint is clamped, there should be no glue squeeze-out.

You can refinish cabinets with water-based products

Q: Our eight-year-old kitchen cabinets need refinishing, and I would like to use a water-based finish. Is that a good choice? If so, can I apply it over the existing finish? (I’m not sure if that’s water- or oil-based.) Or must I strip or sand down to the bare wood first?

A: WATER-BASED WOOD FINISHES are being used increasingly to refinish kitchen cabinets. These products form clear, durable coatings, but proper surface preparation is vital.

Most water-based finishes won’t adhere properly to a surface contaminated by grease or cooking oil. These must be neutralized and removed. Severe buildup requires the use of mild-pH degreasers such as Fantastik or 409. If you use naphtha or mineral spirits to remove the grease, follow it by wiping with denatured alcohol to re-move the oily residue.

If the existing finish is dam-aged, peeling, or the wrong color, strip or sand it off completely. Otherwise, just give the surface a light sanding and remove the dust.
Now, apply a coat of de-waxed shellac as a barrier and bonding agent between the substrate and the topcoat(s).

Clean, sand, and seal. Grease and grime will make a new finish problematic. Use a de-greasing cleaner if the surface is very dirty, and scrub with paper towels or a Scotch-Brite pad. If the old finish isn’t peeling, just give the surface a light sanding. Apply a coat of shellac to seal in any residual grease and to give a firm base for the water-based topcoats.

Dealing with sappy Spanish cedar

Q: I have a humidor that I built and lined with Spanish cedar. The trouble is, the cedar leaks sap, which then collects on the cigar boxes. Every six months, I remove the sap with acetone and resand the cedar, but the sap always returns. What can I do?

A: UNFORTUNATELY, THERE’S NO GOOD WAY to draw the sap out of Spanish cedar. Replacing the lining in your humidor with clean pieces of cedar is the best option. Just be very picky when you buy it. If it’s not bleeding in the lumber-yard, you shouldn’t have a problem later.

If the current lining must stay, there are a couple of ways to deal with the problem. As you’ve found, wiping the sap away with acetone lasts only so long. Heating the cedar, such as with a heat gun, may draw some of the sap out but won’t get all of it.

The simplest solution is to seal the humidor’s interior with shellac. However, while that will end the sap problem, it will also eliminate the cedar’s mild, spicy aroma and reduce its ability to help regulate the humidity level.

Spots that stick. Sap is the bane of Spanish cedar, used as an aromatic lining in better humidors. The sap is sticky and so persistent that you just might have to live with it.

Invisible fix for chipped plywood

Q: While planing the solid-wood edge-banding on a plywood tabletop, I accidentally planed through the veneer, leaving a small but unsightly nick. Can I repair this without having to remake the top?

A: YES, YOU CAN. Start by planing fairly thin shavings (0.003 in. to 0.004 in.) from a piece of scrapwood of the same species, color, and grain pattern as the plywood. Trim a dozen or so shavings some-what longer than the bare spot. Dab a thin layer of yellow glue onto the bare spot and place one shaving on it.

Repeat this procedure until you’ve filled the void and then some—seven to 10 layers. Work quickly in order to finish before the glue dries. Place a business card or a piece of waxed paper on top of the mound and immediately clamp a hardwood block over the repair. A second block underneath the work-piece will prevent denting.

Tighten the clamp to force the wood shavings to con-form to the irregular surface. Let the repair dry overnight before removing the clamp and blocks. Now, carefully handplane the mound with a sharp, standard-angle block plane. As you get close to the surrounding surface, switch to a scraper and/or sandpaper for better control. (For an open-grained species like oak, I also put in fake grain lines with an awl to match the surrounding wood.)

Because of the high wood content and the thin glue bond between layers, the repair holds up and takes stain beautifully.

Now you see it. A nick mars this plywood top, a result of planing the solid-wood edge-banding that abuts it.

Fill and conceal. Glue thin shavings from matching wood to fill the nick. Once the glue dries, the patch is planed, scraped, and sanded. With a finish applied, neither the nick nor the patch is visible.

How to eliminate clamp stains

Q: I recently did a glue-up that required more clamping pressure than usual. I used Jorgensen clamps with soft-plastic pads. When I removed the clamps, the pads had left stains on the wood. What’s causing the stains, and how can I deal with them?

A: YOU’RE ENCOUNTERING OIL STAINS. Adjustable Clamp Co., which makes Jorgensen clamps, uses a softer plastic for its accessory pads than many other companies. Under heavy clamping pressure, the plastic can exude a bit of oil, which taints the wood.

If extreme pressure is required for the job at hand, you can head off the staining problem by replacing the plastic pads with sacrificial wood pads. I use yellow glue to attach pads made from 1⁄4-in. plywood scraps to my Jorgensen clamps. The glue holds the pads in place but releases them under a firm tap from a hammer when the pads need replacing.

If you need to remove clamp-pad stains from existing workpieces, lightly sand the affected areas or wipe them with mineral spirits or naphtha. Either one should do the trick.

Clamp stains. Under extreme pressure, the soft plastic pads on some clamps can leave stains.

Make your own pads. To avoid clamp stains, replace the plastic pads with sacrificial pads made from¼-in. plywood.