How To Repair Cracks And Knots In Wood

Allow'south confront it, none of united states of america are perfect, and neither is woods. Knowing how to repair defects is critical to the success of any job. Many projects need repair or bear upon up in some form or another, whether it'southward a small knot or check, or when our ain curt comings in craftsmanship reveal themselves, like on open seam or the mistaken driblet of a hammer.

Any the crusade, in this two-point series, I will explain a few simple tricks to repair these blemishes. These techniques tin can exist used for raw or finished forest.

I break these issues into voids, like an open up joint or cheque crack; and color changes where the forest or repair needs color touchup. In part 2, I will cover color repairing and fixing lacking finishes. In that location are a larger variety of types, causes and remedies – besides many to cover hither – merely this information will get y'all through some major ones.

It's always best to endeavour and fill a void with matching wood, like in an open seam or joint. Filling information technology with a thin slice of veneer or sliver of wood and gluing it is my outset choice, but most of the time, defects are irregular in shape or too pocket-size for inserting wood.

Open up knots or checks, large or small, are actually the easiest to prepare as they are already a visible and accustomed defect. Because these knots are darker than the surrounding wood, filling them with a matching or darker color is typically all that's needed.

Before whatsoever repair is done, I seal the wood with a low-cal glaze of wax-gratis shellac that brings out the final color of finished wood, because information technology aids in color matching. It also helps with adhesion and protects the surrounding expanse from excessive filler. Always do a color exam on a sample lath first.

When using wood fillers, information technology's vital to brand sure that the surrounding surface grain doesn't get filled or clogged with backlog filler. This is the most common mistake, and leaves a halo of filler around the repair. To avoid this witness line, tape off the surrounding expanse earlier applying the filler. The tape volition also human action as a raised ledge for solvent-based putties, leaving it slightly high later on application and allowing for shrinkage, if there is any.

The woodworker'due south hush-hush

At that place are many types of fillers that work merely fine. They may differ in curing or drying time, expense, odor and available coloring options. Since I like to keep my projects moving and hate to scout the grass grow, automotive putty is my option for large voids.

Fill small-scale holes with a solvent-based putty, taping around the defect for a neater job.

And then, sand flush.

Bondo, for example, is polyester-based putty filler catalyzed with a two percent hardener of benzoyl peroxide. The hardener has a toothpaste-similar consistency and comes in three colors: red, white and blue. I avoid blue because it adversely effects pigmenting or over-coloring. Red is okay when my woods are brownish in color, but white gives me the nearly pigmenting flexibility. Minwax makes a polyester-based filler with a tan coloring.

A downside to polyester fillers is the odor. Information technology has a stinky smell due to the styrene solvent in it, and I don't recommend using it within a firm or basement.

To become a two per centum mixing proportion, apply a golf-brawl sized blob of Bondo to a 1" line of hardener. One time thoroughly mixed, it will set upwards in 5-ten minutes at seventy degrees F, and is and so prepare for sanding and terminate. Polyester pigments or Blenall powders can be added and mixed in to adjust the color of the putty to closely match your woods.

You can also use epoxy to fill up holes just the set time is much longer, typically ane to 12 hours. I don't recommend using five-minute epoxies as I have plant them too soft and mucilaginous when trying to sand. Urethane is a great quick-setting option but not always readily available.

Automotive filler, epoxy and urethane don't shrink. Most other filler options have solvents, such as acetone, alcohol or h2o, which cause shrinkage every bit they evaporate. To gainsay shrinkage, utilize the filler proud of the surface or utilise 2 coats.

Scratching in grain texture helps baby-sit against a repair that looks likewise slick and smoothen, which is another common mistake, specially with big voids.

For smaller voids like thin cracks and pinhole knots, wax is great way to go. Wax comes in a diverseness of colors and a few hardnesses. For very modest voids no larger than 1/16", I like to apply rub-in blending sticks. In a compression, crayons will piece of work. Simply rub it in or use a heat gun to melt the wax and drip information technology into the void. Subsequently it hardens in a few seconds, remove the surrounding smear past rubbing the wax flush with a hard block of wood wrapped in a cotton rag and a few drops of mineral spirits.

There are harder low-estrus wax sticks that are ameliorate for slightly larger voids, ane/eight" to 1/4" in diameter. These waxes are difficult enough to prevent a fingernail from pushing in and require a heat gun, iron or open flame to melt in place. Once they ready, use an onetime credit card equally a scraper to flush it down, then vitrify with spirits and a cloth.

All of these wax crayons come in a multifariousness of colors and it is typically ameliorate to err on the darker side. These specialty waxes volition even take a sprayed finish without fish eyeing.

Solvent-based putties similar Famowood or DAP forest dough are good for small-scale holes and great for edges and corners where wax won't have the structural integrity needed. These come in a variety of colors and tin be intermixed to adjust the colour and dry speedily.

For meliorate adhesion, add together a pocket-size drop of white glue to the mixture, which will also work with water-based fillers. For very fine seams, you can create a simple home mixture of fine sawdust and shellac or PVA gum.

Accent instead

As an alternative, instead of trying to hide a defect, you might consider accenting the natural blemish with a contrasting inlay using colored wax, pigmented resin, and mineral or metal dust.

Filling a void with crushed turquois and mother of pearl or copper grit is like shooting fish in a barrel to exercise. Merely fill the small-scale void with the dry powder and adhere with CA gum. Once set, it can exist sanded flush and finished. For larger voids, add epoxy to the mix. If the void is really deep, make full with resin until left with a small void, and so apply the emphasis pulverisation. Typically a second coat of fine powder is required to fill any remaining pinhole air bubbles.

The last blazon of void that needs filling is a dent. In these areas, the color and grain of the woods is intact and filling with pigmented filler will crusade more of an obvious blemish. First, I try steaming the divot with a few drops of h2o and an iron. Often this will bully the wood, and once sanded back affluent, the color and texture matches perfectly.

If the paring still remains, fill up with any clear resin, which allows the surface to be flush and the color to testify through from below. I like to utilize a UV or blue light-catalyzed resin like BluFixx, which is a pen that has a squeeze dispenser on one finish and a blueish light on the other. BluFixx comes in a variety of colors. I similar clear and blackness for knots.

Lightly sand the void with 220 grit, and then add a few drops of resin to the void. Apply a slice of articulate packing tape and squeegee the resin affluent with a putty knife. Shine the blue low-cal through the tape. It volition set up in about 10 seconds. Remove the tape, sand flush and yous're practiced to go.

Scott Grove is an fine art furniture maker, sculptor, and YouTube personality who selectively teaches and lectures, most notably at the Marc Adams School of Woodworking and The Chippendale Schoolhouse of Article of furniture in Scotland. For more than, visit world wide web.imaginegrove.com and www.scottgrove.com.

This commodity originally appeared in the March 2022 result.

Source: https://www.woodshopnews.com/columns-blogs/filling-voids-knots-and-dents

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