Removing Pitch in Driftwood Sculptures
4Sometimes the most beautiful or interesting woods that we choose for our driftwood sculpture are because pitch inside creates that unusual piece. Pitch is a resinous sap found in pine, fir, spruce and hemlock. Pitch is what has preserved the piece and is what gives its color. Pitch can be very liquid, just soft and sticky, crystallized, run in streaks in the grain, be found in deep crevasses or cavities, or permeate the entire piece.
Removing this pitch can cause us much aggravation and hard work, but remove it we must in order to bring that satiny shine to create a smooth surface. Here are a few suggestions to help make pitch removal easier. First clean and scrape off or dig out as much as possible then try these following suggestions:
Surface Pitch or Pitch in Small Pockets
Products that have been successful:
Murphy’s (or any brand) of oil soap full strength, Verax liquid soap, (the commercial soap found in public soap dispensers) and dishwasher liquid (this is a very caustic product so be sure to wear rubber gloves!) Apply any of of these products to the pitchy surface, allow to remain for 10 to 30 minutes – or more, work in with a stiff brush, rinse off with hot running water while continuing to brush. This process may be repeated until the surface is free enough of pitch that wood will sand when dried.
Also, some have used acetone nail polish remover with good results. Apply to surface with cotton balls or soft pieces of cloth, allow to sit a few minutes, then scrape off the surface.
Rubbing alcohol works well as it will help harden or crystallize the pitch making it easy to scrape off. Place alcohol soaked cotton on the pitchy areas and leave overnight, then scrape residue off. Wash with hot water, allow to dry, then sand as needed.
A naphtha soap thick paste made by grating the soap and mixing with a little hot water applied to the pitchy areas and allowed to sit on the surface overnight can work wonders! Pitch should scrape off easily.
A TSP bath TSP is a very strong cleaner at the dilutions normally used, which vary from 1/2 cup TSP to 2 gal. warm water for “heavy duty cleaning” to 1 cup TSP to 3 quarts warm water for “ridiculously heavy duty cleaning”
Turpentine ammonia and various commercial products will often work well to clean pitch surfaces. Some of these products are: Turtle Wax bug and tar remover, Bruce deep cleaner for wood and chain saw pitch remover, to name a few.
The method used for the above products – apply to surface, work in with a stiff brush, wait 10, 20 or 30 minutes (even longer is necessary.) Wash under hot running water while continuing to brush. Repeat as needed to clean the surface.
Some products will work, but not all pitch in wood is the same, so experiment with a few until you find that one that is best for your piece.
One of our members has found that works wonders to seal the pitch in the wood and makes an easily finished surface. Brush with a stiff brush to remove pitch in the powdery form. This will bring out the colors and may glaze some areas. If the areas turn black, they need more scraping
You can make a working oil solution of 70% boiled linseed oil and 30% turpentine and use on scraped surface. Apply with steel wool or sandpaper to seal surface.
Another possible solution would be to apply either butter, margarine or vaseline to the pitch, place on a sheet of aluminum foil and place in a 200 degree oven for about 5 minutes. This will soften crystallized pitch and can be wiped or scraped off. Do this technique carefully as you could damage the wood.
Using heat to remove pitch is usually a very successful solution. There are several ways to use heat:
Heat gun and torching
Baking pitch wood:Use either method on a low setting to prevent igniting the pitch. (Pitch is very flammable) Apply the heat in short strokes and wipe off excess with a paper towel or old lint free rag or synthetic steel wool clamped in hemostats as the pitch bubbles to the surface. Never work only in just one spot as yo could burn the wood. When the wood is cooler, you can wipe excess off with rubbing alcohol on cotton That alcohol is flammable so use only on cool surfaces. The heat gun is always safer than a torch!
Boiling and baking techniques:
Use an old canning pot that will only be for pitchy woods. This can be purchased at a thrift shop very cheaply. Bring water to a boil, remove from heat and add one or two capfuls of oil soap. Dip it in and out of the water, then wipe off the pitch with paper towels or old rags. If you leave the wood in the water too long it might warp and lose its desired shape. If the water gets too cold to still work, it can be reheated, but do not bring it to a boil as the soap will foam and boil over! Boiling may be repeated as necessary. The wood treated this way may appear to lose the life from the wood, but rest assured that it will return with sanding and finishing.
Heat oven to 150 – 200 degrees and place wood on a double sheet of aluminum foil to protect your oven. Place into oven, but watch carefully until pitch rises to the surface. Remove and wipe off with alcohol. May be repeated if necessary. This technique may darken or warp the piece.
These techniques are useful in handling some of our pitchy problems. Some pieces are so permeated with pitch that if you remove it all, the wood could just fall to pieces. Some burl-like woods have a hollow center filled with pitch, so it is not a good idea to try to remove it all. Many times wood will just shrink and crack open. White crystals, soft sticky pitch and glazed pitch on the surface should be removed, but do not try to remove it all. When the finish is the best that can be achieved, heat can be applied to bring the pitch to a glazed surface, then waxed and burnished or finished with WD40.
