Boil, boil, toil and trouble,
Fire burn and cauldron bubble!
– From Shakespeare’s MacBeth
A Rogues' Galley of Boat Recipes
Once upon a time, we mixed our own.
The better-living-through-chemistry stuff was still in development and, if available, cost an arm and a leg. Slowly, the industrial materials got better and cheaper. Now, when I ask around, I find that it’s only a few old-timers and Luddites that still mix our own.
Not to disparage the new goods… quite the contrary. Adhesives can’t be matched by home-brew. Plastic resins are ultra-versatile; a one-size-fits-most solution. Paints are hard to beat.
But where goes wood, there lies a spectrum of needs. Wood works and swells and shrinks and cracks and closes up again, as one expects of a once living material. To meet the needs of wood, a just-so solution is often the best fit, filling in the wishlist between the broad strokes of modern, industrial magic.
The following amounts to a menu of oil based puckies and schmears with various consistencies and properties. Being mostly oil-based, they can’t easily be painted over or adhered to, neither in the short nor long term.
Using them sets you down a road less traveled. Insofar as they replace plastics, they might be considered ‘greener’ on the whole. Their half-life is certainly shorter. For ‘natural’ wooden boats to be maintained in the field, this approach has a lot going for it. For modern approaches, they may be limited to stand-alone components.
All in all, I can’t really recommend going back to them while modern methods are available. Nor would I advise against them, exactly. They DO represent a set of alternatives, and set one to thinking along pathways now mostly overgrown.
So, for posterity, here’s what I’ve stumbled across from boatwrights and fishermen and women…
The following include materials I’ve heard of as having been used. New stuff shows up all the time (can you say Buckyballs?). Improvise and adapt!
Bees and Microcrystaline Wax - Great bases for filling cracks or waterproofing. Microcrystalline wax is superior… most toilet rings are made from it and cheap.
Asphalt - Fibered or not, is used for roofing. Messy but cheap and versatile.
Tar (aka Pitch) - This used to be common around boatyards. Have to heat it to melt.
Pine Tar - A fave of mine. Anti-fungal. On the thick side.
Tung Oil - Reputed not to mold or mildew. Turns laquery black after long sun exposure.
(Boiled) Linseed Oil - Pleasant oil… ‘boiled’ has drying chemicals added.
Oil Sludges - Generally used crank-case oils.
Corn Oil - New to me via a young old-timer. Inexpensive base. Outdoor apps look great, several years down the road.
NOTE: All of these are prone to spontaneous combustion. Rags and brushes should be immediately burned after use or immersed in water in a closed, metal container. Do NOT leave rags in direct sunlight for even a minute! (Experience talkin’, here).
Turpentine - Distillate of wood. I trust this one irrationally.
Mineral Spirits and Paint Thinners - Cheap and work.
Diesel - Ditto, but smells like you’d expect… not too bad if evaporated.
Gasoline - Careful with this one. Deep penetration, then evaporates.
Acetone - Ditto.
NOTE: All of these are rich in VOCs (don’t breathe them) and highly flammable to the point of explosive (no sparks or flame). Note and employ all pertinent safety precautions!
Wood Flours - Cedars are fungus resistant, as are select exotics.
Talc - Thickens without setting firm (sometimes used above the waterline).
Chalk - Thickens without setting firm.
Cement - Thickens, but also sets firmer (sometimes used below the waterline).
Plaster of Paris - Ditto.
Brown Paper Fiber - Special case additive to tar ‘ties the room together’.
Various Chopped Fibers - Glass, poly, dryer lint, hemp, oakum, etc..
Bottom Paint - Cheap copper bottom paint is antifouling for below waterline.
Cuprous Solutions - Used for toxifying wood in contact with ground (e.g., Naphtha and Cuprinol).
Cayenne and Paprika Powder - High BTU capsicum is anti-fouling. Added to exterior below the waterline. Might work in the interior, and seem to be much less dangerous overall than leads?
Varnish - This is a generic term… lots of proprietary varnishes with various properties.
Powdered Mica or other UV inhibitors - These help slow deterioration and oxidization.
Red and White Lead Powder - Formerly used in beddings and exterior primer coats. Work great, but are highly toxic, especially when in powder form (both applying and repairing/renewing). Available as pottery glaze. Many consider these off-limits… we prefer Pine Tar as our go-to anti-biotic, with copper or capsicum thrown in as needed.
NOTE: Again, these powders and solutions are NOT to be touched, much less breathed in. Consider carving conspicuous warnings to boatwrights down the road who may wade in unawares.
Rogues’ recipes are fuzzy things, and tend to vary wildly from person to person. These proportions will vary in the real world, according to your choices and by ingredients’ specific manufacture. Consider the proportions given a rough starting point.
Get to know the materials and how they react in your environment. Consider your purpose, and select for the properties you desire (flexibility, reset in warm conditions, penetration, hardness, antifouling, etc.). Nuance one way and the other as you deem fit, adjusting for the properties of each ingredient.
Small batches and test samples are strongly advised until you get a feel for it. A graduated Liter makes for easy, proportional math. All recipe parts given by volume. While all can be combined at ambient temperature, most mix better when heated in a double boiler, then allowed to cool.
Feel free - very free - to experiment, innovate and otherwise roll-yer-own. It’s kind of addictive, really!
Here are a small sample I’ve encountered… adjust, extend or modify as desired:
Bedding Compound -
6 parts Thickener : 1 part Oil : Dash of Additive (anti-biotic)
Talc is a common choice for Thickener, while Pine Tar is antibiotic. Adjust mix for consistency.
Radial Crack Filler -
1 part Pine Tar : 1 part Wax
Thicken with more wax, thin sparingly with turpentine.
Seam Compound (below WL) -
2 parts Fibered Asphalt : 1 part Portland Cement : 1 part Cuprous Bottom Paint
Stiffen with more Asphalt, harden with more cement, thin with more paint.
Canvas Waterproofing -
1 part Wax : 1 part Oil : 1 part Solvent
Consider reducing Solvent to effective minimum.
Saturate warm cloth and roll to penetrate fibers. Maybe check YouTube for a range of ideas.
Wood Slurry (Sealer for horizontal exterior surfaces) -
1 part Wax : 2 parts Oil (Corn Oil was suggested to me for this application)
Apply on cooling wood. Scrape lightly smooth once cooled.
Wood Slurry (Sealer for vertical, exterior surfaces) -
2 parts Pine Tar : 1 part Oil
Consider adding Solvent for the first coat and a little Wax for subsequent coats.
Wood Exterior Water-Resistant ‘Stain’ -
10 parts Heavy Solvent: 1 part Oil : 1 part Non-Fibered Asphalt Tar
More Tar darkens; less is lighter. Consider an inexpensive solvent (such as Diesel) that will evaporate.
NOTE: For exterior coatings aka ‘Log Oil’s, I remember seeing a US Forest Service recipe that added powdered Mica to reflect and protect against UV rays. Powdered Mica is widely available, but I’m not sure about effective proportions. One full recipe is cited in the Using Paint, Stain and Oil section, from Dovetails and Broadaxes: Hands-on Log Cabin Preservation by USFS, which I am unfortunately able to access presently.