Crack Filling technique

[Duncan Low]

On another website, I came across a technique that recommended filling cracks/splits
in the wood with melted bees wax, then sanding and varnishing. Has anyone ever used this
technique? If so, what is the largest split that can safely be filled?

[Concordia..41]

Since when does varnish stick to wax - bees or otherwise???

[DougC]

I've used beeswax to fill cracks in wood sculptures (not varnished, waxed). The thinking is that the beeswax will adjust to shrinking and swelling of the wood. It's a very good cosmetic fix, but I don't see what use it would be in boatbuilding.
Doug

[ken mcclure]

Heh. Just don't let it sit in the sun.

[thechemist]

The wood will inevitably expand and contract with weekly or seasonal variations in humidity, and the crack will open and close, alternately stretching the varnish and squeezing out the beswax. Further, varnish will not stick to wood soaked with beesswax, nor to the wax itself, and the mineral spirits in the varnish will dissolve some of the beeswax, spreading it and alloying it with the varnish, producing a degraded product.

You could get away with beeswax on a piece of art that was kept in a humidity-and-temperature-controlled environment, but it is nothing that should be relied upon in the real world, much less on a boat.

You will not be able to clean the beeswax out of the crack, so, as it continues to open up, you will never be able to glue it after a beeswax treatment, thus to fill the crack with any of the various epoxy materials that can actually bond to your wood. Different woods may require different kinds of adhesives......not all glues work on everything.

You should not try to clamp it together with force and hold with glue, for the stress on the joint will be shear, and most woods fail at only a few hundred pounds per square inch. The wood will readily fail by cleavage at that glued joint, with any little environmental stress. Better to use something that really sticks and fill with that, keeping stress to a minimum.

[Duncan Low]

Thanks for the comments. Considering I am in the central valley of California where it will hit 105-107 this week, I would hate to see my "honey" of a project melt downj. It would "bee" a disaster... :D

[ 07-08-2002, 02:27 PM: Message edited by: Duncan Low ]

[Chris Coose]

Probably the best fix I've seen for solid spars hewn from logs. Varnish will take for the season but these checks will require annual inspection and touch up.