Filling Cracks in Reclaimed Lumber
Home-made crack-filler recipes for old wood. October 3, 2007
Question
Where I work we use a lot of reclaimed pine for table tops. A lot of it comes from old barns and houses and is full of nail holes and splits which need to be filled. We use a mixture of carpenters glue, sawdust and stain as a filler. The problem is that it is very time consuming to sand the excess off once it has dried. We have tried to sand it before it completely sets but we usually have to go back and re-fill many of the holes. We have to hand sand (orbital) because they are hand planed tops. Anyone know of a better and more efficient way of dealing with reclaimed lumber?
Forum Responses
(Furniture Making Forum)
From contributor J:
I also do a lot of this type work, and the person I build for requires that we use an epoxy. Sorry, not sure of brand, but it's a black 2 part system. Excellent for filling cracks, nail holes, etc., but takes a long time to fully dry (18-24 hours). It highlights the cracks, etc. rather than hiding them, and that look sells good here in Eastern Mass.
From contributor R:
I build a good many things from mesquite, which has a lot of voids and shake cracks. I use wood flour cement for filling cracks. You mix sanding dust with it and apply with a putty knife. I also use carpenter's glue mixed with sanding dust for items, but the problem with it is that being water based, it shrinks a lot in drying and has to be refilled for many things (as you know). The wood flour cement is petroleum based, so doesn't shrink nearly as much, so you should be able to fill and pretty much scrape the surface flat. I don't know how large a void it would cover and be good for a high traffic area like a tabletop. I learned of it from a friend who makes and installs flooring and he squeegees it over large areas and then uses a floor sander after it's dried. The product I use is made by Glitsa and the spec sheet says it can be stained so you should be able to mix stain in it, although I have never tried. The epoxy application as mentioned before works well if the voids are not to be hidden, and for an item of reclaimed wood with a rustic character may work best. If you try it, I would play with some first to see how it works for your application. See what it takes to get a workable consistency and how well it covers and sands and how durable you think it will be.
From contributor M:
I have used auto body filler (usually gray or pink) to fill checks. These are a two part epoxy and set up a whole lot faster than you want and you don't have to wait to sand. I haven't tried to stain this, but doubt if it would take stain. It does give a nice contrast filler look.
From contributor K:
You can mix universal tint with the gray part of bondo before mixing when you want something that kicks fast.
For other things that need to have better strength, I like epoxy. You can get colloidal silica from most suppliers, which is a very light fine white powder, and combine it with dust from a belt-sander bag from the same species being worked for a pretty good color match with good properties.
The sanding dust alone will usually come out a lot darker than the wood it was from.
From contributor V:
I do mostly mesquite, but also I get a few projects out of walnut and such. I use mostly 2 part epoxy... I use a black dye in it, but they make many colors, so you can make it whatever color you want. I have also used Bondo. I have custom colored famawood. I have also used sanding dust mixed with lacquer or poly or glue. For me it depends on if it is structural first and beauty second. I have also used 5 minute 2 part epoxy as well as the cyano glues. Each has its strong points as well as drawbacks.
