Burl Crack Filler

[Brian Kent]

This walnut burl is going to be a coffee table. It is 1/4" thick over 1/2" birch ply with solid walnut edges.

As it set over the last couple of months, a crack developed. I decided to go ahead with the project.

The question:

How do I fill this crack?

A) Walnut sawdust and epoxy mix

B) Some grain filler I have never used and don't know about

C) Let the de-waxed shellac, wipe-on poly and wax fill the space

D) none of the above / all of the above

The crack is about 10" total. The maximum width is just over 1/64".

Thanks in advance.

Brian

[David Christopher]

I would try ( A )

[Scott Holmes]

A) Walnut sawdust and epoxy mix.
Yes, skip the saw dust; tint the epoxy brown or black

B) Some grain filler I have never used and don't know about.
No thats not grain being filled thats a crack. The epoxy may help keep it closed.

C) Let the de-waxed shellac, wipe-on poly and wax fill the space.
No, I'd suggest filling it with the epoxy first, the finish will not hold it well and that thick (deep) of finish will continue to shrink for a long time.



D) none of the above / all of the above
I would NOT use POLY on it. Get a quality varnish... Pratt & LAmbert #38, or Cabot 8000 series (NON poly), Behlen's rock hard or Waterlox.

I would use Waterlox on this table.

[Brian Kent]

What kind of tint? I've never tinted epoxy before.

My choices today to buy epoxy and tint would be Home Depot, Lowes, or Rockler.

[Scott Holmes]

I don't want to send you to Rockler to buy ~$20 bottle of TransTint dye. Most DIY stains (oil based, Minwax & Cabot) have an oil soluable dye in them.

On cracks like these, darker is usually better, than lighter, when compared to the surrounding wood.

[Brian Kent]

Thanks, Scott. I have a lot of stain samples. I'll try it.

Brian

[Ken Fitzgerald]

Brian,

As a turner, I deal with cracked wood often. I typically will take instant coffee crystals and crush them into a powder and mix that with epoxy. I'll use that to fill the crack and then continue turning sanding and finish as I normally would.

[Mark Ball]

I fixed a crack in a walnut crotch piece I was using for a jewelry box, used CA glue and then after tacky (less than a minute) went over with a random orbit sander. The sander created fine dust which stuck into the crack, turned out well in my opinion.

The CA glue comes in several viscocities (thin, medium, thick, etc) I used the thin and it had no problem penetrating the crack, which was about hte same size you are dealing with, probably the medium would have been better if I had it to do over again.

[Eric Bong]

I used epoxy and black dye from Brownells

http://i244.photobucket.com/albums/gg12/ernmere/Gun%20Stuff/knot.jpg

http://www.brownells.com/.aspx/sid=3992/pid=1038/sku/Black_Dye,_5_packets

[Brian Kent]

The dyed epoxy and sawdust epoxy have both worked well. I have found a couple of larger voids that were exposed through sanding. Two irregular voids about 1/4" x 1/2". I have some similar grain in cut-off pieces so I am considering using an inlay technique.

I have cut wood to fill straight-grain voids before, but never burl. I'll find out if it is naturally more or less forgiving.

I plan to very slightly over cut similarly grained pieces, trace over the original piece, then carve away edges to match and epoxy in place. The plugs will be just under 1/4" thick.

The pieces are very near the center in a place the eyes will be drawn to, do I would like to do this right.

Brian

[Brian Kent]

Scott and everybody,

I'm having problems getting Waterlox. California laws prevent sale of larger containers and the closest source is 40 minutes (or should I say 2 hours away in Orange County traffic). The nearer flooring source no longer carries it because the low VOC version does not perform as well. I also do not know if Woodcraft's Waterlox is the old formula or new.

How is Formby's Tung Oil? Watco Danish Wood Oil? BLO?

I would like to feed my burl.

Brian

[Nathan Hawkes]

Well Brian, I don't do a lot of flat work--I'm mostly a turner, but I've had great luck with Minwax Antique Oil, a wiping varnish that seems to be pretty readily available. I use it on almost everything. Its only sold at paint specialty stores around here-no box stores carry it.

[Brian Kent]

I'm willing to buy some Waterlox, but I will probably order it online. Will one of mine work for today and not cause a problem for Waterlox later.

It's pretty hot here and I see new hairline cracks appear each time I go to the shop. I don't want to dry it out any further.

[Scott Holmes]

Minwax "Tung oil" is an oil/varnish blend. It is a mixture of their varnish mixed 1/3 with linseed oil and ~1/3 mineral spirits. It will not build a high gloss film finish.

As for Formby's Tung oil finish...

It is a quality alkyd resin/soya oil varnish - Thinned 75-80% with mineral spirits. There is no tung oil in it, (other than that which is printed on the label). The varnish they use is not even made from tung oil. I don't like their "marketing" hype (lies).

A better solution would be Pratt & Lambert's alkyd resin/soya oil varnish, which they call: Pratt & Lambert #38 varnish. Buy your own mineral spirits; mix it yourself. SAVE alot of money.

[Chris Padilla]

Brian,

Glad to hear the dyed and wood dust epoxy worked. For a crack that size, I usually dump some CA glue ("crazy glue") into the crack and either sand it to create dust to fill the void or dump sawdust on it and press it into the crack with a putty knife and sand it back a few minutes later.

As to your finish, I'd like to suggest Bob Flaxner's most excellent book: Understanding Wood Finishes.

An oil/varnish blend is easy to apply and easy to fix but it is not very protective.

Lacquer is a film finish and while not so easy to apply and easy to fix, it will protect a table top very well.

There are lots of choices and you should learn about them before deciding which road to head down.

[Brian Kent]

I am studying Bob Flexner's book. Lot's of great information and nice to see these products categorized according to chemistry rather than marketing.

I am really surprised how difficult it has been to find any of the products Scott recommended within 30 miles of my home.

I'll keep reading, then probably use mail-order unless they are not allowed to sell these high VOC products to people in Southern California. I firmly believe in taking steps to reduce the smog, and it does complicate the process as we develop new products.