Creating Checking / Cracking

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Forum topic by swarfrat posted 08-14-2014 07:56 PM 2884 views 0 times favorited 10 replies Add to Favorites Watch
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39 posts in 871 days

08-14-2014 07:56 PM

Topic tags/keywords: oak basswood question veneering finishing

I recently saw some wood projects where cracks in the wood were filled with pigmented resin. This got the wheels turning. Most of the weathering info on the net seems to focus on coloration, dirt, and abrasion. How would I encourage checking, and how can I control the size/depth of the checking?

A little cursory reading would suggest that moisture / drying cycles is the only way to create checking. But what about control? If I want a fine spider webbing, or deep cracks? I found a hardwood floor website which had a nice chart of woods more or less prone to cracking. What about stability of the cracked layer?

What I had in mind eventually was a solid body electric guitar project. Oak is one of the more succeptible woods to cracking, and it’s also more response to ebonizing. That’s nice because the contrasting finish needs to stay on the wood and not cover the resin in the cracks. I think the cracks need to be pretty big to get enough material down in there to be visible. Like deep enough that a thin top (like 1/8 or less) might not be stable. That might be ok if it’s possible to do the cracking after gluing the top onto a base wood which is less prone to cracking. I’d still like to avoid stressing the base wood as much as possible.

Poplar is not a high brow tone wood, but it is accepted and somewhat common in electric guitars, cheap, and not prone to cracking. The oak would just be a thin top. (I won’t say veneer because to me that suggests paper thin.) If I’m accelerating the drying process, should it air dry, oven dry? If the oven is ok, does it need to stay below boiling, or is that OK (or even encouraged)?

Or should I consider an alternate “cracking” method (like stick it between two sacrificial sheets and hit it with a hammer)? Would a thicker (say 1/4”) top provide coarser cracking?

10 replies so far

View SCOTSMAN's profile


5839 posts in 3001 days

#1 posted 08-14-2014 08:24 PM

I once saw a guy actually I am sure it was Norm, mix old toner from a dead printer carriage with resin and it turned out really beautiful.He used it on a table he was making with a large gap in the wood due to an old knot coming out.I have since bought a nice big can of clear resin and many different colour mixes to go with it.I tried it out on the lid of a box I just made for my wife.I created a lot of different coloured ballons with long strings on the top panel using different sizes of forstner bits for perfect ballons followed by a small hand held router-trimmer with a nice long squiggly Vee groove cutter for making the strings.Iit looks really nice I would encourage you guys to try it and incorporate it into your woodwork – woodturnings. Alistair

-- excuse my typing as I have a form of parkinsons disease

View swarfrat's profile


39 posts in 871 days

#2 posted 08-14-2014 08:41 PM

Yes. I’m trying to figure out how to make cracks for the resin to fill. I was sort of thinking a wood equivalent of this.

View Nomad62's profile


726 posts in 2374 days

#3 posted 08-14-2014 09:32 PM

I really doubt you could get any success trying to safely check or crack wood of any size, it’s kind of uncontrollable; moisture is the key, and getting the moisture out too quickly is what generally causes checking. The cracks or checks are the result of the woods edge drying too quickly for the inside of the wood; the inside stays wet and swollen, the too-dry outer wood dries and contracts due to the moisture loss making it physically smaller. It can’t stretch well, so the fibers separate causing the check. The checks tend to follow growth lines as crossing growth lines is very difficult, the old path of least resistance routine. You may get some luck by slicing a veneer (deemed veneer by being 1/8” or less) and soaking it then drying it way fast, it will check and split like mad and you could then glue it to a base wood; hard to do as the veneer will warp and cup as much as it checks or splits; a vacuum bag system may prove valuable there. A look like the guitar pictured may be created by doing the above with heavily burled wood, again quite a guessing game on how to do it. Control? Unlikely. Best of luck with it.

-- Power tools put us ahead of the monkeys

View rick1955's profile


251 posts in 847 days

#4 posted 08-14-2014 10:17 PM

The picture you showed is a crackled paint finish that crackled wood. Wood will only split with the grain. Google crackled paint finishes.

-- Working smarter with less tools is a true crafts person...

View swarfrat's profile


39 posts in 871 days

#5 posted 08-14-2014 10:54 PM

I’m well aware of that. Google crackle paint finish images is where that came from. If you read the original post, I’m trying to create an effect LIKE that but filling the cracks with another material (pgimented resin/epoxy. Like glow in the dark/flouresce under UV.)

After reading the prior responses though, and some thought about what I’m trying to accomplish – I think simply drawing the “cracks” and carving out a channel for the contrast material is a better method. It’s easier to control the width of the cracks and the “chunk size” – crackle finishes can be so busy (small scale pattern) that they blend in from a distance. A dozen or two largish “chunks” is probably better.

View LakeLover's profile


283 posts in 1356 days

#6 posted 08-14-2014 11:33 PM

For the pic shown. may I suggest a laser engraver.

Cover the face with a plastic sheet sticking to the wood and infill from the back.

View distrbd's profile


2219 posts in 1863 days

#7 posted 08-15-2014 01:08 PM

Yes. I m trying to figure out how to make cracks for the resin to fill. I was sort of thinking a wood equivalent of this.

- swarfrat

Maybe this video will help:

-- Ken from Ontario, Canada

View Nomad62's profile


726 posts in 2374 days

#8 posted 08-20-2014 03:28 PM

My post was based on my short-sighted thoughts of using edge grain; I touched on success with burl, but fell short and didn’t think it thru to the end grain. Until I was out cutting firewood last night, I found my three year old chopping block. I haven’t used it in 2 years, so really it’s 5 years old. Bottom line, if you want this beautiful patina (lol!) all you need to do is beat the buhjesus out of it for three years, leave it alone for 2 more, all the while leaving it out in direct sunlight and snowfall. Easy!

-- Power tools put us ahead of the monkeys

View Nomad62's profile


726 posts in 2374 days

#9 posted 08-20-2014 03:29 PM

Dang, missed the pic. Second try.

-- Power tools put us ahead of the monkeys

View TheFridge's profile


5668 posts in 902 days

#10 posted 08-20-2014 04:20 PM

Beating the hell out of something is the rout I usually take. Ask my….

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

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