Wood in the Kitchen - a test

I've done 3 cycles of dish-brush scrubbing with dish soap, rinsing in hot water, and air-drying in the dish rack. This has had major effects on all blocks. The good news so far is that none of the blocks appear dried-out - all seem like they are still protected from total drying. None show any sign of cracking or checking.

Linseed Oil - only a ghost of the surface luster remains. The Oak block still has a small lustrous spot in the center of the top of the block - other than that the blocks have lost their glow.

Veg Oil - about the same as Linseed, but without the lustrous spot on the Oak.

Linseed/Spar/Turp - the Cherry looks as bare as the Linseed and Veg Oil blocks, but the Oak still has a hint of luster.

Salad Bowl Finish - the Oak block has retained a little more luster than the Linseed/Spar/Turp Oak block - a very light even glow. The Cherry block has a curious pattern of low-luster and no-luster - sort of splotchy.

Tru-Oil - Maybe my 9 coat process was not enough or not evenly rubbed down between coats: there is very little remaining luster on either block - and what /does/ remain is in dramatic splotches - as if those areas were applied more thickly or bonded better to the underlying wood.

Permalyn - both the Cherry and Oak blocks have kept a slight lustrous glow.

Epoxy (Penetrating Epoxy, CPES) only: looks just like the Veg Oil blocks except lighter in color.

Briwax on Epoxy base: only a trace of the wax on one end-grain side - otherwise identical to Epoxy alone.

Renaissance Wax on Epoxy base: no trace of the wax - identical to Epoxy alone.

Wipe-On Poly on Epoxy base: very similar to the Salad Bowl Finish (a slight glow remains) except that it is a little blotchy in where the luster shows on both the Oak and Cherry blocks.

CA Glue on Epoxy base: The Oak block looks almost untouched - there is some loss of coating on the end-grain sides. The Cherry block is more affected - the coating remains in blotches on all sides. Maybe I did not get the application or between-coat sanding quite even. Maybe it just adhered better in some places than others. I'm betting that a nice thick CA coating would have stood up completely. I just can't get on board with making the wood look and feel like plastic.

Next up: I'm going to buff all the pieces to see which bring back some shine. I'll report on that and then do a 15 minute soak in hot soapy water followed by air drying in the dish rack.


WoodKitchenAfter3Scrubbings.jpg
 
Wow - for a flip-book before/after effect, go to my Facebook page: https://www.facebook.com/elementalforge and click on the "I've done 3 cycles..." photo. When the photo display page comes up click the left arrow for the "before" image - if you click back and forth between the Before & 3 Scrubs images you can easily see the changes!
 
A couple of nights ago I buffed up the wood blocks - took me until now to photograph 'em.

Linseed Oil - the glow is back, though more muted than before the dish scrubbing... and more glow on the Oak than on the Cherry (maybe the Oak pores held some oil in reserve during the scrubbing?).

Veg Oil - I have to say a little more luster than the Linseed Oil. I'm surprised.

Linseed/Spar/Turp - same as Linseed Oil.

Salad Bowl Finish - same as Linseed Oil.

Epoxy base only - not as dry looking as before buffing, but no real luster either.

Tru-Oil - not much change from before buffing - almost as lustrous as the Linseed Oil - but has luster in small splotches.

Permalyn - the Oak is as lustrous as the Veg Oil Oak. The Cherry is more lustrous than any of the above.

Briwax & Renaissance Wax on Epoxy base - identical to the Epoxy base only - I think the waxes aren't in Kansas any more.

Wipe-On Poly on Epoxy base - similar to Linseed Oil - maybe a little less glow - and a little splotchy (not as dramatically splotchy as Tru-Oil).

CA Glue on Epoxy base - not much change from before buffing.

Next up: Soak the blocks in hot soapy water for a while (15 min? 30 min?) then rinse and let air-dry.

WoodKitchen3ScrbBuff.jpg
 
After rotating the blocks in my drying box for approx 24 hours I measured width & length of each block and put them into hot soapy water for 1 hour. Then rinsed them off and measured them again. I'm using cheap calipers and I figure my measuring is good to 0.01" which is pretty crude when you want to keep the wood tight against whatever hardware you are using for the handle.

and yet... I could measure that each and every block expanded 0.01-0.02" in the long dimension (approx 2-1/4") which is also crosswise to the grain. Each and every block measured exactly the same before and after the soak in the short dimension which is parallel with the grain.

So: NONE of these preparations truly stabilized the wood.

I really wasn't expecting much if any expansion along the grain - and got zero change that I could measure... but I was expecting to see expansion cross-grain with variation between treatments - but given my level of accuracy and looking at each pair of blocks (Oak & Cherry) that received a particular treatment - I can't vouch for any difference between treatments - they all swelled up cross-grain to about the same extent.

I suppose for hidden tang handles this is decent news. The only direction the wood swells with ANY of these treatments is in thickness & width - length (along the grain) is stable - and that's where you'd run into trouble with a hidden tang. I'm not sure how that ~ 0.01 per inch expansion cross-grain would play out with wood scales, pins, etc. Somebody with more knifemaking experience than I have would have to chime in.

None of the blocks have shown any sign of checking. I've got them back in the drying box (I've got the box a little warmer this time) - and I'll do another round of soaking - hopefully tomorrow. The outward appearance is pretty much like the photo I posted on the 8th (after scrubbing the blocks 3 times)... so I have not bothered to take new photos... I'll post results from the next round... I hope this is useful to some folks - I'm kind of scratching my head at this point!!
 
OK: I was wrong. But that's why I did this test.

After two 1 hour soaks in hot soapy water followed by rinse and dry in the drying box (and the 2nd soak ended in a scrubbing with a fresh new Scotch Brite Heavy Duty Scrub Sponge) - the Cherry block treated with Wipe-on Poly on Epoxy base warped enough to pop off the steel... and both the Oak and Cherry Renaissance Wax on Epoxy base blocks have pulled up at the edges - but a modest tap with a rubber mallet does not pop them off yet... and the same with the Oak Permalyn block: it's warped off the steel at the edges but has not popped off yet.

Yes - I cleaned the steel & the blocks with acetone before gluing. This was done after the initial level of treatment - which for the oil-treat blocks was soaking for a week - for the Epoxy blocks was after soaking for 3 days in the CPES/remove and cure/dip in CPES/cure/dip in CPES/cure, but before any of the surface treatments were applied to them - for Permalyn it was after the Permalyn Sealer cured but before the Permalyn Finish was applied.

This blows my mind because the Epoxy (aka CPES) won a test that fishermen did on wood lure treatments. And Permalyn came out looking very good on a test Eric Ochs did on a variety of handle materials.

And what the heck is all this "the surface must be free of any trace of oils for the glue to bond properly" stuff??? The oil-soaked blocks (Linseed, Vegetable Oil, Linseed/Spar/Turp) are all bonded just fine thank you. Yes I cleaned both the blocks and the steel with acetone before gluing, but the blocks had soaked in oil for a week - you really think the block surface was free of oil just from a wipe down with acetone? I have my doubts.

So I may continue this test and see which other blocks warp up and pop off - but as of now my favorite treatment options are - in no particular order:
Vegetable Oil (Safflower)
Linseed (Boiled Linseed Oil)
Salad Bowl Finish
Linseed/Spar Urethane/Turpentine

And Tru-Oil would be in that list too if it weren't such a PITA to apply properly.

Who knows - further water torture may make the Tru-Oil look better by comparison?

I probably won't do a follow-up test until after the OKCA knife show (I have a table - which will be pretty bare)... and at that time I'll have some commercially stabilized wood to add to the test. And maybe some Ironwood & Lignum Vite to throw in the mix for comparison - although I don't feel drawn to using those woods on a regular basis.

If I come up with more results I'll post 'em - other than that: I bet I'll start a new thread on a follow-up test sometime after the OKCA show!
 
Michael,

Thanks for doing the test and posting the results. It show a lot of hard work and dedication to your craft and desire to offer a superior product.

What I have learned from your efforts so far; glue works better with pins to hold wood to steel, wood and glue don't like long soaks in water, and simple solutions often offer the 'best' results.

Thanks for your efforts,
Carey
 
Hi,
Wood handled kitchen knives should never be submerged in water.
They should just be wiped clean with a damp cloth and dried.
If your using carbon steel for the blades, they should not be exposed to moisture for very long either.
Just wipe the blade clean, dry and oil it with plain old vegetable oil.
The old fashion way to treat the wood handles would be to just use butchers wax.
If your trying to create wood handled kitchen knives with stainless steel blades that can make it through the dishwasher then coating the wood in plastic would be the only thing that would survive for very long.
Eventually even the plastic will be worn off.
I know from past experiments trying to create just this type of knife.
Sometimes the old fashion way is still the best way.
Just thought you'd like to know...

knives are quiet
 
I have a couple of carbon steel knives in my kitchen (of my own making & a san-mai chopper I'm fond of) so I'm well aware how fast they rust. Heck. I live in Western Oregon and if I don't run my dehumidifier in the Winter the non-stainless steel in my shop rusts! A little rust can be honed off. A warped handle scale or shrunken hidden tang handle can't be fixed w/o replacing the wood.

I'll warn any buyers against the dish washer - but I do expect to /eventually/ make wood handled kitchen knives for sale and want them to stand up to use and a little abuse by "normal" folks - not just knowledgeable knife mongers like us. So my testing is over-the-top to see long term results in a matter of a few weeks.

Like you guys are saying: the old ways can be the best ways. Actually I'm pretty stunned. I like the idea of using Linseed - that's probably what I'll settle into unless follow-up testing warns me off of it. I just expected the CPES & Permalyn to perform better. Shows how much I know ;-]

p.s. also check out Eric Oche's more general handle materials test: http://www.ochssherworx.com/index_files/Page513.htm
 
Since I missed out on Tung oil on the first round, I'll add it in to my post-OKCA-show test...

Any Tung oil aficionados care to share /your/ procedure for applying Tung oil? Sounds like I should look for "polymerized" on the can?

I'll probably re-try the Permalyn using a slightly different application strategy.

The CPES I'll just set aside to treat any rot that starts in the various buildings around the property... hmmmm the pump house has some sheathing that's starting to go - I think I know where the penetrating epoxy's destiny lies.

I'll drop the vegetable oil, not because it doesn't perform - it does - but more because of "marketing" issues.

I'll do another round with the Boiled Linseed Oil. And maybe the Linseed/Spar/Turp combo.

Unless the Salad Bowl Finish really stands out in my final tortures of the current test I'll drop it just because I'd rather use Linseed or Tung.

And I'll pick up some commercially stabilized wood at the show to throw in the mix. Maybe some Desert Ironwood and Lignum Vite.

Other suggestions?
 
Michael,
Interesting to see what you have going here. If you would like I have some blocks and random stuff that has been stabilized by K&G as well as lots of Desert Ironwood. I would be happy to share a few pieces with you for your testing. Email me if you want them and I will bring to OKCA show....I am curious as to what some other mixtures would do as well. I would assume that the oil is so thin it is getting better saturation. Ultimately that means that thinning things like the Permalyn down would make them more effective especially at first...if you are applying several coats.

See you soon,
Eric
 
Eric - I'll fire you off an email - and even though one of the Permalyn blocks has warped up slightly at the edge, the "look" of the Permalyn blocks is still very nice. I'm definitely going to try it again in the next round. The real looser in this round (for me) is the penetrating epoxy... it is thin, from experience I know it penetrates wood, but this test shows that it does not halt swelling/shrinking.
 
Release the Kraken!

This may be my final note on this thread (unless there's discussion)... after a couple of hour+ soaks in soapy water some of the blocks have started to check/crack:

Linseed - Cherry
Salad Bowl Finish - Cherry
Permalyn - Cherry
Epoxy only (CPES) - Cherry

Not the ones I would have bet against ?!?!?

And you know? That *@&! Veg Oil (Safflower) still looks pretty good. That and the Linseed/Spar/Turp, Tru-Oil, and if you ignore the crack - Permalyn. I may have to keep Veg Oil in the next round of tests.

I won't have many knives on the table, but I'll have these blocks at the OKCA show. If you are curious to see them in person just come by and ask. Table N-13.
 
One problem with the vegatable oil is that it will turn rancid after a while. That is why it is recommended to treat butcher's blocks with a food grade mineral oil.

Doug Lester
 
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