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Help ... warped cutting board

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Forum topic by Rob posted 01-22-2009 09:46 PM 8105 views 0 times favorited 20 replies Add to Favorites Watch
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Rob

197 posts in 2354 days


01-22-2009 09:46 PM

I’m having a problem with this board warping and wondering if anyone has repair suggestions. I made the mistake of shellacing one face only and as a result the base is expanding. What should I do now? Soak and clamp it? Plane it flat again? Burn it and make another one?!!!! In the pic you can see the left side lifting up from the counter. All of the corners do this making a board that rocks really well. Perhaps I should build a chair for the top and repurpose it :)

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20 replies so far

View lew's profile

lew

10088 posts in 2442 days


#1 posted 01-23-2009 01:48 AM

When I made some of these, they warped during the sanding process. I was trying to sand one side thru a grit before starting the other. The heat build up on one side and not the other was causing the problem.

I realize this is not your situation but I was thinking maybe heat- and correspondingly dryness- could reverse your problem. Maybe placing it in a warm oven- bowed side up and weighted to force it down might work. I have never tried this but…...

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View dennis mitchell's profile

dennis mitchell

3994 posts in 3001 days


#2 posted 01-23-2009 02:31 AM

I have 36 grit for my belt sander for just such problems.

View closetguy's profile

closetguy

744 posts in 2578 days


#3 posted 01-23-2009 02:41 AM

Turn it over on the other side and leave it for a few hours. I have experienced this with very large boards. Flipping them over for a while sometimes causes them to flatten back out.

Why did you shellac it? Knifes will cut the finish. You need to sand that off and coat it with mineral oil.

-- I don't make mistakes, only design changes....www.dgmwoodworks.com

View childress's profile

childress

841 posts in 2228 days


#4 posted 01-23-2009 05:24 AM

You might also try to clamp the board over night to your workbench (or table or counter) with a stick under the middle section. Clamp it just over flat (in the other direction) and see if that helps. That has fixed quite a few of my boards in the past. You can also get rubber feet at your local hardware store to lift the board (and help it stay put on the counter) off the counter so if it cups again, you will still have the four feet keeping the middle off the counter.

If you continue to have this problem, it might be due to thickness. I’ve noticed anything under 1&3/8” will have a tendency to warp easier unless it’s a small board. What are the dimentions of your board?

-- Childress Woodworks

View sandhill's profile

sandhill

2128 posts in 2610 days


#5 posted 01-24-2009 12:55 AM

I would resurface it and level it as you go. I use mineral oil and bees wax but I would think on some thig that small the finish would not make that much difference.

View jm82435's profile

jm82435

1280 posts in 2429 days


#6 posted 02-03-2009 05:11 AM

I think the lesson here is: whatever you do to one side you need to do to the other. Especially when dealing with so much end grain such as these cutting boards. I always try cutting equal amounts off of both sides whether planing or sanding. The problem here I am sure is (as you alluded to) that you finished only one side. I would give the other side equal treatment and see if it does not flatten out by itself.

-- A thing of beauty is a joy forever...

View Rob 's profile

Rob

197 posts in 2354 days


#7 posted 02-03-2009 05:23 AM

Childress,
I followed your advise and it worked perfectly. I scraped off the shellac, then clamped it to my bench with a small board underneath. It bowed the board the opposite way and after a day or so when I removed the clamps it was as flat as it ever was. This time I used mineral oil on all surfaces and it seems to be holding up fine. Thanks for your help.
Rob

About mineral oil; does anyone know how to cut it thinner? I want to help it absorb deeper.

View marcb's profile

marcb

762 posts in 2360 days


#8 posted 02-03-2009 05:30 AM

Don’t use a film finish on cutting boards. Mineral oil only.

The chopping will nick the finish causing a gouge where bacteria can grow. Mineral oil fills in imperfections in the wood, keeping this from being an issue.

View joevt's profile

joevt

1 post in 2111 days


#9 posted 02-04-2009 03:06 PM

Dont thin mineral oil, heat it. It should thin and be better absorbed.

View Akallen's profile

Akallen

5 posts in 2073 days


#10 posted 02-17-2009 07:30 AM

I had a similar problem some years ago with a 24” x 60 ” butcher block table I made for my wife. I ended up cutting saw kerfs in the concave side my skilsaw, then on my table saw I cut wedges a hair wider than the saw kerf on the fat edge tappered down to a hair less than the kerf on the skinny edge. I lined up my skilsaw blade with a glue joint on the butcher block and cut the kerfs about 3/4 of the way through the thickness of the top. Then, I was able to clamp the board flat to my workbench, rub some titebond III on the wedges and insert them into the kerf and pounded them in with a board between them and a rubber mallot. Whatever was left sticking up, I sanded off. Yeah, it leaves an ugly edge but I then ran a band around the edge made of the same material as the table (maple). After sanding and oiling, you have to look pretty hard to see the wedges. And, it’s now flat!!

-- Allen, Wasilla Alaska

View sandhill's profile

sandhill

2128 posts in 2610 days


#11 posted 02-18-2009 03:35 AM

I just found this fix and it works great…Seal the convex side with the same finish as the surface to balance out the top.

View BlueStingrayBoots's profile

BlueStingrayBoots

747 posts in 2688 days


#12 posted 03-04-2009 07:13 AM

Take an axe to it cheif! and some whole chickens beef ribs pork ribs etc. Once you smell the food on the grill, that board will be the last of your worries. If that board doesn’t hold up to the chopping then yea, throw it in the fire.

View Rob 's profile

Rob

197 posts in 2354 days


#13 posted 03-04-2009 09:23 PM

Um, I’m a vegetarian and I have plenty of firewood but thanks anyways :)

View Rob 's profile

Rob

197 posts in 2354 days


#14 posted 03-05-2009 12:19 AM

I guess I’m the one that brought up burning it in the first place! Funny how you forget what you said 40-some days ago!

View BlueStingrayBoots's profile

BlueStingrayBoots

747 posts in 2688 days


#15 posted 03-05-2009 04:17 AM

I wasnt very serious Rob, just wet it and use strips of wood and c-clamps or place it on otherside to let dry. I’m not sure but check the stability of the wood choices.

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