How to iron a warped/cupped board flat again!

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[StumpyNubs]

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[mikedurkee]

worked like an absolute charm on an end grain cutting board that cupped during the final glue up... took a 7/64" (2.778mm) cup out in less than 15 minutes black walnut. When I have a question James is the first person I consult. Absolute rock star!

[cgrovespsyd]

Just watched the video, then scampered out to the “shop” (my ex garage stall) and tried out this technique on two 12” long 3/4 inch walnut boards (I split a 1 1/2”+ board to get these two boards). The iron steaming process went great! A little too great at first. Although I was respectfully cognizant of the cautionary advice given by James, this process unwarps boards much faster than I thought possible! Consequently, I had to redo the process on the other side (which I did for a much shorter length of time) and it turned out beautifully! The lesson I learned was to check my board frequently as the process goes very quickly.

[johncannonnh]

This may seem obvious to everyone but me. When referring to "cupping" it is the inside of the cup being referred to aka the concavity. The "convexity" would be like the outside of the cup. This was an extremely helpful video and super well done.

[WallyFuller]

Great, Stumpy Nubs! Trusted advice I can always rely on. Rather than others who make a headline claim— after watching 20 min—in the end fail to deliver.

[jenh.]

I had a dresser drawer in the garage that got wet on the back of the drawer and warped badly. I found your video and your trick worked like a charm! Thank you for posting.

[maryachii]

I did something a little different from watching this. Just to let you know, this was the only video I watched that told you the reason that boards warp. I had a sycamore slab that was kiln dried but as I started working with it, developed a bad cup in the center. I sprayed the wood down with water, flipped it over, put a1x1 in the center and clamped the ends to the table...over clamping it just a bit. Resprayed the next next and let it sit for a few more. I had lifted the slab off the table. It worked! I I’m imbedded a U-channel in the bottom for a preventative measure. My table is beautiful, thanks to your tip! Wish I could figure out how to post a picture!

[lexboegen]

I knew about using an iron and damp cloth to raise dents and dings, but never heard about using that technique for reversing the cupping of a board. Very cool.

[root]

Are you trying to ruin my life? Do you know what would happen if my wife found out I know how to use an iron? Oh no no good sir! a cupped board means I get to go back to the lumber yard.

[janetconran]

Thank you! With your help, I fixed my bureau.

[ThisLifeWeLive]

Well let me tell you my story. I bought a stack of hardwood maple boards (kiln dried) and left them on my wooden board trailer and parked it in my barn. I clipped the metal strands holding it all together so I could oogle over what I had bought. Our barn is dirt floor, and it's getting into spring. I looke at them last week, and saw all the boards on the bottom row had "cupped" upward. These are 1" thick maple boards. One of my subs sent me your video. I do have an extra iron, so maybe I will give it a try! These will be dado-ed into a nickle gap and air nailed into my cabin. My concern is them re-cupping. I will give your method a try later and see what happens!

[blondielegs]

Great tip thank you. I had to glue 3 11½" boards together and then give it an arch. It was perfect when I went to bed and really bad the next morning

[davemeikle]

Thanks. Your advice was perfect. I have a block board of walnut that had curved to 6.5mm concave in the middle. (its only 600mm wide so thats quite a lot). Ive madaged by a combination of ironing with a wet t-towel and just allowing to aclimatise in a warm room to restore the board almost to flat again. Still has about 1-2 mm concave left but thats much more manageable now.

[zfolwick]

I have some african mahogony windowsills that I'm making, and I was thinking of doing this with. Thank you for saving me $40 and from buying a new board!!!

[michaelhirnam]

Works! Within minutes. Seem like you have to be set up and ready to do whatever needs to be done right away or the cup will come back.

Thanks for the tip. Totally lost fear of thinner boards being cupped.

[biggdogg]

How long do you wait for the board to dry after ironing the cup out?

[Ibaneddie]

Great tip, have some camphor burl guitar tops that I forgot to put in my screw press and now they are crazy warped and they are too thin to plane down anymore. I'll try fussing with some humidity and see what I can come up with but I'll probably end up cracking them unfortunately.

[morokeiboethia]

If framing lumber has crown in it, is there anything you can do to straighten the crown out so that it remains straight?

[roadrage]

Ha, I could've swore I heard James say "just keep it off the damn ground"

[chloe]

I think this video is awesome and what might make it more awesome would be a little more visual representation; maybe just let us see the board up close. OR if you're feeling extra crazy a graphic... Thanks for the video!!