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I have protected the plates for my guitar for over two years, making sure they did not warp. Last weekend I was ready to start working on them so I moved them to my garage. I then started building the shooting board and getting ready to glue the backs. Well, I was just about to start shooting the edges and picked up the plates and they have a slight warp.

The grain runs top to bottom and the warp is across the sides. It isn't really bad but its there. I stacked the plates on a flat surface and placed heavy objects on them to try to force them back flat.

The back is cypress. The label says Mont. Cypress.

So, I know I'm not the first to have this happen. What is the fix?

Thanks

Rodney

Rodney, I'm going to assume that you don't have the relative humidity controlled in your garage and that its much higher than where you had them stored. If you take them back in and let them sit for a day or so I bet that they will go back to flat. I brought some wood in that's been in the garage for several years and watched it cup with in minutes. I flipped it, stickered it and let it be for a couple of days and all is well now. The garage is at about 100% in the garage at the moment while the shop is at 45%. Controlling RH matters.

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Aoibeann

Sage advice Lillian!

I also have a back set that although it has been stickered in 45ish% RH for several months it has a slight warp to it that I want to get out so I can build with it. It happened I think during the Ann Arbor gathering last summer when I took this set along and then left it in the trunk of my black car....... I know, I should know better.

Anyway when I take it out of the stack it is still slightly warped.

I think that I read here a few times that there is a trick involving placing it on a concrete floor, perhaps a spritz of water too, but I am forgetting the details. So if anyone has a solution for Rodney and I it would be greatly appreciated?

Thanks!

Yea you're spot on Hesh!

Just wet the cupped side - place on a concrete floor wet side down and the boards will flatten out within a couple of days! You can repeat and put some weights on the pieces once they are getting near to flat! if they go to far just do the same again on the opposite side!

Dave

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Thanks. I'll do it tonight.

Rodney

I had some brazilian which cupped badly after it arrived.I put some damp towels in a bay window and put the backs cup down on the towels.A few hours later the warp disappeared and I quickly stickered the set.

Rodney,

I had a bunch back and side sets out in the shop. A huge multi-day rain storm came through. I never thought about it till I went to the wood supply to get something. Looked like a bunch of large potato chips. Well, I just took it all back into the house and all is fine again.

Until you get it braced, you may see this happen again. My last back set on the harp guitar even warped a bit after braced. But I put it back in the radius dish... spritzed it, applied go-bars, and used a heat gun (low setting) to warm it up a bit. Came out perfect. I guess the main thing is, don't panic or fret about warpage. Its gonna happen from time to time and it is perfectly correctable.

Mike

What is the optimum humidity to shoot for in a shop?


- Phil

Martin keeps their shop at 40% RH. Mine is between 44-48 during the summer and 40-45 during the winter.

Glenn

Thanks Dave and Efialtis that is exactly what I was looking for!! I am printing out your replies now and going to tape them to the offending set for future use.

Phil what Glenn said. I keep my shop at 42 - 48% RH year round. It's a bit of a pain to do and certainly not convenient for everyone depending on where your shop is but for guitar building RH control really is not optional. Over the years we have seen more posts that I can count where builders have had new guitars, work-in-progress, crack or tops cave in etc. for lack of proper humidity control. People have used RH controlled storage boxes, bags, etc and still had problems because their shops were not controlled.

I have seen one of my own tops go from a 25' radius to absolutely flat in 20 minutes time just removing it from 45%RH and taking it to 55% RH to sand it......

I am now convinced that the very first thing that any new builder should do is what ever it takes to secure good RH control in their shop. If your guitars are going to end up in someone else's hands when completed they will be far more resistant to RH swings if they are built in a RH controlled environment.

Resistance is futile...... Guitar builders are slaves to RH control.

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To be someone must be a wonderful thing!