[rkhanso]

Hello.
VERY amateur woodworker here. I normally don't have the patience for it.
I followed some directions on YouTube for making a guitar case. Basically, making a box, cutting it for the top/bottom and then covering it and putting on the hardware.
I went to Menards and bought their select pine - 1x6 to make the box. I wanted about 4" depth on the box so I couldn't use a 1x4 with it being only 3.5".
I used a Kreg jig and screws and glue to build the box.
I put some Home Depot 1/8" plywood on the top and bottom. I glued it and screwed the plywood on. I let it sit in the basement for a few days for the glue to dry.
I then removed the screws so I could use a roundover bit on a router on the edges.
Next, I cut the box on the table saw. I removed enough by where I cut to get the depth about 4.25" and a couple days after that, the top warped/twisted. It rocks when you press on two opposite corners. The bottom "seems" ok visually. The top is noticeably/visually warped.

Can this be fixed? How would I go about doing that? Or do I need to start over and do it differently?

The first picture is of the box before I cut it. The others are it's current state.
The appearance of the wood doesn't matter much since the entire outside will be covered in a vinyl fabric. I used wood filler and bondo to fill in the screw holes and other spots so the vinyl will be relatively smooth.

Thanks.

 

[Steve Neul]

I don't think you really did anything wrong. Some wood just warps. In the future when you make a box like that make the top and bottom as one piece like it was a solid box. Then run it through a table saw edgewise and cut it into the two pieces. That way it's the same wood and you get a better fit top and bottom.

As far as a fix set it on a level surface and put shems under the opposite corners and put something like cinder blocks on the corners and twist it the opposite direction. Bend it about as much the opposite direction as it is off now. It will try to deflect back the way it is now. Hopefully it will stop half way and fit. If it doesn't work do it again and bend it more.

 

[rkhanso]

Thanks for the tip on fixing it.
I'll certainly try that tomorrow.

 

[DrRobert]

When you ripped the 1x6 internal stress was released this is fairly typical depending on the wood, moisture content etc.

If this is the case, you're not going to get the warp out, but you can try. Latches and hinges would close it up, but that's not a really a good option.

My recommendation is take it apart and use plywood for the sides. If you're set on solid wood, be sure to rejoint the boards after you rip them to width and allow them to rest and reacclimate before assembly.

Building it as a box and then ripping it apart is a technique for box making but on something this large its no guarantee the lumber won't misbehave.

 

[allpurpose]

Inexpensive pine is really bad about warping, twisting and such after ripping it especially from some of the box stores since they often sell it before it ever has a chance to dry properly, but that's another story. As someone mentioned let it sit and aclimate in your shop for awhile before cutting into it and even then it'll probably still twist a bit from internal stresses. You may want to carefully check the grain of the pieces you're buying in the store and make sure it's free of knots and squirrely looking grain patterns. Buy ONLY nice straight grain wood if at all possible. Otherwise you're going to keep chasing your own tail trying to keep it straight..