Thread: Warping lid

Hi Dan,

Very frustrating. How thick is the panel on the top? Is it solid timber or veneer over a substrate? If solid, did you give the top panel time to settle after it was thicknessed, i.e. to see what stresses emerged from the thicknessing?

Regards,

Brian

The lid and sides were taken from some firewood that I cut down. The lid is quite thin, I was initially going to put it into the rebate, so it is about 3mm. I did cut it too small so had to add a section in the middle, I also glued some mdf on the inside because after sanding I felt like it had become too and should be reinforced, it was then covered with some felt.

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Originally Posted by Dan74

I also glued some mdf on the inside because after sanding I felt like it had become too and should be reinforced

Dan, that's your problem right there, f you only glue one side of something, it tends want to curl up sorry to say, probably would be better to use the mdf as the meat in the sandwich so to speak. put another thin layer the other side sandwiching the mdf, and it balances out.

Thanks for that, that makes sense. Lesson learned for next time.

Hi Dan,

I think Fumbler is spot on. With a piece of timber less than 3mm thick you are effectively veneering one side of a piece of MDF. Try searching “veneering both sides” on the web and you’ll find a lot of information about this.

I once veneered a 6mm ply panel with an 0.6mm timber veneer one side only. Within 3 days it looked like a banana.

It’s possible, too, that being cut from firewood it may have still had a higher moisture content than most wood we use. If so, that would only worsen the situation as the outside dries.

Regards,

Brian

I don't know if it's coincidence or not, but a box that I made, with a cross-grain inlay like yours, also had the lid warp. At the time, I put it down to interacting forces between the inlay and lid panel.

I was making a brick wall style cutting board and layered 4mm thick Blackbutt on near 30mm jarrah and again, it curled as Brian described, a banana, luckily I was then slicing and flipping to make end grain pattern so I was able to clamp out the curve.

So is your best bet then with a lid to veneer a thin piece of your material to both sides of something stable like plyboard. Or should you just use something thicker. Or does it just depend on the stability of material you are using?

Originally Posted by Dan74

So is your best bet then with a lid to veneer a thin piece of your material to both sides of something stable like plyboard. Or should you just use something thicker. Or does it just depend on the stability of material you are using?

Like your first question, this question can be answered many ways.

I think using a piece of veneered plywood or MDF would be suitable. Drop the veneered lid into a rabbet (or rebate) a hair or two deeper than the thickness of the lid. If you can cut the lid to an exact fit, great, or hide the joint by cutting a 3x3mm (or similar) groove along the join and inlay some contrasting wood. I'd glue a lid like this in place.

Otherwise, a solid lid 10 to 12mm thick could be employed. I'd be tempted to cut a groove (not a rabbet or rebate) around the inside of the box to house this lid. Often the groove is 3 to 6mm wide and the edge of the lid shaped to fit the groove. I'd leave the lid floating in the groove if I made a box this way. Some makers put tiny drop of glue on the endgrain sides if the lid to secure it but still leaving most of the lid to expand and contract. I'm sure you've watched YouTube videos showing this.

I don't think using a thicker piece of wood is the solution. The lid can become too heavy and the box tips over backward when open. Also, thick wood warps and cups, too. Pretty sure that's why we use breadboard ends on dining tables. They're usually pretty thick.

I'm racking both my neurons to remember the American box maker who wrote a book and made a video showing several ways to make boxes.................I'll remember eventually and post it here.

Doug Stowe is his name. Try to get a look at his video or book. It was an eye opener for me when I started to make boxes.

Seems Doug Stowe is now on YouTube:

BASIC BOXMAKING by Doug Stowe part one. - YouTube

Thanks for that link it was really good information. Also not something that I would have normally looked at as it doesn’t really standout and have the production of newer videos. So a bit of a hidden gem.

Originally Posted by Dan74

Thanks for that link it was really good information. Also not something that I would have normally looked at as it doesn’t really standout and have the production of newer videos. So a bit of a hidden gem.

Yes, it was made around 2006, I believe. I had a look at the YouTube link I posted and that video led onto three more videos, none of which shows how to make several boxes. I might be remembering through rose coloured glasses but the video I remember shows different ways of constructing boxes (mitres, dovetails, finger joints) and different ways to attach lids and bottoms. Someone here will confirm or correct me.

I'm sure I bought the DVD or digital download. It was really good.

There are actually 17 episodes in the series if you click on play all and they do show construction methods of different boxes. I am currently watching episode 8 as I write this.

Originally Posted by Treecycle

There are actually 17 episodes in the series if you click on play all and they do show construction methods of different boxes. I am currently watching episode 8 as I write this.

Oh, I'm glad they are available. My YouTube skills need a hone.