My Pallet Wood Shrinkage & Expansion Problem
Working with Pallet Timber (or reclaimed wood) is a great way to create furniture and other bits and pieces for around the home. Pallet wood can give an interesting and rustic feel to most pieces, especially if you leave the timber in it’s rough sawn state instead of dressing it all around.
I only started working with pallet timber late last year, and I’m loving it… until this project.
The Coffee Table Top I forgot about
I started working on a coffee table top last October 2014 (in fact you can see an image of it at the end of this post, with all the clamps still holding it together). I used whatever left over pieces I had lying around. In fact the length of the leftovers dictated the final size of 860mm x 450mm (33.8″ x 17.7″), and also the design of the top itself.
Now, I didn’t have enough longer pieces to create the top with all the pieces glued together lengthways, but I did have some shorter pieces that I could put across at both ends.
But, I only had pieces from 2 different pallets. You can tell that just by looking at the different grain patterns in the center longer pieces and the shorter ends bits.
So I glued and clamped all the pieces together. Then the following weekend after everything was dried, I used my circular saw to trim the edges to make sure everything was lined up perfectly before putting the edge pieces all around.
After mitering and fixing the edge pieces in place I set the coffee table top aside, and promptly forgot all about it.
The original plan was to add the legs and maybe a magazine shelf underneath. Then stain and varnish the masterpiece, before placing it into our home and listening to the all the flattering remarks from my family about what an amazing job I did. (Well that was how it all played out in my head, anyway).
Time to finish that table I started a while ago
Recently, after seeing the table top in the workshop I decided that I would finally complete this project the following weekend. The following Saturday I was all ready to get onto this project and finish it off.
After picking up the top and placing it on the workbench, I was greeted with a nasty surprise. All the time I spent on making sure that everything was perfectly aligned and all the glued joints had no gaps, seemed to be a waste of time.
Because now on both ends of the table top I could see gaps, that weren’t there before.
The timber shrinkage was only on both ends of the table top. But after looking at it more closely I don’t think it was Timber Shrinkage on the end pieces, but more likely Timber Expansion on the center pieces.
Looking at the images, it’s obvious that the center horizontal pieces look greener that the end pieces.
This is definately a problem you should keep an eye out for. Spending a few hours trying to do a good job has ended up being a bit of a waste.
I’m not sure what I’m going to do with this table top now, but instead of being stained, it will probably get a coat of paint. Not really sure what to do. It might be best just to get the legs on, and hand it over to my creative daughters to make it into something they would use.
Now, I know how to make stuff, but I’m no timber expert so I don’t have any particular explanation or solution. I have been doing a bit of research and found a few articles that you may find interesting.
This one on the Popular Woodworking site, explains how to “Calculate Wood Shrinkage and Expansion“.
It explains that:
Wood movement can ruin a seemingly well-constructed project. Luckily getting ahead of the material and calculating wood shrinkage and expansion is fairly easy – all you need to do is multiply three numbers together.
This article I found on the Woodworkers Source site, deals with “Wood Movement and How it Affects your Woodworking Projects”
This one piece of advice made sense in regards to my project:
Wood does not move in all directions equally. The greatest movement is across the grain. There is very little movement along the length.
No Calculations just Common Sense
Both of the above articles are interesting to read, and have a bunch of information explaining how wood moves under certain conditions. But I know that I’m personally not going to go to that much trouble to determine what may or may not move in my future pallet timber projects.
What I will be doing from now on is trying to stick with using only 1 pallet, and if that’s not possible, then look more closely at the grain of the timbers I have available, and try to match them as closely as I can.
If I can get timbers that at least look like they came from a similar batch, and they look more dry than green, then they should react in a similar fashion.
Also I prefer a more general style of reading when it comes to information about timber. Here’s a great article I found on the “The Art of Manliness” site called “The One-Stop Shop Guide to Lumber“.
This article covers a lot of general timber information, including a bit on “Moisture Content at Time of Manufacturing“.
Help and Advice Please
Has anyone else experienced similar problems with timber movement in your woodworking projects. Please share your story in the comments below. Any advice from timber experts would also be greatly appreciated.