February 15, 2023
Unfortunately some of the plywood that we supply won’t be 100% flat. As it is wood and a natural product which contains water so it has a natural tendency to warp. Different conditions can affect it, this is something outside of our control. This is especially true with the thinner 2mm and 3mm plywoods.
In order to understand what is happening its worth considering how plywood is made.
Plywood is a composite material made from wood and glue. There are multiple layers called 'ply' which are glued together like a sandwich. Water content of the material will vary depending on the humidity and temperature in the air. Different rates that water evaporates from the wood will cause an imbalance.
The top and bottom of a sheet of ply will often dry at different speeds resulting in an in imbalance in the internal forces of the material causing the plywood to curl upwards.
Our plywood comes from sustainable Finnish forests which means it has made quite some journey to Ireland. As it travels from Finland to Ireland with all the humidity changes from factory to harbour to lorry to our warehouse and then on to customers.
What we do to minimise warping
When it reaches our warehouse we do our best to keep it flat stacking weights on it and keeping it out of direct sunlight as it inevitably dries out. We also turn it regularly so it can dry on both sides as evenly as possible.
Then we cut it down to size and again stack and weigh down the smaller sheets waiting for your order.
When you order we package it and ship it via An post. Again at different times of the year weather conditions will vary and some warping can occur during transportation to you.
The good news is that we use it like this everyday in our lasers so we have figured out the best way to handle it.
What you can do to get the best results
There are two main ways that you can use to get the best results working with the warped plywood.
Magnets on your laser bed - this is our number one suggestion for quickly being able to use the plywood if the warping is only small. You just need to use some magnets to hold it in place and flatten it on your laser bed.
Wetting and ironing the plywood -
- Place the plywood sheet on an old towel with the curve facing upwards. Sprinkle water on the top surface of the sheet (3 or 4 table spoons).
- Tip off any excess water and turn the sheet of plywood over.
- Put a second towel on top of the sheet.
- Now use an iron to iron the sheet, through the top towel for about 5 minutes. Be sure to keep moving the iron around evenly over the sheet.
- You will find that your plywood sheet is now much flatter and ready to laser cut!
In additon to this you should always store plywood on a flay dry surface with weight on it until you are ready to use it.
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