Hi. I am having an issue where I purchase sheets of plywood and they are warping in the house. Is there a way to prevent this and reverse the issue. This photo is of pure bond maple 1/4” I ordered from Home Depot. You can see the right front corner is up. The back left is up as well, not as bad though. Both sides of the board are twisted up with the center touching the table but those two corners are worse with the board twisting I guess is the best explanation. Any help is appreciated. Thanks Mike
There are several ways to fix a warped board the best I have found was applying heat via a hot steam iron and rags…
Just Goggle fixing warped boards and you will find a lot of information…
I walk the lumber isle in a Home Depot or Lowes and wonder why anyone would buy some of their poorly stored and warped lumber or plywood. The instant the metal straps are removed from stacks of lumber the wood will start to deform. The customers generally discard the top few pieces to find material that has not begun to warp. Storing material flat with weight is about the only way to stop warping. Temporary humidity and storing flat with weight can somewhat reverse the process.
Thank you both for the replies. This was ordered in a box of 10. They are Glowforge sized and supposed to be laser safe. They seemed fine when I opened the box Friday but now look like this.
Mine were warped when I picked them up. I just store all my materials flat in one large pile (it’s close to 2’ tall now!!)
I just pin them down in the machine. With the lack of availability of proofgrade, it’s been one of my most used materials.
Store flat, fully supported, and with a full coverage weight on top. Plywood will warp when it is left exposed to humidity, even small amounts of humidity can cause warping, so it’s best to take the precautions mentioned, but you need to be aware that it’s also possible for finished pieces to warp, so the issue might surface after cutting.
Yup i have a few marble pieces i put on top of my stacks
I get this a lot here in Colorado as we’re way drier than many areas of the country. This usually happens to me when I order the same and I either just use pin hold downs when I cut (search the forums for the pins) or I can take a stack, wet the sheets down with a spray bottle, put on a flat piece of mdf, put another flat piece of mdf on top and then add a lot of weight (i use barbell weights) to let it dry flat. Usually helps a little, but with stuff that thin you’ll usually see some warpage.
Not to mention the poor quality on most lumber. I live in a place that is a major source of very large beautiful trees and yet the lumber that is available locally looks like the seconds pile of a previously discarded pile.
I overheard an old fellow grumbling about the quality and he told his friend all the good lumber was being shipped to Japan. All I know is it ain’t for sale at my Home Depot.
I’ve flattened warped PureBond sheets in the past by wiping both sides with a damp rag, then putting the dampened sheet under a stack of thick draftboard and bricks overnight. The next day it had dried flat.
I have had good success by using the pins from Honeycomb bed holdown pins.
I live in a pretty humid climate, but have not had this problem yet, knock on wood. I like the purebond project packs. They tend to have more flaws in the wood, but up to now, I have been able to work around them.
Any finished project will also be warped, which takes away some of the awesome.
I have salvaged boards with an alcohol spray.
Good misting on the rise side, then flip it over and store with a weight pressing it flat.
Home depot probably also sells 12x24 tiles for not all that much and a wipe with alcohol to get them a bit damp then placed between two tiles with some microfiber cloth in between to help the vapor escape and you will not find much that is more flat that was not milled. Alcohol will evaporate faster than water.
If you use MDF it will suck up the dampness but will be a pain to try and cut in the future.
Thank you everybody for the advice