Omnigrid Cutting Mat
 

I have a large cutting mat, somehow it became warped. How do you get the bulge out?

You don't!

If part of the mat is still flat, the best you could do would be to cut out the warped section, and make some smaller mats.

The mats need to be stored flat.
If transported in a car, laying it flat is important too, as the heat coming thru the glass can warp it.
Touching the mat with a hot iron can do it as well.

i have read that some lay theirs out on the driveway in the sun for a while. don't know the details... maybe another poster will jump in...

There is nothing you can do to fix it as the others said. I learned the hard way not to store mats in the car. I loaded mine up one morning before work. Worked all day and went to a class after work. The mat was warped horribly from being in the car all day. I tried many things to get it to lay flat, but nothing worked. Sorry.

Having warped one , not badle but it did not lay obsolutely flat ... I put it on my deck table in the hot sun for about 3 hours... it was flat again. Not sure the manufacture would suggest this but .. I figured ..what did I have to loose?!!

I would cut it up into smaller mats and buy a new one. A warped mat is usually permanently warped like a metal pan when it gets warped. I can't believe how many women keep a warped baking pan. LOL

Or a warped kettle.

I had the similar problem with a rubber-type mat from a dog kennel. I took it out to clean, left it in the sun, and it would not fit back into it's spot The sun had actually made it expand and warp. I put it in the freezer for 20 minutes. It fit perfectly back in its spot. I wonder if the freezer would help a warped cutting mat?

If it has measurement markings on it, even if you do get it to lay flat again, I wouldn't trust the markings to remain accurate. For those is hot climates, think about when a tar or asphalt road "melts" and the streets markings get all wavy and weird.

I purchase a high quality double sided drafting mat. I have about 6 of them right now and get them for all of my quilty friends....just a suggestion, I buy mine from a college bookstore. They are double sided and professional grade. My daughter brought some home and managed to put them in her car apparently on top of some items for about a week. I have had them downstairs for a few years now trying to get them back in shape. I was just about to cut them down smaller when the weatherman announced that it was going to be 100 today. I put them on the lawn on a sheet for about 5 hours, till they just about felt like they were melting. Then, one at a time, I brought them in the house, laid them on the linoleum floor and completely covered with heavy books. I did this a few days ago, but it was only about 82 and I didn't leave them out long enough. I will peak at them in the morning and see what happens. I figure the AC will stiffen them up again....I hope.