Square, tight and flat is ideal.

And the warped screen will probably/maybe give you issues.

But if you're in a pinch and you HAVE TO use a warped screen, how well it will work depends on a few things. One is how distorted the burned image is. Trapping your art can compensate for some distortion.
Another is how well your press is set up. If your platens are flat, level and all in the same plane and your off contact is consistant at each head you stand a better chance of being OK.
You can start by printing the warped screen and registering the other colors to it. Be consistent with your print strokes and if things are only slightly off you can also compensate with the directions of your print strokes.
If you're not terribly rushed, it's worth trying so you'll know for future "just in cases".
Even with trapping or modifying your art if things are way off and the situation and time allow, get a new screen.

 

yep, it's going to give you fits with registration, toss it and get a new one.

 

It will also depend on how you burned it, and how adjustable your press is, if your off contact varies 1/4" from one corner to the other of the image, you won't have a good time of it. If it's just warped a little, you may not even notice the difference.
The old Hopkins Int'l presses with side clamps, you could force a screen back to square, and if you used a vacuum exposure unit, you could get very little distortion--with a little extra work.

 

Toss the screen and get static aluminum frames until your ready for newmans. I've tried using warped wooden frames when I first started and it is going to give you multiple headaches.

Toss it.

 

I wouldn't toss it--unless it's seriously warped, and/or you can't adjust your print head, they work just fine for one colors.

 

You can also use something to "shim" the one side that is the lowest up and then set your off contact and everything will be level. I have had to do this many times.

 

Yes, because it's Friday at 5:30, the job is due tomorrow morning, I bought these four 200 mesh screens, thought all the screens were OK and for some reason this one is warped. I don't have any other 200's, just 110's and they are all burned for other jobs.

I'll be better prepared in the future by having extra screens on hand and carefully checking them first but I don't have the luxury right now...

Even the worst situations are an opportunity to learn flexibility

 

Dont toss it, use it for one colour jobs.

But yeah. If registration is tight and crucial, use the best screens you have. If its a distressed logo which has multiple colours but they don't actually matter in regards to registration, I would use the warped screen.

 

well i shimmed two opposite corners of the screen then clamped down the other two sides to bring it back to its shape a little bit.....it actually worked, im sure after a day or 2 it will go back to its warped state but it gave me enough time to be able to print the shirts! hah

 

I have actually heard of a guy stacking all of his warped screens on top of each other, and then putting a lot of weight on top of them. He would let it sit there for a few days to let the wood dry out completely and the weight would make them flat again.