I mostly do single color printing on t shirts. So I can get away with using screens with cheap wooden frames. The wood frames warp a little which would hinder multicolor printing, but don’t affect single color screen printing really.
But one of the problems I have had with cheap wooden frames is the screens sometimes come loose. They are only held in by a pressed in cord. You can press the cord back in, but the screen will till be loose.
The solution I came up with was to remove the cord altogether. I position the screen over the wooden frame, and with a staple gun, I staple the screen to the frame in the middle of one edge. The I go to the opposite edge, pull the screen taut, and staple the screen to the frame in the center of that edge. Now go to one of the sides that hasn’t been stapled yet. Pull the screen half-taut, and staple in the middle there. Go to the opposite side, pull the screen taut and staple.
Now you should have staples in the center of all four sides of the frame. Go to a side, pull the screen taut, and place staples a half inch on either side of the staple that is there. Go to another side and repeat. Keep pulling the screen taut and stapling until you have staples every half inch around the frame. After you have stapled the screen to the frame, go around, and tap the staples down with a hammer, so the don’t stick up at all.
You can trim some of the excess screen off. Don’t get too close to the staples though.