I saved instructions for quilting in thirds, useful for large quilts, from Quilt University. Here it is! (try try again)
Subject: Quilting in thirds
Posted By: Carol at Quilt U
Date:
To deal with quilting a big quilt on a home machine, Hari Walner uses a method called Quilting in Thirds. Lay out the quilt sandwich as always but baste only the center section of the three layers together.
Fold back the top only on the left side and cut away the outside third of the BATT ONLY. Before moving it, mark the top and bottom on both sides of the cut line - A/A, B/B. Set that piece of batting aside. The letters will show you precisely where to put the piece back. Your cutting line does not have to be perfectly neat since it will fit precisely against the other piece.
Once the batting has been removed, roll the top and back and pin so they do not flop around or get sewn to the back by accident.
Repeat the process on the other side, folding back the top, cutting the batt, marking on both sides of the cutting line with C/C and D/D at the top and bottom.
Roll the top and backing. Pin in place. I use safety pins so I will not stick myself.
You now have a long skinny quilt. It should fit under the head of your machine with no trouble. Quilt to within 2-3" of the sides. Some lines of quilting will be stopped in the middle of a line. End the stitching so it will not ravel loose but you will be going back and sewing over those places.
When you have completed the middle, lay the quilt out again. You can choose either side to do first. Unroll the top and back. Smooth the back out against the table and tape the loose edge. Put the batting back in place, matching the cut edges and the lettering. Using a basting needle, make a big XXXXX row of stitches to attach the two pieces. Unroll the top over the batting and pin securely in place.
Be sure that you quilt across the join as the first part of your quilting.
The bulk of the quilt is now to the outside of the machine and you are dealing only with this third.
When you repeat all the steps for the last third, you have to rotate the quilt so the bulk is still to the outside.
The borders should be done last and can be done with the bulk to the left (or outside) of the machine during the whole process.
The only tricky part of this is making sure that you spread out the entire quilt when you are adding back the missing batting. It is tempting to take a short cut and unroll just what you need but that can cause a ripple on the bottom.