(1) Do I need to wash the UHaul separately first? (2) How big should I make these pads? For a 2x7 C&C cage, should I make them into 2 or 3 separate sections? (3) Should they fit the cage perfectly or should they be wider, so they go up the sides? (4) Will the piggies burrow under these unless I find some way to attach them to the bottom of the cage?
Here are my thoughts. (1) No, they don't need to be washed separately, but I do so in the preparation phase. Fleece shrinks very little (if at all) but the uHaul shrinks quite a bit. Be sure to wash the uHaul in hot water and dry in a hot dryer 2x before beginning to sew. If you don't, the uHaul pad will shrink inside the fleece and you will have wrinkled and unsightly liners that will be smaller than you originally created them. Not something you want to happen after all the effort to sew them.
(2) Considering that your cage is to be 2-grids wide, I would make one piece liners (two grids seems to be the limit for larger liners....otherwise too difficult to handle). I've tried it both ways and the one-piece are far easier to work with for me. Having liners in two or more pieces just means that poop and other debris will get under the edges. Much more simple to just have to vacuum around the edges of a one-piece liner.
(3) NO, no perfect fit for reasons I outlined above. Make your liners 1in.+ larger all around so that you allow for some continued shrinkage over time. That also will prevent all sorts of things accumulating between/under the edges of the liner.
(4) The liners will essentially be too heavy for the cavies to burrow under them. Of course, there is always the exception.
(5) Sewing machine - There aren't many machines that can handle two layers of fleece plus
two layers of uHaul. Many of us have found that you really don't want to use two layers because the liners then become unwieldy to handle and take too long to dry. One layer of uHaul seems sufficient. I bought a new machine when I started sewing piggy items. You want to find a balance between it being lightweight and yet will do the job. You don't want one that is TOO lightweight or it will walk around the table as you are sewing.
Here is the machine that I and others have purchased....Brother CS6000i.
I located it in a store nearby, took it for a test drive, and then ordered it from Amazon because of their liberal return policy. It is currently listed at $149.
(6) You should consider what you are going to put between the liners and the bottom of the cage. After using all sorts of different items, I settled on incontinence pads. For a long time I used puppy pads, but wanted to find a solution that is kinder to the environment, plus most of the pads have an attractant to encourage puppies to use them, and that attractant seems to lure guinea pigs as well!
I've never had a cavy who didn't love to chew the blue plastic edges.......and then ingest them. Not something you want to happen.
Incontinence pads are the perfect solution for me and last a long time.....which I didn't expect. Look around a source of the pads (I've given you a couple of links to start). You want the longest you can find to minimize the number of pads needed. In contrast to the liners, I alter the pads to the size of the cage with perhaps an extra half-inch all around. The trick with sewing these pads is that you sew the edges BEFORE you cut them. Sew your projected new liners with an overcast stitch and then cut the liner close to the stitches. Otherwise, the waterproof layer and the absorbent layers will separate after cutting and one can almost never put them back together. For your cage size, the 80" pad won't be quite long enough so you will need two pads for complete coverage.
http://www.amazon.com/dp/B0002DMPFS/ref=biss_dp_t_asn (34" x 36")
http://www.amazon.com/gp/product/B003QSDFL4 (35" x 80")
Do use the "search" function here on the Forum....it is the red magnifying glass in the upper right corner. You can find the answer to almost any cavy question that you may have somewhere in the archives of at least ten years of posts.Happy sewing!