The cutting mat has markings for standard paper sizes - so relative position between paper and mat is fixed. How about between mat and machine? There are no guides to help you load the mat into the Portrait. Does the Portrait adjust if you load the map differently?
No. I tried loading the mat in the leftmost and rightmost positions, both while still being under the white rollers, and it cut in different positions. I thought it might use the optical scanner to position the map, but it doesn't. So the cutting mat in the software is only as useful as you can position the real mat in the centre.
The bad news is the machine doesn't accurately position your design on the mat.
The good news is this means there's no special requirement for the mat.
Since it's not reading the mat, that means you can use any mat, e.g. the Cricut ones. People say those are better, and they're about half the price, since there are 2 mats per package. This is what I'm going to try next. I'm also thinking of trying 3M's self-adhesive notice board. It's promising because their famous adhesive is easy to remove and leaves no residue, but I have to check the price and thickness first.
Update 9 Feb 14
Well, my original Silhouette's mat has finally died, after about 1 month. Pieces keep moving around while cutting, making the cuts go all over the place. Fortunately, Amazon ships the Cricut mats overseas, so they're not very expensive. I'm testing them now, and so far they're very good:
- Half the price of Silhouette's mats!
- Much thicker
- Designed to be loaded from either end - this is a great design, since the top of the mat is used more than the bottom.
- It also curls paper when you peel it off, but at least this one doesn't leave any sticky residue
The main problem with Cricut's mats is the alignment. This picture is with the 2 mats with their top edge aligned. The markings on the Silhouette mat are about 7 mm above the markings on the Cricut mat, so that means I should place things higher on the Cricut mat. Or plan to cut about 7 mm lower.
If I position the 2 mats so that the markings align (the Cricut mat also has 1" markings), the Cricut mat extends past the Silhouette one in all directions.