First of all, notice my aqua Singer, circa 1970's, that I found a couple of months ago at the Salvation Army Superstore for $10.00. Serviced and cleaned up, it's one of my favorites. Now, on to the matter at hand; one drawback to sewing home furnishings with a lightweight machine is that it's difficult to get the durability you need from plain old All Purpose thread. What you really need to get the job done right is a true commercial machine that will accept upholstery weight thread. Sewing machines designed for home use, especially inexpensive new machines, aren't set up to handle upholstery weight thread. However, there is a trick I learned from a talented costume seamstress/Hancock Fabric Assistant Manager. Here's what you can do to get strong durable seams and professional looking topstitching using your home machine.
1. Thread the top of the machine with upholstery weight thread and use All Purpose thread in the bobbin
2. Use a heavy duty needle in the machine. I use either a needle made for denim/jeans or leather. The eye is larger so it won't fray the upholstery thread
Check out the difference that heavier thread makes on this canvas topstitching.
1/2" seam allowance on a canvas strip
Topstitching with All Purpose thread in both the top and the bobbin
Upholstery weight thread in the top and All Purpose thread in the bobbin
I didn't even change the tension on my machine. This may not work on all home sewing machines but it's worth a try if you need to do heavy weight sewing.
One other obstacle to sewing heavy weight upholstery fabric on a home machine is that the presser foot only raises so far. Depending on how thick your fabric is, it can be impossible to get double and triple layers of heavy upholstery fabric to move through the machine.