I have used serger thread with no problems at all. Good luck.

you really need to use embroidery thread.,emb thread is thinner thread .go to sewforless.com and they have specials all the time. ebay has a good selection also.. good luck..

I use different threads in my Viking, for instance I was making FSL Easter baskets and ornaments and didn't really need the shine that rayon gives so I used the cone thread for sergers. It took me a while to figure out that I needed to use 2 layers of WS stabilbizer and a sharp needle but I got it to work. I've used my Aurifil if I had a small area of a design and didnt have the right color in emb thread, etc. Labels, I do in cotton thread. It's your machine and if you find what you like go for it. Especially if you are practicing a design, who wants to spend good money on thread for a practice piece. My machine likes all thread so I never have a problem, once in a while I might have to sit the spool on the table or in a cup behind the machine for it to work, but it does work. Metallic thread works well if you turn it upside down in a cup on the table, if you are having issues with it. Good luck. When buying emb thread I try to get different shades of the same color because just about every design I've used has some shading in them so I'll get say like 3 different greens, one just a little off in color to the other one. This has worked well for me.

The problem could be with your needle, either wrong size or wrong type. I like the Inspira needles from Viking, the inside of the eye is round so it goes thru more easily, most are oval.

I would advise just playing with your designs and different threads. Bear in mind that regular sewing thread will have a lower luster than embroidery thread and won't look the same as all the photos and samples you see stitched out. But if the thread works, and you like the look, I see no reason why you shouldn't use any thread you can imagine.

My dealer insisted that you have to use embroidery thread, but my gf used whatever color she needs of whatever thread. It has always worked fo her.

actually I would stay away from serger thread, too much lint..........calla

If you are just doing a label, I would think you could use what you have. I have a ton of embroidery thread because I do a lot of embroidery. I have also use some of the variegated threads to do some of my FSL (free style lace) (when I do wash away type crosses), that works okay.
If you do a lot of embroidery then you would want to invest in the various threads, if not use what you have. Do a sample first with some muslin to see how it works out for you.

I use any thread I want. I've even used serger thread to do FSL, it took me awhile to figure out how to make it work but once I did it was great. I used a sharp needle and one that was a little bigger plus slowed down the stitch length. You can buy cones of thread, even emb at quilt shows that is low cost. I use all threads for my emb machine and just bought a serger and I was told I could use all threads on it too.

Just make sure to use bobbin thread in the bobbin.