Thread question

I am working on a project and I ran out of thread half way through a very visible seam.  The first half of the seam was using Gutterman thread, the second half was using Coats and Clark.  As soon as I started using the Coats and Clark the seam on the underside of the fabric started to bunch up and loop - turning it into a really awful looking mess.  I made no changes to the machine settings.  Is it the quality of the thread that is the problem here?  Or do I need to adjust my tension?  I am very frustrated and disappointed - ARGHHHH!  Any help will be appreciated.  Thanks!

When I bought my new machine the first thing the shop owner did was tell me to throw away all of my Coats & Clark's Thread. The owner showed the difference with a spool of Coats and Clark - how it was easier to break when pulling it and also how it had more 'fuzz' on it than the better threads. She gave more reasons - like how the thread is actually made - but I can't remember the specifics. I now use Gutterman, Mettler, or Sulky.

Also, was the weight of the threads different. In once class I took we were given a number of 'specialty' threads and sewed a buttonhole with each. It was interesting to see how a simple change in weight or polyester vs. cotton changed the look / feel of the buttonhole.

If you have a quilt shop around someone there could probably give you more specifics about the differences between threads.  Good luck, Beth

I  totally agree with everything bethvanduzer said - it's all true! But, a quick solution - did you try to rethread your machine and bobbin.  Sometimes, the thread just doesn't catch right inside.  And it would make sense why it started when you changed threads - because you just rethreaded the machine too.  Good luck!!!

It's sadly true... some of these very expensive newer machines are actually more persnickety about threads than our reliable old machines. My 35 yo machine is such a workhorse - it will sew with any thread, through anything, in a perfect stitch!

Anyhow, as the other ladies said, you wil want to unthread your machine completely and rethread it with the presser foot in the UP position so the tension discs are completely disengaged. You can even use a piece of thread like dental floss in there to make sure there is no lint at all.

Thanks for all your help.  I also consulted with the associates at the store where I bought my machine.  They gave the same advise about re-threading the machine but did also say that I may have issues using Coats & Clark thread.  I was told that Coats & Clark is a polyester coated cotton, whereas Gutterman is a true polyester thread and that seems to make a difference with my machine.  I bought more of the Gutterman and am having no more problems.  Thanks again for all your help!