Tension changed?
 

I've been doing hours of FMQ pebbling on a wall hanging to simulate a stone wall. The top thread is a variegated black to grey and the bobbin is a black to match the backing. I checked carefully to get the tension right when I started that there was no grey showing through and away I went. Well, after many hours, I glanced at the back and it seems that just over the last sewing session the tension has changed and I have grey threads showing on my black backing. I've worked on this piece for almost a year*sigh*.

So, what happened? This machine is newly serviced and I didn't change anything. I just need to know what to watch for so it doesn't happen again.....I've still got hours of pebbling until this wall is done.

Thanks, Watson.

PS...not finished yet...still lots of quilting, some leading and the dragon's eye to do, but here is the wall hanging in progress.....[ATTACH=CONFIG]539176[/ATTACH]

Are you new to FMQ?. What type of machine are you using: LA, DSM or a sit down? It is best to have the same thread in the bottom and the top so this does not show up. It is difficult to match the movement that your machine does automatically when stitching a perfect stitch. Also speeding up around curves can produce what are called eyelashes. This is why it takes a lot of practice to get FMQ done well. What a beautiful dragon you created.

This is why it's best to used the same color thread in the top and bobbin. I have 2 guesses. One is that a bit of lint may have developed in the tension disks. I have also noticed on occasion that as the bobbin gets low, the tension gets thrown off a bit.
Remember, however, this is a wall hanging. If the top thread is showing slightly on the back, who will know??
There is always a black sharpie.

A few things can affect your tension mid bobbin as well as between bobbins. A blob of lint getting stuck in the bobbin case spring can cause it. Change in tension on how the bobbin was wound and sadly, there is nothing you can really do about that one. It is very difficult to keep the tension uniform on your own wound bobbins. Heck even the prewounds can vary. Superior superbobs are notorious for having bad tension for the last bit of the bobbin. Some people can quilt with them down to the last centimeter of thread and others simply stop and save the end bits for hand sewing bindings. Some less than great quality threads can vary in thickness on the same spool and affect your tension. I always recheck tension with every bobbin change. Some quilters will absolutely not use different colored threads in bobbin and top because this is such a very common problem and can happen at any time with seemingly no rhyme or reason.

The good news is you can take a micron pigma pen in black to camouflage the gray pokies on the back. The occasional pokie will not compromise the quilt's integrity so you can also live with it. Your wall hanging is very pretty and the occasional gray pokie on the back shouldn't be of any concern. It would be a much bigger deal if you were getting black pokies on the front. I am curious, is there a story behind it as to why the girl is blindfolded?

feline fanatic, in the end, it will be a mask, with an eye hole. I knew there was no way I'd ever be able to do a decent human eye and it adds to the fantasy idea of the story. This wall hanging is destined for a children's centre.
I took the inspiration for this wall hanging from a stained glass window I saw once.

Watson

If you've done "hours" of stitching perhaps it's just time for a new needle. I've changed needles and the sewing much improved after doing lots of free motion. Hope you find something that helps!

When you first checked your tension, did you check it using the same fabrics and batting as what you're using now?

Another thought - how bad is the thread showing through? Are you planning on washing the quilt when it's done? If the thread isn't showing too badly, a lot of times it will disappear and sink into the quilt with laundering.

All good thoughts. This has happened to me too. I have had it where I've adjusted the top tension all the way as far as it will go to the tight side and it not make any difference so what I did was get out my secondary bobbin case and after taking a picture of what it looked like when I started, I adjusted it by turning the screw maybe several times until the tension looked the way I wanted it to. I don't usually have to keep adjusting once I get this to my liking. It might be worth a try. My dealer can't figure it out either.

I find when you go to fast on curves it can affect your tension