Standard or serger thread is far too coarse to use for embroidery, serger thread is usually cotton and has lots of fuzz.

Is there nowhere nearby you can purchase 60 - 90 wt polyester embroidery thread?

Do you not have a dark navy, brown or grey Polyester or Rayon Embroidery thread you could use?

Either of those would be better than using ordinary sewing or serger thread.

And for future reference you should try buying Brother Bobbin thread on EBAY. Make sure it is genuine Brother though, not one of the cheaper "Just like Brother" imitations.

Hope this helps, Hugs n roses, Meganne

i use Serafil, this is a verry thin lock threat and in manny colors. my janome mb-4 works well with it. it is just as thin as brother and also beatifull

I use the same bobbin thread as the top often when I want to be sure that the bobbin thread doesn't show....I also was informed by my Brother dealer that they don't make a 90wt. black spool...He recommended using the same color IF I didn't want white!!

Use your white bobbin thread and loosen the top tension slightly so more of the top thread shows underneath or as Meg says, use embroidery thread in the bobbin. If you use regular thread the design will be thick and uncomfortable and may even damage your machine.

I've been searching online for bobbin threads, I can highly recommend the Madeira one below too.
Will add more if I find any. HNR,M

Cinder, I have the Babylock Ellegante, before that I had the Esante. My machine dealer recommended the 60 weight bobbin thread called "The Finishing Touch". It comes in white and black. I have used this only with my Babylocks, with very good results. I mostly use rayon embroidery thread, and I know many use poly, 40 weight for both. When I do FSL I use the same thread in the bobbin. There is alot of thread brands out there that my Babylock does not like. You have a wonderful machine, so do not try using cheap thread it is just not worth it. Hope this is of some help, let me know if you need anymore info. that I maybe able to help you with. H&*.

Cinder, I do not know where you are, however, I am in Eagle Creek, Oregpn. My dealer is in Portland. They have a website it is www.montaville.com. If you want to contact them I am sure they would mail you some bobbin thread, as the always have it in stock. H&*.

oh my i hope it is not that hard to find bobbin thread i got a spool when i got my machine it came with it hope you find some soon and me too

Sewforless has 90wt white and 60wt black Brother bobbin thread
Nancy's Notions has Black Madeira 70 wt bobbin thread
SewingSupply Warehouse has 60 wt, White or black finishing touch
Moore's has black Brother embroidery thread (not bobbin though)
ICanHelpSew has Brother Black Bobbin thread, they also have 90wt black or white (link 6)

Hope these help, I also need 90wt bobbin thread for my Brother and Elna machines.
hugs n roses, Meganne