The size thread you use is more personal preference than anything else. Size for size, nylon is generally stronger than polyester, although that is not always the case. There is nothing wrong with using size 69 nylon thread. Size 69 nylon is the thread of choice for furniture upholstery companies and also most auto upholstery companies because it is strong and is less expensive than polyester. The reason I use size 92 Sunguard polyester thread is that polyester stands up to UV rays better than nylon, and is just as strong or stronger than nylon. It is also more color fast than nylon. I also just like the look of the thicker thread.
BTW, Bonded thread is always lubricated, that's part of the definition of bonded thread.
No one lives forever, the trick is creating something that will.
Last edited by DanTwoLakes; 08-19-2010 at 10:52 PM.