Good Morning. Fusing the back of my pieces is mostly for peace of mind. Even on framed work it is an added bit of protection since you never know what will happen. Fusible interfacing can be purchased at any fabric store, such as Hancock and JoAnn's. I use a light weight cloth when using a double fusible for stability on unframed work, like, Christmas stockings and ornaments. Just ask one of the sales people, I have always found them to be very helpful. Good Stitching!!

I would just caution you to be sure your work is blocked first...once you have applied the interfacing, if the work is crooked, you will never be able to square it up. I don't use fusibles myself....on stockings and pincushions...things that will get a lot of wear, I use a sew in interfacing.

I have used fusible interfacing for many years for my stitching projects. It just gives the back of the project a nicer look whether I frame it, put a border on and quilt it or however I finish it up. I buy mine at JoAnn Fabrics when they have Pellon brand by the bolt (10 yds.). I use one of my JoAnn coupons and usually get it for 1/2 price. It is not expensive and lasts a long time. I use the light weight no matter what the project is. if I am quilting the border I will have a batting in it so I don't want a heavier weight interfacing. Hope this helps.

When I do my framing I use sticky boards to mount the project, but still use fusible interfacing too.

some stitchers would be concerned about the effects of the fusing chemical (glue?) & synthetic fabric on their linen & floss over time. Different opinions, but they may want to think of their stitching in a museum several centuries in the future. My teachers were "conservationists" of this sort, so I picked some of it up.

I worried about a wedding sampler mounted on that sticky-type board some 20 years earlier. When I took it apart for cleaning, it was fine -- not affected at all by the adhesive.

I used fusible interfacing on a pillow front that needed a little stiffening recently, but usually do not. I mount the fabric on acid-free foam core, if I'm framing, even if it's Aida. If I'm turning tiny projects into sachets or paperweights, they get a matching cotton bag that fits inside & holds the weights or scents (usually balsam or lavender). Made some ornaments years ago & cut their mounting board from acid free mat board.

Like SYagel, who likes fusible interfacing on her projects, I don't think what I do hurts, and it makes me feel better.

So far I've only used the fusible interfacing on Christmas stockings. I've used sticky board on tiny projects, like place cards in frames. So far I've had everything framed professionally because I don't know the first thing about it. Like you, jlhewes, I was told about the acid free products and to never use sticky board, etc. The back of the picture frame is almost hermetically sealed, so who knows what the shops do. I like the idea of using the interfacing because it keeps the floss from coming lose but framing serves the same purpose. So it's all and individual choice I suppose.
When I have free time I plan to familiarize myself with framing. It's so expensive now.

Wow! I use the sticky boards and went to their website (I'm NOT paranoid...they really are after me!). The most common brand sold say that they will not have an effect on any fabric. Rest easy.
My framer will block (straighten fabric, even needlepoint). I don't pay for that. I have a grid on my ironing board and iron and tug the projects until they are very straight. Taught myself how to do this. Preprinted grid on an ironing board cover. I added more lines to it...Hah!