I hope you're sealing that wood before mounting...some woods have been treated with non-friendly-to-fabric scientific miracles...and then there are wood resins... But you can't guard against everything! What's a stitcher to do? Be aware! I'm not stitching for perpetuity, I'll be joyous if it doesn't disintegrate before somebody decides they want it! Huh! Maybe that does mean "perpetuity"! LOL

Hi,
Would you be lucky enough to have a specialized brick-and-mortar cross stitch shop near you? A call to them for purchasing or ORDERING acid free mounting board would do the trick.
Now, as to some of the big craft stores ie. Michael’s, A.C. Moore, Pat Catan’s , I suggest you go to their Framing Dept. and ask them if they sell ACID-FREE mounting board and if they send you down an aisle and you find mounting board, Be Careful! Acid-Free Mounting board should have a label on it that says, ‘acid-free’; if the label doesn’t say it, don’t buy it. I got caught in that trap once, bought some that didn’t say it, had doubts, returned it for a refund and discovered the salesperson sent me to the non-acid mounting board; I found the acid- free stuff in an entirely different location of the store and it was labeled acid-free.
I’m lucky enough to live a short distance to an A.C. Moore craft store and I went to their framing dept. and was able to order the larger size of Acid-Free mounting board in the thickness I wanted that they didn’t carry in the store itself. They called me when it came into the store for pick-up.
Hopefully, if you are ‘pinning’ your completed project on mounting board, you are using stainless steel pins to avoid rust, though I was told by the framer that ‘lacing’ is the way to go because less likely you’ll pop pins. I use stainless steel ‘bridal’ pins by, I think the company’s name is Kritz?; you can find them on-line or different craft stores.

You can purchase mounting boards at many craft store. It is slightly corrugated in the middle for easy
placement of the pins to hold it. It is safe for material and what I was taught to use at a craft show.
The sticky board is very very scary. My parents had one of my pictures framed at Michael's and they used
the sticky board and it is not good. Sticky board will ruin your work.

And, Bermuda, that company is Dritz!

I was close....but no cigar.
Thanks Su, I was trying to find the pins in my ‘stash’ to check the name and I couldn’t find them...you know how that goes. Hopefully rdosedel saw your chat and wasn’t hunting all over heaven for the pins...

I have found the acid free foam board at Hobby Lobby and it is at a good price. I think the size 16 x 20 was about $6.00 so I bought 2 and cut them to the size that I need them.

It’s the adhesive that makes the ‘sticky board’ bad on the fabric, especially if the fabric of the project has to be peeled off it to redo/renew the project. Good luck with that!
An older couple came into the local brick-and-mortar cross stitch shop I would frequently visit (many, many years ago). The shop owner attempted to help them with cleaning, fixing and reframing a small cross stitched piece that the woman’s mother had stitched years ago for her.
Removing the frame wasn’t the problem. It was what the person who framed it had done; the framer had used a glue - that looked like a thick, yellow globby ingredient that was shaped as if had come out of an industrial tube of glue with a chalk gun - on the fabric to hold it to the inside of the frame and they had used a LOT of glue. The older couple had come to see if there was any way the glue could be removed chemically without ruining the fabric. Sadly, the owner, after assessing the whole situation stated the only way to get the glue off would be to cut it off, which would definitely have removed enough fabric that would come very close to the edge of the design ( there wasn’t more than an 1 -1 1/3 inches of extra fabric). The couple left disappointed because they had ‘got the same answer’ from two other framers they had shown the cross stitched piece to before coming into the one I was visiting. They left to see if they could get other opinions, but if you had seen the amount of glue that was applied in layers, all of you would’ve seen that cutting the glued areas out was the only alternative. A very sad testament to a elderly woman’s keepsake given to her by her mother.
I always wondered what the couple decided to do with their piece of stitchery...