Sorry, no experience in using matte medium as a fixative for flocked tree armatures.
Crandell
Yes I hit the 3M tree with hairspray after it set, also did the same for the trees that the foliage was applied with the hairspray. I sprayed the matte medium tree with more of the glue per the instructions, but didn't put any hairspray on it.
Will the hairspray seal better, or the matte medium, or really no difference to be concerned about? The Scenic Express instructions specifically say not to use hairspray. But then I am sure they want to sell more glue, so I tend to take this sort of message with a grain of salt unless I hear otherwise from those that have experience.
I did soak all of structures in diluted glue per the instructions and let them dry before painting the trunks and applying foliage. That did make sense to me.
Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger... doing it my way. Now working on phase 3. - Walt
For photos and more: http://www.wkhobbies.com/model-railroad/
When I first learned how to make the furnace filter trees about seven years ago, the instructions printed here were to spray first with the 3M product, sprinkle the ground foam, and then spray the ground foam with the hair spray. I have quite a few trees done that way, and they have all kept their foliage.
I am still playing around with scenery techniques on my test board while working on the layout grading and I bought a Scenic Express super tree kit to try out. It comes with about 15 "natural armatures" and quite a variety of different flocking materials- enough to do a whole bunch more than the 15 trees that come with the kit.
I selected four of the most ragged-looking to try out using different glues and flocks suggested by web links and videos. The one to the far left was done similar to the instructions using the supplied matte medium glue. The one in the center was done with 3M spray adhesive. And the ones to the right and the rear were done with hairspray. I also made a few bushes from scraps using both scenic cement and hairspray (my wife really likes the berry bushes.)
All adhesives seem to work fine, with the hairspray producing the most "delicate" trees. And the 3M adhesive produces a fuller tree and is much quicker to do. So, here's the question- are there any advantages or disadvantages to the different adhesives long-term, or is it just a matter of taste? I would hate to have "leaves" falling off or turning an un-natural color a few months or years down the road.
I think the biggest downside to the super-trees is that they are all about the same shape and size, and the 7" max height only scales to about 50' in HO which is too low for virgin forest. Need to think about how to get the same effect cheaply and easily (because I am going to need a whole lot of trees!) but end up with some that are taller and with more variation. The pre-made WS trees like toward the far right are too costly, and though the shape is kind of nice they really don't have a lot of detail.