I’ve been making some of the Woodland Scenics “trees in a bag” this weekend (those kits where you bend the flat armatures into shape and stick on the ground foam foliage). I used my bottle of Hob-E-Tac that had been sitting in a drawer for several months to apply the foam, making about a half-dozen trees at a time. After finishing the trees, I’d set them aside temporarily on their little plastic bases until deciding exactly where to put them on the layout. After coming back a few hours later, there would be a debris field on the tabletop of ground foam that had dropped off the trees in the interim. I’d say the trees lost about twenty percent of the foam I’d applied.
I’ve used this bottle of Hob-E-Tac before with no problems, so I’m rather perplexed. Does this stuff have a finite shelf life?
I haven’t found that Hob-e-Tac has a ‘finite’ lifetime, but it does need to ‘dry’ tacky for about fifteen or twenty minutes before you apply the ground foam to the armatures. And sometimes those ‘clumps’ aren’t as ‘clumpy’ as you think they are, they start separating. I’ve had some of my deciduous trees begin dropping clumps about fifteen or twenty minutes after you think they’re firmly attached. I finally began using the WS flat scenery mats on the trees, tearing off small pieces and ‘lacing’ them onto the branches, then spraying the tree with cheap hair-spray and filtering fine ground foam over them, then re-spraying the tree to fix the foilage. Gives them a little more of a ‘leafy’ look, and I don’t have the clumps dislodging.
I haven’t had the problem with their pine trees, as I use much smaller amounts of the ground foam on the branches after letting the Hob-E-Tac set up for about 20 minutes.
I’ve had it solidify in the bottle and become totally useless. Aleene’s Tacky Glue from the crafts section at Wal-mart works just as well and is much cheaper.
The biggest problem I’ve encountered is that Hob-E-Tac evidentally has a taste that pack rats (the animal type) and Chuckwallas (a large desert lizard) like because something keeps eating the trees on our HO scale club layout.
I used some of those trees in a bag that you’ve described- I’m glad I got them on clearance. I am mostly satisfied with the way that the “nude” trees turned out, yet applying the hob-e-tack and letting it sit for a half hour then applying the clumps I’ve had many of them shed without warning. I can place the clumps back on the trees (usually the hob-e-tack is still very very sticky) yet the clumps fall off continuously. Needless to say I am dissapointed with the results of the trees and don’t plan to buy them again.