You can always use "hidden Pins". Drill shallow holes in both the handle and tang. Use enough epoxy to "butter" the slab/tang and fill the holes. When the epoxy sets up, you will have an invisible connection through the tang and between the handle scales. An alternative corbys might be to use plain stainless or brass rod. Depending on the knife, you might consider using JB Weld as an alternative to epoxy. It will take longer to set up, but has the downside of being colored (grey), so this would only be acceptable on hidden tang knives or knives where the grey would fit in with your design...
I'm not trying to start something, so just bear with me...
For me, hidden pins are exactly that. Hidden PINS. I use all-thread actually and drill about 1/8" into each scale from the back. I then keyhole the pin holes to crate an hourglass shape when everything is together. I thread the all-thread into the tang leaving just shy of an 1/8" sticking out of either side. Then when it's all glued up the thread-rod is mechanically fastened to the tang, the epoxy grips the threads, and since the holes are undercut there is no way the scale is coming off without leaving a piece of itself behind. Peened pins are preferable to this method IMO, and only use hidden pins when absolutely critical for appearance reasons or, most frequently as back-up to fasteners that pass all the way through the materials...
JB Weld can be done on a scaled knife too as long as you mind your p's and q's keeping everything dead flat and square on contact. But isn't the best candidate out there. You should strive for zero gaps. Not just unnoticed gaps because the epoxy matches or is clear. This being your first, probably going to have a gap or two. Best to stick with clear. Most automotive stores actually have a better selection of epoxies. I've seen long cure quasi-flexibile stuff in Pep Boys... This is a good place for abrasives too... And also hit up any gunsmiths in your area. Most of them have made a blade or two in their day... plus they use a lot of the same stuff knifemakers do.
Look up a Loveless bolt or Loveless style fastener. I know the local Tractor Supply Company (another gem of a place for knifemaking/fabricating, etc) has threaded barrels in their screw and connector bins. You can make up a Loveless fastener out of those. There are also copper rivets, Chicago screws, heavy needles, thread.... d-rings... etc etc etc in the tack supplies for your sheath making.
You don't have to have a knife supply store on the corner to get it done as 85% of this stuff is shared amongst a few genre of hobbies. Really slick stuff like corbies though will be an order online type item no matter where you live... But hey, the knife is amongst humanity's oldest weapons... predating reliable epoxies or trick fasteners by several millenia. And we obviously didn't starve into extinction.
The best stuff is usually the stuff you were able to scratch together into a useful/useable creation with as few $$ spent while doing so. Now, if the goal is ultimately quality and thd knife is for a customer or a gift... spend the few extra $$ and get the best components you can afford.
-Eric