The 1/32" thick plywood is joined at corners (with tabs into slots) by applying a thin layer of glue to one edge. This doesn’t leave a lot of surface area for the glue to hold to. So, after this minimal amount of glue sets, I try to lay a fillet of glue along the inside corner to strengthen the bond. The trouble is, the glue doesn’t “flow”. I try to even it out with a toothpick but it spreads itself everywhere but the joint!. It is fresh glue but may be a little thick for this application. Should I thin it a bit with water or alcohol?
You shouldn´t be using white glue at all. I use CA (the gel type) for joining thin plywood. I use a toothpick to put the glue into the hard to reach places. Make sure the glue you get has a little longer setting time.
I worked for a company that produced laser cut wood structures, and they recommended using Weld Bond - which we also used exclusively for our custom builds. Works similar to white glue, but doesn’t dry brittle hard like white glue does. If you make a mistake, you can heat it up with a heat gun and the parts will easily separate.
Mark.
There is nothing wrong with using white glue for wood models.
Different modelers use different glues in different ways. Use what works for you.
Now having said that, I don’t use white glue on wood RR building models because it will soften when wetted during scenery work. I use carpenters glue or wood working glue. These are usually tan or cream in color and won’t soften when they get wet after they are completely dry. If I want to build it FAST, I use thick CA or Super Glue.
Gel ACC is the only way to go, much faster and it will take quite a shock and not come apart (guess it is all those fibers. Was the only thing I used as a test builder, deadlines require some speed.
A filet of white glue won’t help much. The hardened glue isn’t very strong. If you need to beef up the joint add a square length of wood ( a batten) to the inside of the right angle joint. Glue it to the plywood pieces. For real strength with white glue (or yellow carpenter’s glue) you want to clamp the joint while the glue dries. For model railroading purposes white glue is about as good as the yellow carpenter’s glue. The yellow stuff is a bit more waterproof, and per haps a skosh stronger, but the difference isn’t great and I never have enough moisture on my layout to matter. For wood-to-wood, long-grain-to-long-grain joints, white or yellow glue, clamped, is about as good as it gets, it will make a bond as strong as the original wood. The strength comes from some kind of magic that happens between the two pieces of wood, not thru the strength of the hardened glue.
one difference between white and carpenters glue is the carpenters glue is ez to sand.