"Quick and dirty injection molding. :D" Topic

Okay, so browsing on the web, I discovered that they use simple molds and hot glue guns to teach the principles of injection molding. So I took one of my old self-made drop cost molds, and clamped them together, and then squirted hot glue down the central bore. My first shot was imperfect, but the detail came out very nicely, much better than my drop casting attempts.

One problem, the figs are very rubbery, anyone know of stiffer glue sticks? This is definitely much less messy or smelly than resin, and while my first shot was not entirely successful, there were no pits or air pockets marring the surface of the model.

So anyone know if "Hot melt guns" use stiffer glue than the low temp stuff?

Looks like these folks could help you out. The dental stuff looks like it may be a candidate.
link

I picked up a neat tool on eBay a couple of years ago called an Ear Syringe (or something like that). Its basically a large metal syringe.

auction

Anyway, I load it up with uncured resin and inject it into my molds. Does a good job in my opinion, and as it is metal its not too hard to clean. Some pointers:

- Make sure your mold is well vented, or the resin may squirt right back out the top (getting resin out of your arm hairs is no fun).
- Get one with the guard and use it
- After use take it apart right away or you will glue it all together with resin.
- Clean the nose first, and as quickly as you can after use.

I've been using ordinary, cheap plastic syringes for years to resin cast with. I try to clean them after use but eventually they gum up and I chuck them. Literally pennies a cast and much easier than trying to pour into small molds.

If you're a DIYer:

link

Zephyr:

I got the Lindsay book, but you need access to a lathe and milling machine to build it, so it is not the typical DIY project.

The hot glue is very interesting. If the dental stuff doesn't work, hit your hobby shop (Michael's or Hobby Lobby) and ask some of the old ladies who work there. They know LOTS of stuff about the craft uses of the items they sell (in general, avoid talking to the young workers -- to them, this is just a job and they don't know very much about what they sell).

Also, plastic syringes are dirt cheap at feed stores. They come with needles that can be discarded.