Filling Hollow Bases

I hate hollow bases on miniatures. Honestly, it's a really silly thing to care about. I guess a hollow base just strikes me as cheap and unfinished. From a more practical perspective, however, consider that a filled base provides a stronger foundation when attaching the model via a pin. Since I almost always pin my models, I've gotten into a habit of also filling each and every base.

I've developed a few tricks over the years to accelerate the process, although it's still pretty time consuming. It usually takes about 2 hours from start to finish to complete a batch of 10 to 20 bases. The big time sink is waiting for things to dry. Here's how I recently completed a pile of bases for the game Heavy Gear Blitz! from Dream Pod 9.

I start by covering the slot on the base with masking tape. This reduces the mess in subsequent steps.

Next, I attach the bases to a sheet of paper or cardboard with rolled-up masking tape. With bases facing bottom-side up, I schmear wet plaster onto the bases using a putty knife. After drying 15 minutes in the oven at 200F, I apply a second coat of plaster and repeat the drying.

At this point, there's a good amount of excess dried plaster attached to the sides of the base. I scrape away the excess with a hobby knife and sand the bases flat using sandpaper attached to a flat surface. 220 grit sandpaper works well and removes the plaster very quickly. I wipe away the dust with a towel moistened in isopropyl alcohol (it's fast drying) and re-attach the bases to the sheet of paper with rolled-up masking tape.

I apply a few drops of cyanoacrylate (CA) glue to each base and spread the glue using a piece of scrap sprue bent at a right angle. I do this to ensure that the plaster will not break away from the base. After another 10 min trip to the oven to dry at 200F, I flatten the bases once again with sandpaper (usually something fine like 400 grit), wipe away the dust with alcohol, and call it a day.

Update: 28-Oct-2014

I made a few bases recently using this technique and experienced a problem. After building a miniature and attaching it to the base, I used a hot glue gun to attach the base to a wine bottle cork. Like many hobbyists, I prefer to use a cork as a handle while painting. After all my painting was complete, I tried to pop the base from the cork and I experience a small disaster. Much of the plaster broke free from the base and remained attached to the cork. I suppose it wasn't the end of the world, but it was most definitely a pain to refill the base and sand away plaster now that the model was painted.

Usually hot glue is an acceptable temporary bond. With a gentle twist, the model has previously popped right off of the cork without incident. I believe it failed this time because the bottom of the base was a bit porous. A close inspection of the base suggested that I didn't spread much CA glue across the bottom.

Next time I plan to do a few things different:

Avoid overfilling each base with plaster and instead apply a heavy coat of CA glue.

After the CA glue has cured and the base is sanded smooth, coat the bottom with a gloss sealer.

When attaching the base to the cork, give the hot glue a bit of time to cool and thereby create a weaker bond.

If this experience sounds like a real turn-off for you, the other alternative is to use an epoxy putty rather than plaster and skip the whole CA glue step. I used to do this prior to my switch to plaster but I found it was costly in terms of the amount of epoxy putty I used.

Good luck!