Thursday, January 28, 2010

Saying Goodbye to Sawdust

By Sean Ostruszka

It has finally stopped snowing.

Almost every night for a year, my apartment’s living room would get a dusting of snow. It gingerly fell through the air, coating everything once it came to rest – my coffee table, the couch, the TV remote, a wastepaper basket. It even got in what little hair I have on my head.

Then I discovered polyurethane resin. Now the snow storms come far less frequently.

To clarify, the “snow” was actually balsa wood sawdust. As an avid lure maker, almost every night I tinker, fiddle with and make lures. However, living in an apartment with no work room means most of my work is done on the coffee table in my living room. Hence the snowstorms. Honestly, I can’t believe my wife actually put up with the mess for a year.

To my wife’s joy, some six months ago I began talking with a medical student in Brazil who was making lures out of polyurethane resin. Seeing as he had little spare time away from studying, the student needed a way to make lures that was faster than carving them from balsa. Resin lures were the answer.

Polyurethane resin is an extremely tough and rigid urethane that is similar to the plastic most mold-injected lures are made of. In fact, many of the hard swimbaits coming from out West are made from resin. It comes in two parts that have to be mixed together, and in its unaltered state, the resin doesn’t float. However, by adding microballoons – hollow glass spheres that look like a fine powder and decrease the weight of a casted piece – the resin can reach a density of roughly 0.5 to 0.6 g/cm3 (water has a maximum density of 1 g/cm3). To put that in perspective, balsa wood has a density ranging from about 0.1 to 0.13 g/cm3, while basswood and pine range from 0.3 to 0.6 g/cm3. That means the resin isn’t near as buoyant as balsa wood, but it is still buoyant and light enough for lure building.

The beauty of resin is its capability to quickly replicate the same lure over and over. Any lure builder knows every lure made from wood will work slightly different from the next depending on slight differences in shape, wood density and weight placement. With the resin, one lure is exactly like the next. Better yet, lures can be made in seconds.

Alumilite is a company that specializes in making these casting resins, and they have a multitude of options. Some of the resins are actually cured hard in 90 seconds, though I prefer resins that allow for a little more working time. Compare that to the hours that go into building one balsa lure.

The downfall is price and initial time. A plank of balsa costs next to nothing. A 28-ounce kit of polyurethane resin and a jar of microballoons will run around $43. Builders will also have to purchase RTV silicone rubber to make the mold to shape the resin. A 1-pound jar goes for $27.50 on Like I said, it is not cheap, though Alumilite does sell complete starter kits that come with everything a builder would need, along with instructions. Go with the Super Casting Kit for $70, as the smaller one doesn’t really have enough silicone for most lures.

As for the initial attempt, that can be a hassle. First, a master has to be made of the lure, which can be carved from wood, resin or even wax. All the rest of the lures will end up like the master, so extra time has to be taken to make sure it is perfect. Then the mold has to be made. How to make a mold is explained in the instructions, and there are some great videos on the Web.

Once those two steps are done, though, it’s all gravy. I can go home, mix up a batch of resin, pour it into the mold and have a finished lure in minutes. I’ve since gotten into making two-part hollow lures with the resin that are better for making topwater lures or adding rattles. However, I’m learning they can be a headache that takes a lot of forethought and effort. Then again, that is what most lure builders enjoy about the hobby – figuring out those little headaches and creating something that may one day catch them the trophy of a lifetime.

Personally, the more I use the resin the less I believe I’ll ever go back to balsa. Don’t get me wrong, there will always be lures that are simply better when made from balsa, like shallow crankbaits. But the possibilities are endless with this stuff. Besides, I also like being able to see my coffee table again.

If you are interested in learning more about polyurethane resin or lure building in general, feel free to e-mail me at

1 comment:

  1. Another more economical place for silicone is