DIY polymer training blades

**blindside** · Posted On: 8/28/2012 6:07pm

This is a revised post that I originally put up on FMATalk, but given the interest in DIY sparring sticks, I thought I would post this here as well. This thread sort of compiles my experience and some tips on making these types of training blades.

DIY Polymer Training Blades

Last year I ordered some polymer training blades from a FMA supplier that I really liked. But because I'm a cheap bastard and the training blades weren't exactly inexpensive, I wondered if I could make my own. So a $30 Craigslist "used once" bandsaw, a completely useless $20 router attachment for my dremel, a bunch of paracord, and several purchases of scrap plastics later I think I figured it out, and thought I would share for other DIYers out there.

At this point I have probably made 30 or so training blades and I am pretty happy with their performance.

Some (early) examples:

training blades types by wyldbio, on Flickr

training blades sample by wyldbio, on Flickr

training ginuntings shr by wyldbio, on Flickr

Design wise I modeled the blades with a guard off of the Kris Cutlery Pinute. The other blade was very roughly modeled to be a trainer for an antique Itak that I had just won on Ebay. Both blades have overall lengths of 29" or so. Particularly on the pinute trainer you can see the variation that occurs between blades as I played with shapes and hilt angulation.

The top two white blades were my first two test runs, I started with .375" Nylon 6/6 sheet, and though I find it difficult to cut and shape, I really like the feel when work against another training blade. They are stiff enough that you don't get much vibration when you strike another stick or training blade, so you get a better feel for the blade. I am no longer using the Nylon for training blades mostly because Nylon is expensive, and as previously mentioned, I am a cheap bastard. Nylon costs for cut-to-order nylon would probably be close to $23 per sword. It would naturally be cheaper to buy a 4x8 sheet, but I don't have $290 +shipping.

The longer black blades in the top picture are protoypes for cutlass and messer blades for a friends WMA class. These blades run 31" or so, both have a 24.5" blade. Some discussion on guards for these swords is below. And I have added a pic of two ginunting that I made for one of my students based off of a Traditional Filipino Weapons ginunting.

I shifted to 1/2 inch HDPE (High Density Polyethelene) for the next set of blades and have been pretty happy with it. It is far cheaper (something like $7/blade) for cut-to-order stock. An additional benefit of the switch is that you can get black HDPE which has the added cool factor versus white/natural for the nylon. HDPE is basically the plastic cutting board material, and that is a cheap source for smaller training blades. The product that use is called “Starboard.” The "orange peel" exterior finish has varied between different orders, so that may depend on the supplying company. The softer HDPE interacts with sticks better than the denser/thinner nylon. Nylon and HDPE trainers don't play well together the nylon puts fairly large dents in the HDPE blades.

The HDPE is not as stiff as nylon and you will feel vibration if you clash sticks and you are not in appropriate edge alignment, this is actually a very useful training tool for beginners, they immediately know when they muff a shot. I am not sure how much longer past 31" HDPE will be a viable plastic stock, I suspect it will get too floppy.

Make sure that the hilt to blade transition is radiused, a sharp angle at this juncture leads to a stress point and an easy break. We have had two catastrophic failures in HDPE and nylon after just a couple of hits due to us not realizing that. It is amazing how depressing it is to have your cool new training sword break off at the hilt after only two or three hits. Also make sure you heavily radius the striking edges, having close-to-square edges on the main striking edge will quickly get you serrated training blades (in HDPE, apparently not an issue in nylon.)

I recently purchased a $15 router on craigslist and a 1/8” roundover bit ($14!) and this has really improved the appearance of the blades. It takes care of the issue about radiusing the striking edges quite easily and far faster than my original filework and sanding.

Guards:
Some early D-guard variants:

d-guard2 by wyldbio, on Flickr

The D-guard is surprisingly strong even with how thin the material is. I got several comments from the class how it saved their fingers from abuse during some drilling.

Working on developing a cutlass hilt for my friend who teaches messer and cutlass. One of my students built a completely uneconomically viable model, built from stainless steel:

stainless hilt by wyldbio, on Flickr

Very cool, but would cost way too much to produce for a training blade, even in a mild steel. So then I went to the D-guard combined with an ABS plastic guard.

cutlass trainer by wyldbio, on Flickr

cutlass hilts by wyldbio, on Flickr

That worked pretty slick, and in class it frees guys up to try to pick the hand more often, it also matches up well with many of the D-guards and S-guards you see on the Filipino bolos.

Overall:
The 29" training blades average something like 10.5 ounces, they hit harder than rattan and you would have to use good control if you were going to spar with them. That said, they do allow sparring without the armor jump that the shift from rattan to aluminum long blades requires. I have been very happy with being able to provide my training group with a relatively inexpensive blade trainer. I hope this post helps you all to build your own trainers.

**Permalost** · Posted On: 8/28/2012 6:30pm

Very cool! One of the guys I train with uses a training knife crafted from an old cutting board, and it kinda looks like those. I've tried a composite bolo trainer made in that way and it was kinda cool, but I'm not sure how they respond to vigorous repeated impacts.

**jspeedy** · Posted On: 8/28/2012 8:00pm

Nice work! Any chance you could post a work in progress? I just made my first aluminum trainers. I post pics when I get a chance.

**Mr. Machette** · Posted On: 8/28/2012 8:28pm

Originally Posted by jspeedy

Nice work! Any chance you could post a work in progress? I just made my first aluminum trainers. I post pics when I get a chance.

Jspeedy, how did you cut your blanks?

I've got a piece of aluminum that I need to turn into two trainer sword but there's not a lot of extra material in case of mistakes. Not sure how I should cut the stuff.

**Fuzzy** · Posted On: 8/29/2012 3:15am

Awesome stuff blindside.

How do they stand up to contact sparring?

**blindside** · Posted On: 8/29/2012 4:00pm

Originally Posted by Fuzzy

Awesome stuff blindside.

How do they stand up to contact sparring?

Very well, once we figured out that you have to radius the join between the hilt, the guard, and the blade, we have haven't had a failure yet. I haven't torture tested the ABS shell guard, but the expectation is that it will take a couple of shots and then fail. The D-guard is very strong, I was able to break one, but that took laying it on a hard surface and then striking it full force, not something that will generally be replicated when held in the hand.