I've made a few sets of grips over the years with varying results. Some of them are very "homebew" while others are a bit more advanced and practical. I've lumped them all together on this page for easier viewing.
Epoxy Resin Panels:
I don't have a lot of information about these grips because I got the materials from a friend, and I don't know what he did. Also, I didn't have a digital camera while making these, so I don't have pictures during that process. But I can fill in some of the gaps. Here's the finished grip panels for reference...
The grips were made from a two-part resin that you could dye different colors (I used blue for my one and only set). In order to make the molds I simply took some thin pieces of wood and carved out the inside shape to roughly match the area being covered by the grips. These had to be made into single-side panels because the material was very stiff and couldn't be bent around corners.
When the initial molding was complete I basically had a couple of hardened resin blobs that were larger than grips. The next step was to cut away all the extra plastic in order to make them into something resembling a grip shape. For this I simply used a hacksaw and hand file, using Hogue grip panels as a basic shape template. Once the grips were cut out I smoothed out the edges using a half-round hand file.
The grips were very hard when finished but they provided a unique appearance. I used them on my Logic USF frame Nerve as seen in one of the pictures. They were well-suited for this frame because it has a more upright shape that isn't fully gripped in my hands as often, so the stiff feeling isn't a big deal. I also liked the semi-transparent visuals; you could see the fiberous internal material of the epoxy if you looked close.
Milled Delrin Prototype Panels: (v1.13)
In 2010 I was working on several new frame designs which all required a new grip screw hole pattern. I developed a new screw pattern but the exact shape of the grips wasn't compatible with anything I had already measured from another marker, so it meant we needed to make new grips. For a quick prototype I made a few pairs of milled panels that were machined from solid delrin. Ultimately the grips turned out nice except the obvious drawback of being very stiffness and rigid plastic. For prototyping they certainly worked just fine. You may have seen these grips on the leaked TAS Zealot pictures from 2011 (the orange Zealots). I also used them on my older Shocker SFT/NXT frames before modifying them to use 45 grips, and I also used these grips on a couple other frames that weren't prototyped.
The grips were milled out in one complete setup on the machine. I used double-sided 3M "automotive" tape to hold down chunks of the raw plastic which makes holding easy since I didn't need to make any special jaws/clamps/tiedowns/etc. Automotive tape is very strong so it can withstand quite a lot of cutting force, just as long as the workpiece has a lot of surface area to hold against. In this case the grip panels indeed had a lot of surface, so they were very rigid. I use similar double-sided tape methods from time to time in the machine shop with varying results; the tape is great to hold onto the workpiece but it gets tricky once you remove the finished workpiece. Bending or warping the part is easy since the tape is so strong; to help with this I use an acetone solution to loosen some of the tape glue. However, you must then thoroughly clean your baseplate before sticking on a new layer of tape for the next workpiece. In the end this is very good for prototyping of something where the thickness isn't very critical, but not so good for other situations.
TAS Wraps: (v3.37)
During a phase of Zealot prototyping we had to come up with grips to use on the new marker frame, but I wanted to use something that appeared a little more realistic than the machined delrin grips used in the past. The delrin ones would be more acceptable if not for their machining marks. The marks could be reduced but only at the cost of making them more time-consuming to create.
To solve this problem I decided to make a set of mold dies that could be used to create molded rubber grips. I've done this before at various contract jobs in the past, but usually those items were larger and easier to mold. Grips are fairly thin and generally made from at least two different materials for strength, whic isn't an option here so I tried to make the mold die as simple as possible. The grip CAD model was fairly simple and only had a few small details to break up the smooth surface, so processing time was low.
Off to the CNC. The mold die took about 10 hours to machine, but came out nicely. The dies needed almost no work coming right off the machine. I very lightly buffed a few spots, then had the piece anodized clear to keep the prestine surface from being scratched in the future.
To actually make the grips themselves, I used an 85 durometer silicon rubber, a little less flexible than an o-ring due to the shape. The material takes 24 hours to set and another 24 hours to fully cure. I would equate the feel of the material to something like the Dye Sticky3 grips, where the outer grip layer is very flexible.
TAS OLED Panels: (v3.39)
The next iteration of the TAS grips involved a cutout for a display screen. This time I decided to resurrect the single-side panels because I was worried about the front wraps splitting apart from prolonged bending (the material I use is unpredictable when it comes to bending). I also wanted to showcase the small front-to-back size of the Zealot grip frame, and future color schemes for the prototypes, both of which is easier to do with panels compared to wraps.
The fabrication process for this mold was similar to the previous grips; in fact I used the previous mold program as a basis for the step-by-step process, which helps to save programming time. However, despite saving some upfront time, ultimately these took MUCH more time to program because of the high complexity. Each grip panel had around 700 surfaces so creating the toolpaths required quite a lot of processing power. My CAM software took about 15 minutes simply to regenerate the complete file when any changes were made. So you can imagine how long it took to program this item; if I adjusted the program a dozen times over the course of designing it, the math says over 3 hours of time disappeared simply for waiting on my computer to create the necessary machine code. The final machining file for was over 4 million lines of code at about 80 megabytes. I almost never make a file this complex unless it's a mold or other part with a ridiculous amount of 3d surfacing.
Regardless, the grips turned out very nice. I milled out a couple sets on the same subplate, in order to mold more grip sets at once. Due to the high surfacing, this workpiece took over 20 hours to machine. The amount of detail found on the smaller features was fairly good. Originally I had planned to use some smaller tools in order to achieve even more resolution in the detail, but doing so would add another 7-8 hours to the total machining time. This workpiece was already going to consume a lot of milling time, so making it longer was to be avoided.
I used a different casting material for these grips. The new stuff is PVC-based instead of silicon rubber. It's a heat-activated thermoplastic that can be easily re-heated and recycled in case of problems. This makes it much easier to prototype.
