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Posted: 12/1/2009 1:22:44 PM EDT
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I have several years of experience molding fiberglass. So when I couldn't find the type of handguards I wanted for my AR15, I decided to make some.
I really like the "bottom heavy" handguards used on the FN FAL and the H&K G36 / SL8. I'm going to borrow design elements from both. The basic shape will be a distorted hexagon, like the G36 / SL8 handguard. And the cooling slots will resemble those of the FAL. The new handguards will be made of fiberglass, with an aluminum heat shield. The first step in building the handguadrs is to build a mock-up. The material of choice was wood. I glued two 2x3" pieces of lumber together to form a block, then went to town with the table saw. Below, you see the basic form taking shape. http://www.tweaktech.com/rifle/ar15-handguards01.jpg To be sure the mock-up was the correct length, I test-fitted it onto my AR15. http://www.tweaktech.com/rifle/ar15-handguards02.jpg After I was satisfied with the fit, I made and attached pieces of wood on the ends, to fit the delta ring and handguard cap. I then brushed on 4 coats of polyurethane (sanding between coats), and topped that off with 3 coats of parting wax. Below, you see the mock-ups attached to a piece of masonite (which is also waxed). http://www.tweaktech.com/rifle/ar15-handguards03.jpg Now that the mock-ups are done, it's time for step 2: making a mold. The mold will be used to make the final product. I decided to make the mold from fiberglass. So I applied a few coats of PVA film, and started the fiberglass layup. Below, you see the fresh mold. http://www.tweaktech.com/rifle/ar15-handguards04.jpg I'm going to let the fiberglass cure for a day or two, and then start making the handguards. BTW, you may need to refresh the page to see all the photos. Not sure why it does that. |
| Cool project. I would have chosen to mold them in top and bottom halves instead of left and right, but that's just me. After you get the bugs worked out with fiberglass you ought to do a run in carbon, carbon/kevlar, and colored carbon. They'd sell like hotcakes. |
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Quoted:
This is shaping up to be a very cool project. I would prefer a focus on the fiberglass mold technique and not necessarily the details of your handguards. Those handguards don't really appeal to me, but the technique certainly does. ^^^^  I need to learn to work with this stuff.
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Thanks to everyone for the compliments.
Today, I started molding the handguards. They're made from 4 oz glass cloth and epoxy resin. The 4 oz cloth is pretty thin, but follows contours pretty well. It also has a tight weave, which will make it nice and strong. So I built up 9 layers of it. That may seem like a lot, but the resulting part will only be about 0.1" thick. Unfortunately, the handguard shape has some sharp corners that the glass cloth can't follow. For those spots, I mixed up a slurry of epoxy resin mixed with short strands of glass fiber (which I affectionately call "snot"). The slurry has the consistency of thick mucous, and can be slopped on like putty. Here's a quick photo: http://www.tweaktech.com/rifle/ar15-handguards05.jpg The epoxy resin will have to cure overnight (and probably half the day tomorrow, too). Then I'll pull the parts from the mold and start trimming. . . . For those who are interested in learning how to mold fiberglass, there is LOTS of information online. A Google search for "Fiberglass 101" will turn up a bunch of good stuff. Also, Fibre Glast has some instructional videos on their website (in the Learning Center). |
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yeah i agree i would have done top and bottom halves just so i could mount a stud or a rail on the bottom if I chose to. Tactical sling studs mount on the side of the rifle. And I want to see the finished product NOOOOOWWWWW!  I should have clarified myself. the stud would be for a bipod and unless you are shooting gansta, a bipod would look goofy on the side 
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The epoxy hardened nicely. So I pulled the handguards from the mold this morning. The fiberglass is very strong, much stronger than the molded plastic originals. However, there are a few air bubbles that need to be filled. And of course, the excess fiberglass needs to be trimmed off.
Here's a quick shot of the raw fiberglass parts. In the photo, they're still wet from washing (the mold release film is water soluble). http://www.tweaktech.com/rifle/ar15-handguards06.jpg I'll post more updates when available. |
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THEY FIT!
http://www.tweaktech.com/rifle/ar15-handguards07.jpg Now I just need to make 'em look pretty. |
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The breathing holes are cut. I also made some minor tweaks to improve fitment.
http://www.tweaktech.com/rifle/ar15-handguards08.jpg To fill the air bubbles, I mixed up a paste made of epoxy resin and glass micro-spheres. It's curing as I type this. I'm NOT putting Bondo on my rifle!
I still have 3 things left to do on the handguards: 1) make mounting pads for the heat shields 2) make heat shields 3) finish handguards with rubberized paint |
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HEAT SHIELD MOUNTING PADS: CHECK!
HEAT SHIELDS: CHECK! RUBBERIZED PAINT: CHECK! The custom handguards are finished. 
The heat shields are made of aluminum flashing, which you can buy by the roll at the hardware store. It's thin enough to cut with heavy scissors. Below is a (blurry) shot of the heat shields. http://www.tweaktech.com/rifle/ar15-handguards09.jpg To mount the heat shields in the handguards, I saturated some pieces of thick felt with epoxy, and put them in the corners. After the epoxy hardened, I drilled holes in them and attached the heat shields with small screws. Below, you see the mounting pads with holes drilled in them. http://www.tweaktech.com/rifle/ar15-handguards10.jpg And last but not least, I coated the handguards with rubberized paint. The surface finish is matte black, and feels very "grippy". Anyway, enough blah-blah. Here are the "money shots". http://www.tweaktech.com/rifle/ar15-handguards11.jpg http://www.tweaktech.com/rifle/ar15-handguards12.jpg Hopefully, I'll be testing it out at the range in a few days. |
Very cool; nice write-up- good to see how something like that could be made.
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Here's what this reminds me of: the Daewoo K1 carbine. It's basically a piston AR but the receivers aren't compatible. The OP should try to fit a complete piston recoil system under the handguards and then use a folding stock. 
http://upload.wikimedia.org/wikipedia/commons/e/e9/Carbine_Daewoo_K1.jpg The K1 is D.I., the K2 is a piston. Otherwise, Sweet Job OP |
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Here's a quick follow-up.
I went to the range yesterday and ran a little over 240 rounds through the rifle. The barrel got nice and warm. I could feel the heat rising out of the ventilation slots. But the handguards didn't get hot. Also, my hand naturally wraps around the handguard contour. And the rubberized coating is nice & grippy. I think I'm going to keep them.
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