Utility Cycling - Anybody ever fashion a DIY Chainguard?

This would be for a triple front ring setup (since most used American bikes have triples). I'd like it to be a long top guard type like this one:

http://www.barnardsschwinn.com/repopaccessories/coaster_stingray_chain_guard.jpg

As a matter of fact, DIY would probably be better for a chainguard since most bikes have the downtube, seattube, and rear stays at differing angles.

Really looking for inspiration, if any. Basically looking at the materials you've used, type of clamps etc. Thanks in advance.

I have not done it but I've been contemplating it for a while. My imagined chainguard would be made from epoxy resin inlaid with fiberglas or other fabric. My only experience with this was that years ago I made a parabolic dish (for concentrating sounds onto a microphone) out of epoxy resin and burlap cloth. I used a plaster mold for that and it turned out rather nicely. It had the right attributes (stiff but flexible, relatively lightweight, and thin) that I think a similar epoxy-based composite material would work pretty well as a chainguard. I was able to drill holes in that to mount a support for the microphone and the electronics for the amplifier, so I imagine mounting an epoxy-based composite on a bike as a chainguard would work reasonably well. Still, it's only so much day dreaming at this point. Maybe somebody here can take this idea and run with it.

I have not done it but I've been contemplating it for a while. My imagined chainguard would be made from epoxy resin inlaid with fiberglas or other fabric. My only experience with this was that years ago I made a parabolic dish (for concentrating sounds onto a microphone) out of epoxy resin and burlap cloth. I used a plaster mold for that and it turned out rather nicely. It had the right attributes (stiff but flexible, relatively lightweight, and thin) that I think a similar epoxy-based composite material would work pretty well as a chainguard. I was able to drill holes in that to mount a support for the microphone and the electronics for the amplifier, so I imagine mounting an epoxy-based composite on a bike as a chainguard would work reasonably well. Still, it's only so much day dreaming at this point. Maybe somebody here can take this idea and run with it.

Thanks.

1) There was someone who posted here who made some fenders out of old campaign signs. Of course, these signs were some kind of special type plastic that were not too common. I just did a search and could not find that thread.
2) Also, there was a guy in the commuting forum that made some pannier bags out of plastic grocery bags. If i remember correctly, he ended up ironing(fusing?) stacks of plastic bags that eventually were strong and managed to hold their form. I can't find that thread either.

Both of the above materials seem to fit the bill of a strong material that would keep its form. I'll keep looking. I wanted to avoid "reinventing the wheel" but in this case I may have to.

Two ways you can go about it if you want to make a composite chainguard.

If you wish it to be a repeatable process you make an original, make a mold of that, and lay up your composite material and resin in the mold.

If you want to do a one off, you can carve your chainguard out of a soft material like balsa wood or styrofoam, and then lay fiberglass over that to give it strength and durability.

West System makes a very easy to use epoxy resin.
Fiberglass cloth found at an auto supply store is more than adequate for making a chainguard.

Before you go "reinventing the wheel," have you seen the OGK chainguard for triple ring/front derailleur set-up?: http://www.rivbike.com/products/list/cranks_bottom_brackets#product=12-269. Mind you, it's not great, and can certainly be improved upon. There are two pieces, in front of the derailleur and then one to the rear of it. The front fits well and doesn't move when you knock it, but the rear one moves too easily when you bump it and is pretty small so doesn't cover much. I had hoped with this that I could ditch the ankle strap for the pants, but still get plenty of oil on my pants. The concept is good, though, it's just the execution that leaves something to be desired.

Then there is the minimalist approach.
This one is made by Sögreni (http://www.sogreni.dk/).
http://www.sogreni.dk/Images/Chainguard_r5_c1.jpg

Thanks.

1) There was someone who posted here who made some fenders out of old campaign signs. Of course, these signs were some kind of special type plastic that were not too common. I just did a search and could not find that thread.
2) Also, there was a guy in the commuting forum that made some pannier bags out of plastic grocery bags. If i remember correctly, he ended up ironing(fusing?) stacks of plastic bags that eventually were strong and managed to hold their form. I can't find that thread either.

Both of the above materials seem to fit the bill of a strong material that would keep its form. I'll keep looking. I wanted to avoid "reinventing the wheel" but in this case I may have to.

Your thinking of coroplast, a corrugated plastic. It is common, you can find it at most sign shops, or they can tell you where to find it. It comes in 4'x8' sheets around here, and isn't too bad price wise. However a 4'x8' sheet just to make bike fenders isn't too cost effective. I bought two sheets 3-4 years ago for a ill-fated RC aircraft project. Sorry, don't remember the price.

Follow-up: I found this http://www.sheldonbrown.com/rinard/carbon_fiber.htm when I googled "how to mold epoxy composite"
Way more sophisticated final product, but the techniques and tools are largely the same - provides some detailed descriptions and illustrations of the suggestions made by AllenG.

I have a Staiger Florida that is a 27 speed Shimano LX drive train. It came with a plastic(Lexan?) chain guard. The guard has broken at a couple of the attachment points, I am fabricating a new replacement out of mill finish .024 aluminum. Picture is of the current model.

Aaron:)

http://www2.staiger-fahrrad.de/2009/radbilder_klein/ST_Florida_Da_600x375.jpg

I really like that rear rack....not perfect, but I think I'm going to steal those curves. Very elegant way to clear the heels of my size 14s.

I really like that rear rack....not perfect, but I think I'm going to steal those curves. Very elegant way to clear the heels of my size 14s.

Here is a picture of the one I have, if you need dimensions or better pictures I can provide them.

Aaron:)

http://inlinethumb09.webshots.com/6984/2910368300066886751S500x500Q85.jpg

Did you see this? Must be better options than making one?
http://www.velo-orange.com/chpr.html

The metal ones often bend, and the plastic ones often break. I bet it'd be rather simple to use an old chainguard as a form for making a fiberglass one. I've got some epoxy and glass cloth around, I bet I could make a nice chainguard for my Big Dummy.

The full chaincase is easy enough to modify with machine tools. Installation requires a couple of screws. Its rarely used because its a bear to remove a flat rear tire with it on.