We are currently touring and while riding behind my wife I WS once again reminded that I really need to put a rear mud flap on her bike! I fashioned front onts out of plastic stair treads material and they work OK but are a bit too stiff. Wondering if anyone has a suggestion for a material ? I know there are leather ones but I don't want to spend the$.
Thanks!

I would suggest plastic from either a milk jug or a 2 liter pop bottle. Those are both durable, cheap, and easy to cut up with a scissors or utility knife. Another option is a food storage container, since you invariably end up with more containers than lids or vice versa.

See if you can find a chemical drum made of plastic and used by, say, cleaners. The plastic is a little heavier duty than that used in milk jugs, but not so stiff that they pull the fender out of shape. Milk jug plastic can be used, and I have, and is reasonably effective.

^^^ Yes, that's a good idea. It also occurs to me that the big jugs of liquid laundry detergent might be somewhat thicker than milk jug, and come in snazzy colors.

My milk jug mudflap isn't winning any beauty contests, but it has beaten all my expectations for durability. It's lasted through two snowy winters so far:

Thanks for these ideas!

Another nod to the laundry jug, the 46 oz (1.37l ) additionally has a nice contour that cups the tire. Fitted my winter/ rain bikes with them.

Another option would be the one-use polyethylene pots plants are sold in at garden centers. They also have the desired
built in curve, are thicker than the bottles mentioned and designed to last years in full sun. Generally available in black
only however. The "1 gallon" size is about right, but "2 gallon" will do in a pinch. One has been on the end of a too
short fender on my bent for 15 years.

Stiff plastic flaps don't work well with many racks that clamp at the front fork-if the front flap is long enough to be really effective, it will hit the roof or the bed of the truck before the fork reaches the clamp.
I buy scraps at the local industrial rubber distributor and have made dozens of flexible, attractive, durable front and rear flaps for pennies. They have sheets and rolls of dozens of kinds of stock in a hundred thicknesses, plain or reinforced. The stuff used for conveyor belts makes great flaps.
I'm still searching for someplace that will sell me chrome silhouettes of attractive young ladies to attach to the flaps....

I tried the milk jug flap. I found it too flimsy and didn't like it very much. After trying a variety of plastic containers I settled in part of an Indian Summer apple juice bottle. I know that's very specific but the plastic has just the right amount of give in it without flapping around everywhere. It's lasted me almost a year so far and shows no signs of breaking.

I've made some good stuff from a large inner tube

(fat bike?) scrounged from an LBS dumpster.

Maybe I have lost track of the right forums, but this thread reminds me of my early years on the bent (2000-2005) when there were numerous posts
by DIY makers of windshields and the use of coroplast for making head/tail cones and total bike covers for bents. Some enthusiasts made homebrew
heated molds for taking acrylic sheets and forming them into front windscreens 4-5' long and 18" wide before being complexly curved... Coroplast was much
easier to deal with and more commonly used. On a memorial bike ride recently I did see a tricked out Surly LHT with beautiful wooden fenders made
of glued up veneer with a form.

The flexible plastic used for some bicycle tire packages works really well. The Serfas tire package flap on my wife's bike has actually outlasted the tire that came with it. I also have some Panaracer packaging on my commuter bike after the the factory flap was torn off.

Do you have any extra water bottles? (I have about 70.) Cut off the bottom then chop the rest in half top-to-bottom. The curve of the neck fits against the fender pretty closely. Bonus if the water bottle has a cool logo on it.

That's cool!