Its a work in progress. I will finish the mud guards in the next week or so, updating as i go along.
My inspiration came from this guy.
Earlier this year, i built a bamboo bike from this instructable, although mine is a fixed gear . Now, i am planning to do some bicycle touring on it, so i need to outfit the bike in an appropriate way.
Why make fenders?
Because nice fenders are expensive. Because my bike is home made so standard fenders wouldn't mount easily. Because i like making things.
Why make wood fenders?
Because wood is beautiful, and will go well with a bamboo bike. Because i love working with wood, and am well set up to do it.
My fenders are 1.5 inches wide, and approximately 1/4 inch thick. they are designed to cover 3/8 of the diameter of my wheel. they have an inside radius of 14 inches, which is perfect for a 700c wheel with size 23-25 tires.
They are laminated (a process of gluing several thin layers of material together to form a thicker piece. this also allows the glued up wood to be bent around a form or mold and clamped until the glue dries, leaving a laminated piece that will stay curved) from three layers of wood. the top layer has a "racing stripe" pattern made by alternating light and dark wood across its width.
These plans are simple to adapt for, say, chunkier mountain bike tires.
Step 1: Materials and Tools
Wood -- I am using beech, a light colored wood, for the majority of the fender, and Brazilian mahogany for the darker racing stripe.
Plywood -- for making the form to bend your wood around. since my fenders are 1.5 inches wide, i used to thicknesses of 3/4 inch ply i had lying around.
varnish -- I am going to use some marine-grade spar varnish left over from another project.
glue -- normal wood glue, doesn't need to be waterproof.
screws -- for joining the two thicknesses of ply, alternatively they could be glued. make sure they are long enough to reach through to the second peice of ply, but short enough not to poke out the other side.
drill bits -- for drilling pilot holes in plywood to accept screws. size depends on thickness of screw.
tape -- masking or duct, to glue-proof certain things you don't want glued
thin (1 or 1.5mm) stainless steel sheet -- for making a mounting system. i also purchased "sheldon fender nuts" for the mounting system
drill -- for drilling pilot holes for form. dremel would work too. also needed for mounting system.
jig saw -- for cutting the curve into the plywood for the forms. could be done by hand with a coping saw. you probably want ear and eye protection with that too.
wood plane and table saw -- to cut and shape your wood to the correct dimensions. or do it the easy way (i did) and get a local carpenter to do that bit for you. also consider constructional veneers, which can be bought in thicknesses up to 2.5 millimeters, but are a bit pricy. you may still need the plane any way you do it.
sharp utility knife -- for cutting the strips to length.
clamps -- a good number. i used 10, of various types, mostly spring clamps, and a few
circle-drawing device -- i didnt have a compass big enough, so i improvised with a pencil, a nail and hammer, and a length of string.
set square ---or triangle, to draw right angles
sand paper -- i used 80 and 240 grit, its what i had. and a small block of wood to use as a sanding block.
screw driver -- that works with your screws
rag or paper towel -- for wiping off superfluous glue
Step 2: Getting Started: Planning and Measuring
so this is the stage at which you need to figure out how much wood you will need. because of my racing stripe, i needed wood 1.5 inches wide and .5 inches wide (so that a light-dark-light pattern on the top layer would still be 1.5 inches wide).
here is how i figured out how much to get:
each 20 inch fender needed:
2 layers 20"x1.5"x1/8"
1 layer formed of 2x 20"x.5"x1/8" and 1x 20"x.5"x1/8" of a different(in my case darker) wood
3 fenders per bike (split between both wheels)
10 linear feet of dark wood in .5"x1/8"
20 linear feet each of same light wood in .5" and 1.5" x 1/8" wood
I got a little extra of both woods in all widths, just in case i messed anything up.
Step 3: Making the Forms
you will need the plywood, the tape measure, the pencil, string, nail, hammer, screws (i used three), drill with appropriately sized drill bit, and the jig saw.
bang your nail into your ply, and measure a point 14 inches (or whatever you decide on for your radius) from it. tie the string around the pencil as close to the tip of the pencil as possible. i used a round turn two half hitches. then, making sure the pencil is at right angles to the surface of the ply, take up the tension on the string, and then wrap it securely around the nail. keeping one hand on the nail end of the string to stop it slipping, carefully draw out your section of circle. i drew what i thought was the correct length, then used another bit of string to measure around the curve. it wasnt quite 20 inches, and i wanted a few extra inches on the form, so i drew an extra bit and re-measure. i think it was around 24 inches along the curve.
from here there are two ways to proceed. either reposition the nail, and do the whole thing again, or if you are lazy, whip out your jig saw, cut the curve, then use it to draw the next one. i did the lazy way. one thing to note: for the base of the curve, i just drew something on by hand, with no care. this caused problems. you can draw it by hand, but try to make sure the two bases are similar or you will have trouble getting clamps to stay. also, pay attention to how thick your form ends up, because if you have small clamps, you my have trouble getting them around the laminated wood and the thick form.
once you have your two plywood curves cut, play around with getting them to line up smoothly. once you are satisfied, clamp the pieces together. once they are clamped, mark the positions for your screws and using the drill (or a drill press as i did) drill your pilot holes, all the way through both pieces. then, with the pieces still clamped, screw in your screws. now, you are ready to begin laminating.
Step 4: Beginning Laminating
start off by cutting your wood to length. you can do this two ways. you could cut your wood too long, planning to trim it down at the end or you could cut it more precisely, making the most efficient use of your wood, and saving yourself work later. i chose the latter.
i wanted 20" long fenders. but i did not cut every layer to 20". this is because each successive layer goes around a larger radius curve. so my bottom piece ended up being 20 inches, and each successive layer was 1/8" longer.
so i marked up the lengths, used the set square to get a right angle line, then cut the pieces with the knife.
before i started gluing up my pieces, i added in a step. i took one of my left over lengths of 1.5" wood, and covered it with tape to glue-proof it. i used this as a fourth layer that would both protect the top layer from being marred by the clamps, and spread out the force of the clamp more evenly.
the glue i used only required that one surface be coated, but check yours. so
i covered one surface of the bottom layer, and one of the middle layer. this means the more fiddly, three piece top layer didn't need glue on the bottom. however, i did dab a little glue onto the thin edges of the mahogany piece, to make sure the strips stayed together, edge to edge. i aligned the ends of my pieces, then added my fourth, glue-proof layer on top, and placed my first clamp in the middle of the form. then i put clamps on either side of that one, about half way to the end. on each end, i used my heavy duty bar clamps. then i started filling in the gaps between those 5 clamps with other clamps. i looked for places where the three layers of wood weren't pressed tightly together. in some places i had to use my little wooden shims to get even pressure all over. i wiped off all the glue that had been squeezed out. then i let it dry. for about 12 hours with my glue. once again, check yours.
after it was all dry, i removed the clamps and my glue proof strip, and viola! the fender came right off, and looks great. it is very stiff, there is almost no flex along its length, which is great.
Step 5: Advanced Laminating
I'm only including this section because this happened to me. after making my first mudguard and test fitting it on my rear wheel, i figured out a way to have my mudguard go as one piece all the way around my rear wheel. but now i have made my forms too small for a mudguard that long. not to worry. there is no need to go and make a new one, and in some ways this way works better than when the form is the "correct length." however, this method does require at least one very long bar clamp.
Essentially, i did everything exactly the same, except had the ends of the mudguard stick out on either side of my form, and then used one long clamp to pull both ends
towards each other, following the curve of the form. one thing to note is that the mudguard aught to be centered on the form, i.e. with the same length of fender sticking out beyond the form on each end.
I decided to make one fender with a more complex pattern. the top layer will still be a racing stripe pattern, but it will be interrupted by slanted dashed lines composed of alternating light and dark parallelograms. (pics coming soon if you cant visualize it).
This is where you an get really creative, and come up with something unique and tailored to your tastes.
If you end up with a complex pattern that is hard to keep organized, you can stick all of the pieces onto a piece of tape for the entire lamination process.
As far as i know, this has never been done before! so i have no idea about how well the lamination will stay together with all those separate pieces. i made this with bits of extra wood, after i had made all the fenders i needed. so if it breaks, i have a replacement anyway.
Step 6: Wood Finishing
Trimming the wood
I will refer to a few different parts of the fender in this section. by "edge" i mean the long, thin edges. by "end" i mean the short stubby ends. "top" means the outside of the curve -- what will be visible on the finished bike. "Bottom" means the inside of the curve, which wont be visible.
To trim the edges, i used a wood plane. adjust the blade so that it only takes of the tiniest sliver of wood. then, hold the plane in one hand (i use my left, being right handed) and the fender in the other. bracing the plane against your body, draw the wood along
Step 7: Mounting Your Fenders
Here is how i went about devising a mounting system. this is certainly not the only way, and may require tweaking to work with your bike.
First, i ordered Sheldon Fender Nuts made by Problem Solvers. you can find them easily online, and although they are pricy for what they are, it makes for a slightly more elegant mounting system.
The basic system