Introduction: Fiberglass Cupholder

About: I am a senior this year at Drexel University in Philadelphia, PA. I expect to graduate with a degree in Mechanical Engineering in 2013. I've always loved science, but i find i stretch myself t…

I have a 1991 Chevy S10 Pickup truck, 5-speed manual transmission. There was always one thing about this vehicle that I never understood, and quite frankly, despised. For some unknown reason, Chevy decided to not include a stick shift. Well I was completely fed up with trying to balance my beverage while shifting, so I decided to make a cupholder. The costs for the project were less than $30.00 as I already had most of the materials.

I decided to attach the cupholder behind the center section of the bench seat. There is not bottom, so the bottles and cups actually rest on the back of the seat itself. It is a minimalistic design that looks great and really adds to the truck.

Step 1: Creating a Base

The first thing that I had to do was to decide on a good size for the cupholder. I did not make any measurements, but I rather based it on the sizes of the cups and bottles I most frequently used (gatorade or chick-fil-a for example). Once I had a ballpark figure of size, I looked for a piece of MDF (medium density fiberboard) that I could cut down. Using a miter box, I was able to do this with ease. I then sanded the edges of the MDF smooth so that there were no sharp corners.

I then drew two lines from opposite sides to one-and-other. I further subdivided the length into quarters, such that i would be able to have 2 cups fit (see pictures). Using the largest hole saw I possessed, I cut out two circles from the MDF. I then used a soup can to trace the final size I wanted the holes to be. Using my Dremel with a sanding drum, I sanded the openings up so that the can could easily fit through the openings.

In order to attach this portion to my truck, I needed to attach a base to this. I had some left over poplar wood, so I chose this as it is a straight and strong wood. For support i cut a small triangle, put it under the center of the cupholder portion as seen below, marked the excess portion, and cut it so that it fit flush.

After I had all the pieces of the base organized, I glued them together using standard wood glue. I then clamped the three pieces together and allowed them to cure overnight.

Step 2: Resin Basecoat

Next I wanted to seal the wood and MDF (as anybody who has ever accidentally gotten MDF wet knows, we will want to seal this as it expands a lot). I could have used polyurethane; however, I had purchased a one quart container of epoxy resin earlier that day, so why let it go to waste.

After the resin was allowed to cure overnight, I sanded off the globs of resin that were on the base. One problem with resin is that it will build up if you are not careful and can be difficult to remove.

I am not sure of the name of the component I attached the cupholder to (see picture 4); however, I had one leftover from a visit to the junkyard. I stripped the carpet off of my sample piece, marked the location i wanted the cupholder, and drilled holes to attach it to the metal piece from the truck. The screws I had were too long and they needed to be Dremel'd down after being pushed all the way through the base.

Step 3: Laying the Fiberglass

For this project, I did not actually use fiberglass, but fleece fabric. Fleece is often used for cosmetic fiberglass work where a certain shape is desired, but does not necessarily require the strength of fiberglass. As fleece is stretchy, it is easily formed over a wooden base such as this. In order to keep the fleece attached to the base, I used a pneumatic upholstery stapler to secure it. Wrapping with fleece was actually rather difficult to have it happen seamlessly (pun intended). Many staples...many more than were required, were used to hold the fleece on the base. I started along the top of the cupholder and worked my way around, keeping it taut the entire time and pretending that it was the world's toughest-to-wrap present.

Step 4: Resin Coating the Fleece

The next step is to coat the fleece covered base with fiberglass resin. I will not go into the process of mixing the resin as you can read the back of the can. I was able to hold the piece as I put on a majority of the resin; however, when it came time to do that backside, I found it easier to partially screw in one of the screws by hand and hold the screw. Depending on the amount of hardener you add to the resin, you will need to work diligently to coat the entire thing. Hopefully you will be done saturating the fleece by the time the resin starts to become gummy (it begins setting).

I suspended the soon-to-be cupholder with a magnet attached to the screw in the back. Allow it to cure overnight for best results.

the resin is exothermic, so avoid getting it on you because it gets very hot (the more hardener, the hotter it gets)

Step 5: Cut Out Holes

After the resin has fully cured, you need to cut out the holes. I used my dremel with the cut off wheel to create a small opening, then i switched to the drum sander and had at it. Its time consuming and very, VERY messy. Wear proper a dust mask, safety glasses, and ear protection.

Slowly sand open the hole in a circular motion, but be careful when you get close to the edges, you do not want to sand into the wood at all. Unfortunately, you will need to do this 4 times, front and back for both holes.

Step 6: Sand the Outside Smooth

Using a relatively fine grit sandpaper, you will want to sand the entire outside. The surface from the resin and fleece is rough, we want to sand it pretty smooth. DO NOT sand through the fleece! There are some areas that you will not be able to completely level off, and this is because they are low spots and if you try to, you will sand all the way through to the wood. These spots will be filled in with bondo in the next step.

Unfortunately, I did not take any action shots of the sanding process, but you should be able to see that the surface is a lot smoother than it was. This is just a preliminary sanding, the sanding in later steps will be much more important.

Use a tack cloth to remove the dust as a preparation for the next step.

Step 7: Bondo, Bondo, Bondo

Like the title says, this step is all about the bondo. Like the fiberglass resin, I am not going to go into lengthy details about how to mix is up or use it, the directions are right on the container. I am just going to say wear gloves and don't add too much hardener. This stuff sets up faster than the fiberglass resin. Be careful not to add too little hardener though (like i did at first...) because then it doesnt properly set and its gummy for hours.

Mix up some bondo and, using a scraper, apply to the low spots. Try to coat the entire thing (minus the back side). Fill in all the voids that you want filled in. When you sand it, you dont want to have a layer of bondo, you want to sand down to the fleece/fiberglass, but allow the bondo to fill the voids. (see pictures)

There are going to be two little pockets on the bottom side of the cupholder, one per holder. These are going to need to be filled with excess bondo, so don't worry about this until you're second pass.

After the first layer has cured, sand smooth and reapply if necessary in certain areas. Fill in the pockets with a lot of bondo, allow to cure, sand, and proceed to the next step.

Step 8: Sealing the Wood

In the circular cutouts (the holders), you will notice that there is just wood. This is an issue as the cups might sweat (condensation) and cause the wood (MDF) to swell, and this isn't good. The solution to this is to sand down any lumps in the openings, mix up a small amount of fiberglass resin again, and apply evenly around the holders. You may want to add more hardener for this part so that the resin does set up faster (this means it will be thicker and therefore less likely to run -- less sanding for you later). Allow the resin to cure for a few hours and sand the inside smooth, being careful not to sand through the resin into the wood (if so, you'll have to add more resin, which I doubt you wanna do).

Step 9: Primer and Paint

Use a tack cloth to remove any dust from when you sanded it. Lay down a piece of cardboard as a backdrop and coat the entire cupholder with primer (be certain that whatever paint you have to use, the primer is compatible with it, else the paint may peel). The length of time you need to let it dry depends on the manufacturer, so just read the can. I used one coat of primer, but if you'd like to use two you can. Make sure to get the top and bottom as well as the inside of the openings.

Once the primer has dried sufficiently, you can being painting the cupholder. I actually had a can of paint meant for my vehicle interior, so the color match is the same as my bezels. Paint the same way you primed, just avoid streaking and spattering, so take your time.

Step 10: Mount and Attach Cupholder

After the paint dries, the cupholder is ready to be attached. Use the screws and carefully screw the cupholder to the metal piece by hand to avoid over tightening and piercing the front side. After it is attached to the metal piece, the final step is to attach it back in the vehicle.

At last I can keep my beverage close at hand while driving stick shift....again, I will never understand the engineers that decided a vehicle is complete without a cupholder.