Monday, March 31, 2008

More fender work- rough trim to test fit.


The fenders are coming along nicely, I was able to release the Kevlar from the fleece (male mold) without too much drama. The shape gives the fender some rigidity, but it is still a little too flexible with out being securely fastened to the car. I may add some supporting layers of fabric to the back side later on. The photo above shows a quick and dirty trim so that I could test the fit, the finished product will be more refined.

The next step is to add a matching flare to the bumper so that the lines can continue uninterrupted. I would like to make a complete bumper cover, but I think I'll wait until I'm finished with the flares all around. I may start on making some lightweight door skins at the same time, a fixed-position door setup will save about 55lbs over my current setup.

FYI- the weight of the new fender is approximately 2.25 lbs :)

Sunday, March 30, 2008

Fender progress



I added two layers of Kevlar this morning (with help from my neighbor- thanks again!) The fleece hardened up really well and made a good surface to mold to. I used some liquid poly wax as a release agent and I think it was working a little too well...we had a tough time getting the first layer to stick. The second layer went on easily and laminated thoroughly. The creases aren't super-sharp, but that's what you get using a moldless process. Overall I'm pretty happy and it looks like the technique will work well enough to do the rears as well.
I should be able to release and trim the fenders in the next day or so (the epoxy has a longer cure time due to the cold weather.) Meanwhile I'm prepping the rest of the panels for fleece. The driver's front is done, I just need to cut the MDF for the rears.

Saturday, March 29, 2008

Started making the new fenders---

Today I finally got around to starting on the fenders. I'm using a composite technique called "fleece" where you stretch some fabric over a wooden form to get a smooth shape or curve. Fleecing works perfectly for the shape of these fenders. I used 1/4" MDF to cut the wheel shape and the flare. The flare is about 2.5".

Next I stretched some cotton spandex over the forms ( I hot-glued the wood to the body to hold it in place). 3M 77 spray adhesive holds the fabric to the wood and body.


...taking shape!


Here is the fleece with a couple thin coats of epoxy. The epoxy will give the fleece just enough stiffness to add the layers of composite fabric. After the Kevlar is molded, I can release it from the fleece and removed the wood forms.



Friday, March 28, 2008

Doors are for wusses.

I took of the doors today in preparation for making the new fenders. I was pretty surprised to find they weigh 30lbs each, even though they are completely gutted and most of the sheet metal has been removed. I'm going to consider making some new door skins made from composite and just pin them to the car. It's easier to "Dukes of Hazard" in and out of the car anyway. 50lbs off the car would be great, especially since I added about 150lbs from the cage.

Thursday, March 27, 2008

Kevlar testing and passenger seat installed

I made a test piece of the Kevlar fabric and wetted it out with epoxy- the Jeffco epoxy seems to work well with the fabric, even in the low temperatures (50 degrees F). I'm using the Jeffco quick-set epoxy, it works a little better in the cold. You can buy it at http://www.aircraftspruce.com/
Two layers of fabric should be enough for the fenders, the sample is pretty rigid, similar to sheet metal. The plan is to mold the new fenders from the existing ones, then cut away as much of the old one as possible to save a little weight.



The passenger seat has also been installed, it is the same as the driver's seat, except it's an inch wider (16") to accommodate a wider range of passengers. I haven't decided if I'll add the halo to the seat yet, I may have to in order to comply with instructor safety rules. Some clubs specify that the instructor or passenger's seat must have identical safety equipment as the driver's.

Friday, March 21, 2008

Wing supports finished, rear firewall added


I finished the wing supports, it is now very rigid. You can easily push the car by the wing, and it's very stiff laterally as well - the whole car rocks back and forth if you push the wing. I had to fabricate a lower brace in the trunk to stiffen up the sheetmetal- it added some weight, but I can use a little weight in the rear anyway.




I also made a new rear firewall since we cut out the original to fit the roll cage. I used 20 gauge sheetmetal and used a cardboard template to finalize the shape. I am going to use epoxy with micro to fill the seams, or a little caulk or something.


My Kevlar fabric arrived, so I'm getting ready to make my new fenders. Kevlar is a pain to cut, but I found a special pair of snips at Home Depot that seem to do the job --- Wiss MPX serrated blade shears. They were about $15 (versus $65 for the special Kevlar shears) and they cut the fabric well, as long as it is under tension. If you don't hold the fabric taut, it is almost impossible to cut.



Tuesday, March 11, 2008

Wing supports cut to proper height-


Yes, I know my garage is a disaster. I need a 10,000 sq ft workshop. I cut the wing supports down about 8", now it's a little less crazy...maybe even a little DTM style which isn't bad.

Sunday, March 9, 2008

Hahaha...this is just a test...

No, I'm not keeping the wing like this...I figured it would be easier to cut the wing down to the right height instead of adding to it to make it higher. I love the photo, funny.

I also fab'd up an X brace out of aluminum tube to add some lateral support. Not the most elegant solution, but I really don't want to use guy wires or anything.

Saturday, March 8, 2008

Super-ridiculous wing fabrication begins!




I really want my rear wing to be functional, so that means making my own. Most of the wings on the market are designed for looks, and not much function. One of the most important things for wing efficiency is getting it "clean" air...not the turbulent crap spinning close to the trunk. My solution- raise it as high as I can! In the end it will be almost level with the roof line...should look pretty lame, oh well.

I started with some 1/8" aluminum and plasma cut the shapes using a cardboard template. The wing will mount to the floor of the trunk and tie in to the rear crash rails for extra support. I cut some slots near the license plate to allow the supports to go through uninterrupted.

MIG welding aluminum is possible, but a big pain in the ass. Get a spool gun or a TIG. I got the job done, but I had to fix the spool every 2 minutes due to feed problems.

Wednesday, March 5, 2008

Ghetto-fabulous wheels arrived!



My new cheapo wheels came in - Sportmax 16x8"s. They aren't my favorite, but they were the right width, bolt pattern and offset. For $99 each, I guess I can't complain. Someday I'll add the $800 (each) custom Kodiak wheels. Anyway- the wheels are 8" wide with 0 offset, so they stick out quite a bit...at least until I fab up my new fenders to cover them. For tires I'm using Sumitomo 16-245-45s...pretty damn wide. I think the section width is almost 11". Tirerack shaved them to 4/32nds for me so they should be pretty grippy. $69 each too, plus $15 each for shaving. I also had to get special tuner lugnuts from Summit Racing, my old lugnuts wouldn't fit in the holes.

Monday, March 3, 2008




The cage is 95% done, I just have to finish a few welds on the A and B pillar ties ( I ran out of welding gas). I'm very pleased with how it came out, very strong and it stiffened the chassis 1000%. I may add a few more gussets in the future, but for now I think it is in good shape, and according to the rules if meets or exceeds all the regulations. I had to pop out the windscreen to get to a few welds, and of course I broke it in doing so. Luckily a replacement is only about $200, and it's always nice to have a brand new non-pitted windscreen.

I also removed the HVAC system. I was going to keep the heater, but my goal of low weight and simplicity overrode the convenience of heat. I guess we'll see if I made a good decision the first time I drive out to the track at 6am on an Autumn day. Removing the HVAC system allows for a lot of simplification of the wiring harness too, and simpler is better on a race car, especially when tracing a bad ground or other electrical gremlin.

Wheels and tires are on order- I bought an inexpensive setup for this year until I decide to drop the $2700 on custom Kodiak wheels.