Inspired by Ed Roth, Plowboy and Racerdad

Another design facet that deserves to be revisited is the front fenders and hood area. The fenders were going to allow the exposed headers/lake pipes to be viewed, (since they exited via the wheel-wells) with continued plumbing out the back. The hood needed to be tapered and as was very helpfully pointed out, some version of the hood from an early '60's 'Vette hood scoop would fit right in.

Power train wise, I sold the original aluminum V8/3-speed when I left Idaho. What to replace it with? I'd like to go aluminum again, either a V8 or a V6, maybe with a blower or twin-two's (carbs)? I wouldn't be opposed to a modern power-plant but the hood would have to remain closed to do that.

 

If the original F-85 is no longer available or if transporting what's left of it proves to be unfeasable (Idaho to Texas), I'd still like to use the lines of that body. During my time in Experimental Aircraft Production, I became adept in composite fabrication. That does not mean that the methods used in that field are a direct match to techniques in an Ed Roth type of build. Sure, it's all composite work but, parts made for aircraft are built to maximize light-weight and strength. Those same parts are weighed, right down to grams! An Ed Roth type of build is much less concerned with a few excess pounds.
Aviation composites (wet lay-up) are very specific layers of varying weights of cloth, these combined layers are what, when combined together in a single article/part meet the specified weight/strength of that part's design parameters.
In an Ed Roth build, first and foremost is the 'look' of the design. Second is structure and last is weight if that is even considered. Too, most of the highly visual bodies I have seen have were largely made using fiberglass-mat instead of cloth. Mat is cheap, easy to use and especially when building in a 'moldless' technique, may be the best material to start from.
However, there are some things about mat-based fabrication to be aware of, one is repair-ability/collision damage. Mat has the distinction of being both heavy and weak. It is one step above a 'chopper-gun' for build quality/strength. That doesn't mean that both methods are total junk/crap. They are neither. They are built for specific needs. Chopper-gun fabrication is fine for shower stalls and other stationary appliances that are not exposed to vibration/twisting moments. As long as they are supported by an interior structure of wood-wrapped in fiberglass and epoxied into the shell or glassed in, they are fine and hold up to daily use for years. Chopper-guns have a preset fiber to resin ratio that is usually a bit heavy on resin. The optimum ratio is just to saturation of the glass fibers and no more.
Mat-construction can have a better resin to fiberglass ratio since it is adjustable by the technician, 'on the fly', it may be a better overall finished product. Where mat falls short in the strength department is in it's random mat of compressed glass fibers. It is inconsistant (not the same density of fibers per square inch) and without an actual woven pattern to the glass fibers the strength is random too. This 'lack of' strength/consistancy really doesn't matter too much for day to day driving as long as the interior structure keeps the body from flexing beyond its ability to absorb those forces.
Where mat-construction really falls apart is in a collision/impact situation. Mat structures will not only break 'across the grain' but, the energy travels along the glass fibers longitudinally and breaks their bond with the resin and other fibers. This transfer of damage is usually hard/imposssible to see from the surface. Both the gel-coat and or paint won't show what is hiding underneath. Tapping with a coin along side of the damage will give you some idea of how extended the damage is from the area of impact (solid sound vs hollow/dull sound).
I believe, that damaged mat structures should always be repaired with cloth. My reason for this belief is, with mat, you can only see on a normal level and the damage continues (much)further on a microscopic level. Since you and I can't see this damage or how far it extends, err on the side of caution, do the repairs in cloth which will be stronger than the original mat fabrication. The area of transition from repair to undamaged area is crucial, should be done in a ground 'step' for every layer of cloth used (in 1" wide steps). Your end product should be layered from the bottom up, smallest pieces of cloth to largest and extend beyond the repaired area by at least 1" all around the perimeter of the repair.

 

Sometimes, you hear comments about this or that, regarding fiberglass techniques. I have 'heard' it touted that mat is 'strong in all directions' when compared to cloth, which is strong in two directions (@90*). What this really means is, mat is 'equally strong' in all directions. When compared to cloth the strength of mat is much less, however it does have that same strength in all directions. Cloth is much stronger but, it is directional, conforming to the direction of the fiber's length, two directions @ 90* to each other. There is a way to add strength @45* and that is by adding a layer of 'bias weave' cloth. This cloth is woven 'on the bias' @45*, this adds the strength needed for compression/tension of the glass-fibers in the direction that normal weave is weak.

 

The technique I use for repairing RV collision damage is compatible with the original mat constructed article, whether it is an end-cap or something else. The 'trick' to doing moldless repair of collision damage is forming the foam-plug to 3/16" below the original surface. To do that, you need depth markers. Depth markers don't appear to be available commercially, (not that I've found). I have decided to make some, using tooth-picks and wooden-plugs for furniture' screw holes. These markers can be placed and removed without compromising the foam's very limited structure. You sand until the marker clears the contour gauge. If it doesn't, remove the marker and sand some more, easy-peasy! The marker should have enough thickness to allow for surface variances.
Once the 'blue-foam' is sanded to the right clearance, 'below grade', it needs to be sealed. this can be done using either commonly available latex paint or aluminum-tape. If there are details that need to be added that foam does not support, they can be created in 'modeling clay' then, sealed in aluminum tape in a secondary layer.
This sealing process is critical, if the blue foam is not sealed, the resin-mixture process can degrade the surface and compromise the shape you have worked so hard to create.

 

Dan, glad to hear your doing good. I have often wondered how your travels have gone since leaving our beautiful state. I occupationally run into Al during events in this area.

 

Good to hear back from you! Al and I have stayed in contact, last month he sent me some pin-striping supplies I had left with him on our departure from Nampa. He also has custody of the F-85! I know he'd like to see it done. as would I but, I simply don't have the financial ability to assemble another metal-shaping shop. Building a 'hybrid' part metal/part fiberglass structure may be the only way I can proceed with that project at all ...

 

Interesting read about cloth vs. mat.
The C cab body was built from ply and MDF (seriously) over a steel frame. Inside was covered in heavy grade mat, outside was covered with woven cloth. Only problem I had was "print through" of the cloth weave showing in the paint. Took a lot of priming and sanding to get rid of it.
Some folk were aghast at the idea of using MDF as a material (soaks up water) but it was thoroughly soaked in resin. Bare body sat outside for an entire winter: snow, rain and all, during the build. That was ten years ago and it's still holding together!
I've also heard a lot of caution about mixing metal and 'glass (different expansion rates), but again, I've had no issues.

 

I have also decided to use an inner structure but, I too am not comfortable with the differing expansion rates of steel to fiberglass. You have constructed a 'C-cab' using MDF/steel as inner structure and it is not new, what has the aging process done?
I'd be more comfortable with the MDF than the steel, the MDF would have a similar expansion rate, especially once it's resin soaked and 'glassed in. I wish I could inspect your ride first-hand, not to be critical, just curious about how the weather has impacted your structure?
The use of MDF really intrigues me, MDF has many qualities as a building material, I've used it as jigging material several times, it makes a pretty good buck/jig for welding if you use cut-outs for the weld junctions.
I have also heard of people using flexible plastic tubing that is epoxied in and 'glassed over as structure for weird curves and to round-over and reinforce firewall edges. Some have even suggested garden hose?!

 

So, I have just gotten back from my evening 'dog-walk' (I always think better while walking), my conclusion? I think I am going to scratch-build a car body using a mold-less technique. I would like to base it on the F-85/Cutlass project Al and I had going in Idaho.
I'm going to see if Al will supply me with 'data-points' from the original '61 Cutlass body he and I modified. If I could get some forms/profiles in specific locations I should be able to recreate the body as it exists in Idaho.
I think for a first 'mock-up', I'd like to do this as a scale model. I'm thinking 1/3 scale should give me a good view of the entire shape and allow me to critique the lines/modifications and still be big enough to make any changes doable and not too small.

 

Why not up the scale to go-kart size and have a little fun with it. Money could be made selling those.

 

I've found mdf to be very useful stuff. Can be bent when thin, carves easily on thick panels.
Regarding the use of steel, I use "liquid nails" construction adhesive as a bond to the 'glass and MDF, which remains slightly flexible. I've had no issues at all with cracking or warping on this body, and it's been off the frame a couple of times, so it's proven very durable. I used Epiglas marine epoxy based paint for both primer and topcoat, which needless to say, helps with weather proofing.
In retrospect, I'd say using MDF alone would be enough, as long as it's well coated in resin. The reason for the steel was as a provision for mounting points etc.
Regarding the use of plastic tubing and so on, yeah, I know a guy who built a Model A coupe body who used garden hose and plastic ducting to form curves. Use whatever comes to hand!

 

Sorry for the delay in responding, got locked out/computor issues ...
Regarding the question of size/scale, I'm considering maybe a golf kart body? We use them at work to get around the dealership, maybe I could induce the dealership to sponsor the build for the paint-shop? It would be kinda cool to have a distinctive kart for the paint/body shop, Lol ...