CarBEN EV5 Full Sized Prototype Construction - 5 Seat Electric Car From Scratch

[NeilBlanchard]

Here's a longer, more detailed walkaround video:

http://www.youtube.com/watch?v=A49N2onsN64

I tried the stabilization in the camera, but it still needs the YouTube processing...

It's got it first dirty bird, and there are glue drops and runs, and rough edges... My son will be helping me move it back into the shelter soon, so I can continue smoothing. The left side in particular needs a fair bit of work. They all show up much more readily in the full light of day!

[NeilBlanchard]

This is how I am using the longboard sanding tool I bought from Jamestown Distributors. It is a tool normally used on boat hulls, and it is nearly perfect for this, too. The swirling motion and figure 8 motion tend to avoid any gouges or divots.

http://www.youtube.com/watch?v=K3d64d3_S-g

I was able to even up the surface so that the several low areas are largely gone.

I wish that my video camera had a wide angle lens - I had to position it quite far away, and I hope things so up clearly enough.

[Galane]

Originally Posted by NeilBlanchard

It's got it first dirty bird,

The bird wants to buy the car. It left a deposit on it.

[Rokeby]

Ain't long boarding fun? The necessary sideways upper body motion calling heavily on otherwise little used, easily tired lats, arm and stomach muscles. Learn to love the 'burn.' Oof!

Smoothing the relatively soft foam is the easy part. After you 'glass the outside of the foam you'll be doing more, a whole lot more; initial glass and epoxy layer(s), filler coat(s) -- do not use 'micro balloons' or other lightweight fillers, final epoxy-only top coat. The surface will be harder, you'll be using successively finer grits, down to 320 for sure, 600 maybe.

I recommed that you consider a pneumatic long board. Nowadays, it is more often associated with automotive body work. Something like this,


From onlinetoolsupply, 'only $90' if you have access to a compressor of sufficient capacity, volume more an issue than pressure. (Don't worry, you'll get used to the post-use buzzy, pins-and-needles feeling in your hands, its not permanent.) Also, it'll be cheaper to buy bulk rolls of abrasive strips (automotive body shop supply) rather than packaged precut to length (Home Despot, etc).

[Edit] Come to think of it, when you get to final sanding the last filler coat and epoxy topcoat, the preferred tool is a light weight, pneumatic circular random orbit sander known in the trade as a 'jitterbug.' When used with a flexible rubber supply hose, vice the more typical stiffer, cheaper, hard plastic hose, it is much more resonsive, gives better 'feel' or 'touch.'

[NeilBlanchard]

I'm planning on using the same waterproof wood glue that I've been using to glue the foam together, for the fiberglass, too. I am going to focus on finishing this prototype to get to testing it - only the functional problems will get fixed.

Do they make a flexible version of the pneumatic longboard? I'm only on the second abrasive sheet - I bought the better 3M ones, and the foam is obviously easy to work.

[Rokeby]

Neil,

You got me. I've never done any full size prototyping. I forgot where you're coming from; low cost short term validation of concept. I'd guess you'll be going for less than near-perfect curves and smoothness. Thoroughly understandable, but not an option in my typical buyer expectation driven experience. (There is a truism among boat builders that goes, 'Finish is the modern substitute for build quality.')

I've never used anything other than 'glass/resin for covering purposes. However, I do know that when sanding wood glue you have to be mindful of heating the glue due friction. It causes the glue to soften and roll off in balls. The surface is not smooth. This can be minimized by using abrasives with a built in release agent evidenced by some overall color; typically white, green, or yellow, not the sandy color of the typical craft/shop grade 'sand paper." The little rolly-ball phenomena can also occur with just too much sanding dust between the abrasive and work surface. Use light pressure, and clean the loose sanding dust from the abrasive and work surfaces by frequent blowing/wiping.

I'd guess that you'll be finishing up with waterbased vinyl paint. Good enough. It may be overkill, but a final clear topcoat would add shine/depth/luster.

So, for you, never mind my earlier post, although I hope it has some applicability for other readers.

I'm not aware of a flexible platen pneumatic long board. I think it would lead to rapid heat build up and friction between the moving platen holding the abrasive sheet and body of the tool. It's been quite some years since I bought a new one… like any pneumatic tool -- they are built for commercial, continuous use applications -- they last and last if you remember to squirt a small amount of pneumatic tool lube into the air supply fitting before each use.

A user work-around for a flexible platen might be to attach a somewhat soft foam pad between abrasive and platten. i would think something about the density of those puzzle piece edged shop/playroom flooring squares would be a good start.

[Edit] As a final point; once your baby has a hard external surface you should consider adding padding on perimeter sharp edges. This to prevent unsightly and sometimes not easily repaired dings, the ubiquitous 'shop rash,' as you focus on other matters. Folded strips of the puzzle piece edged shop/playroom flooring squares would do just fine. This stuff is relatively cheap. IIRC, comes in 6 or 8, 2 ft. x 2ft. piece packs at Home Despot,etc. It is also very useful when applied on hard hand sanding blocks used for smoothing as opposed to shaping purposes.

[NeilBlanchard]

I did some initial searching via Google for a flush hinge with a long enough leaf to pivot the main hatch door about 4" forward of the front of the opening - so that the door will "lift" straight up out of the opening to clear the slightly arched roof edge.

I also would be using a piano hinge on both the front wheel skirts; and I'm hoping to find small round individual LED's to make up the turn signals and the tail and brake lights in the back.

If anybody knows where to get any of these things, I'd appreciate it very much.

I've rolled the chassis over on it's right side today to do some more work on the underside, and to give me another view of the left rocker panel and wheel strakes, etc.

[Galane]

If you're looking for super bright LEDs try superbrightleds.com If you're wanting the best price and don't mind waiting on the slow boat from China, besthongkong.com

As much flex as you're getting in the side while sanding, I'm still thinking the wood glue won't be stiff enough, nor crack resistant. Before slathering glue all over your thousands of hours of hard work it would be a good idea to make a test piece of a thin part of the body like an upper rear corner.

Spending the time to fully finish out a duplicate section to its end state then testing it to destruction will give you the best idea of how your proposed finishing method will or will not work.

I'd really hate to see you put so much work into this project only to turn it into a garage queen or a wreck with an "alternative" finishing method instead of one that's been well tested and proven to work on many types of vehicles, including very high stress applications on homebuilt aircraft.

[Xist]

Originally Posted by Galane

As much flex as you're getting in the side while sanding, I'm still thinking the wood glue won't be stiff enough, nor crack resistant. Before slathering glue all over your thousands of hours of hard work it would be a good idea to make a test piece of a thin part of the body like an upper rear corner.

What about a scrap piece. Neil, do you have any scraps?

[NeilBlanchard]

Most of the motion you are seeing in the video is the whole chassis moving on the supports I have it propped up on. The whole thing weighs about 100 pounds. Any flexing has the glue is flexing with the foam (between the layers), so that is a good thing. I will certainly test it. I still have to glue up the wheel skirts, so I can test on one of those, or make piece from the scrap that I have not thrown out yet...

The SuperBrightLED's site has some 5mm LED's that have built in resistors for 12v operation, and they have 3' long wire pigtails on each. The thing I am trying to find is a small round reflectors with flat lens.