Project: ECOfamily Civic and its Aero Hitch Box / Boat Tail

[MetroMPG]

I've had an itch to put this on the car and snap a few pics.

I bet you have!

[NeilBlanchard]

Do it! Do it!

[slowmover]

Man, we need to get you some cool tail lights (after all that work).

Grote 52782

[Xist]

How does that storage space compare with your trunk?

I think that it is curious to see your box after Top Gear's electric car. Granted, it was far larger and complicated and I do not think that they took it seriously, but compared to your work, theirs is like Wolverine's weird cousin!

[christofoo]

Originally Posted by slowmover

Man, we need to get you some cool tail lights (after all that work).

Grote 52782

My boxy tail lights aren't "cool"?



Just kidding. I admit the circular lights match the look of the box better, so I should think about it... later... but before I paint...

Originally Posted by Xist

How does that storage space compare with your trunk?

I think that it is curious to see your box after Top Gear's electric car. Granted, it was far larger and complicated and I do not think that they took it seriously, but compared to your work, theirs is like Wolverine's weird cousin!

When I get around to it I should revise my estimate, but the number I got from CAD clear back in Jan was 18 cuft for the aero hitch box, vs 11.9 cuft for the existing trunk. Both together at about 30 cuft is like 250% of the stock trunk.

Thanks (I think).

[christofoo]

I've been feeling too busy to update lately. Fab first, post later.

Actually, most of what I'm doing is really typical fiberglass over foam construction. Like this: Fiberglass parts

One point of difference; I'm using a foam-compatible construction adhesive that I've found has excellent bond strength even when the joint is sloppy and the adhesive has to fill a gap. I didn't test other adhesives, I just tried this stuff and liked it right away (except for the price and the 24 hour cure). Loctite PL Premium FAST GRAB Polyurethane Construction Adhesive from Loctite Adhesives

Here's a sample I tested to failure; the 2" pink foam actually has some ridges cut into it that cause it to fail early, long before the adhesive.


(Except that later I had a joint fail where I had bonded to an unsanded smooth face, also I was using the other Loctite stuff, the 3X, which I don't feel has quite the same properties. Scuffed it up and rebonded with the 8X that I like.)

So here's my blanks 'clamped' together with tie down straps and weights:


And then sanded down:


I felt like I should inlay some wood strips along the hinge and where the latch and lock will attach:

Then bonded it in with the Loctite adhesive... although afterwards I wondered why I don't just add a few layers of glass manage stress at the attachment points... if I'm wrong call it lack of experience... but anyways this will work... maybe it works better...

With luck, I should be doing glass tomorrow. More to come...

[christofoo]

Yesterday morning I found my attempt to rebond this piece got messed up.

I was using the weights to clamp the pieces together, roughly a right angle, but a little obtuse. Apparently the weights weren't balanced and were momentarily hanging on by the high viscosity of the Loctite 8X PL, probably tipped over right after I left.

Sanded the hardened adhesive smooth with the belt sander, and did a test strip with 5 minute epoxy, which actually yields a very good bond in the pink foam. Made a trip to Home Depot to get 8 oz of 5 minute epoxy (for $15!), because I can't wait another 24 hours to do this with a less expensive adhesive.

So about 1 hour later I was ready for glass.

The resin that you can buy at Home Depot (polyester I think?) dissolves the pink foam. This information can be found by googling, but I didn't notice it prominently in any of my fiberglass readings. I might have known better on the basis of the smell; the resin smells very strongly of solvent. I went back to 3wheeler's Insight Tail and realized he used epoxy resin, which doesn't share the problem.

This is the result:

As the foam melts, the air bubbles out and it shrinks, in some cases the air pockets weaken the structure. In other cases is merely makes it looks uneven, depending on what order I lay the glass, how long the resin gels in the cup before it gets applied, and whatnot.

Surprisingly, I think it will be okay and I intend to live with it if it doesn't prove me wrong and break.

I've always liked Metro's axiom:

Originally Posted by MetroMPG

...You know what they say: the perfect is the enemy of the good. (I'm typically on the other side of the battle from "pefect" )

For the remaining surfaces that will get glass (i.e. the underside), I've coated with a thin layer of the Loctite 3X PL (since I had most of a tube of it leftover) to seal up the foam.

... so at least it will look nice where no one sees.

===========================================

In other news, 3dcadbrowser has finally accepted 2 of my submissions. Much to my surprise, I received no download credit for them. So I hunted through what little info they provide, and realized that I don't get download credits for uploading a model; I get a download credit every time someone else downloads one of the models that I've submitted. I'm sure I'll have this project finished by then.

[Xist]

Irony is a harsh mistress.

Good luck!

[christofoo]

Been working hard to try to meet a deadline. I'm behind a few updates and won't have time to post much until next week.

But here's a little teaser:


Things are shaping up. Drove it to work this morning for sanity testing. Looks like it's ready for the weekend excursion (tomorrow).

[freebeard]