Boat Tail Construction-Civic Sedan

[bs25942]

Thanks for the replies. I finally found a few days to go home and start construction. I went the EMT/Rivet route as it is super easy to rivet. I will definitely be using the rivet gun for everything.

Similar to the Redneck Boattail I attached the top two bars to the car using existing Kammback holes and bent them until they matched the template. Then I bent the end elliptical piece which was easily the hardest part without a conduit bender. Then I attached the bottom two bars and started making cross members to add strength. I unfortunately ran out of time and conduit so I had to stop. I also tried to at least get the wiring complete but I need a 5 to 4 pole tail light converter for my car and the lights I got for it to work. I will resume production as soon as I graduate in August.

BTW, the boattail extends 36" past the bumper.

[redneck]

.

Looking good.

Be sure to put a big x in between the lower bars to help control lateral movement. Also a bar on each side attached where the bar is bolted to the bumper up to the top of the back panel which will help control vertical movement and bouncing. The more cross bracing added, the better.



>

[freebeard]

You might consider these to be improvement. ..or not.



Please find 3 magenta lines (I had this blown up while I worked on it). The middle line, at the rear fender, is a much shallower curve than the other two. Shouldn't it be intermediate?

The yellow line shows an opportunity for a '57 Mercury type fender skirt.

If you carry the character line that runs through the door handles onto the boat tail it will tie it together visually. What will you skin it with?

[bs25942]

My plan is to use 1/2" expanded polystyrene and cover it with a single layer of 6 oz fiberglass/polyester resin and a top coat of just resin.

[freebeard]

Good luck with that. A good surface finish can be obtained with a carefully worked female form.

I have experimented with, but not bough a good quantity of PolyMetal. It's like a metal/plastic plywood; equivalent to 5/8" ply but with 1/10th the weight. I have sheared, rolled and braked PolyMetal by hand (18" lever arm). Right now I'm working on a fastener detail, but I need to get a router repaired. I see the joining done with an H-channel strip glued and/or riveted along a simple curved edge of adjacent rolled sections.

Peel the protective paper off and you have a prefinished enameled aluminum skin. I really want to build a teardrop trailer this way.

[bs25942]

Update: I went home for a few days and finished the frame as well as electrical. I think I will put two straps from the trunk lid to the bottom member about 10" from the end of the tail to give more support. After using rivets and bolts I now see the huge benefit a weld joint would have on stiffness. Since there is still some pivot play in the large X I will have to put a lashing around it to stop any rotations and will hopefully weld it when I can get to my grandpa's place. I plan to start the skinning process on the 14th of August when I finally get done with school.

[freebeard]

After using rivets and bolts I now see the huge benefit a weld joint would have on stiffness.

Look into gusset plates.

[elhigh]

Be careful welding galvanized metal.

[bs25942]

Ok for now I am done. I put the foam over the frame and held it down with zip ties and bolts. I then fiberglassed over it and that's when disaster struck, for the left side anyway. The resin fumes got under the foil and ate away at the foam over a large area on the side. I cut it open and sprayed some Great Stuff and made it look as good as possible before taping it back down. I then taped the edges and painted everything. I plan on redoing it in 6-12 month with foam sandwiched between coroplast. The urethane foam is too stiff to work with without cutting and gluing it together so no more fiberglass...it was expensive anyway. I am thinking the corofoam sandwich should be very strong and stiff. I have only driven it 90 miles or so but it seems likes it is doing the job. It will take a while to tell how effective this iteration is.

[Xist]

Great progress!