Civic VX Boattail

[Jyden]

Originally Posted by gijoe985

Yeah, because of the wood, it is stronger, but heavy. I don't string would cut it. IN fact, my dowels have a hard time supporting the wight. I may just need to get some more cardboard and redo those panes...

Cut out the middel of the plywood pieces. They dont add anything but weigth for the construction.
Cutting out the middles will reduce weight with 2/3 or more.

[gijoe985]

Here is some progress. I DID cut out the middle sections. It reduced the weight a ton. I am now just fabbing up the shape. We're trying to decide of we want to piece together sheets of abs or FRB OR if we want to create a fiberglass shell. I think a two piece shell would be cool. We'll see.

[UltArc]

Craftsmanship looks great. Can't wait to see the final product.

[gijoe985]

Well... This project was not abandoned. Just moving slow.

how does this approach sound: shape the foam as close as possible, fill with what, plaster? Car filler? Once filled and smooth I could cover with fiberglass or I could make a female mold and then make a super nice mold... If I make a fiberglass mold, I assume I'll need to reinforce the inside. And then comes the fun of figuring out how to attach it. I was waiting to cross that bridge when I got there.

Thoughts? I'd like it to look nice. I'd also like to figure out a way to have a hatch that opens still too...

[aerohead]

Originally Posted by gijoe985

Well... This project was not abandoned. Just moving slow.

how does this approach sound: shape the foam as close as possible, fill with what, plaster? Car filler? Once filled and smooth I could cover with fiberglass or I could make a female mold and then make a super nice mold... If I make a fiberglass mold, I assume I'll need to reinforce the inside. And then comes the fun of figuring out how to attach it. I was waiting to cross that bridge when I got there.

Thoughts? I'd like it to look nice. I'd also like to figure out a way to have a hatch that opens still too...

Since you're working in foam,check out 'Honda Insight Tail Extension Project',by 3-Wheeler.
He used micro-baloons (CABOSIL,fumed silica) and epoxy as a ultra light weight filler.You might want one coat of resin on the foam first.WEST SYSTEM sells this.I get mine at a local marina which does Chris Craft restorations.With a single layer of glass it would be strong enough to remain on the car.Or you could make a female mold from it and layup your finished part.

[Xist]

Originally Posted by aerohead

Since you're working in foam,check out 'Honda Insight Tail Extension Project',by 3-Wheeler.

http://ecomodder.com/forum/showthrea...ect-13533.html by 3-Wheeler

Honestly, I think that anyone planning on building a boat tail or anything out of foam and fiberglass should start with this thread. He has some of the most beautiful craftsmanship that I have seen on this site!

[freebeard]

Thoughts?

My introduction to the thread was that last picture, then I went back and read the whole thing. My thought is that everything up to the penultimate picture sounds reasonable, but that last picture is scary!

If you want to know why read CarBEN EV5 Full Sized Prototype Construction - 5 Seat Electric Car ..., around page 31 where he starts confronting the problems of fiberglassing over glued-up foam strips.

Were it I, I'd strip off all the foam and figure out how to attach it to the car. Wrap it with plastic cling film until it holds it's shape. Then use a thin material that has a finish surface that can be rolled into simple curves (to save hours of tedious finish work). Or dampen, slump-form, and dry cardboard.

Here's an example of a form made from gored flat strips.


See also

[gijoe985]

Freebeard- I'll look into it.

That aside, for the fiberglass. If eventually it was only fiberglass, how many layers of oven cloth should I go?


These guys seemed to have decent success.

http://www.rqriley.com/frp-foam.htm

[gijoe985]

The guy in that article states this-

A typical exterior lay-up consists of two layers of 6 ounce fiberglass cloth and polyester laminating resin, applied one lay-up at a time. In order to avoid uneven surfaces, do not use mat on the exterior. Apply similar lay-ups (two cloth) of fiberglass over the back side to completely encapsulate the foam. Extra cloth lay-ups and mat reinforcement may be used on the back side, along inside corners, and over areas where the foam has been sanded especially thin. When fiberglassing is done, cut hatches, doors, and windows from the body, then detail the interior.

I have a lot of cloth, the woven kind. Not a lot of mat. Think I should buy some mat? I thought cloth would work better...

[Xist]

You can purchase fan-fold foam board from Hope Depot, Lowes, and Menard's, although I needed to special-order mine. It is about a quarter of an inch thick, so it should be really easy to handle, but I would recommend just purchasing thin sheets or use a wire cutter on heavier ones, this comes with a thin layer of plastic with many perforations. When I tried to peel off the plastic, it hit the holes and just shredded, it would be way too much work.

I mention this because it seems like two layers of fiberglass with foam in between is the best solution and I wondered how much foam you really needed.