Honda Insight Tail Extension Project

[123]

Neil I own a fiberglass car body so from experience I can give you a few good reasons why to stick with epoxy, but Jim or others probably now a few things I don't. Epoxy is stronger then other types of resin used with fiberglass and in an application like car bodies where structural integrity is important I would stick with Epoxy.

Here is what can happen to fiberglass given enough time, weather and stress.




If your concerned about biodegradability of the composite skin a plant based plastic/composite would be better, although not as simple in a backyard application.
Henry Ford was working on building cars with this method almost a 100 years ago.

[3-Wheeler]

Originally Posted by NeilBlanchard

Jim,

Were you the person who mentioned using Elmer's Glue on fiberglass? Would the waterproof (yellow) Elmer's work? I am concerned about several things; one is the biodegradability of the composite skin. And the very low VOC and cleanup of this glue would be much better than epoxy.

Hi Neil,

Yes, I mentioned the use of Elmer's Wood Glue about one year ago.

The cool thing about Elmer's is there is basically no cleanup, it's very inexpensive, no smell, and holds the glass cloth better to the substrate when wet than the West System epoxy that I have used.

The Elmer's glue does require some precautions however.

1) It's strength is about 25% less than that of West System Epoxy. I have made test samples that were 14 inches long, 2 inches thick, with one layer of 6 ounce glass on each side of the foam core. The samples were cured for one month, then tested by adding weights on top and the deflection measured with a 1 inch dial indicator.

2) The Elmer's glue needs to be sealed from the elements. This should be easy to do, but chipping of the outer layer of paint can be an issue. Yes, the Elmers glue WILL soften again if left to the elements. I built an earlier fairing for another motorcycle, and the paint chipped enough that water started getting into the glue, which then caused the painted surface to bubble and delaminate! It was a very rainy spring that year.

3) I have a full coverage motorcycle fairing that has lasted almost 20 years by using Elmer's glue to adhere the glass to the foam. Since the foam is soft, rocks kicked up from the road can and will chip the outer layer of paint. This usually happens down to the layer of Bondo Spotting Putty for some reason, even though the surface was sanded carefully before priming and painting.

4) It's possible to glass the front of your new vehicle with epoxy and then use Elmers for the sides and back, where rocks getting kicked up will less of an issue. It's certainly something to think about.

5) I don't think that Elmers has an issue with UV light similar to what the epoxy has. This could certainly be a plus in your favor for using this glue.

6) You obviously can only add one layer of glass at a time with Elmers (with 6 ounce cloth).

7) I have two DVD's regarding airplane construction of glass over foam, and both the Rutan and Arnold copies both make full use of Epoxy resin on their builds.

EDIT after readings 123's post.

7a) The foam/fiberglass fairing has not shown any tendency to crack or otherwise show a degradation of performance through all types of road surfaces, rain storms, snow, extreme summer heat. As mentioned, road stones seems to be the biggest issue with foam over fiberglass. If done properly, you should not have to worry about cracking.

At least you have some facts and figures to mull over.

Jim.

[NeilBlanchard]

I wonder if the yellow "waterproof" Elmer's would also work? I'll give it a try on my 1/4 scale CarBEN EV.

[Joenavy85]

Jim,

One of these days i'm going to drive up there and get your opinion on how to put a tail on my Jeep, as well as a Fiberglass belly pan. I'm looking to build it around a 60"x24" hitch mounted cargo basket. The look of your boat tail is ridiculous, I really wish i had your skill with fiberglass(or any skill for that matter). It looks like it came from the factory with that thing already installed. Outstanding job.

Robert

[3-Wheeler]

Originally Posted by NeilBlanchard

I wonder if the yellow "waterproof" Elmer's would also work? I'll give it a try on my 1/4 scale CarBEN EV.

Neil,

The waterproof glue may work, but I have not tried that.

Another approach to keep rock-thrown-chipping to a minimum would be to follow aircraft recommendations of using at least two layers of glass on any leading edge forms on the plane.

My take is that this is done for safety in case one runs into a bird in flight, which gives the leading edge of the wings more strength against impacts.

On the motorcycle I wanted to keep the weight down by using a single layer of glass, but after seeing the DVD's it may be wise to use at least two layers on any forward facing elements on your design.

That may stiffen the outer layer enough to minimize any chipping.

Jim.

[Joenavy85]

Jim,
Looking through all the pages of this thread(whew!!) I noticed you don't have any pictures of your Alien at night with all the running lights on. I'm really curious how all those LED's look, as well as how it all looks from the side when lit up.

as far as dealing with heavy cross winds, have you considered VG's on the front belly pan?

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my buddy put them on the front belly pan of his Civic and he agreed with the autospeed article, he noticed a significant difference in how it handled cross winds and passing Semi's

[3-Wheeler]

Originally Posted by Joenavy85

Jim,
Looking through all the pages of this thread(whew!!) I noticed you don't have any pictures of your Alien at night with all the running lights on. I'm really curious how all those LED's look, as well as how it all looks from the side when lit up.

Hey, that's a good idea. It's rainy today, and will be for several more, but I'll try to get some pictures at dusk with the lights on when it's dry.

Originally Posted by Joenavy85

...as far as dealing with heavy cross winds, have you considered VG's on the front belly pan?

The car seems very stable in side winds up to 50 mph so far. The biggest thing I have noticed in those conditions, is that the front end still pushes, or understeers.

I'm not sure, but my hunch is that small section VG's would not help much in that condition to make the steering more neutral. For that to happen they would have to make the front end more slippery to the effects of side winds, and allow the tail to be pushed sideways by the same winds, to make the steering more neutral on windy days.

Now it is possible that a large tail fin would accomplish that, but would also impose large side-load forces on the fin and require more weight added for extra strength in that area.

Jim.

[jime57]

Jim, are you going to make an appearance anywhere this summer with your Insight boat tail?

Have you been able to reach any conclusions about Cd from your coast down measurements?

[3-Wheeler]

Originally Posted by jimepting

Jim, are you going to make an appearance anywhere this summer with your Insight boat tail?

Have you been able to reach any conclusions about Cd from your coast down measurements?

Yes, I may end up going to the Madison HybridFest this year.

As for coast down testing, I literally spent hundreds of hours examining the data and discovering that the GPS does not have the quality of data necessary to reach concrete numbers.

It does show some trends between the extreme cold in the winter versus the hot weather in the summer, but as for determining the difference between the tail and without, that could not be determined with the GPS.

I think to do a proper coast-down, one would need a much better way to record actual speed reduction with much more accuracy.

Jim.

[aerohead]

Originally Posted by NeilBlanchard

I wonder if the yellow "waterproof" Elmer's would also work? I'll give it a try on my 1/4 scale CarBEN EV.

Neil,all the fairings for my trailer,except for the axle fairing were done using Elmer's Carpenter Glue ( yellow) over open cell Styrofoam, which allowed the use of polyester resin for a sealer and primer/top coat base.
The parts I didn't knock off in Odessa look as good as the day I finished them in '09.
I just paint it on using a cheap China bristle chip brush.
The brand which competes with Elmer's ( Tite bond?) is equally as good.