Building a gas tank

I'm at the point where I need to build a gas tank or 2. The sport
plane builder book shows a great way to do a custom tank but materials
it calls for are not listed (or I'm reading it wrong) so, any
recommondations on a foam core that will stand up to gas? Any
recommondations for a fiberglass system? I'm all ears, or in this case
eyes.
Lou

I made a custom shaped gas tank a couple years ago. I had no experience at
all doing such a project but I ended up making a nice tank for my plane.
http://www.mitchellwing.com/FLYING_F...s/MVC-340F.JPG




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On 12 Aug 2004 02:55:43 -0700, (Lou Parker) wrote:

I'm at the point where I need to build a gas tank or 2. The sport
plane builder book shows a great way to do a custom tank but materials
it calls for are not listed (or I'm reading it wrong) so, any
recommondations on a foam core that will stand up to gas? Any
recommondations for a fiberglass system? I'm all ears, or in this case
eyes.

The G-III uses Vinyl Ester Resin and foam cores for the header tank.
I don't remember as they actually tell you the chemical composition of
the foam. It is a light tan color.

The cut the sides, bottom and back from 5# 1/2 inch foam, seal the
foam with a thin micro sphere (Q-cell) mix, then give it two layers of
fiberglass and resin on each side. These lay-ups are a bit on the
resin rich side.

You don't even get Styrofoam near Vinyl Ester resin. It dissolves it.
Vinyl Ester Resin contains liquid Styrene. Let it set around too long
and it gets "chunky".

The only drawback I can see to the Vinyl Ester Resin is the short
shelf life. Supposedly only a couple of months after being promoted,
but I get 6 months to a year after promotion. I'm just finishing a
gallon that was promoted in March and it shows no sign of getting
chunky. Only a couple more lay-ups and that can will be empty. I'm
promoting a new gallon so it'll be ready to use by tomorrow night.
Contrary to the instructions in the manual. I just pour in the proper
amount, and shake the can in all axis for about 5 minutes. Let set
over night, shake again, and then run a test batch about 6 hours
later.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Lou

On Fri, 13 Aug 2004 06:02:41 GMT, Roger Halstead
wrote:

You don't even get Styrofoam near Vinyl Ester resin. It dissolves it.

Back when I was about ten, I tried to build a styrofoam wing for a
U-Control airplane. When I was carving the airfoil, the wing broke in
half. Being both lazy and poor, I just slobbered glue over the broken
edges, put the pieces back together, and set them down on a piece of wax
paper.

When I came back a half-hour later, there was a ~1/2" gap between the
halves of the wing. "That's strange," I said. I slathered some more glue
on the two pieces, jammed them back together, and set it on the wax paper.

A half hour LATER...well, there *still* was a 1/2" gap. Right about then,
I started to figure it out. :-)

Ron "Nod's as good as a wink to a blind bat" Wanttaja

Lou Parker wrote:
I'm at the point where I need to build a gas tank or 2. The sport
plane builder book shows a great way to do a custom tank but materials
it calls for are not listed (or I'm reading it wrong) so, any
recommondations on a foam core that will stand up to gas? Any
recommondations for a fiberglass system? I'm all ears, or in this case
eyes.
Lou
If it's a relatively simple shape & you aren't just addicted to resin
fumes, aluminum works great & stands up to just about any fuel. If you
don't have access to a bending brake, most sheet metal shops can do the
bends for you. If flanges are external to the tank volume, you can seal
the joints with 'proseal' & rivet it with 'pulled' rivets.

Charlie

Charlie England wrote:

Lou Parker wrote:
I'm at the point where I need to build a gas tank or 2. The sport
plane builder book shows a great way to do a custom tank but materials
it calls for are not listed (or I'm reading it wrong) so, any
recommondations on a foam core that will stand up to gas? Any
recommondations for a fiberglass system? I'm all ears, or in this case
eyes.
Lou
If it's a relatively simple shape & you aren't just addicted to resin
fumes, aluminum works great & stands up to just about any fuel. If you
don't have access to a bending brake, most sheet metal shops can do the
bends for you. If flanges are external to the tank volume, you can seal
the joints with 'proseal' & rivet it with 'pulled' rivets.

Charlie

Gotta agree with Charlie on this one.
Aluminum is way mo betta.

I haven't tried this myself (no guts?) but one of my builders
reported good results using a novel technique.

Flange the end pieces, and make a wrapper skin.
Etch both using the green stuff (phosphate etch from Home Depot?)
Prime with something like Epibond.
Then assemble using PL-1 urethane adhesive (i believe) and pop rivet
the tank together.

Hey, that's why the cal it experimental!

Richard

Richard Lamb wrote in message ...
Charlie England wrote:

Lou Parker wrote:
I'm at the point where I need to build a gas tank or 2. The sport
plane builder book shows a great way to do a custom tank but materials
it calls for are not listed (or I'm reading it wrong) so, any
recommondations on a foam core that will stand up to gas? Any
recommondations for a fiberglass system? I'm all ears, or in this case
eyes.
Lou
If it's a relatively simple shape & you aren't just addicted to resin
fumes, aluminum works great & stands up to just about any fuel. If you
don't have access to a bending brake, most sheet metal shops can do the
bends for you. If flanges are external to the tank volume, you can seal
the joints with 'proseal' & rivet it with 'pulled' rivets.

Charlie

Gotta agree with Charlie on this one.
Aluminum is way mo betta.

I haven't tried this myself (no guts?) but one of my builders
reported good results using a novel technique.

Flange the end pieces, and make a wrapper skin.
Etch both using the green stuff (phosphate etch from Home Depot?)
Prime with something like Epibond.
Then assemble using PL-1 urethane adhesive (i believe) and pop rivet
the tank together.

Hey, that's why the cal it experimental!

Richard





These have been great responses. But what about places to attatch fuel
sending units, gas caps, and drain plugs? How do they attatch and
where? Do you glass in a peice of wood to screw to? or better yet, a
peice of corian that can hold screws but not be affected by wood? What
about support flanges to fiberglass? With enough bouncing around,
screws will rip through fiberglass.
Loiu

Wouldn't a composite fuel tank be a static electricity risk?

Dan, U.S. Air Force, retired

(Lou Parker) wrote in message . com...

These have been great responses. But what about places to attatch fuel
sending units, gas caps, and drain plugs? How do they attatch and
where? Do you glass in a peice of wood to screw to? or better yet, a
peice of corian that can hold screws but not be affected by wood? What
about support flanges to fiberglass? With enough bouncing around,
screws will rip through fiberglass.
Loiu

Phenolic makes a good hard point where you need one. Aluminum
"welding flanges" as sold by AS+S, can be bonded into the glass
depressions, as described by another poster, for fittings. Just drill
some holes in the flange and encapsulate the aluminum part with flox
(chopped cotton fiber and resin). The resins we use do NOT bond to
aluminum. Phenolic doesn't bond all that much better but as long as
your not using the aluminum/glass or phenolic/glass bond as a
structural member this has proven to work well.

Test the tank for leaks before putting fuel in for the first time.
================
Leon McAtee

On 15 Aug 2004 21:01:03 GMT, (B2431) wrote:

Wouldn't a composite fuel tank be a static electricity risk?

I haven't had one blow yet, which I know doesn't answer the question.
Kinda like putting static wicks on a plastic airplane.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Dan, U.S. Air Force, retired