Fuel gauge cork

Discussion in 'Firewall Forward / Props / Fuel system' started by Dana, Feb 25, 2017.

Help Support HomeBuiltAirplanes Forum by donating:

1. Feb 25, 2017

Dana

Moderator

Joined:
Apr 4, 2007
Messages:
8,457
2,855
Location:
CT, USA
My new Starduster has the typical cork and wire fuel gauge in the main tank. Problem is, the cork is waterlogged ("fuellogged") and so reads low. I've asked the seller (I'm not going to pick the plane up for a month or so) to pull it out of the fuel to see if it dries out and he's doing that, though he said he tried it before and it didn't help. When I had my T-Craft I kept it out of the tank when not flying, though the main reason was to keep water out (I stored the plane outside so I had an unvented rain cap or it). But I also recall that the cork in the T-Craft was shellacked or something... is it ordinary shellac? Or something else? Obviously shellac would be a no-no if you're using auto gas with ethanol, but I'll be using only avgas.

Dana

2. Feb 25, 2017

Dana

Moderator

Joined:
Apr 4, 2007
Messages:
8,457
2,855
Location:
CT, USA
I should have searched first; sounds like the best solution is to replace the cork with a replacement Ford Model A float that's made out of plastic.

Dana

3. Feb 25, 2017

TFF

Well-Known Member

Joined:
Apr 28, 2010
Messages:
11,128
3,012
Location:
Memphis, TN
I never thought of that.

4. Feb 25, 2017

lake_harley

Well-Known Member

Joined:
Jan 5, 2007
Messages:
938
295
I wonder what the diameter is of the Model A plastic float? I use a cork on my float rod for my MiniMAX that I coated lightly with JB Weld, but it's borderline heavy to float nicely. The problem I'd have though is the tank cap I used when building my fuel tank only has an opening about 1 1/4" diameter at best (going from foggy memory).

Lynn

5. Feb 25, 2017

Wanttaja

Well-Known Member

Joined:
Sep 15, 2013
Messages:
1,127
1,310
Location:
Seattle, WA
The first time I replaced the cork on the Fly Baby fuel cap, it turned into a real goat rope.

I found a nice big cork at the local hardware store, installed it on the wire, slid it through the cap, bent the top, shellacked the cork, and let it dry.

Turned out the cork was too big to go into the fuel tank opening. It was tapered, not cylindrical like a wine cork, and the small end was small enough but the flare was too much.

Grabbed my trusty jackknife, whittled the cork down, shellacked it again, let it dry. It fit...but the cork plunged to the bottom of its travel. Worked in water, but the change to gasoline meant it didn't have enough buoyancy.

Took it of, bought TWO corks, put them inline, an shellacked them. By this point I was getting impatient. Didn't want another overnight wait for the shellac to dry. I grabbed my big mondo heat gun (bought at Boeing Surplus), cranked it up, and pointed it at the corks.

A few seconds later, they caught fire. Looked like a couple of abused marshmallows at a cookout.

So... two new corks, lather, rinse, repeat, and flew Fly Baby N500F for years with the stacked cork system.

About ten years later, I'd bought my own Fly Baby. It needed a new cork on the fuel cap.

I bought a J-3 unit from Wag-Aero....

Ron Wanttaja

6. Feb 25, 2017

Aerowerx

Well-Known Member

Joined:
Dec 1, 2011
Messages:
4,591
1,215
Location:
Marion, Ohio
Well, there's a source for your cork!

7. Feb 25, 2017

N8053H

Well-Known Member

Joined:
Jan 31, 2013
Messages:
2,511
436
Location:
Right here in front of my computer
My fuel gauge is made from hardware store cork. They had many different sizes of cork. I found the one that would fit in the throat of my tank and have been using it now for over 7 years. It sits in fuel 365 days a year and only comes out to fill the tank. I used nothing on this cork and used it as it came from the store. After bending a 90 Degree angle on one end of a rod about 1/4 of an inch long, I stuck the rod through the cork. I then used an RC cars wheel collar to hold the cork into place. On the cap I used a brass nipple like you would find on a fuel primer line were the line goes into the head. That nipple is then threaded into the cap. The rod runs up through this. On the end of the rod that sticks out of the tank, I bent that at a 90 also. I made the length of the rod that when the tank is empty this 90 degree is touching the cap. I then drilled another hole beside this and inserted a piece of aluminum pipe. I made this pipe about 3 inches long with a curved bend in it. This is then flared and stuck into the hole drilled in the cap. It then points into the prop blast. A very simple fuel gauge and vent.

Tony

8. Feb 26, 2017

Dan Thomas

Well-Known Member

Joined:
Sep 18, 2008
Messages:
4,712
1,941
I used a hardware-store cork for the fuel gauge in my Jodel, and coated it with epoxy. Been floating in there for 21 years now. Never comes out, as the gauge isn't part of the cap.

If I did it again I'd use the plastic float off a worn-out Cessna fuel sender. They've been using that plastic since 1996 or so, and the floats outlast the rheostats in the senders.

9. Feb 26, 2017

BBerson

Well-Known MemberHBA Supporter

Joined:
Dec 16, 2007
Messages:
11,415
2,092
Location:
Port Townsend WA
Maybe the rod is too heavy. An aluminum wire would be lighter. 1/16" aluminum welding rod.

10. Feb 26, 2017

plncraze

Well-Known MemberHBA Supporter

Joined:
May 12, 2006
Messages:
1,438
284
I saw a very experienced a and p replace a cork with one of those bottles that you get at weddings so you can blow bubbles at the newlyweds. When you saw fuel in it you drained it.

11. Feb 26, 2017

pwood66889

Well-Known Member

Joined:
Feb 10, 2007
Messages:
1,323
120
Location:
Sopchoppy, Florida, USA
12. Feb 26, 2017

pwood66889

Well-Known Member

Joined:
Feb 10, 2007
Messages:
1,323
120
Location:
Sopchoppy, Florida, USA

Attached Files:

• IMG_0373.jpg
File size:
25.1 KB
Views:
14
17. Feb 26, 2017

Dana

Moderator

Joined:
Apr 4, 2007
Messages:
8,457
2,855
Location:
CT, USA
I like the brass float, but attaching a wire to stick straight out the end is messier. I think I'm going to go with the Model A float described here, purchased here. I was going to wait until I got the plane home to deal with it, but I think I'll buy a couple of those floats and premake a wire with shaft collars as Tony suggested and bring it with me when I go to pick up the plane. After all, a working fuel gauge is a comforting thing on a long cross country in an unfamiliar plane! Using shaft collars will also let me adjust it as I work out its position (ideally, the bend or collar on the top of the wire should touch the cap when there's a half hour of fuel left), and the collars will let me remove it and clean up the installation when I get home.

Dana

Last edited: Feb 26, 2017
18. Feb 26, 2017

N8053H

Well-Known Member

Joined:
Jan 31, 2013
Messages:
2,511
436
Location:
Right here in front of my computer
Mine shows empty with 4 gallons left in the tank. Its an 8 gallon tank. The float sits on the bottom at 4 gallons. This is how the tank is designed. The tank is smaller at the front and wider at the rear, its also thinner in the front then the rear. If I am explaining this correctly. As the fuel is burned the fuel slowly drops from the front of the tank. At 4 gallons used if you take the cap off the tank and look in side it looks empty. But there is still four gallons in the tank that is usable. I use that as reserve in the worse case type of event. I burn around 1.5 -2 gallons an hr dependent on throttle setting. But when I see that rod getting about half as tall I like to refuel. So to me when that rod is down all the way I am out of gas. But I am not.

I made a float type of gauge for a friend. The neck in his tank was really small. I took some brass flashing type material and an electric soldering gun. I used my Craftsman soldering gun. It's one huge gun. But a small torch would work. I took or found a socket that fit down this gas tank neck and used that to make my shape. After soldering the shape together cut a square piece for the top. After soldering in place I trimmed to fit. I took some piano wire like what I used on my fuel gauge and bent one end at a 90. Before I put the bottom on this float I drilled a small hole in the top. I then stuck the piano wire up through this and put the bottom on the little brass float as I did the top. I then hung the float by the wire and soldered the piano wire into place. It worked great and is still being used today.

What I have not found is a way to mark the wire. I would like to mark the wire at each gallon. I do not want to use paint in case it flakes off. But you can make these floats.

Tony

19. Feb 26, 2017

Dan Thomas

Well-Known Member

Joined:
Sep 18, 2008
Messages:
4,712
1,941
Test it in gasoline for a few weeks first. Some plastics will dissolve or turn to goop in fuel, which could cause engine failure by clogging the screens or lines. When brass plug-type fuel valves (as used in trucks and machinery) started showing up with plastic rotors in them back in the late '70s, there were some homebuilt accidents when the avgas ate the rotor. They were designed for diesel.

20. Feb 26, 2017

Dan Thomas

Well-Known Member

Joined:
Sep 18, 2008
Messages:
4,712
1,941
Just go to a local aircraft maintenance shop and ask them to save an old fuel sender for you. They used brass floats for decades.