broker-len

Sending unit float

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I heard that the cork used on sending unites loses its ability to float??? Who provides this material?

 

SENDING UNIT.JPG

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3 minutes ago, broker-len said:

is it true they loose their buoyancy with age ????

 The cork can become "gas-logged". Over many years, the  shellac that originally sealed the cork gets worn away or dissolved. Especially if using gasoline with alcohol - the common solvent for shellac. . Then the  air that is naturally trapped in cork gets  slowly replaced with gasoline and the cork can't float well.

 

If the cork is not badly damaged, you can dry out it by putting it out side in the sun for a few days (never heat it !). And then as mentioned, use Bill Hirsch gas tank sealer to completely coat the cork and any fasteners that attach it to the metal arm.

 

Paul 

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I would say go with the nitrophyl.  Do not use Bill Hirsch tank sealer as it will not stick to cork very well.  Another solution is to collect a few wine corks.

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You can buy blocks of solid cork on ebay or other places on line.  Remember "GOOGLE" is your friend.

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I bought cork from the local Fishing Tackle shop,

sealed it with varnish from the local Tru-Value hardware store,

Worked perfectly for less than $5,

including the gas to drive across town and back, and buy my grandson an ice cream cone!

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Posted (edited)

Bob's Automobilia has new floats like those floats in the picture.

 

I wasn't ready to believe that cork could lose it's buoyancy. I sunk the original floats in ethanol-laced gas for a few days and no change. So, I put them back in. Worked fine for a few months. I think they sunk. I have not pulled the unit yet to verify that, but if I were you, I would replace them.

 

No nitrophyl for me. They use that stuff in carburetors, and when it gets old, it sinks. I don't know if it is any better or worse than cork, but I'll take my chances with cork.

Edited by Bloo (see edit history)
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I had that problem with the cork in my Model A. I thought the Bratton float was neoprene, not nitrophyl but it's the way to go.

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will try to find cork locally      it has been suggested it has to be sealed     shellac will be dissolved by gas with alcohol       and hirch sealer will not stick           any ideas ?

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Posted (edited)
11 hours ago, nickelroadster said:

I would say go with the nitrophyl.  Do not use Bill Hirsch tank sealer as it will not stick to cork very well.  Another solution is to collect a few wine corks.

 

I beg to differ. The Hirsch sealer sticks just as well to a dried cork float as it does to gas tanks. I've done a few for my customers cars and there have been zero problems even decades later.

 

It's the cork oil level floats used in some engine crankcases that the Hirsch gas tank sealer won't stick to.  And not much else will either after they become oil saturated. For those I make new cork floats and seal them with a good slow-cure marine grade epoxy.

 

Paul

Edited by PFitz (see edit history)

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Posted (edited)

I bought it from a cork manufacture that has since gone out of business. There are plenty of places to get cork, hobby shops, restoration supplies such as the Buick one. And you can use epoxy glue to laminate the cork to the thickness you need, such as cutting up a bulletin board. Laminating it will not cause any flotation problems once it's sealed. 

 

Nothing says the gas tank float has to be round, it just has to float and stay floating.

 

Paul

Edited by PFitz (see edit history)
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12 hours ago, nickelroadster said:

I would say go with the nitrophyl.  Do not use Bill Hirsch tank sealer as it will not stick to cork very well.  Another solution is to collect a few wine corks.

 

I agree. I have tried to reseal cork only to have it sink a week later. The new stuff is the only way to go. 

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The "Bob's" ones are sealed. I don't know what with.

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went to a hobby store  got two almost identical pieces to what is on the unit for  $ 3.00      will seal with Hircsh sealer which I have       thank you for all your input

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Seal it after you fasten it to the metal arm. All the originals I've seen were done that way to seal around where fasteners or the arm go into the cork so it doesn't leak at the edges of those points.

 

Dip the float, or pour the sealer over it and let the excess drip back into the can. Don't use a brush as it doesn't give as even coverage. Let it dry 24 hours and repeat with a second coat to be sure it's well sealed.

 

Paul

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If you use hobby store stuff, be sure to get real corks, and not ground up cork glued together with rubber (like gasket material). I have seen both types. The buoyancy is probably different.

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All very good advice here. I have not only restored my own pre war cars for the past 50+ years but also taught art for 40+ years. DO check the art supplies as mentioned as you want to be sure what cork you get isn't a composite material made from cork bits or filings and then glued together with some adhesive - the art supply companies do not think that their product will be applied for automotive use! Doesn't mean it won't work, just let the buyer ( you ) be aware to read what the make up of what you want will work well. Art supplies usually do not get submerged in gasoline! 😁

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Posted (edited)
41 minutes ago, PFitz said:

Seal it after you fasten it to the metal arm. All the originals I've seen were done that way to seal around where fasteners or the arm go into the cork so it doesn't leak at the edges of those points.

 

Dip the float, or pour the sealer over it and let the excess drip back into the can. Don't use a brush as it doesn't give as even coverage. Let it dry 24 hours and repeat with a second coat to be sure it's well sealed.

 

Paul

 

Paul is correct about sealing the cork AFTER it is attached to the arm.

That is the way I did mine - dipped the lower assembly into the sealer so the rod and cork were sealed together.

Edited by Marty Roth (see edit history)

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21 hours ago, broker-len said:

Who provides this material?

Wineries….

 

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on my 48 Buick the cork was water log ha (gas log). sending unit was shot so i needed to be through with it so i went new unit with brass float . had the choice to go cork but all brass i have seen has out lasted cork . don,t get me wrong i am not disputing the old timers on sealer . 

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I would disagree with Bill Hirsch sealer being ok for floats.  I tried to use it on a carb float a couple of times and it came off in sheets.  I don't think that the floats were exposed to grease or oil.  Two things that can be used to seal cork floats are very thin superglue or model airplane Butrate dope.  If you use superglue, just be sure to use the thin stuff.  If you use new cork you don't actually have to seal it.  I have always sealed mine  just in case. 

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