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  #31  
Old 05-18-2011, 03:26 PM
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heinke heinke is offline
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Default Preventing tin worms

So I guess the most appropriate follow-up question on how to prevent tin worms is what sealer(s) work best for SS blind rivets. For those of us with new suppleggera construction (i.e. no tin worms yet) and that now have a plethora of sealants/paints available to us, which one(s) have people found to work best?

C5 GTO chassis:


I'm using stainless steel fasteners and have powder coated the chassis tube exterior, so I don't worry about these. I do worry about the untreated interior of the chassis tubes (especially because once water/moisture gets into a vertical tube, it's pretty much trapped there until rust holes let it out ).

Any suggestions?
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  #32  
Old 05-18-2011, 04:32 PM
steve.murphy steve.murphy is offline
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Building steel tube aircraft fuselages, they slosh the inside tubes with hot linseed oil or some other preservative and let it drain out and seal the holes with a rivet.
I have also seen where all tubes are interconnected and it is pressurised with nitrogen (which will not allow rust as it replaces oxygen). And if you put a presssure guage someplace, it can also tell you if a crack develops someplace as the pressure is lost.
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  #33  
Old 05-19-2011, 02:43 PM
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Default Aircraft fuselages not comparable

They must not fasten the aircraft skins directly to the fuselage tubes if the tubes can hold nitrogen. They must fasten them to tabs or something. The core purpose of suppleggera tubes is to fasten the skin to them.

My chassis will end up with at least a 100 holes (maybe upwards of 200) in it with rivets and screws in them. I worry a bit less about screws leaking but blind rivets have a hole in the middle where the mandrel passes through. These are sure to wick/pass moisture unless sealed.
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  #34  
Old 05-19-2011, 05:05 PM
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Kerry Pinkerton Kerry Pinkerton is offline
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Joel, I've had the same concern over the years...long before I knew anything about shaping metal. I did something back in the 80's that might be useful.

The problem was how to seal the inner part of rocker panels on old rusty Mopars after repair. What I did was get a cheap garden sprayer and put a long flexible hose on it with a radial spray tip on one end. I shoved that hose through a drain hole and sprayed the entire thing with POR-15. The excess drained out the drain holes but later inspection showed the entire inner surface was thoroughly coated with POR.

I'd think you could do something similar to your tubes. Put a plug on the top and bottom of each tube, put the chassis on the rotisserie, and fill each tube about 1/4 full, cap the plug and rotate a while, then drain out any excess.

One caution...NOTHING will remove POR-15 but time. NOTHING! I got some on my hand once and it took two weeks to go away. NOTHING takes it off.
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  #35  
Old 05-19-2011, 05:28 PM
steve.murphy steve.murphy is offline
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Joel.
You're right about no holes in the tubing. Tabs are used, or they glue the fabric right to the tubes. I posted somewhere else about aircraft fuel tank sealer, its pretty good stuff. Maybe something like that to seal the rivets? You can get it in different thickenss/viscosity down to brush on consistincy

Nice project by the way! Cant wait to see it done.
Regards,
Steve
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  #36  
Old 05-19-2011, 07:35 PM
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I know a lot of you have concerns about holes in tubes, sealants, etc to stop corrosion, etc -- but after restoring umpteen plus Ferrari's, Alfa's, Bugatti's, etc -- the problem usually isn't the corrosion from within! Most of it is due to external corrosion due to poor storage of the vehicle itself -- and then and only then does the corrosion get internal.

I very much doubt most of you will spend 3000+hrs building a handfabricated car and then drive it as daily transportation in the rain, snow, or incliment weather. When you do -- you will typically clean it up asap as well as store it in "dry storage".

I just look at all the racecars, etc from over the years that we brought to concours and now are used on occasion on the street, vintage raced or rallied. They are exposed to incliment weather at times -- but it isn't that often. I can't remember in the last 25+ years when I took a vintage racer and got out the garden hose and suds and washed it either. If you put that much time/effort into building it -- you typically keep it clean and are aware of any deterioration as it happens.

About the only major deviation of current day restorations -vs- original builds is that today we will paint the chassis before wrapping the aluminum coachwork around it to avoid the galvanic problems that might occur 15+ years from now.

I wouldn't be that concerned about 25/50+ years from now -- I'd be more concerned about having fun with it today. (who knows what the future holds for gasoline engines, our old cars, etc or even legality of driving given the politicians as of late)
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  #37  
Old 05-19-2011, 07:35 PM
jmcglynn jmcglynn is offline
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Quote:
Originally Posted by heinke View Post
They must not fasten the aircraft skins directly to the fuselage tubes if the tubes can hold nitrogen. They must fasten them to tabs or something. The core purpose of suppleggera tubes is to fasten the skin to them.

My chassis will end up with at least a 100 holes (maybe upwards of 200) in it with rivets and screws in them. I worry a bit less about screws leaking but blind rivets have a hole in the middle where the mandrel passes through. These are sure to wick/pass moisture unless sealed.

Joel, use avex rivets, they are a blind, sealed rivet. The aircraft guys use them to build wing tanks.

http://www.avdel-global.com/en/produ...ers/avexr.html

Available through Aircraft Spruce and probably a lot of other places.
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  #38  
Old 05-19-2011, 09:28 PM
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Kerry Pinkerton Kerry Pinkerton is offline
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Quote:
Originally Posted by Superleggera View Post
... -- I'd be more concerned about having fun with it today. (who knows what the future holds for gasoline engines, our old cars, etc or even legality of driving given the politicians as of late)
Sage advice Mark!
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  #39  
Old 05-24-2011, 09:55 AM
David Gardiner David Gardiner is offline
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I read this thread and I could not see any reference to the size, wall thickness material type used for the tube (body) frame. The only dealings I have had is on Aston Martins and I simply matched what was there as closely as possible but does anyone have a definitive answer?. (Or any kind of answer for that matter!.)

David
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  #40  
Old 05-25-2011, 04:20 PM
David Gardiner David Gardiner is offline
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Does no one have an answer? You guys who have worked on these cars ? what is the type of tube used? Steel? Seamless? drawn? welded?
Someone must know.

David
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