Atom Frame - is it rust-proofed internally?

[AtomFun]

Whilst at the Haynes trackday yesterday, a gentleman spectator asked if the Atom's frame  is protected from rust internally?

I had no idea! Anyone know?

[atomic]

Haven't heard of internal protection as such, but all the tubing is phosphated before being painted so I can't see rust being a problem.

Had a couple of stone chips repared by Ariel before collecting my car, on one you could see the phosphated surface exposed, but the stone hadn't penetrated this layer.

[AtomFun]

I think the concern was that rust might occur from the inside outward if water was trapped inside. I don't know if the frame is completely sealed but even if it was, condensation would still form.

Be easy to apply a coating of waxol or similar - his suggestion, not mine.

He's lived through the eras of cars just falling apart due to rust!

[atomic]

Fair enough, I don't know the answer but I'm happy to speculate below:

If the tubing is properly sealed, there will be a finite oxygen supply in the air within the tubing. Should condensation cause rust, the supply of oxygen would be exhausted and no further rust would occur. I'm making the assumption that the oxygen inside the tubing isn't enough to cause a substantial amount of rust, and given I'm qualified in Chemsitry only to GCSE level this is quite a large assumption! Sounds similar to the way a central heating system rusts though, the cast iron components (boiler) will rust only until the oxygen is removed from the water, then no further corrosion occurs until someone puts fresh water in (with rust inhibitor though, so is my argument still sound)?

Would be interested to know more about this if someone's got a proper answer!

[Atom120]

I really wouldn't worry about it - kart chassis never have sealed tubes, and I was driving a '93 chassis a few weeks back, and much as I tried, I could not break it. No signs of the tubes rusting. Atoms should be fine too.

[AtomFun]

If you were offered a choice of two cars identical in every respect except one had an extra line in the sales advert that read something like:

Chassis frame professionally treated internally with rust inhibitor.

Even though it might make no difference whatsoever, which of the two would you buy?

[Atom120]

Depends if it was an ex-Rover dealer telling me it'd been treated with a rust inhibitor...

[AtomFun]

Okay, lets assume it was James - Fast Buck 

[Monza]

The type of tube Ariel/Arch is using is internaly treated against rost by the tube manufacturer. It's a specifiq reference of tube.

[Matt F]

This is an interesting question, and one I've often wondered about concerning other types of cars.

First, I'd be curious to know the alloy of the steel used in the tubing, and also who the tubing manufacturer is.  I'd also like to know the way in which the tubing is produced. Usually it's either seamed, seamless, or drawn over a mandrel.  The mandrel type (DOM) is the most common for frame construction, and I assume that it's what Ariel uses.  (Then again, I would assume that they weld the tubes rather than braze them, wwhich shows you what I know!)

Most space-frame manufacturers don't make much of an issue about internal corrosion.  For race cars, their life span is too short to worry about corrosion inside the tubing.  For other road cars, most manufacturers assume that they are fairly air-tight, as atomic suggested, and don't worry about it either.

The worry of internally treating chassis tubing first came to me a few years ago.  I was building a hotrod, with a 1932 Ford frame.  It's made from the same sort of C-channel that's found in many pre-war cars.  Mine was very similar to the pre-Rolls Royce Bentleys.  A popular way to stiffen the chassis of these hotrods is to "box" the chassis, which means welding a flat plate against the open side of the C-channel, effectively turning it into a rectangular tube.  I asked my fellow hotrodding friends if they ever felt the need to rustproof the inside of this channel before (or after) they enclosed it with the welded plates.  Almost no one had worried about that before.  (Then again, most of those guys come from sunny California, not from the "rust belt" in which I live.)

Many of the old school hotrodders that I talked to also raced on the famous Bonneville salt flats.  If anything can cause corrosion, the salt flats can.  Add to the salt the water used in attempts to clean off said salt, and you have a seriously good recipe for rust.  But it really never became an issue.

So, I would conclude that it really doesn't make much of a difference if the insides of the tubing is coated with some sort of rust preventative or not.  It most very probably won't rust from within.  I'd also suggest against trying to add a Waxoyl-type substance, since drilling the holes necessary for injecting the stuff may be the same holes that let in the water and oxygen, which would defeat the purpose.

Finally, I'm skeptical that the tubing manufacturer actually treats the tubing against rot.  They may treat it with an oil, or even a zinc coating, like glavinization.  Either way, this coating would need to be removed at the joints of either a weld or a braze.  This then would be the vulnerable point.

I say: don't worry about it.

--Matt

[coxm]

Adding to what Monza said, the chassis is also sealed, so as to keep the water out as well.

MC

[AtomFun]

I know this is very much academic but despite the frame being sealed, I bet there's moisture collecting in all of them. I'm not gonna chop my frame up to prove the point!

Condensation is a wonderful thing!

[coxm]

Agree.  Me neither, but I think Puff will have been traded for something even faster by the time internal rust starts being a problem.

MC

[AtomFun]

[quote="coxm"]
Agree.  Me neither, but I think Puff will have been traded for something even faster by the time internal rust starts being a problem.

MC
[/quote]

An Exige maybe? 

[coxm]

Absolutely, something with some proper mechanical grip......

MC