Thanks Owen. Excellent stuff as usual.
TC David. _____ From: Owen Jenkins [mailto:[email protected]] Sent: 02 July 2012 18:03 To: mogtalk2 Subject: Re: [mogtalk2] chassis at G.E.E. Writing as one who teaches materials and corrosion science, these are my thoughts. 1. Powder coating is fine until it gets damaged, when crevice corrosion can occur underneath it. Once it does, you have to get it all off, grit blast the rusted chassis and start again. Looks nice and lets you clean the chassis, thus suited to concours types. 2. Galvanising works. Galvanising with Waxoyl on top works even better at resisting corrosion. This is my preferred option and what my +8 has. By this means you have three barriers protecting the chassis: (1) the Waxoyl, which is easily replenished, (2) the passive oxide film on the zinc galvanising and (3) the zinc acting as a sacrificial anode to protect the chassis cathodically. 3. Do not expect to repair a galvanised chassis. Two problems: appallingly noxious welding fumes and possibly liquid metal embrittlement of the steel by molten zinc, if the steel gets too hot. A bent galvanised chassis is scrap. Been there. That's what insurance is for. 4. If you are given to doing patch-welding of things, go for an uncoated chassis and weld in new bits when it rusts. The thought of this makes me shudder. 5. Have an uncoated chassis, make sure that it is grit blasted, etch-primed and finished with high-build epoxy. This works well on subsea equipment designed to stay on the bottom of the North Sea for decades. Mind you, they have a cathodic protection system, too. 6. Have a traditional, steel chassis, grit blasted and painted, and keep it well Waxoyled, with annual top-ups. This is what happens on my 4/4. This also works. I suspect GEE don't like galvanised chassis because they are not economically reparable and getting them galvanised is a pain for them, as they will have to subcontract the work; not because of any inherent advantage to you, the punter (unless you make a habit of bending chassis). This is my guess, as an ageing and cynical freelance engineer who has bent a chassis but hopes not to repeat the exercise. Cheers, Owen. ----- Original Message ----- From: Richard Jones <mailto:[email protected]> To: mogtalk2 <mailto:[email protected]> Sent: Monday, July 02, 2012 5:23 PM Subject: Re: [mogtalk2] chassis at G.E.E. I 'm certainly not a fan of powdercoating as once the surface gets cracked water gets under and it bubbles - some of the surfaces on my plus 8 that look to be powder coated like the scuttle and some suspension parts are not good and once it goes you can only take it off and paint it. At least you can touch up galvanizing with a cold touch up - but don't know how effective that is. They must have a good reason for not recommending it though - did think the chassis fitted by the factory were galvanised. Have certainly had a galvanised climbing frame in the garden for the past 20 years and that is stiil as good as new, if not as bright and Alko caravan chassis are all galvanised to good effect. Richard M800RGN+8 From: "[email protected]" <[email protected]> To: mogtalk2 <[email protected]> Sent: Monday, 2 July 2012, 16:43 Subject: [mogtalk2] chassis at G.E.E. Why do they not recommend galvanizing? My 1973 4/4/4 was re-chassied 20+ years ago, and unlike the original ungalvanized one was after about 18 years, is quite sound. That original one had new box cross members fitted and repaired and the rearmost one re-plated. TC David. -----Original Message----- From: Paul Fileman [mailto:[email protected]] Sent: 02 July 2012 15:44 To: mogtalk2 Subject: RE: [mogtalk2] 4/4 chassis on ebay >> Which advert and which month's Miscellany are you referring to? I meant the G.E.E. ad which I cannot find in the July issue. The price list on their web site refers: http://www.geeltd.co.uk/index.php/chassis-prices.html - I have not used them so cannot comment on the accuracy of this information. Best regards Paul ------------------------------------------- View posts on The Mail Archive http://www.mail-archive.com/[email protected]/ [http://www.mail-archive.com/[email protected]/] Modify Your Subscription: https://www.listbox.com/member/? <https://www.listbox.com/member/?&;> & 86 Powered by Listbox: http://www.listbox.com/ ----- No virus found in this message. 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