Popular Post CHANGES 1,289 Posted May 16, 2018 Popular Post Report Share Posted May 16, 2018 After I did the S300 restoration a few years ago quite a few asked questions about procedures I used to get that just like new factory fresh finish.. Well I have a customers 1982 S3 Turbo chassis to do and thought i would share it with you to help answer those questions.. Firstly I must say what a straight chassis this is before I even start. All datum points are spot on or within 0.5mm What a great example to work with.. The let downs were a couple of rusty spots where the brake pipes were attached.. These are not unusual and a bit of a let down . They can be easily addressed with a local repair and use of a protective paint.. But when you investigate the zinc and measure the consistency of the etch film thickness you realise its showing its age in a couple of area's .. This particular chassis had previously been painted in the accessible area's .. This had cosmetically tidied it up , but as with all paint on zinc unless specific for the job will chip and peel very easily.. as a result will let down any other work done long term . So the first thing to do is total strip , check and record all the dimensions . Next step is off to the media blasters to remove all the paint... This is so important as the acid treatment prior to re galvanizing will not remove paint which will pollute and compromise the procedure/ finish. .. If your media blaster can not get into all the crevices then it may require additional costic/ chemical strip dip. Back from media blasting, which has also removed quite a bit of the zinc coat , especially where it was going thin.. A quick re check on the dimensions and a thorough check no blast media is lying in box sections etc. A final check that all the vent holes which are all over the closed sections are clear and correct size. This is important to (A) let the acid and zinc flow in / out of all the cavities (B) to prevent air pockets forming during the process , this would prevent full coverage of zinc and may also cause an blow out damaging the chassis >>>>> Next step is the Galvanizing process On arrival the chassis goes for an acid dip which takes a couple of hours, this will remove all the remaining zinc and any surface corrosion on unprotected areas during transit. This is followed by twenty minutes in the preflux tank.. This tank is at around 65' so when removed quickly drys.. Next step is into the galvanizing bath.. The chassis is hung over the molten zinc for a period of time to heat it and reduce thermal shock that can distort the structure when immersed in the zinc .. The company I use are very experienced in this type of work a lower the chassis in very slowly to minimise any distortion. When fully immersed it is agitated to ensure any tiny air pockets are released. After a soaking period it is retracted again slowly with careful checks on quality.. ooops I have run out of mb on images so will have to continue later.. '' just as it was getting exciting'' 7 2 1 Quote Link to post Share on other sites
PhilW 403 Posted May 16, 2018 Report Share Posted May 16, 2018 Great. Very interesting. Look forward to more Quote Link to post Share on other sites
Popular Post CHANGES 1,289 Posted May 16, 2018 Author Popular Post Report Share Posted May 16, 2018 PART 2....... After its 450' dip and soak in molten zinc it slowly reappears clean and just like new.. But the process has a bit more to do . The next step is into a passivate bath to give an extra protection against white rust. This also brings the chassis back to temperature that you can handle. Next step is fettle off any little burrs or drips and a final check... And then we have one as new S3 turbo chassis The final steps on this restoration stage are the Dimension check and to drill and tap all threaded sections along with reaming pivot pin/bolt holes. The post dimension check is what most seem to be concerned with... well I am pleased to say this very straight chassis did not move one bit.. its dimensions are exactly the same as pre dipping.. The thread / machining will be done over the next few days. This will complete my tasks with the section of the restoration , I am sure Richard will be keen to get it back to fit all his new suspension.. Hope this answers the questions on how it is done .. D, 9 3 1 Quote Link to post Share on other sites
Gold FFM Barrykearley 7,140 Posted May 16, 2018 Gold FFM Report Share Posted May 16, 2018 Now that looks amazing Quote Only here once Link to post Share on other sites
RichardJGC 381 Posted May 16, 2018 Report Share Posted May 16, 2018 Fantastic work Dave....as always! Looking forward to getting my hands on it and fitting the shiny new suspension. A millimetre perfect chassis. What a starting point! 1 Quote Link to post Share on other sites
stephenwhyte 2,001 Posted May 16, 2018 Report Share Posted May 16, 2018 25 minutes ago, RichardJGC said: Fantastic work Dave....as always! Looking forward to getting my hands on it and fitting the shiny new suspension. A millimetre perfect chassis. What a starting point! C’mon Richard we really need to see some pics of progress as you go😎 Quote Link to post Share on other sites
RichardJGC 381 Posted May 16, 2018 Report Share Posted May 16, 2018 8 minutes ago, stephenwhyte said: C’mon Richard we really need to see some pics of progress as you go😎 I'll see what I can do! 🙂 1 Quote Link to post Share on other sites
CHANGES 1,289 Posted May 17, 2018 Author Report Share Posted May 17, 2018 8 hours ago, RichardJGC said: Fantastic work Dave....as always! Looking forward to getting my hands on it and fitting the shiny new suspension. A millimetre perfect chassis. What a starting point! Nothing like a nice clean / straight starting point to build from.. Plus the peace on mind it has been done correctly not bodged to just look good , This will now last at least another 40 years.... Especially with the new brake pipe mounts to stop a repetition of the bi metal corrosion that took place. I will contact soon to arrange suitable delivery date.. Dave ( in this case only very slight Changes) Quote Link to post Share on other sites
910Esprit 576 Posted May 17, 2018 Report Share Posted May 17, 2018 How was the chassis rail that runs by the manifold. Do you treat this any different or just get it clean? Quote Link to post Share on other sites
CHANGES 1,289 Posted May 17, 2018 Author Report Share Posted May 17, 2018 39 minutes ago, 910Esprit said: How was the chassis rail that runs by the manifold. Do you treat this any different or just get it clean? On this particular chassis , other than zinc depletion ,there was no damage at all .. A fairly straight forward procedure. However there are many where the Zinc has burnt off and rust and even rot has set in. This presents a different set of problems.. Even with just rust pitting the integrity of the section has been compromised.. Most owners look at the outside and assume that is it. Unfortunately the same applies to the inside.. For those that have this issue, they should use an endoscope to inspect the inside , they may be surprised . On the ones that have rotted through , it is clear to see that a great deal of the corrosion has come from the inside as well ... So in those cases, on a chassis I would be doing the above procedure on , I would set the chassis in a jig . remove the offending section and replace with a new piece of the same specification.. This would give the chassis its full integrity and once re-galvanized would be completely invisible.. good as new again... 2 Quote Link to post Share on other sites
Lotusfab 3,297 Posted May 18, 2018 Report Share Posted May 18, 2018 Looks really good. 1 Quote Link to post Share on other sites
Fridge 1,022 Posted May 23, 2018 Report Share Posted May 23, 2018 @RichardJGC I think you now need to get your finger out as it looks like @CHANGES is on the delivery warpath! Make good use of the summer sunshine, and stock up on factor 50! 1 Quote Link to post Share on other sites
RichardJGC 381 Posted May 23, 2018 Report Share Posted May 23, 2018 Yes....coming soon to a garage near me. Think i will just set up a chair in the garage and stare at it for the first day! Its a work of art. Lots of frantic sorting of plating and powder coating batches going on now. It certainly focusses the mind! 1 Quote Link to post Share on other sites
Fridge 1,022 Posted May 23, 2018 Report Share Posted May 23, 2018 Oh yes! Armchair, kettle and an old mug best installed into that garage of yours. Quote Link to post Share on other sites
Ginger pig 17 Posted May 25, 2018 Report Share Posted May 25, 2018 Hi Dave, Great write up by the way! I am just in the process of repairing an s2 chassis. I would love to go down the galvanisation route. Is there any reason that you could think of; why I couldn't galvanise a previously un-galvanised chassis, and would you think it necessary to drill venting holes etc. in preparation? Would appreciate your help on this. Cheers Mark Quote Link to post Share on other sites
CHANGES 1,289 Posted May 25, 2018 Author Report Share Posted May 25, 2018 Hi Mark, Absolutely no reason why a previously un-galvanized chassis can not be prepared and done. As you say the drain and vent holes need doing, this can be done by you or left to the specialist as long as they are well versed.. I personally would do yourself and ask them to check as well.. (Use previously galved chassis info as a guide for drilling etc.) It would in this case be well worth a comprehensive media blasting first , with emphasis on any enclosed sections... Also as the chassis will have years of weathering and paint in enclosed area's that media blasting can not fully access , can i suggest chemical/costic dip to make sure all surface impurities are expelled.. Also ask the Galvanizers to allow a little extra time in the acid process to eat out any tiny corroded points on said closed of areas unseen which media blast will not have removed. As long as the chassis is in good order once fully prepared properly there is no reason why your end product should not look as the one featured above.. D Quote Link to post Share on other sites
Ginger pig 17 Posted May 25, 2018 Report Share Posted May 25, 2018 Dave, you are a fountain of knowledge... galvanising is definitely the way I will go!!! cheers Mark Quote Link to post Share on other sites
NR2k 75 Posted May 25, 2018 Report Share Posted May 25, 2018 On 16/05/2018 at 21:15, CHANGES said: All datum points are spot on or within 0.5mm Interested to know how this check is done? I would like to be sure that our chassis is ok. Quote Link to post Share on other sites
CHANGES 1,289 Posted May 25, 2018 Author Report Share Posted May 25, 2018 3 hours ago, NR2k said: Interested to know how this check is done? I would like to be sure that our chassis is ok. I use Chief jig frame alignment measuring bars.. They are old hat buy today's standards but very accurate in the right hands. However you can get a fairly accurate assessment of you chassis alignment yourself buy using two people and a quality steel tape.. You measure the various datum points and compare to factory spec.. The biggest tell tail is the diagonals. if a pair of these are out then the rest generally follow.. .. on the later chassis the factor spec allows up to 5mm.on these , but you don't often see them that far out unless after a shunt. If your Esprit tracked up well prior to stripping with no noticeable lay back on the wheels then you will have little to be concerned with.. 1 Quote Link to post Share on other sites
silverfrost 1,390 Posted June 12, 2018 Report Share Posted June 12, 2018 Just read through this Dave, Great right up and cheers for posting. Fantastic finish and also hope for lots of folks with early S1 and S2 cars to get this done. Hopefully you can gigi Mike at Lotusbits.com the nudge to get his elite and eclat ungalvanized pile done What would be the cost to pop an esprit chassis on you jig for spec check ? Quote A Link to post Share on other sites
Jared_nomak 13 Posted June 21, 2018 Report Share Posted June 21, 2018 What sort of cost are involved to get this done? 1 Quote Link to post Share on other sites
silverfrost 1,390 Posted June 21, 2018 Report Share Posted June 21, 2018 Looks like you may of started a trend Dave , Everyone will now want a new shiny looking chassis during their restoration rather than chassis paint finish ! Quote A Link to post Share on other sites
GTK 684 Posted June 21, 2018 Report Share Posted June 21, 2018 On 16/05/2018 at 21:52, CHANGES said: The post dimension check is what most seem to be concerned with... Yes yes! we need to know how to do that! Pretty please Dave, my chassis is in a heap 🤓 Quote Link to post Share on other sites
eeyoreish 892 Posted June 21, 2018 Report Share Posted June 21, 2018 How much are we talking to get a chassis re galvanised? Just asking you understand, nothing to do with the Turbo project sitting in my garage... 1 Quote Not worth starting anything now...🍺 Link to post Share on other sites
Popular Post RichardJGC 381 Posted July 31, 2020 Popular Post Report Share Posted July 31, 2020 ....and now reunited with its body. Happy days! 6 2 1 Quote Link to post Share on other sites
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