Elan '68-Replacing triangulated steel ladder in inner cills
Discussion
Hello chaps,
Im hoping that someone out there may have successfully completed this work and may be able to advise me of the best way to approach the job.
At the moment, a small split has appeared where the outer cill joins the floorpan and ive been advised this is because the ladder is rusting.I presume you have to cut away the inner sill section and that the bottom rail of the ladder sits in a small channel.Is this ladder easy to remove when cut into small sections? What about the bottom rail that sits in the glassfibre channel, is this covered by matting? is it feasible to install the new ladder in small sections and tig/mig weld it insitu?
Im proposing to remove just the horizontal ladder section, leaving inplace the members that go up into the wheel arch sections, these look in good condition.
Finally, is it a feasible alternative to use stainless steel , when replacing this ladder?
Any advise would be gratefuuly recieved.
At first sight, it looks a 'pig' of a job!
Im hoping that someone out there may have successfully completed this work and may be able to advise me of the best way to approach the job.
At the moment, a small split has appeared where the outer cill joins the floorpan and ive been advised this is because the ladder is rusting.I presume you have to cut away the inner sill section and that the bottom rail of the ladder sits in a small channel.Is this ladder easy to remove when cut into small sections? What about the bottom rail that sits in the glassfibre channel, is this covered by matting? is it feasible to install the new ladder in small sections and tig/mig weld it insitu?
Im proposing to remove just the horizontal ladder section, leaving inplace the members that go up into the wheel arch sections, these look in good condition.
Finally, is it a feasible alternative to use stainless steel , when replacing this ladder?
Any advise would be gratefuuly recieved.
At first sight, it looks a 'pig' of a job!
Bloody hell! the classic Lotus enthusiasts are coming out of the woodwork today, aren't they!? 
First off, subscribe to the forums on LotusElan.net and do a search...this topic has been discussed fairly comprehensively.
The splitting fibreglass is quite probably down to rusting trellis/ladders in the cills, so you have been advised correctly.
Good news and bad news...
The good news is that you don't need to cut away anything on the inside to assess the condition of the steel trellis. If you remove the seats and strip out the carpets on the inside of the cills, you will find that there is a hardboard cover panel which is simply held in place with self-tapping screws. It's probably pretty mankey and rotten, anyway, so you're probably as well just ripping it out and renewing it with a new one cut from fresh hardboard/MDF.
The bad news....
Once you get these cover panels off, you will see that the trellis frames are glassed into place. There is no 'channel' as such at the bottom - they just sit against the inside face of the bodyshell, though the bottom rail does sit against the angle between the cill and the floorpan, and the upper rail against a moulded profile on the upper part of the cill. There is a good diagram in the workshop manual (reproduced in Mike Taylor's book 'Lotus Elan - the Complete Story'), which I can scan and e-mail to you if you like, but the best way to understand it is probably just to strip of the internal cover panels and take a good look for yourself.
It will all be very obvious when you see it, but basically you will discover that the whole trellis has to be removed by carefully cutting away the glassfibre, and a new trellis bonded in its place. The trellis kicks up at the back, behind the doors, and at the front, up to the scuttle, and provides structural stiffness to the bodyshell in both these areas.
To fit new ones, you'll have to strip out the interior, including dashboard.
I don't think it would be feasible to mig/tig weld individual sections in situ and I don't think it is feasible just to replace the horizontal bottom half...because the trellis functions to stiffen the scuttle and 'b-pillar' area, it needs to work as a whole, so you need to be careful to ensure that the loads are spread evenly through the bottom ladder and up into the scuttle/b-pillar sections. I think it would be difficult to ensure this by welding in sections in-situ, and in any case you'd be a braver man than me trying to weld in such restricted access areas, in close contact with fibreglass.
I'm afraid you need to do the job properly, as a whole frame, and yes, it's a pig.
I think the concensus when it was discussed on the LotusElan.net forum was that stainless steel would be an option, particularly if you have the ability to bend up and weld replica trellis frames yourself but AFAIK stainless trellis frames are not available to purchase from the specialist suppliers.
Also, you will find that the original trellis frames are made of 'T-bar' steel reinforcing rods meant for reinforced concrete. These are twisted, in order for the concrete to get better grip on them in their intended role, and this helps the fibreglass bond effectively round them in the Elan. The fibreglass would not grip a smooth, stainless steel rod anything like as well, so you might find that the stresses in the bodyshell in use would be enough to crack the bond between the glass and the steel. It might work, but only if you are careful to bond plenty of glass over the junctions of the triangulation on the trellises so that they are restrained in two dimensions. Perhaps you could weld drilled/mesh plates onto the trellis in key locations, to give the fibreglass something to bond to, as well?
AFAIK, you can't get twisted 'T-bar' in stainless, mainly 'cos a little bit of surface corrosion again improves the bond between steel and reinforced concrete, so all concrete reinforcement is of mild steel.
I must admit, my personal opinion would be that since galvanised mild steel is likely to last 30+ years in any case, I'd rather save a lot of time and effort an just buy a pair of trellises ready made from a specialist rather than bugger about designing and fabricating a stainless steel alternative that may or may not work effectively.
>> Edited by Mutant Rat on Sunday 11th September 10:13
First off, subscribe to the forums on LotusElan.net and do a search...this topic has been discussed fairly comprehensively.
The splitting fibreglass is quite probably down to rusting trellis/ladders in the cills, so you have been advised correctly.
Good news and bad news...
The good news is that you don't need to cut away anything on the inside to assess the condition of the steel trellis. If you remove the seats and strip out the carpets on the inside of the cills, you will find that there is a hardboard cover panel which is simply held in place with self-tapping screws. It's probably pretty mankey and rotten, anyway, so you're probably as well just ripping it out and renewing it with a new one cut from fresh hardboard/MDF.
The bad news....
Once you get these cover panels off, you will see that the trellis frames are glassed into place. There is no 'channel' as such at the bottom - they just sit against the inside face of the bodyshell, though the bottom rail does sit against the angle between the cill and the floorpan, and the upper rail against a moulded profile on the upper part of the cill. There is a good diagram in the workshop manual (reproduced in Mike Taylor's book 'Lotus Elan - the Complete Story'), which I can scan and e-mail to you if you like, but the best way to understand it is probably just to strip of the internal cover panels and take a good look for yourself.
It will all be very obvious when you see it, but basically you will discover that the whole trellis has to be removed by carefully cutting away the glassfibre, and a new trellis bonded in its place. The trellis kicks up at the back, behind the doors, and at the front, up to the scuttle, and provides structural stiffness to the bodyshell in both these areas.
To fit new ones, you'll have to strip out the interior, including dashboard.
I don't think it would be feasible to mig/tig weld individual sections in situ and I don't think it is feasible just to replace the horizontal bottom half...because the trellis functions to stiffen the scuttle and 'b-pillar' area, it needs to work as a whole, so you need to be careful to ensure that the loads are spread evenly through the bottom ladder and up into the scuttle/b-pillar sections. I think it would be difficult to ensure this by welding in sections in-situ, and in any case you'd be a braver man than me trying to weld in such restricted access areas, in close contact with fibreglass.
I'm afraid you need to do the job properly, as a whole frame, and yes, it's a pig.
I think the concensus when it was discussed on the LotusElan.net forum was that stainless steel would be an option, particularly if you have the ability to bend up and weld replica trellis frames yourself but AFAIK stainless trellis frames are not available to purchase from the specialist suppliers.
Also, you will find that the original trellis frames are made of 'T-bar' steel reinforcing rods meant for reinforced concrete. These are twisted, in order for the concrete to get better grip on them in their intended role, and this helps the fibreglass bond effectively round them in the Elan. The fibreglass would not grip a smooth, stainless steel rod anything like as well, so you might find that the stresses in the bodyshell in use would be enough to crack the bond between the glass and the steel. It might work, but only if you are careful to bond plenty of glass over the junctions of the triangulation on the trellises so that they are restrained in two dimensions. Perhaps you could weld drilled/mesh plates onto the trellis in key locations, to give the fibreglass something to bond to, as well?
AFAIK, you can't get twisted 'T-bar' in stainless, mainly 'cos a little bit of surface corrosion again improves the bond between steel and reinforced concrete, so all concrete reinforcement is of mild steel.
I must admit, my personal opinion would be that since galvanised mild steel is likely to last 30+ years in any case, I'd rather save a lot of time and effort an just buy a pair of trellises ready made from a specialist rather than bugger about designing and fabricating a stainless steel alternative that may or may not work effectively.
>> Edited by Mutant Rat on Sunday 11th September 10:13
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