12 replies to this topic

[[email protected]]

Need to reskin the doors on my 1991 Mainstream Cooper due to bottom rust and PO Bondo layer.

Considering going with Aluminium because A. they are touted to not rust and B. since I don't weld and this article talks about epoxy'ing the skins on, I thought I could still DIY it.

Can anyone recommend going with aluminium Door Skins over Heritage steel?

 

[sonikk4]

Never fitted them so cannot comment on that, but Aluminium does corrode and especially if it contacts bare steel. This is then called dissimilar metal corrosion.

So if you do go down this route make sure you have a protective coating on the door skin and no bare metal on the door frame.

No reason why you could not DIY it at all. Some decent clamps would be needed and care taken.

[Steve220]

Alloy skins can buckle and dent easily. As Neil mentions above, galvanic corrosion is what to watch out for. Either paint the inners then bend the alloy over, or put Duralac or similar between the join.

[nicklouse]

And as the doors are “wet” make sure the drainage is good and maybe add more holes.

[slidehammer]

I remember one of the Mini Magazines a few years ago fitting some to make light weight track car doors. They removed a lot of the inner frame skin as they were putting perspex windows in. They mentioned the importance of isolating the 2 metal and bonded them on with Tiger Seal as you obviously can't weld any thing only bond and crimp edges. I would imagine crimping the edges without marring the outer skin would be all but impossible. They made no mention of a poor fit in the article though.

[imack]

I think the alloy internal hinge skins are made by magnum, so I'd guess the fit is similar to a magnum steel skins.
I have read reports of the skin denting easily around the door handle but don't know if they were talking about internal or external hinge doors.

[sonikk4]

With a little thought you could reinforce certain areas by bonding on another piece of aluminium internally ,but this would need to be the right heat treatment.

 

So T0 is very malleable and easy to shape but also very easy to damage / bend /dent etc. T3 is better, can be folded and rolled and on a curve would be better to use. T6 is the hardest but also its the least workable. 

 

I can imagine the door skin being T0 or possibly T3 if the edges can be easily folded.

[Cooperman]

Aluminium door skins are really only suitable for race & rally cars where a few dents will not be an issue. For a road car they do dent and distort easily, although I take the point about being easy to bond on with Tiger Seal.

I don't see why a steel skin cannot be bonded on in a similar way. The only welding needed normally is at the tops where the skin is welded locally to the door frame at the lower window edges. I use Tiger Seal for the rest of the skin even when fitting a steel skin as  it stiffens the structure and prevents rust building up at the join line. Remember, the skin is mainly just crimped on (using the correct crimping tool!).

[imack]

I'm currently restoring some all aluminium BMC Special Tuning mk2 bonnet and boot lid from the late 60's. They're very delicate and easily damaged compared with steel items.

[[email protected]]

Wow!  First off, thanks to everyone for contributing so many thoughts and recommendations!

 

I hadn't thought about the dissimilar metal / galvanic rusting issue - the recommendations sound like you can compensate for this by properly coating and isolating the two metals, but I never would have even thought about it without you folks pointing it out! (thx to sonikk4 & Steve220)

 

Additionally, I hadn't realized that the aluminium would be so delicate - thanks to everyone who had information to share on this possibly important CON for going Aluminium.(thx Steve220, imack & Cooperman)

 

Street parking in NYC as I do, that might be a reason to go for the thicker steel Heritage skins and maybe find a welder to do the needful with that assembly. 

 

And finally thanks to everyone who contributed Tips & Tricks pointing me in the right direction for getting this done right either way I go forward (thx sonikk4, Steve220, nicklouse, slidehammer).

 

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A side note / follow-up: 

 

I have a 1991 Mainstream Mini Cooper, and as such the doors do not have the crashbar which was added in 1996.  But since I live and drive my Mini in New York City, this might be a sensible addition!

 

At 1:51-2:17 in this video...

 

 

...you can see the late model crash bar simply being screwed into the inner frame above the roll-up window channel.  

 

That, in my estimation, would make it an easy add-on to an older door while the door skin is off:  Beyond possibly drilling the two holes in the front & rear of the inner frame, at most one might want to weld in a strengthening plate on each side of the frame, front and back... but other than that it seems almost a "drop in" modification.

 

I reached out to British Motor Heritage to ask if I could buy two door side crashbars (and screws) as a separate purchase and they replied:

 

We don’t list the crash bars as a separate item, as the bar can only be fitted with the door skin off.  We are currently running on limited staff and if you can wait until the current situation improves, it would be easier for us to help you with your special request.

 

So it sounds like they might be willing to come up with an ad hoc price and simply pull two crashbars off the assembly line...

 

As long as it is not crazy-expensive, do folks see this is a worthy "upgrade" to pursue while I have the skins off anyway?

Edited by [email protected], 19 June 2020 - 06:33 PM.

[nicklouse]

seen these

http://www.minidoor....eetfighter.html

[sonikk4]

To be honest that crash bar is just a tick box exercise to conform to later legislation. Will it do anything, probably not as the actual door carcass is no stronger where it mounts to.

[[email protected]]

Oh yes! I have seen those Street fighters nicklouse!

I stumbled on them when I was trying to find someone to reskin my doors.

I even corresponded with Mick (often recommended in this forum, by the way) but we worked out that even with his exchange program" which not only keeps the price down, but reduces the turn-around time (where he sends you a completed door, and your door frame, shipped to Mick, becomes the next buyer's), the shipping back-and-forth from the US to the UK made that option cost prohibitive.

I need to be conscious of overall cost here as my Accountant/Financial Advisor (read: Wife) is already upset about what I spend on "my Mistress" (read: the Mini).

Speaking of cost, I appreciate the "hard truth" about the crashbars Sonikk4, if they aren't going to actually do anything, then they won't be worth the extra cost or effort.