Delaminating bonnet & deck lid

[pmb]

This must not be "usual" or it would have been posted earlier - however: Both the bonnet & deck lid on my otherwise-very-nice car are coming "unglued" - i.e., the outer skin is separating from the inner portion of the assembly. We are proceeding to apply epoxy & clamp to restore original rigidity, but find it odd that both lids are exhibiting the same problem. On the bonnet it's beginning to the right side (of the car) of the latch at the front, and the deck lid is "coming apart" at both the front edge (right side again) and both sides at the rear edge.
The biggest "nuisance" is needing to unbolt the deck lid to access the leading edge, whilst trying not to cut the wiring to the centre stop lamp. (before you ask, yes, I remembered to pencil-mark the location of the bolts on the hinge first!) Any additional thoughts/suggestions welcome.

[GeoffSmith]

Someone in Dallas is having similar issues. I think Regogo Racing are looking into it for him. His is white too.

EDIT: There's a red one at Regogo right now and they are having to completely remove the bonnet (hood) outer skin.

[CalElan]

There is some definite separation at the rear of my bonnet from the frame. Not a huge amount, but I would like to resolve it before it gets worse.
What's the recommended adhesive to bond these two things together with?

[CalElan]

Giving this a little bump - the soft-top cover is definitely going to need some attention..

[GeoffSmith]

Pretty sure that LGM recommends gorilla glue.

[CalElan]

Pretty sure that LGM recommends gorilla glue.

Really? I thought that stuff was pretty crappy..

[Elanlover]

I think they may make several types. However, the one with the most renown requires water to activate it after which it expands. Perhaps a high quality contact cement or E9000 type adhesive?

[CalElan]

Ideally what I'd like is something I can inject / pour into the gaps, but I suspect that this won't give a great bonding surface with all the old black 'goop' in there.
Kind of in two minds if I should try this or go the whole way and split the panels - clean the surfaces and then re-bond. I think that makes the most sense but it seems like one hell of a job, and I don't really know if it's achievable without damaging the panels.

[ElanSteve]

Bumping this because still haven't seen a good solution.
They did totally separate the bonnet at Regogo and cleaned off all the old black sealant before gluing it back together (adhesive unknown, but I'll find out). We need a solution for less serious delimitation. The problem is the original stuff has decomposed into a black tarry substance - every time I lift the rear deck lid I get some of that black goop on my fingers. Need to be able to inject something that would still stick i spite of the black stuff.
In the case of my bonnet it's just the corner at the back of the right side that keeps popping up so I just push it back down.
Obviously this will only get worse over time, I'm surprised more people haven't reported this.

Steve

[Brit-Car-Nut]

The only way to correct this is to disassemble, clean thoroughly and then re-bond with a urethane windshield adhesive. Your local windscreen installing company has tubes of it. I think I paid around $12.00 per tube.

The stuff you need is what they use to install all of the new windscreens that are not held in a rubber seal. Most Fords and Chevy as well as just about every other make use this stuff.

Measure the original gaps between the panels and then apply a bead that is "thicker" than that and then assemble and squeeze so the dimensions are correct. Let it cure for at least a full 24 hours and then you should be done.

When I was installing the rear quarter panel and boot floor on mine, I used 3mm drill bits for the final spacing and just clamped the parts together to get the correct fit. I don't suggest that you leave the drill bits in the bond, just pull them out once the panel is at the right gap and touch up that spot of adhesive.

[CalElan]

Do you have advice on splitting the panels John?
They seem like they're coming apart, but only until you try and take them apart. I'm sure you know what I mean..

[Brit-Car-Nut]

I am not sure what you are suggesting...

I tried the "official" Lotus tools:

tools.jpg

That was a JOKE!
I then bought an air powered windshield removing tool which cut thru the urethane like butter.

WS-Tool.jpg

I am assuming the urethane is completely across the underside of the "rib" sections so you will need to cut more than 50% from each side...

I think the outside edge "rib" seams are epoxy glued so will require a steady hand and a dremel to cut thru the bonds. Obviously, you will need to re-glue those with an epoxy. I would look at the Lord Fuser line of adhesives. They specialize in solutions for SMC and other plastic issues.

If I am wrong about how the ribs are bonded to the outer shell, explain or post a picture. I will look at a bonnet and boot lid when I go back to the shop tomorrow.

Once you get the ribs off, you will need to clean up all of the "GOO" with scrapers, solvents or even lacquer thinner (be careful! Lacquer thinner will eat plastic and skin and is flammable as well as toxic).

It is not an easy task no matter what tools or skills you bring to the project.

Patience and perseverance are necessary requirements.

[CalElan]

Thanks John, you really are a mine of information. Really appreciate it.
I fitted a new windshield a couple of years back and dealing with all the black goop was the hardest nastiest bit.

I'm not sure I have the heart to take on this task this year - I finally got the doors back together after doing the weather strips, so I may rest on my laurels for a while until the bleak days of next winter roll around again.

[ElanSteve]

Think I'll put off this job for as long as possible, only one corner of the bonnet so far and the rear deck lid -for now I just take a rag soaked with mineral spirit towhee off the excess goo every so often.

The guys at SCW did exactly as suggested and confirmed it is a major PITA to "do it right"!

On a related note have you noticed how you can see the outline of where the inner skin is attached from the outside? Seems more noticeable on the darker coloured cars. Not sure what causes it though?

[chrisP]

Can I offer a little bit of advice, when using the polyurethane glue, prime the panel areas that are to be bonded prior to glue application. You should be supplied with a black primer as part of the glue package.

http://www.rejel.com/pur500t1k/

This should prevent any solvent print through, like some people have seen on their bonnets/hoods
I have found when taking the door skins and other panels apart that lotus originally did apply the primer in some places and not others - where they didn't there is 'print through'

Best
Chris

[Brit-Car-Nut]

Chris:

The urethane adhesive I used had the primer in the mix and the manufacturer states no priming is needed. I asked it there was a primer I could use and the manufacturer said NO, the new product won't work as well...

It has been almost 10 years and there is no odd marks or sections, so keeping fingers crossed.

I don't remember the brand now and they have probably changed the product anyway.

[tigerdog]

I'm guessing that, with time, more of us are facing this. Has there been any further discussion or experience by forum members? What's the current best practice?

[FunElan]

I'm guessing that, with time, more of us are facing this. Has there been any further discussion or experience by forum members? What's the current best practice?

Last I saw (on the facebook group), there were two methods to do this:

1. Split the panels totally in half, clean all the old goo, apply new goo, clamp together, wha-la you have a new panel
2. Inject some new goo between the two panels, clamp, pray

the goo might be some form of adhesive used on boats

[dapinky]

From reading section BJ of the workshop manual, it isn't very helpful, as it just tells us (as we already know) that the panels you are struggling with are 2 pieces bonded together.

Earlier in the chapter it just says that panels are bonded using a "flexible polyurethane adhesive"..... Page BJ23 lists the procedure for repairing bonded panels, and makes reference to various primers, adhesives and ways to use them.....

...... if it were me I'd be putting some plastic wedges between the 2 separating parts to hold a gap, squirt some Polyurethane adhesive in there, then remove the wedges - I usually use Pu18 (made by Bond-It) or Tigerseal.... but there are plenty of similar items out there, and i don't know what you can get in the USA (makes of the same stuff).