Mike's Cabrio Build

[greyV8pete]

Re: Mike's Cabrio Build

Hi Peter

Yes, I chose the lockable filler neck, giving myself the option in the future, but how prevalent is petrol syphoning these days?

Mike

Mike. Have sent you a PM. Peter.

[Mike]

Re: Mike's Cabrio Build

I always know its been a long while since I last updated my diary when I can not find the thread easily in the current threads section.........

But its a big week this week:
I've dismantled the bodywork ready for painting! - all 26 pieces of it.



and will it fit in a Q5?

Yup!



.....well nearly!!



My Cabrio kit is now at the painters - Normandale in Daventry, with whom I am very impressed - I knew they would make a good job of the paint - that was a given - their two other Marlin paint jobs have each won Best in Show at Stoneleigh. It was the entire operation, additional advice, and service I found so impressive.
Phil Drucker runs a very efficient Paint and Refinishing shop, and offered some very matter of fact advise regarding my kit and how he could improve the long term durability of its construction. I have therefore agreed that he will now bond the front inner and out wing edges together (the aluminium to GRP), and then mechanically rivet them together (removing the stainless counter sunk screws I had fitted). I have no doubt it will make a much better long term joint.


And despite having 10 years to think about colour while I built my Cabrio, I still do not know what its going to be?! - I have a week to decide whilst Normandale prep all the panels ready for the colour coat the week after next.

Sadly, although the panels will be ready just prior to the Bank Holiday weekend, I will not have sufficient time to re-assemble my Cabrio ready for the Stoneleigh show - but I should be able to complete the build and have it on the road for this summer - assuming we get one!

[greyV8pete]

Re: Mike's Cabrio Build

Decisions, decisions! C'mon! At least post a photo of the colour before Stoneleigh if you can't get the car there Mind you it might just be possible if you work at it all night .......

[dogoncrazy]

Re: Mike's Cabrio Build

I would rather that my wings had been put together with countersunk stainless screws, much easier to then replace a wing should it ever get damaged. Are they going to etch prime etc the inner before bonding/riveting? Interested in why they consider it to be better their way ? Longevity - I'm doubtful on that one.

[Mike]

Re: Mike's Cabrio Build

I would rather that my wings had been put together with countersunk stainless screws, much easier to then replace a wing should it ever get damaged. Are they going to etch prime etc the inner before bonding/riveting? Interested in why they consider it to be better their way ? Longevity - I'm doubtful on that one.

Hi Alan

Phil's reasoning is that a set screw and nut will work loose: there is no spring in the design, whereas a rivet can be set in tension so always stays tight.
I had already had some experience of this, as I had tightened the set screws at the point of construction but found several of them were very loose when I came to dismantle the wings.
I am persuaded that bonding the inner and outer wing together chemically is a good idea, and then reinforcing this with rivets makes just adds extra reliability.

Another consideration was that Marlin had counter sunk my GRP wings far too deep so the screws heads were going to have to be covered with filler. In a perfect world I may have chosen to counter sink the screw heads flush, but this would have been nigh on impossible to get right factoring in a coat of paint. So I resigned myself to covering the screw heads, but then I was never convinced the heads would not rotate when the nut was tightened, and would ruin the paint.

I concluded bonding with a very good modern material, plus a rivet was a safer bet.

How have others made the connection between inner and outer wing?

[milliemarlin]

Re: Mike's Cabrio Build

How have others made the connection between inner and outer wing?

Millie’s are bonded using military aircraft technology. As it used by Aston Martin I guessed it was good enough for me. The high tech bonding technology is also known as Araldite. She is then riveted using holes drilled somewhat imperfectly prior to my ownership. I used countersunk pop rivets, another aircraft technology, to hold the panels in position and reinforce the bond.

[Mike]

Re: Mike's Cabrio Build

Millie’s are bonded using military aircraft technology. As it used by Aston Martin I guessed it was good enough for me. The high tech bonding technology is also known as Araldite. She is then riveted using holes drilled somewhat imperfectly prior to my ownership. I used countersunk pop rivets, another aircraft technology, to hold the panels in position and reinforce the bond.

This is very interesting, as it sounds like how mine will be now.
How long have your wings been assembled?
Has everything remained stable?
Have you any sign of any relative panel movement - any signs of paint cracking along the joint area?

[milliemarlin]

Re: Mike's Cabrio Build

Millie is a little over 11 years old.
The painter was not as good as I would have liked and I think he could have done a better job of finishing off the rivets. The heads can be seen through the paint also some of them have clearly expanded and cracked the paint to expose the head’s outline. But you do have to look very closely to see these flaws. The aluminium inner wing to fiberglass looks fine. The joint is not very visible so I can’t be sure there is no cracking of the paint. The underside has been undersealed and I can’t see any cracking on this side. I will need to clean the underside to have a closer look as I only got back from a somewhat soggy Silverstone last night.
Overall I am satisfied with the result.
Paul

[danny_nelson]

Re: Mike's Cabrio Build

All the (factory) built cars that I have had experience of have been bonded and riveted, but I did not think it had anything to do with paint longevity.

[dogoncrazy]

Re: Mike's Cabrio Build

I have to disagree on the rivet thread. I had 12 years in the military replacing them as part of my role. I will accept that aircraft are subject to quite different stresses. Pop rivets of any type are ok if access is only to be had to one side just try removing them without leaving a larger hole than you started with!!

[milliemarlin]

Re: Mike's Cabrio Build

ASFAIK there are two potential problems with the paint. One is the dissimilar materials can show through the paint. The second is that the different expansion and contraction rates can cause cracking/marks on the paint. I think an expert painter should be able to avoid the first the second I don’t consider a big problem in this case.
I agree that pop rivets are not perfect but the hope is that once riveted together the assembly should never need to be taken apart.
A couple of pictures of Millie’s wing to show the problem but as you can see she has still not been washed.

[Mike]

Re: Mike's Cabrio Build

I have to disagree on the rivet thread. I had 12 years in the military replacing them as part of my role. I will accept that aircraft are subject to quite different stresses. Pop rivets of any type are ok if access is only to be had to one side just try removing them without leaving a larger hole than you started with!!

Hi Alan
I was looking forward to your input, knowing your aircraft background. I guess the decision each of us takes is based on what criteria we judge to be important, and that is heavily influenced by our experience?

In my case, I had not bonded the joint, which, when pointed out, sounded like a very good idea, (and from Danny's comment is supported by what Marlin do), so I asked Normandale to do this prior to painting.

Normandale did advised that I would be able to see the rivets below the surface of the paint - but when he showed me an example of a classic Jaguar bonnet with rivets, I honestly could not see them, and decided I would be happier knowing I had mechanical rivets giving additional strength to the chemical bonding.

Originally I chose stainless screws as they offered me the theory of being able to bolt the two wing parts together on the car, allowing a minor degree of panel to panel adjustment, as well as for their anti-corrosion properties.

However, I was always concerned that the only forces preventing the head from rotating would be friction, and a very thin layer of resin above the head. My concern was that this would fail when I tried to re-assemble the wings, and I would crack the paint surface as I tried to tighten each nut. Normandale's comments struck that nerve. By bonding, and then riveting the joint, I should at least avoid that problem.

On aircraft, what is/was the reason for replacing rivets?
Had they worked loose?
Do they fatigue?
Is it routine maintenance purely to avoid possible failure issues?

I take your point about drilling them out, but I guess if I am ever in the position that I need to separate the inner wing from the outer because of damage, I will be looking at a new paint job anyway!

[dbazdavies]

Re: Mike's Cabrio Build

there is a product called Tiger Seal that we used to use on 'wobbly' vintage wooden Rolls and Bentley bodies and it worked a treat - made the bodies strong and rattle free - to test the strength we put some between 2 pieces of metal in a vice - next day you could not pull them apart..

for the smooth look , you could put some between the inner and outer wing bolt them together, clean the edges , and when dry take out every other bolt , use loctite on the remaining bolts and then cover all the holes for that smooth look !!!

[Peterx]

Re: Mike's Cabrio Build

And despite having 10 years to think about colour while I built my Cabrio, I still do not know what its going to be?! - I have a week to decide whilst Normandale prep all the panels ready for the colour coat the week after next.

Hi Mike,
made up your mind yet??

I think this coulour scheme looks very classy.....

pr1_cabrio_blue_moors_m1b.jpg

cheers, Peter

[Mike]

Re: Mike's Cabrio Build

Hi Mike,
made up your mind yet??

I think this colour scheme looks very classy.....

[ATTACH=CONFIG]7370[/ATTACH]

cheers, Peter

Nope!

I've been outside several times this week holding out sample colour cards trying to decide which one............
Out of the 4 sample cards I have, I've picked three of them that were "Definitely this one"........... only to change my mind later in a different light!!

To be fair, I probably know the colour, just not the shade, or mix (metallic/pearl effect etc?).