MatraSport Forum

I have small tears and chips in in all four wing panels.  I think the previous owner must have used a 'sonic' parking technique and only stopped when he heard the 'crunch'.  :)

I have 2 questions...

From what I read on the web, epoxy resin sticks better than polyester although it is more expensive. So I am guessing that it may be stronger for small repairs around the lips of the wheelarches.  What is the group consensus on which resin to use?

If I remove the rear wings does the glass have to come come out of the small rear windows?  Presumably the adhesive is mainly at the area near the top of the panels and around the windows.  Is it hard to get the panel unstuck once all the rivets are out?

It is very difficult to remove the rear wings, so if the tears are only around the wheel arches, I would definitely leave them on. The front's are easy, as they are only riveted on.

I don't know anything about resin types, so someone else will have to give you advice on that ;)

- Anders

I have rust in the chassis above the trailing arms and I would like to see the extent of the damage properly if I can.  The rust that I can see could be repaired without removing the wings and sills but it would be easier if I could.  I remember how hard it was to remove some panels from my Bagheera so I believe you when you say it is going to be difficult!  If I have to give it a go, will I have to remove the side window glass?

Probably, in Europe, my car would be scrapped and used as a spares car (the car you broke for spares recently looked to be in much better condition than mine).  Luckily it is here and so it will be saved even if the cost of doing so will far exceed its value in Europe.  There are about 20 million people in this country who have never seen, let alone heard of, a Murena so that alone makes it worth saving.

Yes you should remove them.  You will probably find that the metal lip just below them is also rusted and will need attention.  You will need to use a blade between the body and chassis around the tailgate opening to break the mastic seal.

I have not done this job but I know someone that did.

Roy

I agree - mine has rust exactly there. I have had a repair done now from within the wheel arch. It was NOT easy (thanks moes!), and we have not even attended to the rust in the lip under the windows, or in the engine room, which I will need to do something about at some point.

I appreciate your reasons to restore your car, Ron - you are doing it the right way.

- Anders

The panels are BLOODY hard to remove intact..
They were never meant to be removed.. Proof?? Matra made a fibre glass repair piece to repair the wing while it is still on the car!.

Hans and I spend a couple of hours trying to remove a rear wing from Waldo's spare parts car... In the end I gave up..
It CAN be done (Hans has removed the wings from his Bagheera),but
chances are that you will end up cracking the fibre at some point.

The best way to go about it, is by carefully heating the edge that has been glued, and then, like Roy said, cut along it with a thin blade.
The key word here is PATIENCE!!, taking the time, and having a nice place to do the work.. preferably somewhere indoors... with a radio.. and access to plenty of cold beer... (mind your fingers though)  ;D
 

Thanks Krede - good to hear from somebody who has actually tried and failed.  I think I will avoid the experience unless absolutely necessary.

Anybody have any idea as to the best resin to use for repairs to the panels?

Don't know whether this helps or not, but Practical Classics magazine did a complete rebuild of a Bagheera a couple of years or so ago, in which all the panels were removed and resprayed off the car.  I believe the magazine is available in Australia, so you may be able to get hold of the back issues.  Perhaps someone on these forums has a copy they could scan and send.  I would but I gave all my back issues away to make room in the garage for the vanload of spares that came with my car.  In the photographic history that came with my car, there is a picture of it with the offside rear wing removed, so it must be possible.

Thanks.  We do get Practical Classics here.  I will keep an eye out for the issues with the Matra in it on eBay.  I will also see if the magazine has a back issues section. It will be really interesting to see the Bagheera restoration.

I've had a search round and found a few back issues.  The series consisted of twelve articles starting in April 2005, but is pretty unhelpful on the subject of taking it apart, it simply says that they prised the panels off until the glue let go, no mention of applying heat, although that sounds like a good idea to me.  Another point , which may be of interest to Titus, was that the panel repairs and painting were done by a firm called Option 1 of Bromsgrove, Worcs, at a cost of £2500, although that was with the panels off the car.  Don't know what sort of a job they made of it, but the car is now owned by a MECUK member, so someone must be familiar with it.  May have been a special price, of course, in return for publicity.

I took the rear wings of both of the Bagheeras that I owned.  One for welding purposes and one when it was being broken for spares :(

It wasn't difficult on a Bagheera but the murena looks a bit different....  It looks like I will need to do a bit of welding at the back but so far I am hoping that it will just be the end of the sills that require work.  If I end up taking the rear wings off I will get the camera out.

If you people can hold om a bit, I will try to see it Ulf from Norway has anything about it. He has (completly) stripped his white Murena (the V6). Willl return when I have some news on the matter...

http://home.online.no/~utinglum/matramurena.cfm (http://home.online.no/~utinglum/matramurena.cfm)

http://home.online.no/~utinglum/murenav6_08.cfm (http://home.online.no/~utinglum/murenav6_08.cfm)

I dont think you can compare the removing of fibreglass parts from a Bagheera, and then on a Murena. It is well-known that Bagheera chassis rusts. After some years the rusty frames lets go of the glue, and you can usually take it apart without any problems. I have done that to a couple of Bagheeras. But taking a look at the Murena, and seeing how all sealings are still intact, I do believe that it is close to impossible to take it of without cracking some of it. (Believe it or not. The rusty Bagheera chassis actually has a possitive side right here ;D)

Lars

I did my Bagheeras in 1986 and 88 and one was a '78 and the other was a '79 (it was bought for spares as it was already getting rusty underneath and around the screen :( (If I had it now in that condition I would be restoring it but it was different times). 

However, the areas where the wings were attached were not rusty and the sealant was still sticky. 

I think the problem with the murena is that the design is different, however I will let you know if I manage to remove mine....

Yes you are right,epoxy does stick better and its stiffer to. The good thing about polyester is that is cheap, but has tendency to dry up and absorb for a few reasons (shrinkage) and works only with glass fiber.
Its more evident on bigger areas, and for small cracks it is much important to use good and adequate fiber.
Some hints,  use twill fiber, glass or carbon, of less g/m2 applying few layers on both sides of crack.
The biggest problem is air which get traped inside, so got to be careful.
Have you worked with resins, do you need procedure info

The last time I did anything worth mentioning was 35 years ago when I made a couple of car seat shells so my experience is very out of date.  The few times I have mixed resins since, I have had very variable results so I have been looking on the Lotus forum for hints.  They seem to recommend the West system

 http://www.westsystem.com.au/west_system/

What attracts me is their dispenser system so as to get the proportions correct as I feel this is an area where I have gone wrong in the past.  Either too much or too little catalyst.

One of the cracks on the rear skirt had been 'repaired' by the previous owner and I was able to pull the patch off by hand as it had not bonded at all well.  This got me thinking that I had better get up to date with current thinking and find out what are the pros and cons of the various materials.

Also I have one small area of stress cracks which I intend to fix with tissue and resin after grinding away the gelcoat.  Stress cracks worry me as I have not been terribly successful with repairs to my Lotus. (again 25 years ago). The repairs have tended to shrink over time and become visible.  I have thought to avoid this problem by waiting a month or so before applying a final coat.

Dispensation can vary by manufacturer,but common for polyester is on 100g resin 0.5g or 0.5ml of accelerator (usually already mixed) and 2g or 2ml of hardener. The temp cant be below 15C, the ideal is 20-23C, if below the accelerator can be raised (hardener not) and vice versa.
Westsystem site have pretty much everything you need about epoxy and working with it.
For cracks, for first layer, just to fill crack, I use glass cutting or powder or ash, after, another two thin layers of twill.
After epoxy you dont need primer, chemicals dont etch it, just good sanding. Polyester gets weakly stick to it to. At the end you can put plastic foil, expel the air and you will get nice surface. If there are some air hole after, fill them with resin- air bubbles contour after few month if is used some filler.
The stiffnes mostly depend on air between layers and in fiber coating, it must be complet transparent after applying.If its very stressed spot,with epoxy you can use carbon fiber and youll get most you can.