Repairing damaged carbon fibre car doors


Author
Message
RyanParle
RyanParle
Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)
Group: Forum Members
Posts: 20, Visits: 1.2K
A few years ago i bought some carbon fibre doors for my classic mini from a fairly well known supplier and on unpacking them i discovered that they were both damaged, there is a linear fracture about 2" long on one and a "spider" fracture on the other about 2" x 3"from what i can see the fractures are in the resin and the fibre beneath looks intact. The supplier refused to replace them or repair them, i said i would pay for the repair if he aranged them to be collected from me by courier, the supplier agreed, but never sent a collection despite many phone calls. in the end i decided that i would live with the damage.

since then i got them fitted which turned out to be a much harder job than it should have been as they turned out to be a bit thicker than the original steel doors and would foul on the body work and then after a few weeks exposure to the elements they also started to discolour (even though i was assured that they wouldn't!

After taking on my first carbon fibre project of making a fog light pod using the wet lay technique I decided that i would have a go at repairing the doors, but i am not sure how to go about it.

I originally though about carefully sanding back the gel coat / resin and then spraying on a new coat and flatting / polishing them up to a smooth finish, but i am unsure if this will remove all of the discolouration or if there will still be some discoloured resin in the weave of the carbon. Is this a viable method to repair the cracked resin and remove the discolouration?

Then on the weekend i was looking at the way the doors are assembled and realised that the extra thickness comes from the way the inner and outer sections are bonded together, the join has about 8mm of "bonding material"  which looks like it is resin and a bit of loose fibre re-enforcement,  between the two sections. I feel that the two sections could have been bonded in a better way (for example the way demonstrated in the tutorial videos on here) so i am now considering taking a mould from the existing door skins and making new skins myself. then i can remove the original skins, clean up the inner frames and make a neater job of bonding the two sections together.

Any thoughts on this would be much appreciated. 

Obviously if i go down the route of making new door skins i would choose to use the resin infusion method in order to achieve the best results possible, so it will cost a fair bit more to do, however i am also in the process of designing a new dashboard so that i can get the instrumentation & switches mounted in a place where it can all be seen / operated whilst harnessed in, so at some point buying the resin infusion kit will be required.
Matthieu Libeert
Matthieu Libeert
Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)Supreme Being (7.5K reputation)
Group: Forum Members
Posts: 955, Visits: 3.4K
sounds like a lot of problems you got there with your supplier...
The doors probably started to change colour because they didn't had any clearcoat on top and the resin was not UV-stable.

Looks like your way of thinking is good... but now that you allready have your doors fitting well?! you would have to do that step again for your new doors coming out of the moud?
I was thinking about something else you could do; you could skin your doors with just one new layer of CF (could be the cheapest way to get good results) and add a clearcoat on top. 

Matthieu Libeert
Founder MAT2 Composites X Sports
website:
www.mat2composites.com




RyanParle
RyanParle
Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)
Group: Forum Members
Posts: 20, Visits: 1.2K
matthieutje65 (25/11/2013)
sounds like a lot of problems you got there with your supplier...
The doors probably started to change colour because they didn't had any clearcoat on top and the resin was not UV-stable.

Looks like your way of thinking is good... but now that you allready have your doors fitting well?! you would have to do that step again for your new doors coming out of the moud?
I was thinking about something else you could do; you could skin your doors with just one new layer of CF (could be the cheapest way to get good results) and add a clearcoat on top. 


Yeah I'm not very happy with the supplier and next time I see him at a race meeting I will be telling him all about it!  When I purchased the doors along with a removable front end, a boot lid, a parcel shelf and a boot floor panel I asked if I needed to do anything to protect the resin from UV I was told that all parts used a UV stable resin. The way I see it there was either a mistake made during manufacture or the supplier was telling lies about the products used.

I did consider skinning over the top but I don't think it would work as if I were to add an extra layer of carbon I would only make the problem worse,  the doors fit fine in the closed position but when opened they foul the A panel,  the driver side door isn't perfect but can be opened a reasonable amount, but on the passenger side the door can only be opened about 2/3 of the way, if I open it any wider it will damage the paint on the A panel. This is due to the thickness of the bond between the outer skin and the inner frame.

if I chose to remove the original door skins and re fit new ones I would make the bond between the skin and the frame as thin as possible, this wouldn't upset the gap around the door, but would reduce the thickness and allow them to be fully opened.
Edited 12 Years Ago by RyanParle
RyanParle
RyanParle
Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)Supreme Being (206 reputation)
Group: Forum Members
Posts: 20, Visits: 1.2K
Not sure why but the quote feature seems to be playing up, my previous post  has been included in the quotation for some reason,  the code looks like it's formatted right to me though. 
wozza
wozza
Supreme Being (4.9K reputation)Supreme Being (4.9K reputation)Supreme Being (4.9K reputation)Supreme Being (4.9K reputation)Supreme Being (4.9K reputation)Supreme Being (4.9K reputation)Supreme Being (4.9K reputation)Supreme Being (4.9K reputation)Supreme Being (4.9K reputation)
Group: Forum Members
Posts: 688, Visits: 5.4K
I did a similar job for a customer who had purchased a very badly fitting Metro 6R4 Bodykit. The leading edge of the doors fowled on the Front Wings/Arches and the tops of the doors were 20mm out of line ie not flush with door opening/roof line. I ended up separating the inner and outer skins with a slitting disc. I then made wooden fixtures to hold the inner skins flat/true and bonded the outer skins back on and baked the doors at 70 degrees C still in the fixtures. I had to do the same thing with the Hatchback.
I may have some pictures somewhere.

Warren

Carbon Copies Ltd
andygtt
andygtt
Supreme Being (1.2K reputation)Supreme Being (1.2K reputation)Supreme Being (1.2K reputation)Supreme Being (1.2K reputation)Supreme Being (1.2K reputation)Supreme Being (1.2K reputation)Supreme Being (1.2K reputation)Supreme Being (1.2K reputation)Supreme Being (1.2K reputation)
Group: Forum Members
Posts: 157, Visits: 1.2K
Im pretty sure there isn't a UV stable epoxy resin so that was a mistake from the supplier... you could sand back the top coat of the resin and clear coat it assuming its not too badly discoloured.

What I would do is take moulds and make my own... then sell the existing doors to fund it. but its a lot of work.

When I bonded my carbon doors together I had around 1-3mm of bonding filler between the panels at most... if you use the correct materials you don't need loads of material between them. The correct materials are more expensive however which is probably why they did it the way you describe... cutting them apart and bonding them closer shouldn't be that hard especially if you do go the clear coat route.
GO

Merge Selected

Merge into selected topic...



Merge into merge target...



Merge into a specific topic ID...




Similar Topics

Reading This Topic

Explore
Messages
Mentions
Search