With my car I try to do everything myself, sometimes with good results and sometimes not. The following is a rundown on how I made custom panels for my boot, parcel tray, fridge and door pods.

I might not use the best techniques but it got me there. All of these still need to be taken to a auto trimmer for carpeting.

Tools:
Jigsaw
Angle grinder with sanding disc
Orbital sander
Dremel
Pens
Flexi curve (flexible graphics tool used for making unusal shapes)

Materials:
3mm Mdf
2 part builders putty
Cardboard
Fiberglass tape

The process is very much the same no matter what you are doing. Ill explain how I did my boot and post pics of the other projects. I could have used fiberglass for most of this but decided on putty as i have a bit more experience with it.

Here I have started to get the basic shape of the cover panel. I cut one large sheet of 3mm mdf to cover the front of my box. Then I cut smaller sections to start to fill in the gaps and around the corners. Most is these angle panels are screwed in place to begin with. To get some of the curves use your flexi curve to get the shape from the panels and then transfer it to your mdf. Once you have a rough shape you use putty to hold it all toghther as I have done in this photo. It is a good idea to use foil to protect your panels from putty here.

This is me using a dremel to cut out the putty from the screw heads. I would strongly suggest getting a dremel for this sort of work as you can use it to shape the final product as well.

Once the putty has set and you have removed the panel you can remove the screws and apply more putty for strength but also to start acheiving the desired shape. Now when it gets to bits like this where you have no wood but need a point or an edge all you do it staple some cardboard to the back of the wood and the fill the area with woodchips and putty. After a few minutes with a grinder it looks as good as the rest.

So now you have the basic shape of your cover plate. As you can see there are still gaps but its starting to get there.
Now the fun part cover everything in foil. Why foil? Well the putty wont stick to the shiny side so its easy to remove. This is where the fiber glass tape comes in handy. You tape from the cover panel to the foil then smear it all with putty. This will give it that fitted look. Once agan take to it with the dremel and a cutting disc to clean up the edges.

Using this fiberglass tape allows you to shape into corners. Its the same tape they use for joining plaster board walls

And here you have the finished product, All it needs now is some carpet and maybe a layer of fibreglass just for added strength.

Here my fridge wouldnt fit inbetween the seats so I took to it with a jigsaw:)

Joining it up again

Almost done just needs a sand and carpet

And these two are some of my other creations using the same techniques.
Sorry for this been so long, its still only a rough outline of what to do and if you have any questions feel free to ask...
Cheers, oh and any comments would be appreciated.

far out mate... great effort...

looking good mate.. make sure you post up some pics after it's been trimmed aye.

and get inside ones of ur fridge.. never thought of that.. great idea

Good on ya mate

nice work is that a farenhiet 12" or 15" and are u runnin it of that amp>?

i think whoa pretty much sums that up. in-bloody-credible dude. my mate's just finished his door pods 4 his 6" splits, he used wood, fabric and fibreglass and it looks awesome.

does the putty weigh a lot more than fibreglass, cos my centre dash panel needs remodelling for a new head unit, and seeing as it's already shredded i was going to remold it in fibre, but that looks great, and a fair bit easier. be cool to see the finished product man, keep us posted. cheers

Yeah timy it is a farenhiet 12" the amp is way to small for it but im upgrading to a dd sub and new amp soon so it does the job for now.

As for the weight of the putty it is more. In the end.

With putty you fill the entire space with it. But with fibre glass you can just put a few layers of it with large gaps underneath so it works out hollow but still giving the same shape if that makes sense. The thing with putty is you can really shape it, with fibre glass you need a outline be it bits of wood or fabric to then cover.

Since writing this up I have fiberglassed the panel for extra strength. And im about to get it all covered.

make a putty mold... then fiberglass that???

could that be an option?

You would be best of using many layers of say 30mm mdf and shaping them with an angle grinder and then putty to get the finer details and then make fiberglass mould. But that is actully a brilliant idea. If you were going that path you could also get away with paper mache and clay etc. Anything to get the shape then cover it in foil and fiberglass away.

bet u didnt have to lower you car with that in the back nice work and go the farenhiet value for money

Where's the MDF secured to? i thought of doing same with my VS berlina and the car from the sound shop (where i bought my shit subs) said you have to be careful securing shit to your boot cos you can get fined. Just wondering how you got round that prob?

Great work and thanks for showing us!

This kinda stuff is difficult....I always begin but never end up finishing. I think it's all the sanding involved after applying filler/bog.

Anyway, look forward to seeing the finished photos!