Custom GRP Door Cards

Custom Door Cards

If you are a serious ICE fan, then you will love this guide. Using standard door cards, here is how to turn those into a masterpiece to house a good mid range woofer and crossover neatly into a door card. This particular install was done on a Supra, though any car will support the same method!

Before starting, understand that this will forever change your door cards. You cannot ever remove this! Plan the positions well for space! With you doors closed, roughly mark positions with a marker and what depth you have to play with. If you build up to much, the assembly will get in your way OR WORSE, you door may not close.

Door Card in GRP

First a list of materials:

Some Door Cards & day or two of your time!
MDF Sheet
Cotton based fabric (something like good quality T-Shirt material), enough for both doors.
Fibreglass Resin (at least a 1kg tin per door) & mixing equipment
FibreGlass Filler
Car Body Filler
Hot Glue Gun & Sticks
Staple Gun & Staples
Snub nosed Pliers
Electric Sanders & various grades of sandpaper
Safety Mask & Goggles
17amp Cable
SuperGlue Gel
Lollipop or Waxing Stick
Piping or cable
Grey Primer

There may be a few other ancilliaries, plan ahead, but essentially you are looking at a finished result like this. It looks very professional, and in fact if you were to take this to a pro installer, we would imagine you would be paying a small fortune for it!

Original Door Card

Stage One

Remove all the bezels, handles, buttons, trim parts etc etc. You basiclly want to strip the door right back.

If covering the entire door card, not partially like this, remember you have window rubbers and runners! Personally we would suggest removing these during install BUT laminate just to where the rubbers overlap the card. This make for a neat install and hides any rough edges.

Using the templates provided with your kit (make some from paper or card if required) cut out some supporting rings. Make sure the ring is wide enough to cope with the full speaker and its grille.

Also make some straight pieces, these are cut to length to angle the ring towards the central listening point in the car, to produce the correct staging effects.

Now using the fibreglass filler, mount the ring and supportive frames and allow to set, around 45 mins. You can use superglue gel to hold things in place initially so that you dont have to hold things and wait for cure! Take your time, this framework stage is important to achieve the angles you want!





Door Card Frame Work

Stage Two

Using the cotton cloth (dont use polyester or some other synthetic material, it will melt!) stretch the fabric over the area. Don't use too much force the framework is still relatively weak, the strength comes from the resin impreganted fabric!

Start at the bottom of the door working methodically to cover the area with taut material. Use a staple gun to hold things in place. Again the staples are a temporary fix, angle them a little to stop them pulling out. Pop a few on the speaker and crossover framework.

Pay attention to where door handles and trims will refit. Staple around these areas well as you will need to cut away the material before the next stage, though if you forget its not the end of the world, you can still cut the thin laminate with a serrated knife. These staples will be removed after the next stage.





Fabric Covering

Stage Three

Mix up some polyester resin @ 3% and apply to the cloth. Ensure total saturation! At this stage if your cloth sags, you have not put enough tension into it. STOP! You need to remove the cloth and reapply it or you will have a disaster to recover. If you need to remove the cloth, do so briskly so the resin is not set before total removal.

Wait for the first coat to harden. Apply a second coat and a third if you still have any dry spots. The resin combines with the cloth to form a low duty composite! If you would prefer a full on glass fibre laminate (excessive weight from many speakers may need this) paint a second coat of resin on, sprinkle chopped glass stands over every part and allow to cure. Add the third layer at this stage.

Now remove each and every staple with some long nosed pliers. If you have gone for extra reinforcement then you will need to do this after the first layer of resin. It is time consuming and labourious, but if you do not, screws may foul them etc. Also, being unprotected steel, they may rust at a later date. Get Rid!

Also remove any parts you need to with a serrated knife. If you upgraded the reinforcement with choppies then you will want to do this after layer ONE of the resin impregnation into the cloth. Cutting glass reinforced resin is hard work and can create fine glass particles not good for your lungs. You should be wearing a mask anyway!

You now have a door card with a complex interesting shape. You are not finished! Apply an easy sand filler to the whole area that has been coated. Rub down until smooth, take your time, Rome was not built in a day and neither will your door cards. Rushing it will give a bad finish.

You may need more than one attempt to get a reasonable finish!

You can also modify angles and curves at this stage.








Resin Impregnation
Resin Impregnation

Stage Four

After a good rub down, mask up the original areas and spray with a good primer. This helps find imperfections which you can go back to with filler. Rub down the area before applying the filler to the imperfections for best bond.

Once you have completed this, you have a few options:

In this case the cards were taken to a bodyshop for spraying. Its unlikely you would get this finish with rattle cans. But if you are good with them and happy to take it slow and polish up, you could achieve this.

You could also have this wrapped in vinyl or a carbon weave. If going for carbon, use epoxy to impregnate the cloth and wet lay real carbon over. Finish with laquer. Or cheat and use 3m Carbon Wrap!

Polyester resin can continue to smell for some time after cure, especially if it gets warm. Trapped styrene is the enemy there! So you could always use a good quality epoxy to do this, no post cure smells at all.








Primed for perfection checks
Back from the body shop!

Stage Five

Not quite there yet. As with all home projects there are usually a few defects to hide. Here cable has been used along with superglue gel but if you can get proper piping, use that.

Go steady with the glue and dont ever touch it with your fingers. It will dry white if you do. Excess glue will be visible, we suggest a little practice run on something else first.

When all the piping is on and everything looks tidy, you can install the speaker(s) and grille(s) and electronics. Finally replace all your trims, handles etc and reinstall the door card. The speakers may need to be removed for wiring up, but this is a simple process in itself.








Adding Piping
More piping addition!

Project Complete!

The finished article. A pro looking job and a seriously low budget! The key is taking your time and not rushing. This is a hobby level project that anybody can attempt.

We hope you find this guide useful. If you undertake this project, submit a ticket to us with your finished article, or contact us about writing an article for publishing.

Above all have fun and BE SAFE!




The finished article installed