Introduction: Fiberglass Car Front Speakers

About: Really enjoy a good build, even if it takes months to finish. Have a horrible habit of starting projects, smashing them out and then stopping near end.

This is a instructable about how to make your very own Fiberglass speaker shell.

My car is a 1994 520i BMW, Its my pride and joy :).

This project can be a bit pricey but it is cheaper then buyig custom made ones from a shop. this all up in materials was probably AUD $200, but i brought extras and more then i needed and for future projects. But look around and find the cheapest stuff if you can!

All steps are how i did  mine, you can change how you do them or follow mine, compeletly up to you.
I did a lot of research on how to do these but no one did a instructable on how to do speakers for the front of the car, only Subwoofers. I take no credit for coming up with this competely by my self, i looked and read a lot of instructables on how to do this.  I will update this instructable when i have painted mine as i am not at university for the moment where i can use a painting room with free paint :)

please comment, i will try to reply!!

And please ignore all Spelling Errors haha


* Fiberglass Mat ( 2 Metres )
* Resin & Hardener ( 2 / 3 Litres )
* Body filler ( 1kg )
* Wooden dowel ( Single lenght, 6mm )
* Speaker Spacers or MDF Cut to size
* Fabric ( Fleece or simular ) ( 1 Metre )
* 1" Brushes (least a dozen, cheap ones)
* Cups ( For mixing )
* Syringe ( For Resin Hardener )
* Masking Tape
* Painters Blue Tape
* Plastic ( Bin Bags or Protection plastic )

** All Materials are based Roughly on what i used **


* Dremel or other cutting device
* Hot Glue Gun
* Saw
* Sanding paper
* Ruler
* Fan ( Big )
* Safety Glasses or Goggles ( Safety First!! )
* Face Masks ( Suitable for Fiberglass Fumes AND / OR Fiberglass Fibers )
* Gloves ( 50 pack )
* Radio ( Help the time go by )

Time to get cracking!

Step 1: Preperation


This is very important as this will protect your car from stains that i have heard are very hard to get rid off.
If you follow this carefully you should have the same result as me. No Stainage.

Also Make sure the area your doing this in is well ventulated. I did mine in the carport with a fav next to the door airing the car while i did this.

Step one:

Pull off any Interior panels that are covering the speakers and the areas you want to fiberglass and the surrounding areas. atleast by a few inches.

Step 2:

Once Step one is done, Time for the taping to begin.

What you want to do is begin with the masking tape and cover the surrounding area and then put a few strips going into the the gap or speaker space to create the depth of the shell.

Im sorry i forgot to take pictures of this bit but i have the pictures of blue tape.

Step 3:

Same as step 2 but with the blue painters tape, this will hopefully prevent any resin slipping through to the carpet. Make sure to leave no gaps. Have a look at the picture.

Step 4:

Lay plastic down on floor or if there is no floor, then around the lowest part as gravity is a Heartless Bitch. Make sure to tape over the edges of the plastic so that the resin can not seep through under it. Make sure that any part that could get resin on it is covered.

Step 5:

Prepearing materials. Cut the fiberglass into either 3" squares or managable strips, entirely up to you. You probably want a sizable pile so you dont run out during the resin stage.


* You can draw a line with a marker on the tape of where you want the fiberglass final edge is to be, the ink should soak through to the fiberglass.

* Dont be shy with the tape. Seriously, if you care about your interior then cover the thing in tape.

Step 2: Fiberglassing

Now this will take a long time, but this is the most enjoyable part.

You should have your pile of fiberglass matting cut up and ready, now all is left is the resin. This will have to be mixed to the instructions provided with your hardener or resin. I have put mine as an example of roughly how much you should need for each coat, if your area is roughly the same as mine. You should be able after the first coat to figure how much you will need, for future coats.


** Measure with water first into one cup, 100ml 200ml and 300ml and mark it with a marker pen. This means you can pour the resin into this cup and get the right amount of resin and then pour that cup into a blank cup for the mixing. :) **


** BE SLOW **


* 200ml Resign
* Hardener 2.0ml

** Hardener will depend on the instructions and temperature **

Step 1:

Get your damn safety equipment on!! This is very important, you dont want to gas or harm yourself with the fumes.

* Disposable Gloves
* Fumes Mask
* Glasses ( Optional )

Step 2:

Pour and mix your resin into the disposable cup and add the right amount of hardener. Using a brush, Mix them together.

step 3:

Using the paper mache technique, smear some resin mix on to the tape, and place a peice of fiber mat on to it. then add more resin onto the matting until it turns transparent and sits nicely on the tape. Repeat this until the area is covered.

** Remember, you want to fiberglass more then where you want the final line, so you can cut it down later and have a nice even thickness. **

** I started paper mache'ing mine from the middle and worked my way out **

Step 4:

When your area is covered you can let it dry now. this can take upto 2 hours before you can add your next layer.

** I would do one side, and as that side is drying, start the next side. **

Step 3: Layers

You will probably want least 3 Layers before you remove the shell from the car.

To do this just carefully start pulling the fiberglass from the car and it should be strong enough not to break. Its a bit scary but just be patient and slow.

Once you have pulled out the shells, you can add another 2 layers to them. I would also remove the tape or anything else that might bug you as you do this.

5 Layers should be plenty but if you arent too sure, adding a few more layers shouldnt hurt, but you shouldnt need too. 7 layers is usually for subwoofers, since they have more force and pressure being released.

Step 4: Trimming

Now once you are happy with the amount of layers for your shell, you can start trimming it down to size.

If you marked the tape earlier on you should have a faint line on the outer side of the fiberglass.

Or if you didnt now is the time to plave the shell back where it belongs and draw the line on the inner side.

Now is time to start cutting!!

But before that, remember that face mask, make sure its one suitable for fiberglass or dust, dont want any of those fiberglass fibers floating into your lungs!!

Carefully cutting along your line with your dremel or other cutting device, go around and trim off all the excess. this should give you a even layer when the excess is cut off.

Step 5: Placement and Fleecing

Now you can get to the placement of your speakers.

What you need for this is :

* Fiberglass Shells
* Wooden Dowel
* Saw
* Hot glue gun
* Fabric
* Speaker Spacers or MDF cut to size
* Ruler

Step 1:

If you havent got some speaker spacers that fit your speaker i would get some cut from 1" MDF. Find your speakers and see what clearance they need for the speaker and the screws.

If you want your speakers to be submerged into the shell then cut another ring with a bigger inner diameter and place that on top of the main ring, so that the speaker can sit in it.

If you do have speaker Spacers then simply hold them where you want them on your shell and measure two or three points for the dowel to go, and then cut them.

Then glue your dowel and Rings to the shell.

Step 2:

Place your shell back where it goes and see if it looks ok or needs changing.

If change needs to be done, then redo step 1.

** Make sure to look if any objects will interfer with the ring **

Step 3:

Once happy with the placement of your rings and checking to see if there are any interferances.

** My driver side has the bonnet handle, so i made a note of it **

You can get your fabric and pull it over your shell.

To do this, firstly drop the fabric over the shell and make sure some hangs over on all sides. Then get your hot glue gun and put a droplet on a spot on the ring and place the fabric over.

Then pull the fabricto the other side of the ring and do another droplet of glue. Repeat this on the edges of the ring, make sure its tight!

Now just do the same but with the egdes of the shell, going behind the shell and placing droplets of glue and stretching the fleece over the whole shell.

If the fleece starts to ripple, either stretch it more or cut some slits into it, this should help, cause you dont want many ripples in the fleecing.

** Make sure if you need to make clearances, to do it now!!!!! **

Step 4:

Make sure you are happy with the fleecing and look of your shell!!

Step 5:

Trim off excess fleece, so it just goes around the bad of the shell.

Step 6: Fiberglassing Again

Once your happy with the fleece, you can move on to the next step.

Fiberglassing. Again.

But first your going to need to coat the fleece with the resin mix. Coat all the fleece but the centre of your speaker ring, since you will be cutting that out later. ( you can if you want to, doesnt matter ) You want the fleece to go a darker colour like mine.

For the passenger side i needed roughly 300ml's and 200ml for the driver side.

Once again, dont forget your protection!!

Let this dry and then you can start fiberglassing again!!!!

I only put on one layer of fiberglass after the fleece as it had hardened pretty well. But feel free to do more. Also with mine i only fibberglassed up to the very edges and bit over, i trimmed of the extra afterwards.

** Just dont forget the more layers you do, the heavier and thicker it gets!! **

** I have had mine a few weeks now, and they havent cracked or anything so one layer should be ok **

After you have finished fiberglassing, you can cut out the middle of the ring. Try and get this as close to the MDF as possiable. Now just tidy up the edges and Place your shell back in your car to make sure it still fits.

You can now remove the wooden dowel if you want, but if you do, make sure you have more then one layer of fiberglass, i left mine in and it isnt a problem.

Step 7: Body Filler & Sanding

Now to cover your fiberglass in Body filler or Bog.

Any should do, car body filler, builders Bog.

Now each has different instructions so, make sure to read them right!!

Now cover the whole thing in it pretty much, Fill in any waves or ripples, and get a good layer all around. You might have to fill in the waves first and then let it dry and then go around the whole thing again.

Once this has dried, you can start the painfull process of sanding.

Start of with a rough grit sand paper and go around, then finish of with some wet and dry smooth. This with give it a nice surface for the finish.

Now place your speaker into the shell and mark where your holes are going to go. Then drill them! :) i simply used my dremel with a 3mm drill piece.

Also while drilling, drill a hole in the back for the speaker wire to go through.

Step 8: Temporary Finish

Now i am finishing my instructable here for the moment. i will update when i have finished mine in feburary hopefully.

Fixing them in place.

They should fit nicely in the area you chose. Should. If not you can drill in to them and into the car. But  if yours like mine fit good, i only used 2 strips of velcro to secure them. And they havent fallen out.

Now Wire them up and screw the speakers in!

Now if you want to paint them.

I would suggest you do a few coats of primer over the shell, and sand them down after each coat. Once you have a good surface you are happy with you can go and paint them whatever colour you want. I would do 1 or 2 coats, and then do a final coat of Clear, probably a few coats wouldnt hurt. This should seal the whole thing.

I will add pictures of painting when i have done it myself.

I really hope you liked my instructable!! And please feel free to comment on anything i might have missed.

Step 9: Painted

Ok so, I painted my Speaker shells a while ago and i'm sorry for not posting sooner. Uni has been crazy. like insane.

So, i primed and found a colour close to my interior and decided to paint them.

First thing i found out is to bog really smoothly. REALLY SMOOTHLY!! other wise when it comes to painting you will have bumps and ditches..

lets just say im going to Upholster mine... My new plan is to when i have some more money to buy Fabric similar to my interior and cover them, so you cant see the bumpiness.

Other then that the paint job holds well, i used multipy layers of primer and then 3 coats of beige. and to finish it off i used 2 coats of clear. using a air spray gun, so the layers are pretty thin.

They have been in my car for a few months now and only a few black marks have appeared but no scratches!

So if you want to paint then make sure you have a really nice surface!

Anyways, I'll update when i have more pictures of them in my car and when i have upholstered them!

** Note : Thanks for so many people looking at my Instructable! Im so happy that i hit 1k and now on 3k! woooh! **

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