Make Speaker Pods for Contoured Shaped Doors
This process is much like paper mache, except you have to be more careful as you can't just wash the resin off and there is aprox 30min time frame for you to do your thing.
Please read this thread thoroughly and understand all the steps before undertaking any activity.
I am not responsible for any accidents that are incurred by following this tutorial, be it from ruining car trim or hurting yourself. If you are not sure of what you are doing, then hire someone to do it for you.
Tutorial is the property of David Choong and cannot be reproduced without the authorisation of me, the writer. Feel free to print it out though
Tools/Materials:
- paint brushes disposible/cheap (you'll throw away later)
- gloves (gotta protect them hands)
- respirator (fumes and glass fibres are bad mmkay)
- protective googles
- old jersey/clothes (because you may get messy)
- clear packing tape
- 1m of fibreglass (either chopped matt or woven)
- Couple of litres of resin (polyester or epoxy
- catalyst for resin
- icecream container or 2L milk container cut in half (clean out thoroughly)
- sharp craftknife
- spray glue
- fleece
- scissors
- mdf
- angle grinder or dremal with good cutting disc
- jigsaw / router / saw / drill
- screws
- newspaper or even wax paper
- marker pen
- bog / filler
- hot glue gun
- staple gun
- sand paper 40/80/120/150 etc etc
(depends on what finish you want or how much work you want to put in)
In this tutorial, I'll take you through what I normally do when making up some speaker pods or other fibreglass bits. This will also provide a guide to using fibreglass be it for chopped matt or woven.
I've added photos from other projects to be clearer in instructions.
Notes:
- I never give specfics on material quantity. Each project is different and the amount of materials required changes accordingly. Plus, I buy in bulk (like a drum of resin) so I just use as much as I need when I need.
Please use safety equipment like googles, respirators and gloves.
- fibreglass resin is toxic and messy. when you get it on your skin, it is not the easiest to remove
- fibreglass doesn't break down in the body, so if you inhale, it will stay around like asbestos. This is doubly important when you are cutting or tearing up glass matt as small particles of glass get air borne and can be easily inhaled. Wear your respirator! A basic dust mask is an absolute minimum.
- googles are always helpful as you may flick resin as you brush it around.
Tips:
- double glove before you start. This allows you to pull off messy gloves and keep a clean set on.
First steps:
- Before you start using resin, tear chopped matt/cut woven matt into peices first. I use all types of different square pieces from very small (5x5cm) to large (25x25). Depends on application really. Large peices are used for sub enclosures. Small peices for tight corners and kicks.
- get setup with your gear. Normally on my workbench, I'll spread out a little and chuck some newspaper so I don't make a mess. Wax paper is also helpful as you can put down a fibreglass piece on it and it will come off easily.
- chuck 1/2 litre of resin into your container.
The ratio for polyester resin is 2% ie 1 litre of resin = 20mls of catalyst. In cold weather I sometimes use slightly more catalyst to combat the cold. Polyester resin shrinks with more catalyst added, so be aware.
The ratio for epoxy resin is 1:1 and ensure you keep your ratio's right otherwise it won't set.
- cut up your rings for the speakers. Some small blocks of wood are also helpful to raise/angle the speaker to where you want it pointed towards.
1. Take off the trim and clean the surface with wax/grease remover or turps or the like. Apply strips of clear packing tape to the surface and ensure you overlap it. I normally double layer the tape to ensure that no resin can seep through. Make sure you extend a lot farther than the area you intend to glass. You don't want to ruin your door trims. Sometimes I bother to make a tape barrier so no resin will go farther than necessary.
If packing tape doesn't stick down, I'll use wide green painters tape as my initial surface and apply tape over it. I also use scissors to cut tape to shape or section bits out to allow for contours
Contours are a bitch to account for. If you want the perfect fit, take your time to apply the tape.
2. With your resin in hand, add your catalyst in the right ratio. Stir thoroughly with your paint brush to push the catalyst through the resin. Use a disposible teaspoon as you don't want to wash off a metal teaspoon as the catalyst is poison.
First, brush a light coat of resin over the covered area. Lay your first layer of glass down. You won't need to cover the whole area in glass. Just a small portion. Then paint the resin onto the glass. Push the resin through the glass using a dabbing motion and the tips of the bristles. We don't want weak parts or air bubbles.
Keep working your way methodically adding layers and applying resin on and through the glass until you have built up at least 3 layers. The more layers you have, the stronger it will be.
3. The resin will start to set after 30 minutes and depending on the ratio (if polyester) will harden up to an hour later, but will have some moisture retention. I normally glass up and leave for around 12-24 hours to ensure that the resin sets properly. If you lift up a f/g piece too early then the polyester resin can continue to shrink and subsequently deform your final shape. Be warned.
4. With the glass set, pull the glass piece off the trim. Pull tape off the back. Leave for a while to let any moisture evaporate.
5. Time to cut up your fibreglass shapes. First see whether the shape fits well.
Commonly, factory trims have moulded speaker grills. (shot is from behind)
Using my trusty angle grinder, I cut out the factory grill, cleaning the edges by whittling with a craft knife.
Once the hole is cut out, use a marker pen to trace around the hole you want to make on the fibreglass. This will allow the speaker to vent into the doors.
And presto
Depending on what you want to do, be it simple or complex pods, take some time to think about the aesthetics and the lines of the pod.
Commonly a simple pod can appear factory if some time is taken to consider the final product.
eg:
6. Assuming you've already cut up your rings, add some blocks to get the right angle if you want to orient/align or to mount the speaker away from the trim. To match up both sides, I'll make marks on both sets of rings and mount the blocks on both rings ensuring I account for the same orientation.
Mount the rings with some hot glue. If you use a screw from behind, make sure you mark out the final position of the ring mounting points with your marker. Drill out a hole for the screw and make sure you pre-drill the wood as well. You don't want to a) crack the glass b) split the wood.
Hot glue down
If you are mounting the pod from behind and can't access a certain area of the pod, glue a piece of wood down to screw into
7. Time to add the shape to your pod.
- if you using fleece material, the fleeces will absorb the resin and harden into the shape without adding additional fibreglass for strength
- if using lycra, then you will have to strengthen with a couple of layers of fibreglass.
Cut out your material to cover the whole pod and then some. Excess can always be cut away later. Using some spray glue, super glue or trimmers glue, stick the material to the back of the pod, constantly adjusting the material position to reduce the amount of creases. Work your way around as required.
Once all stuck down, cut away excess material, leaving around 2 inches of material glued to the pod. Resin will loosen/release the glue so the more glue you have the more the shape won't deform.
Tip: fleece is thicker and will add a couple of mm dimension to the overall fit of the pod to the trim. Account for this!
For more complex shapes, recessed speaker rings, use a staple gun to attach the material to the ring. This helps attache the shape of the material to the ring for dimensional stability and ensures resin adheres material and ring together.
8. Mix up your next batch or resin and soak the fleeces through with the resin. There will be a colour difference between fully soaked resin and partially soaked.
9. Once the resin has hardened, you'll want to cut the main centre hole. You can normally do this with a craft knife if just fleece. Let the internal inset of the ring guide your knife around cutting in a downward stroke action. If you used fibreglass for extra strength, break out the angle grinder. Remember your respirator folks!
From the back you can see the differences with the pod trimmed and the excess excess cut away and cleaned up.
If you resin has all set and you think you have gaps, then chuck a little resin on the inside of the pod and swirl around inside to fll gaps between backing plate edge and material.
10. So with the main shape formed, time to break out the bog and start on the final shape. I'll mix up a bit of filler and build up the shape depending on what you want to do.
Alternatively you can make a milkshake to create a smooth shape instantly, which consists of mixing filler with resin. The slurry can be thicker or thinner depending on how much filler you add. Hardening is activated by the MEKP (polyester resin catalyst) in normal 2% ratio. Commonly I'll use a 1/2 and 1/2 mix if i make a milkshake up. Otherwise I'll just use filler and sand back to shape.
Like anything, using a heavier grit sandpaper can knock back filler faster. I'll normally start with 40grit and work my way up in sandpaper grade, adding and sanding filler to finalise the shape.
11. And some partially finished and finished basic pods.
If you paint then sand to a high finish. If you vinyl, then you can get away with going to around 150 grit and covering with vinyl. Note: material backed vinyl doesn't stretch as easy as non backed vinyl. But non backed vinyl will show flaws in your sanding more.
These were painted up and installed for a happy Sam.
Vinyl application:
Using a heatgun or a hairdryer, heat the vinyl so that it can stretch easily over the pod. Ensure you keep the gun moving over the vinyl to gentle heat because if you keep the gun in one spot, it will melt the vinyl.
Apply spray glue to the pod, letting the solvent dissipate after a couple of minutes until glue is tacky and then stretch the vinyl over. Ensure no creases by pulling up the vinyl is required. If any area is not sticking properly, apply more glue. Use the heatgun to constantly keep the vinyl in a elastic state.
Like making the initial shape, glue the edges of the back of the pod to stick the vinyl on to. Once dry, cut excess away with the craft knife.
Cut the hole with the craft knife just like you did the fleece, using the inner ring as your guide in a downward strok action.
Some more progress pics.
For this set of pods, I used some colour matched spray paint to match to the trim. I initially sprayed down a bonding layer to the pod before application of the spray paint.
Finished pod looking fantastic. Of note, I worked out the lines of the pod for the trim of the caldina and designed and built to suit.
Other examples:
WRX pods
A Pillers:
Cheers
Dave
