I decided to replace my speakers with a Vifa D26NC55 and Peerless 850518 combo with a Madisound custom crossover.Of course, this means that my speakers don't fit anymore. The tweeters were easy -- I removed the grill off of the tweeter pod and ground the tweeter enclosure to fit. It came out ok.

The woofer basket was another thing altogether. The woofer was a bit bigger diameter and is deeper, so the stock basket didn't fit.

Stupid idea #1 - I would mold a new plastic basket to replace the original one, but I would make it the size I need.
Stupid idea #2 - I have done some composites before and know how to make molds for fiberglass. It is a bunch of work to make a nice mold, so I thought I would come up with a better way to make the mold that was easier and quicker.

On the off chance that someone may learn from my mistakes, I will try to show all the places I screwed up and what I did to deal with it.

 

Day 1:

My first idea was to make some outlines on a couple pieces of plastic of the outline of the speaker and the outline of the original basket. Then I took some modeling clay and "connected the lines" on one of the pieces of plastic. Here is a picture of the original clay mold.



So far, so good. I applied a bunch of mold release and poured some epoxy. Two stupid ideas creeped in. I know that one should always test epoxy mixtures to make sure everything is working *before* making the real part. I didn't so this next picture looks ok, but it contains epoxy that never dried. The other piece of stupidity is that I mixed multiple new things at once. I added some epoxy fillers to make things cheaper and lighter. It also turns out it changed the mixture so it never hardened. Had I tested the mixture, I could have caught this and adjusted.



One day down, no parts

 

Day two

What did I want to change? I became clear that the clay was not stiff enough to reuse, and at this point I still had dreams of a reusable clay mold. So I went to a clay mold that could be baked hard. I also stopped using filler in the epoxy and tested the mixture before I made the part. Here is a picture of the new part.



This time I used glass as a base, as I didn't want the plastic to warp when I baked the part and I thought that epoxy would not stick to glass as much as plastic (based on no facts).



Here is the baked mold with mold release and epoxy poured in. I used a black epoxy dye to color the part like the OEM part. I also tested the epoxy mixture -- it hardened this time.



The clay consumed itself in part removal, but I could deal. You can see the clay residue on the part. End of day 2

 

Day 3
I was all excited and went to put the speaker in the part and --- it didn't fit! I guess I wasn't as precise as I would have liked in laying out the part. So after much complaining, I bought a new carbide bit for the Dremel and went agrinding.



Here is a picture of the part Dremeled to make the speaker fit. Of course there is no way it could be that easy, so when I put it in the car, I found that the tabs weren't big enough and the outside needed modification. You can see the problem in the next picture. I needed to make the tabs bigger.



I put the part on the glass and build little tiny clay molds around the tabs and poured extensions to the parts. End of day 3

 

Day 4
I woke up to admire my handywork and celebrate my genius of fixing the tabs and not starting over. Ah, the irony. It turns out I forgot to put mold release on the glass. Big mistake. I had a big piece of glass glued to my part (I couldn't have glued it this well if I tried). I took my a good 5-6 hours to chip, hammer, file, sand, and curse the glass off of the original part. I would never have imagined the difficulty of getting a piece of glass off of a piece of plastic. Oh, and I cracked one of the tabs off in removing the glass.

So some re-evaluation was in order. I decided I was going to modify, file, Dremel, and hot glue my way into an accurate, but not necessarily structural part. I would then make a urethane mold of this part, then make thousands of copies, sell them on EBay, then reap millions for my hard work. I made the part purty. It more or less looked like the picture above, excepte the holes were holes, instead of slots. In my anger at wasting a day, I forgot to take pictures.

After the glass incident, I decided, the day was over. End of day 4

 

Day 5
Ok, I made a new clay mold and poured some urethane. I then hot glued some wire on the part, and suspended the part in the eurethane. Oh the mold release! I applied mold release like you wouldn't believe.



After waiting for the eurethane to dry, I pulled the part out, and to my amazement, I had a completely (ok, remotely) competent mold of the part!



End of day 5

 

Day 6
I applied mold release and poured some epoxy. I waited for the epoxy to dry and I had a part! Good God, this might work!





After about 5 minutes of filing touch up, I had a usable part. I poured a second part, and the agony was over. Here is a picture of the part in the door.




End of day 6

 

Ok, what did I learn?

- Making plastic molds is possible, and clay can actually be part of the process.
- Urethane molds are pretty neat and they can work. You don't have to consider draft angles and the like, much because the mold is flexible.
- Making plastic parts from a mold is a lot of work, so there should be a good reason to do it. This project is not a good reason. A few layers of 1/4" plywood, a jig saw, and some glue would have this project done in a day.
- Never forget mold release. I knew that, but one can never know it enough.
- Clay should be sealed before pouring epoxy into it. the surface finish of the part was much more pourous than the original clay mold.
- Get some foam weather strip and wrap your wire you run in your door. It took me several cycles of taking the door panels off to get rid of all the rattles.
- If you want speaker the way you want them, pick them from Madisound and have them make the crossover. $25 for a two way design. What a deal! It sounds great and I could have spent weeks doing as good a job as they do. I even have a frequency response plot of my speakers with my crossover.
- When I was checking the wiring for my crossover, I hooked up the stock woofers with the new crossovers and the new tweeters. What a difference! The stock speakers get very congested sounding on some voices at volume, and that largely went away with the crossovers. I think the stock woofers have a big resonance high up in their range.

 

WOW! That looks like a lot of work... Nice job but way to much work for a speaker ring... That must be a hugh speaker because I made the same thing in 10 minutes
I just cut the basket part out of the stock speaker holds, I know you said they wouldn't fit but man,... the Dremel is your friend


Just out of curiosity why didn't you just make these out of MDF?? What was the reason for doing this out of plastic?

Either way nice work