Golf III carbon fiber build (SQ car)

[Haakon]

Only the one? I have two you know

[Haakon]

A few pics of the exterior

[Haakon]

This is what used to be here:

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Half of the spacer tore apart when removing the driver, from having been wet...

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The rest was removed by hand, until only the last bit remained that were bonded to the door skin:

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Result:

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This is how the door looked before scraping away all the Tec-7:

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Forgot to take pics here, but I've made a fiberglass baseplate that follows the contours of the door. Put the door card back to see how the Dyns would fit (you can see the fiberglass plate behind the driver)

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Running Dynaudio in a VW surely should give an extra OEM point, no? hehe

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[Haakon]

Ok.. making a dummy of the door spacer to see how much space is available, and how it needs to be shaped in the end to clear the inside of the OEM door card. No craft stores here on the island, so getting a bunch of icicle sticks was pretty hard. Settled for a bag of barbeque skewers and a hot glue gun from the supermarket

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Made a cutout of the external diameter of the driver of thick cardboard, and taped it loosely in place where it needs to sit:

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Sticks and hotglue

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When it was firm enough and did not flex when pushing on it, I removed the door panel:

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Added some more sticks since the access was a little bit better with door card removed

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Removed it afterwards. Not pretty, but functional enough too show that it can be done this way.

[Haakon]

Some more progress on the door spacer. To get the baffle actually round, and not the handcut "round" shape I made first, I routered out some 3mm composite plate rings. Fastened it to the top like this:

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And cut a piece of speaker grille cloth to shape:

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I could not stretch it to the edges of the bottom plate, as it would not have fit behind the OEM speaker pocket on the door card then. Had to pull it almost straight in. Not a big issue that it became full of folds as these will be smoothed out with body filler on the outside later on.

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Next step was to soak the fabric in resin (used polyester this time, the epoxy I had used on the bottom plate took forever to set) Let it stand overnight. Today it was rock hard.

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Then I could remove the sticks that once held the shape up:

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And then remove the cardboard ring they were fastened to, leaving the alloy/plastic composite ring inside.

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Now to get some body filler to smooth out the outside, so it can be made a mould of later on.

[Kyblack76]

[Haakon]

I've come a little further on the spacer now. Did a test fitting of the doorpanel over the current state of progress on the spacer:

and some minor trimming had to be done. Easy to do luckily, the door pocket (oem speaker grille) is a separate piece that can be unscrewed and removed.

Needed some trimming here:

Traced out a cutline from the back and got out the dremel:

Dremels are the most dangerous tools in my toolbox, the brittle cutting discs disintegrate ALL the time. This is #3 today:

More or less cut away everything not needed (as long as the door pocket covers the hole)

And starting on the body filler bridging.. This is a skill for sure. A skill I don't possess! Will get there in the end though..

[Haakon]

Made a test box for my DD 3518 today, just over 4^ft sealed. Box suggestion by a well known audio constructor over here in Norway.

SMD IM-SG measures a FC point of 41,5hz, add cabin gain to that and all points to smooth and effortless bass all the way down

Krink'ed up the test box, plain beige MDF is so sorry looking, even for a test box

[Haakon]

Updated the thread title, from now on it's three basic build materials. Carbon fiber, plexiglas and steel. No more MDF of wood of any kind

Soon finished with the first door pod, when it's perfect in finish I will make a mould of it and then make a new one from carbon fiber (vacuum resin infusion).

Now that I know that the sub works well in that box size and placement (built a test box from MDF), I can with confidence have a custom Plexiglass box made to the same shape. Most ambitious build yet, but about time after nearly 20 years of being into car audio

[Krakin]

How will that affect the acoustics of the system, seeing as how MDF is a favored material for being an acoustically "dead" material?