Q: Great job on the magazine, it's been outstanding! Here's my question: Where can I find more information (preferably free) about working with fiberglass? Do you have any issues that go into more detail? Are there any sites on the web that seem to be hidden from me? I've put several different topics into numerous engines, without results I want. The few sites I've found list a bunch of steps without many images. If I do get to a site with pictures, they're too small, and I can't see what's going on. I know using fiberglass is a grueling task with much time involved, but it greatly interests me.Thanks for the help!Jeremy T. Kalaf
Q: Hello, I want to build a fiberglass enclosure for my system and I really don't know how to go about doing it. I've an idea of what materials to get, but I don't know how to do the basic setup of the enclosure to get the best sound possible. If there's any place I can go to on the web for some information or a book I could get I'd appreciate it.Thanks,KevinKansas City, KS
Q: I wanted to build a custom enclosure in my Mustang using fiberglass to make it wild and unique, but I don't know how to build it, and I can't find any books in the library or the bookstore. I've found books on bodywork, but they don't tell me the specifics on speaker enclosures. Can you help me?Name withheldVia the Internet
A: The Internet is known as the home for free information, but there are several problems with information out in the public domain. First, it's all heavily set into a particular context. I've run across websites with what looks like a really good attitude towards the topic, but as I read on, two things become apparent: First, the writer is making the topic fit his agenda and opinions, rather than delivering all of the knowledge that enables you to make the decision that best suits your particular situation. Second, the information is often missing essential knowledge or is just incorrect. This can be hazardous depending on the situation.
The best source of technical information is the manufacturer's product application sheets. These documents specifically address the product they sell, so if you get past the sales hype, the information is correct in terms of using their product. But don't think the same process will work for another brand. Small chemical differences will affect the outcome. The downfall to this source of information is the limited nature of the data - the manufacturer tells you how to mix and use the materials, but not in the context of boat building or aircraft fabrication or the world of car audio.
When I first researched fiberglass as a new installer, sales reps and experienced users of the material told me things that were clearly wrong for what I intended to do. For instance, a technical specialist stated that I didn't need to make a subwoofer cabinet more than 11/48" thick. He based this on pressure, in that a 11/48"-thick fiberglass container would hold more air pressure than a subwoofer could generate in the early '80s. That's probably true, but misses the point - the cabinet must not vibrate or a bunch of acoustic problems will occur that are far more serious than a leaky box. The car audio context is about control over the acoustic conditions, and a bit of overkill for show biz effect is never a bad thing.
Fiberglass usage and technique is directed closely to the particular field. For instance, boat builders use different techniques than boat repairers and dramatically different ones than aircraft builders. I can think of no aspect of car audio that needs to use vacuum-forming techniques where normal hand lay-up techniques wouldn't work just as well.
Information in car audio forums is all over the map in terms of context, and a lot of it's just plain wrong. In one forum, a responder who admitted to not knowing anything about Mobile Dynamics' polycrete stated that you could add anything to resin. That is both incorrect and dangerous. Introducing a reactive agent to polyester resin can cause any number of reactions. I'd fully expect that more than one chemical has the ability of causing polyester resin to emit poisonous or combustible gasses. He suggested adding sawdust, polyfilla and flour as materials that are compatible with fiberglass resins, without realizing that certain materials will react and alter the chemical bonding properties of the polyester molecules. In other words, it appears to be a great way to ruin a gallon of resin.
One of the better sources of information is found at the Fiberglast website (www.fiberglast.com) with their selection of books and videos. You'll notice by the titles, that they're contextually slanted to boat building, boat repair, model airplanes and general repairs, but you'll learn enough about the materials to adapt to car audio projects. For instance, the process for using Kevlar for building a canoe is different for building a subwoofer cabinet, but the materials and mixtures are fine.
Remember that free material may be worth every cent you pay for it.