Home made multicells

**cradeldorf** · September 25th, 2011, 02:21 AM

Originally Posted by GM

Unfortunately, I don't know what type plastic it is or where to get it these days, I special ordered it from a long gone hobby shop as sheet stock of varying thickness for making slot car front/rear air dams.

GM

Slot car body's and plastic car models are polystyrene plastic, toss some white stryrofoam into some acetone and you'll get polystyrene.

**Panomaniac** · September 25th, 2011, 10:40 AM

Will it be mush? Could it be formed or molded?

GM. Is there a horn spreadsheet somewhere that will give me an exponential profile for making something like this? I'll look for one, if you have one please let me know.

GM · September 25th, 2011, 01:17 PM

Thanks for the thoughts guys, sometimes when you roll the dice you get 'snake eyes'. At least I'm still rolling, I've already buried way too many friends, relatives, acquaintances that didn't make it to retirement age, or if still alive, can't do much of anything physical anymore, in pain or not. Doesn't mean I'm not frustrated/mad/bitter about the circumstances that has put me in this position though!

True, toy slot cars are made of polystyrene plastic, but since the late '60s all the racing classes I've been involved in use clear Lexan bodies that you paint from the inside and it just dawned on me that's what the various sheet material I have is, just thicker, with the thickest being the milky colored one.

There's a number of [expo] calculators on the net, but I've lost the links.
Googling:

Exponential Horn Calculator

mh-audio.nl - Expo Horn

Single Driver Website

This one you can use on-line or DL and if they haven't dumbed it down/'streamlined' it/whatever, an excellent one:

Ishtek
Ishtek

GM

GM · September 25th, 2011, 01:50 PM

BTW, I'm not getting instant email updates even though it's listed in my 'general' settings plus my subscription folder only has [14] when it should be in the hundreds at least and maybe over 1 k since I have well above this on several other forums, so are they lost forever?

GM

**cradeldorf** · September 25th, 2011, 06:13 PM

Originally Posted by Panomaniac

Will it be mush? Could it be formed or molded?

GM. Is there a horn spreadsheet somewhere that will give me an exponential profile for making something like this? I'll look for one, if you have one please let me know.

It'll probably be mush until the Acetone evaporates.

**edharbur** · September 25th, 2011, 06:21 PM

Aircraft plywood is readilly available in 1/64", 1/32"', 1/16" and 1/8" thicknesses. The material would offer greatly improved stiffness over paper. The thinner two thicknesses are easily cut with heavy duty scissors, the 1/16 with metal shears. Aircraft Spruce and Specialty would be a good place to try. Sheet fiberglass and carbon fiber are available in any thickness you like as well.

The construction technique is pretty simple as long as you have accurate patterns to work with. Contact cement the patterns to your material, cut your pieces, tape together with masking tape and glue together from the inside with cyanoacrylate (CA) in a well ventillated area, or epoxy. After the glue has set the joint can be reinforced un the outside with fiberglass etc...

Ed

**Panomaniac** · September 25th, 2011, 10:02 PM

Thanks guys, I'm going to have to try a mutli-cell tweeter.

**Altec Best** · September 26th, 2011, 01:14 AM

Looks like a Fun project Pano !

**bowtie427ss** · September 26th, 2011, 08:00 AM

It'll probably be mush until the Acetone evaporates.

Most likely. Acetone will also dissolve butyrate which will re-solidify as the Acetone evaporates.

I would be very careful with styrene tho as it's sensitive to a wide variety of petroleum distillates and light hydrocarbons.

I'm in the process of cleaning up from a major flood in which i lost a full tank of heating oil in my basement. Styrofoam peanuts all melted and have re-solidified, they look like disgusting hunks of snot. However, they are quite hard and thier edges can be sharp enough to cut you. Rigid foam insulation also dissolved and re-hardened into dense, hard, and sharp chunks of styrene plastic.

My point here is that some of the distillates and hydrocarbons found in the fuel oil are also prevalent in a number of stains and finishes that we like to use on speaker cabinets. Be careful what you mix, and/or expose.

I don't see myself using that anytime soon ! My luck I would be getting my fingers stuck to everything !

Just to clarify and reiterate, there's no danger until it is heated to the point of combustion or just slightly below. Keep the soldering iron and open flame off it and all should go well.