Well I wanted to make a mold and start making fiberglass AC delete heater box shells for awhile now.

Here's my mold:

The mold gets one layer of gelcoat for the replica. Also it gets 2 to 3 layers of biaxial fiberglass, which will make up the replica piece.

I drilled 3 holes into the mold backside so I could tap on the replica piece. This helped vibrate it apart from the mold. I used clothes pins to wedge around the outside till it pops out.

Here's what it looks like now:

From what I can tell it weighs about 1/2 what the OEM piece did. Also I see it as an advantage that fiberglass will never rust out like the steel factory piece. Once everything is done it should look identical to the factory piece in the picture.

I used a jigsaw with a very fine blade to cut the excess fiberglass off and cut out the blower, tube, and resistor locations.

I have test fit the box in place too. It's a little tight in spots but I'll trim it up until it's exact. Then I can scribe the exact pattern for use on future boxes.

I also picked up the fastners. I'll be using machine screws, washers, and nuts. Most of the factory attachments can be reused on the firewall.

Non-AC motor was attached to the box along with the AC resistor. Reason for using the AC resistor was no modifications other than power and ground hookup on the blower unit. If it's an older AC blower you shouldn't even have to do that much. Appears GM switched over to a new connection on the later years.

Hooked the wires up. Appears to be blowing a fair amount of air. I might have to go back and put on wedge in the box to divert air flow more like a factory box. It might be hurting the efficency a little by not having it there. I believe the air is spooling around the blower wheel more than it's being pushed. I might be wrong though. More than likely I'll add a fiberglass wedge in there too.

I have two fiberglass replicas done with wedges in them. There primed and painted.

I went ahead and made a mold for the cooling hose attachments. I used the old bolt on style off my AC box. The plug did not survive the mold making but it looks like I have a working mold. It's ready to start making replicas with whenever I get some free time.

I have the hose attachment mold with a plug in it now. I need to let it cure before I can pry it out. As for now I'm out of fiberglass resin. So if this plug survives then I'll have one working heater box to sell off.

Here is a picture of the mold and plug.

The hose attachment has been finished.

Here is the final product!!!

Currently thinking a finished shell with fasteners will run ~$70 (+ ~$10 shipping). I will probably include instructions on how to convert a 4 speed AC fan into the box. The buyer will have to either convert their AC fan over to the Non-AC box or buy a new fan from a parts store (~$40 for a lifetime warranty). Still at this price for a fiberglass piece is a steal. I've seen the steel one goes as much as $152 + shipping on Ebay without the motor. Object isn't to dominate and make tons of money. I rather help out other 3rd gen owners and not go broke myself.

I've managed to sell one of these so far. I have another box almost complete. Nice to actually see people interested in my fiberglass work.

Once I make my money back and start turning a profit, which will take many sales. I might consider making "hybrid" AC delete boxes. A hybrid will allow the user to retain their 4 speed fan by simply bolting it onto the box no extra parts or conversions needed. This will take a great deal of work on my part (custom fabricating, testing, molding, replicas, etc) so my guess will be these will run ~$100+. I'll have to custom the whole mounting part of the box, since it is very tight in that area of the car. Course the "Hybrid" is still just an idea at the moment so it might not even happen.

Site Index:
Page 1 - Introduction
Page 2 - Current Project To Do Lists
Page 3 - The Interior
Page 4 - 2 18" Kicker particle board box (old design)
Page 5 - 2 18" Kicker fiberglass box custom
Page 6 - General Mods
Page 7 - My Z20 Special Appearance Package
Page 8 - My fiberglass non AC heater box mold (1LE version that has been discontinued by GM) <-- You're here
Page 9 - New High-PO 383 in the build
Page 10 - Glasstek Hood Repair
Page 11 - Fiberglass Box How-To
Page 12 - My Xbox Game for 1� I bought from the store with proof
Page 13 - SOLD! Twin 62mm T4 Turbo Kit From BBS DESIGNS for 1200 HP! SOLD!
Page 14 - To Do List before motor completion