Composites

By Dan Chen, September 12, 2014

For this week, I want to make my own speakers out of the burlap composites. After some researches on how speakers work in terms of airflow and speaker placements, I quickly found out that most of them are just in boxes with different air channels. I decided to go with something less boxy looking, a speaker that shapes like an old speaker cone.

speaker sceme4

image

I printed the model with a 3D printer with a very thin walls since I will be using this as the model to lay burlaps on. I also made the base with the 3D printer for the vacuums mold.

IMG_9995

After seeing the speakers in person, I realized that it looks like David Lynch’s speakers…

davidlync_Speakers5

Preparations

I used the laser cutter to cut out all my burlaps. I used high speed, 25% power and 25% frequency as my settings and it came out pretty well and it didn’t take all that long.

I used Johnson Wax, Release Fabric and Mann Release Technologies Ease Release (yes, all of them, might be over kill) in between my 3D printed mold and the composites layer (burlap and Epoxy Resin by Entropy Resins).  The holes in the Release Fabric helps the bleed/ white sponge material to absorb the extra resin.

IMG_0002 IMG_0008IMG_0006

I spread the clear Entropy Resins (2 part A and 1 part B) onto each burlap and stack them layer by layer. They are extremely runny. I then vacuums it with a vacuums plastic, designed to store clothing.

IMG_0009 IMG_0011 IMG_0020 IMG_0168

It was pretty easy to break the mold apart, and take out the 3D printed mold. I then trim and sand the pieces to size.

IMG_0169 IMG_0171 IMG_0172 IMG_0175

All the sanding and cutting leaves the surface white and rough, so I coated it with another thin layer of resin, using it as paint. I had to wait for about 12 hours before I can do anything with it.

IMG_0182

Assemble

I use laser cutter to cut out the supporting materials/plexiglass for the speakers. The wiring was pretty tricky since I am working within a pretty tight space.

IMG_0189 IMG_0200 IMG_0211 IMG_0212IMG_0213 IMG_0214IMG_3996 IMG_4009

Wire up the an Amp

With some hot glues, the speakers are in position and ready to wired up with an Amp. The speaker wire jack makes it easy to attach and detach.

IMG_4016 IMG_4023 IMG_4030 IMG_4041

IMG_0220

Testing the speakers

Acoustic Improvement

The speaker doesn’t have the richer bass and deeper sound that I was looking for, so I dod some experiments by covering the front air vent with plexiglass. The speakers sounded a lot better after I cover the front vent, the one directional airflow makes it sound louder  with much better bass.

Before

IMG_4043

After

speak-2x

 

What would I do differently

I should pay more attention with the 3D model unfolds before I cut them with laser cutter.
I would make the speaker cone 2 times larger so it produces better bass.
I should do 2 part compression mold to get better surface on both sides with burlap composite.

 

Stuff that we used in the shop

Entropy Resins https://entropyresins.com/
https://entropyresins.com/product/super-sap-100-1000/ Super Sap 100 Epoxy and 1000 Hardener, 3 gal, Complete Starter Kit (Pumps, cups, sticks, gloves) $254.95
https://entropyresins.com/product/super-sap-ccr-clear-casting-epoxy-resin/ Super Sap CCR Epoxy and CCF (FAST) Hardener, 3 gal, Complete Starter Kit (Pumps, cups, sticks, gloves) $254.95
Fabrics-store.com http://www.fabrics-store.com
http://www.fabrics-store.com/first.php?goto=big_fabric&menu=f&menu=f&fabric_id=740 IL020, 100% Linen, 57 inch, per yard $10.39
Amazon http://www.amazon.com
http://www.amazon.com/LA-Linen-15-Inch-Natural-100-Yard/dp/B00HTVMX08 LA Linen 15-Inch Natural Jute Burlap Roll, 100-Yard, Natural $50.9
http://www.amazon.com/Wiss-28N-Industrial-Shears-Scissors/dp/B000TDILJA Wiss 28N Industrial Shears / Scissors $26.32
http://www.amazon.com/Reynolds-910M-Length-Width-Metro/dp/B004NG9120 Reynolds 910M 2000′ Length x 12″ Width, Metro Line PVC Food Wrap Film $19.88
http://www.amazon.com/Duck-Stretch-20-Inch-Single-970700/dp/B000NHTUCE Duck Brand Stretch Wrap, 20 Inches Wide x 1000 Feet Long, Single Roll (970700) $19.97
http://www.amazon.com/RELEASE-FABRIC-60-inches-yards/dp/B002IZBNJ2 RELEASE FABRIC 60 inches x 2 yards $32.75
http://www.amazon.com/Warner-250-Tool-covering-Perforator/dp/B000I6JLAQ Warner 250 Tool Wall covering Perforator $31.62
http://www.amazon.com/Morning-Glory-Batting-81-Inch-96-Inch/dp/B0040ZOOEY Morning Glory Great Glory III Full Extra Loft Batting, 81-Inch by 96-Inch $12.16
http://www.amazon.com/Space-Saver-Vacuum-Storage-Jumbo/dp/B004X98B5A 50 PACK Space Saver Vacuum Storage Bags Jumbo Size 51″X40″ $102.95
http://www.amazon.com/Mann-Release-Technologies-Ease-200/dp/B004BNAN3G Mann Release Technologies Ease Release 200 14 fl. oz. $10.44
http://www.amazon.com/Johnson-Fine-Wood-Paste-00203/dp/B0000DIWIM Johnson Wax 16 Oz Fine Wood Paste Wax 00203 $7.99
http://www.amazon.com/Gorilla-Glue-50008-Adhesive-8-Ounces/dp/B0000223UV 8oz Original Gorilla Glue $12.99
http://www.amazon.com/Members-Mark-Clear-Plastic-Cups/dp/B001KJFPR8 Members Mark Clear Plastic Cups – 100/16oz Cups $12.39
http://www.amazon.com/All-you-Containers-Lids-32/dp/B00IEBYLKM All 4 you Containers w/ Lids 32 oz (24) $12.99
http://www.amazon.com/Chenille-Kraft-Natural-Sticks-3776-01/dp/B001GXD6BU Chenille Kraft Natural Wood Craft Sticks, Jumbo Size, 6 x 3/4, Wood, Natural Wood, 500/Box (3776-01) $7.27
http://www.amazon.com/Perfect-Stix-PAINT9-Birchwood-Paddle/dp/B009EE61MY Perfect Stix 9″ Wooden Paint Paddle Stirrer Sticks Length (Pack of 100) $13.25
http://www.amazon.com/Mountain-4526-4-Inch-Plastic-Spreaders/dp/B000LQDATG Mountain 4526 4-Inch Plastic Spreaders, 100/box $28.39
http://www.amazon.com/dp/B003K15D9E Ansell TNT Blue 92-575 Nitrile Glove, Chemical Resistant, Powdered, Disposable, Rolled Beaded Cuff, 9.5″ Length, 5 mils Thick, Large (Pack of 100) $7.95
http://www.amazon.com/Denali-30-Piece-Bar-Clamp-Assortment/dp/B000NDMO94 Denali 30-Piece Bar Clamp Assortment $124.99
http://www.amazon.com/BLACK-GARBAGE-TRASH-INDUSTRIAL-GALLON/dp/B000Y3PPK8 BLACK GARBAGE (TRASH) BAGS FOR HEAVY INDUSTRIAL USE, 60 GALLON XXX. HEAVY, BLACK 2.1 MIL – 4 MIL STRENGTH, 100/CASE $53.99
http://www.amazon.com/3M-Scotch-Seal-Mastic-Width-Length/dp/B0010XFTQ6/ref=sr_1_3?ie=UTF8&qid=1412974975&sr=8-3&keywords=scotch+mastic+tape 3M Scotch-Seal Mastic Tape $$11.72
http://www.amazon.com/FJC-6900-Operated-Vacuum-Pump/dp/B002ER1IA8/ref=sr_1_2?ie=UTF8&qid=1413288098&sr=8-2&keywords=air+operated+vacuum+pump Air Operated Vacuum Pump (if have access to compressed air) $$26.03
http://www.amazon.com/Brake-Bleeder-Vacuum-Pump-Kit/dp/B005BT90DI/ref=sr_1_5?ie=UTF8&qid=1413287609&sr=8-5&keywords=Brake+Bleeder Brake Bleeder and Vacuum Pump Kit (if no access to compressed air) $$29.99