[[equipment:storage]]
 
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equipment:storage [2019/07/05 19:03] – [Table] mcmasterequipment:storage [2020/11/22 04:11] – [Table] mcmaster
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 ====== Foams ====== ====== Foams ======
  
-3/8" (10 mm) thick seems to work well for putting DIPs on both sides+===== Brands =====
  
-This section was added to try to learn why some black conductive foams degrade into powder and others degrade into a (mildly corrosive?) sticky mess+^ Image  ^ Vendor    ^ Model                                                                                                               ^ Size                   ^ Cell    ^ Density lb/ft3        ^ Tensile Strength PSI  ^ Color  ^ mcmaster\\ bag  ^ mcmaster\\ bag each       ^ mcmaster\\ bag lg  ^ mcmaster\\ bag lg each    ^ DIP usable?   ^ Notes                                                          ^ 
 +|        | All-Spec  | [[https://www.all-spec.com/Catalog/Static-Control/ESD-Safe-Cushioning-Materials/ESD-Safe-Foams/713-2935|713-2935]]  | 3/8 x 29 x 35"         | Closed  | 50kg/m³               | 515KPa                | Black  | Cut: 7-1/2      | $33.60/(3*4)\\ $2.80/sht  | Cut ~8.5           | $33.60/(3*4)\\ $2.80/sht  | Yes           | "Non-staining, non-corrosive"\\ "Closed cell - non-absorbent"  | 
 +|        | All-Spec  | [[https://www.all-spec.com/Catalog/Static-Control/ESD-Safe-Cushioning-Materials/ESD-Safe-Foams/750-2436|750-2436]]  | 1/2 x 24 x 36"         | Closed  | 1.8 pcf (28.8 kg/m3)  | 31 PSI (215kPa)       | Pink   | Cut: 7-5/8      | $17.61/(3*4)\\ $1.47/sht  | Cut ~8.5           | $17.61/(2*4)\\ $2.20/sht  | Yes           | Ethafoam 180 as                                                | 
 +|        | Zoro      | [[https://www.zoro.com/zoro-select-foam-sheet-36-l-36-w-38-pink-5gdc4/i/G1112921/|G1112921]]                        | 3/8 x 36 x 36"         | Open    | 1.4 lbs. cu. ft       | 13 PSI                | Pink   | N/A             |                           |                    |                           | No: too soft  |                                                                | 
 +|        | eBay      |                                                                                                                     | 1/2" x 15.5" x 11.75"  |         |                       |                       |        |                 | $1.30/(2*1)\\ $0.65/sht   | Cut 9-5/8          | $1.30/(1*1)\\ $1.30/sht   |               |                                                                |
  
-Terms [Foam vs]: +3/8" (10 mm) thick seems to work well for putting DIPs on both sides. However, 1/2" (12mm) was easier to source at the time
-  * Conductive: surface resistance < 1 x 10 5 ohms/square +
-  * Dissipative: 1 x 10 5 ohms/square < surface resistance < 1 x10 11 ohms/square +
-  * Insulative: surface resistance > 1 x 10 12 ohms/square +
-  * Anti-static: inhibits triboelectric charging, "the buildup of an electric charge by the rubbing or contact with another material"+
  
 +{{:mcmaster:foam:cut_foam.jpg?400|}}
  
 +mcmaster bags: U-Line S-3704 (pink, 8x8"). Fits nicely into divided boxes.
 +
 +===== Degradation =====
 +
 +This section was added to try to learn why some black conductive foams degrade into powder and others degrade into a (mildly corrosive?) sticky mess
  
 <code> <code>
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-== Brands ==+Repairing: mcmaster cleans up pins using glass fiber brush then briefly soaks in HCl. Finally, use liquid tin to re-plate
  
-^ Image  ^ Vendor    ^ Model                                                                                                               ^ Size            ^ Cell    ^ Density lb/ft3        ^ Tensile Strength PSI  ^ Color  ^ mcmaster\\ bag  ^ DIP usable?   ^ Notes  ^ +===== Conductivity =====
-|        | Zoro      | [[https://www.zoro.com/zoro-select-foam-sheet-36-l-36-w-38-pink-5gdc4/i/G1112921/|G1112921]]                        | 3/8 x 36 x 36"  | Open    | 1.4 lbs. cu. ft       | 13 PSI                |        | N/A             | No: too soft  |        | +
-|        | All-Spec  | [[https://www.all-spec.com/Catalog/Static-Control/ESD-Safe-Cushioning-Materials/ESD-Safe-Foams/750-2436|750-2436]]  | 1/2 x 24 x 36"  | Closed  | 1.8 pcf (28.8 kg/m3)  | 31 PSI (215kPa)       | Black  | Cut: 7-5/8      | Yes           |        | +
-|        | All-Spec  | [[https://www.all-spec.com/Catalog/Static-Control/ESD-Safe-Cushioning-Materials/ESD-Safe-Foams/713-2935|713-2935]]  | 3/8 x 29 x 35"  |         | 50kg/m³               | 515KPa                | Pink   | Cut: 7-1/2      | Yes           |        |+
  
 +Terms [Foam vs]:
 +  * Conductive: surface resistance < 1 x 10 5 ohms/square
 +  * Dissipative: 1 x 10 5 ohms/square < surface resistance < 1 x10 11 ohms/square
 +  * Insulative: surface resistance > 1 x 10 12 ohms/square
 +  * Anti-static: inhibits triboelectric charging, "the buildup of an electric charge by the rubbing or contact with another material"
  
-===== Density =====+Typically ESD bags are aluminum coated mylar. Pink bags are dissipative, while blue bags offer no protection, but don't generate static. Do foams carry the same convention?
  
-Vendors talk about low and high density foams.  There doesn't seem to be any agreement whatsoever as to what these mean, even within the same vendors.  Look at the kg/m3 ratings I guess if you care about density 
  
- +==== Pink foam ====
-===== Blowing agent ===== +
- +
-In order to turn a liquid into a foam, you need a way to aerate it.  Looks like traditionally this was done with CFCs but looks like it may now typically be done with nitrogen. +
- +
- +
-===== Pink foam =====+
  
 Also seen in the form of bags and packing bubbles. Also seen in the form of bags and packing bubbles.
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-===== Blue foam =====+==== Blue foam ====
  
 Like above, but less sensitive to moisture [Why pink].  Unclear if it has any disadvantages (cost, lifetime, etc) Like above, but less sensitive to moisture [Why pink].  Unclear if it has any disadvantages (cost, lifetime, etc)
  
  
-===== Black foam =====+==== Black foam ====
  
 From private communication (speculative but may be good lead): From private communication (speculative but may be good lead):
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 Maybe could UV irradiate foam to simulate aging Maybe could UV irradiate foam to simulate aging
 +
 +
 +
 +
 +===== Density =====
 +
 +Vendors talk about low and high density foams.  There doesn't seem to be any agreement whatsoever as to what these mean, even within the same vendors.  Look at the kg/m3 ratings I guess if you care about density
 +
 +
 +===== Blowing agent =====
 +
 +In order to turn a liquid into a foam, you need a way to aerate it.  Looks like traditionally this was done with CFCs but looks like it may now typically be done with nitrogen.
 +
  
 ====== References ====== ====== References ======
 
equipment/storage.txt · Last modified: 2021/12/09 05:48 by mcmaster
 
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