Sheet molding compound having improved characteristics

Abstract

A composite part made from a sheet molding compound is disclosed as having improved characteristics over traditional sheet molding compound composite parts. The fibrous material is introduced as a veil layer adjacent a paste layer, the veil flows well during the molding process. The improved flow and surface characteristics of a composite part are attributed to the elongation of the veil during molding and to the improved filling capabilities.

1 . A single ply of a sheet molding compound sheet prior to compaction used for making a composite part comprising: 
 a first carrier film layer;    a first paste layer provided adjacent the carrier film layer;    a preformed veil of fused fibers provided adjacent to the first paste layer opposite the first carrier layer;    a second carrier film layer; and    a second paste layer provided between the veil and the second carrier film layer;    wherein said fused fibers in said preformed veil are held in place during compaction in order to provide said composite part with smooth surface characteristics.    
   
   
       2 . A single ply of a sheet molding compound sheet prior to compaction used for making a composite part comprising: 
 a first carrier film layer;    a first paste layer provided adjacent the carrier film layer;    a preformed, nonwoven veil provided adjacent to the first paste layer opposite the first carrier layer, said veil including a plurality of irregularly shaped filaments or fibers fused in position in said veil,    a second carrier film layer; and    a second paste layer provided between the veil and second carrier film layer;    wherein said irregularly shaped filaments or fibers remain fused in said veil during compaction and thereby allow production of said composite part with improved surface characteristics.    
   
   
       3 . The ply of  claim 1  wherein said first paste layer comprises a barrier layer capable of producing an external surface substantially free of surface pores and cracks when molded.  
   
   
       4 . The ply of  claim 3  further comprising a layer of chopped fibers located between said veil and said second paste layer.  
   
   
       5 . The ply of  claim 4  further comprising a third layer of paste between the veil and the layer of chopped fibers.  
   
   
       6 . The ply of  claim 5 , wherein said ply is compression molded in a mold having a surface, and wherein said veil comprises a plurality of fibers, wherein said fibers flow with the paste during compression molding, and wherein said veil covers substantially the entire surface of the mold in a substantially continuous form after molding.  
   
   
       7 . The ply of  claim 6 , wherein said veil comprises a binder which is highly soluble in a resin of the first paste layer.  
   
   
       8 . The ply of  claim 7 , wherein the binder has a solubility of over about 35% in the resin.  
   
   
       9 . The ply of  claim 8 , wherein the binder has a solubility of over about 50% in the resin.  
   
   
       10 . The ply of  claim 9 , wherein the binder has a solubility of over about 75% in the resin.  
   
   
       11 . The ply of  claim 10 , wherein the binder has a solubility of nearly 100% in the resin.  
   
   
       12 . The ply of  claim 7 , wherein said veil further comprises long fibers.  
   
   
       13 . The ply of  claim 12 , wherein one of said first paste layer and said veil comprises a conductive material.  
   
   
       14 . The ply of  claim 1 , wherein said veil comprises a binder which is highly soluble in a resin of the first paste layer.  
   
   
       15 . The ply of  claim 14 , wherein the binder has a solubility of over about 35% in the resin.  
   
   
       16 . The ply of  claim 15 , wherein the binder has a solubility of over about 75% in the resin.  
   
   
       17 . The ply of  claim 14 , wherein said veil further comprises long fibers.  
   
   
       18 . The ply of  claim 17 , wherein said ply is compression molded in a mold having a surface, and wherein said veil fibers flow with the paste during compression molding, and wherein said veil covers substantially the entire surface of the mold in a substantially continuous form after molding.  
   
   
       19 . The ply of  claim 18 , wherein said fibers have a length between about 100 mm and about 300 mm.  
   
   
       20 . The ply of  claim 18 , wherein said veil is made using a dry 
 forming process, and wherein said dry formed veil is needle punched.    
   
   
       21 . The ply of  claim 20 , wherein said veil is made using continuous filaments in said dry forming process.  
   
   
       22 . The ply of  claim 18 , wherein said veil has a dry tensile strength of at least 5 N/m in each of a width and a length direction thereof.  
   
   
       23 . The ply of  claim 22 , wherein said veil has a dry tensile strength of at least 50 N/m in the length direction.  
   
   
       24 . The ply of  claim 7 , wherein said first paste layer further comprises a polyester resin, fillers, a resin inhibitor and initiator, an alkaline earth oxide, and an internal mold release agent.  
   
   
       25 . The ply of  claim 24 , wherein said chopped fibers are selected from the group consisting of chopped glass fibers and chopped carbon fibers.  
   
   
       26 . The ply of  claim 1 , wherein one of said veil and said first paste comprises a conductive material.  
   
   
       27 . The ply of  claim 26 , wherein said conductive material is selected from the group consisting of a plurality of irregularly shaped carbon fibers, carbon flakes, carbon fibrils, and carbon powders.  
   
   
       28 . The ply of  claim 1 , wherein said veil comprises fibers, and wherein said ply is compression molded in a mold having a surface, and said fibers flow with the paste during compression molding, said veil covering substantially the entire surface of the mold in a substantially continuous form after molding.  
   
   
       29 . The ply of  claim 28 , wherein said veil has a weight of between about 20 grams/square meter and about 200 grams/square meter.  
   
   
       30 . The ply of  claim 29 , wherein said veil has a weight of between about 40 grams/square meter and about 120 grams/square meter.  
   
   
       31 . The ply of  claim 30 , wherein said veil comprises one of a group of: longer chopped fibers, continuous filaments cut to discrete lengths, and irregularly shaped fibers.  
   
   
       32 . The ply of  claim 31 , wherein said veil has a dry tensile strength of at least 5 N/m in each of a width and a length thereof.  
   
   
       33 . The ply of  claim 32 , wherein said veil has a dry tensile strength of at least 50 N/m in the length thereof.  
   
   
       34 . The ply of  claim 28 , wherein the veil has a thickness of at least approximately 0.1 mm over substantially the entire mold surface after the ply is molded in the mold.  
   
   
       35 . The ply of  claim 34 , wherein the ply is cut to a shape and placed in the mold so the shape of the ply covers more than about 40% of the mold surface before molding.  
   
   
       36 . The ply of  claim 35 , wherein the shape of the sheet covers more than about 60% of the mold surface before molding.  
   
   
       37 . The ply of  claim 36 , wherein the shape of the sheet covers more than about 80% of the mold surface before molding.  
   
   
       38 . The ply of  claim 1 , wherein the ply is compacted and the veil is integrally compounded with the first paste layer.  
   
   
       39 . The ply of  claim 38 , wherein said veil comprises a binder which is highly soluble in a resin of the first paste layer, and wherein said veil is wetout by the paste layer and said binder is substantially dissolved by said paste.  
   
   
       40 . A method for making a single ply of a sheet molding compound sheet comprising the steps of: 
 introducing a first carrier film layer;    introducing a first side of a veil adjacent to said first carrier film layer;    introducing a first paste layer between said veil and said first carrier film layer;    introducing a second carrier film layer adjacent to a second side of said veil;    introducing a second paste layer between said veil and said second carrier film layer; and    compacting said combined veil and paste layers to form a single ply of sheet molding compound.    
   
   
       41 . The method of  claim 40  further comprising the step of introducing a plurality of chopped fibers of a first type between said veil and said second paste layer, said chopped fibers selected from the group consisting of chopped glass fibers and chopped carbon fibers.  
   
   
       42 . The method of  claim 41  further comprising the step of introducing a third layer of paste between the veil and the layer of chopped fibers.  
   
   
       43 . The method of  claim 42  wherein said first paste layer provides a barrier layer capable of producing an external surface substantially free of surface pores and cracks when molded.  
   
   
       44 . The method of  claim 43 , further comprising the step of introducing one or more additional alternating pairs of paste and reinforcement layers between the veil and second film layer.  
   
   
       45 . The method of  claim 40 , further comprising the steps of positioning said ply within a mold in a compression molding machine, compressing said ply within said mold, flowing a plurality of fibers from said veil with said first paste during said compression step to substantially cover an entire surface of said mold with said veil fibers and wherein said veil remains substantially continuous after molding.  
   
   
       46 . The method of  claim 45 , wherein said veil elongates over about ten percent in each of the width and length thereof during the flowing step.  
   
   
       47 . The method of  claim 45 , further comprising the step of substantially dissolving a binder of said veil prior within said paste layers prior to the compressing step.  
   
   
       48 . The method of  claim 45 , wherein said veil comprises a plurality of irregularly shaped fibers  
   
   
       49 . The method of  claim 47 , wherein the first paste layer comprises a barrier layer having an external surface substantially free of surface pores and cracks when molded to form a Class A surface.  
   
   
       50 . The method of  claim 40 , further comprising the steps of wetting out said veil with one of said paste layers and substantially dissolving a binder of said veil within said paste layer.  
   
   
       51 . The method of  claim 50 , further comprising introducing a conductive material within one of said veil and said first paste layer.  
   
   
       52 . The method of  claim 50 , further comprising the steps of positioning said ply within a mold in a compression molding machine, compressing said ply within said mold, flowing a plurality of fibers from said veil with said first paste during said compression step to substantially cover an entire surface of said mold with said veil fibers and wherein said veil remains substantially continuous after molding.  
   
   
       53 . A method for making a composite part having improved surface characteristics comprising: 
 forming a single ply of a sheet molding compound sheet, the method of forming said single ply comprising: 
 (a) introducing a first carrier film layer;  
 (b) introducing a veil adjacent to said first carrier film layer;  
 (c) introducing a first paste layer between a first side of said veil and said first carrier film layer;  
 (d) introducing a second carrier film layer adjacent to a second side of said veil to form a sheet molding compound sheet;  
 (e) compacting said carrier films, veil and paste to form a single ply of sheet molding compound.  
 (f) thickening said single ply;  
 (g) cutting said single ply into a plurality of moldable plies having a desired shape;  
 (h) introducing at least one of said plurality of moldable plies into a mold having a surface;  
 (i) compressing said moldable ply within said mold;  
 (j) flowing said first paste layer of said moldable ply to cover said mold surface;  
 (k) elongating said veil of said moldable ply during said flowing step (j) across substantially the entire mold surface; and  
 (l) curing said moldable ply at a first pressure and a first temperature for a sufficient time to form the composite part.  
   
   
   
       54 . A method according to  claim 53 , wherein said first paste is placed directly onto the first carrier film.  
   
   
       55 . A method according to  claim 53 , wherein said first paste is placed directly onto said veil using a doctor blade and extruded through said veil under said doctor blade to wetout said veil and form a layer of paste between the veil and first carrier film.  
   
   
       56 . A method according to  claim 53 , wherein said first paste is applied using a calendering device, and said veil is wet out by said first paste using said calendering device.  
   
   
       57 . The method of  claim 53 , wherein (d) introducing a second carrier film layer adjacent to a second side of said veil to form a sheet molding compound sheet comprises (d) introducing a second paste layer onto said one of a second side of said veil and a side of said second carrier film and thereafter positioning said second carrier film layer onto said veil to form a sheet molding compound sheet.  
   
   
       58 . The method of  claim 53 , wherein the step of curing said moldable ply comprises the step of curing said moldable ply at about 140-163 degrees Celsius and between approximately 5-10 MPa for between approximately one-half and three minutes.  
   
   
       59 . The method of  claim 57 , further comprising the step of introducing a plurality of chopped fibers onto said veil prior to introducing said a second paste layer onto said veil.  
   
   
       60 . The method of  claim 59 , further comprising the step of introducing a third layer of paste between the veil and the layer of chopped fibers.  
   
   
       61 . The method of  claim 60 , further comprising the step of introducing one or more additional alternating pairs of paste and reinforcement layers between the veil and second film layer.  
   
   
       62 . The method of  claim 61 , wherein the third layer of paste is applied using a calendering device, paste extruder or funnel applicator.  
   
   
       63 . The method of  claim 53  wherein said first paste layer forms a barrier layer having an external surface substantially free of surface pores and cracks when molded to form a Class A surface.  
   
   
       64 . The method of  claim 53 , wherein the step of (b) introducing a veil adjacent to said first carrier film layer; comprises (b) introducing a veil adjacent to said first carrier film layer, said veil comprising fibers and a conductive material.  
   
   
       65 . The method of  claim 64 , wherein said conductive material is selected from the group consisting of a plurality of irregularly shaped carbon fibers, carbon flakes, carbon fibrils, and carbon powders.  
   
   
       66 . The method of  claim 53 , wherein the step (k) further comprises elongating said veil during said compression step to substantially cover the entire surface of said mold, and wherein said veil remains substantially continuous after the compression step.  
   
   
       67 . The method of  claim 66 , wherein said veil elongates over ten percent in each of a width and length thereof.  
   
   
       68 . The method of  claim 67 , wherein said veil elongates over fifty percent in each of the width and length thereof, and wherein said fibers do not melt when exposed to a temperature exceeding 200 degrees C. for 20 seconds.  
   
   
       69 . The method of  claim 67 , wherein said veil comprises a plurality of fibers and a binder, further comprising the step of substantially dissolving said binder in one of said paste layers, and wherein said veil elongates by flowing said fibers with the paste.  
   
   
       70 . The method of  claim 69 , wherein said elongated veil has a thickness of at least about 0.1 mm over substantially the entire mold surface.  
   
   
       71 . The method of  claim 70 , wherein said binder is highly soluble in a resin of the first paste layer, said method further comprising the steps of: wetting out said veil with said paste, and dissolving said binder in said paste.  
   
   
       72 . The method of  claim 71 , wherein said veil further comprises long fibers.  
   
   
       73 . The method of  claim 72 , further comprising the step of forming said veil by a dry forming process.  
   
   
       74 . The method of  claim 73 , further comprising the step of needle punching said veil.  
   
   
       75 . The method of  claim 66 , wherein said veil comprises a plurality of irregularly shaped fibers.  
   
   
       76 . The method of  claim 53 , wherein said veil experiences a curing temperature of over 200 degrees C. during the curing step, and wherein said veil does not melt at said curing temperature.  
   
   
       77 . The method of  claim 76 , wherein said veil comprises a plurality of long fibers and a binder, further comprising the step of substantially dissolving said binder in one of said paste layers, and wherein said veil elongates by flowing said fibers with the paste.  
   
   
       78 . The method of  claim 77 , wherein said elongated veil has a thickness of at least about 0.1 mm over substantially the entire mold surface.  
   
   
       79 . The method of  claim 44 , further comprising the step of introducing a second ply on top of said moldable ply prior to the compression step.  
   
   
       80 . The method of  claim 79 , wherein said second ply comprises a different paste than the paste of the moldable ply.  
   
   
       81 . A single ply of a conductive sheet molding compound composite sheet used to make a composite part having surface conductivity comprising: 
 a first paste layer;    a preformed veil comprising a plurality of nonwoven discrete reinforcing filaments or fibers, wherein the filaments or fibers are fused in said veil and do not melt when exposed to a temperature of 200 degrees C. for twenty seconds; and    a conductive paste layer, said conductive paste layer comprising a thermosetting resin and a graphite material.    
   
   
       82 . The conductive sheet molding compound composite sheet as in  claim 81 , wherein the graphite material comprises a graphite powder.  
   
   
       83 . The conductive sheet molding compound composite sheet as in  claim 81 , wherein said graphite material comprises a graphite flake.  
   
   
       84 . The conductive sheet molding compound composite sheet as in  claim 81 , wherein said graphite material comprises not less than approximately 20 weight percent of said conductive paste layer.  
   
   
       85 . The conductive sheet molding compound composite sheet as in  claim 81 , wherein said thermosetting resin comprises a polyester resin.  
   
   
       86 . The conductive sheet molding compound composite sheet as in  claim 81 , wherein plurality of reinforcing filaments or fibers comprises a veil, and wherein said sheet is compression molded in a mold having a surface, and wherein said veil fibers flow with the paste layers during compression molding, and wherein said veil covers substantially the entire surface of the mold in a substantially continuous form after molding.  
   
   
       87 . A method for making a single ply of a conductive sheet molding compound that may be subsequently used to make an electrically conductive composite part comprising: 
 introducing a first carrier film layer;    introducing a first paste layer onto said first carrier film layer, said first paste layer comprising a first paste formulation;    introducing a plurality of chopped reinforcing fibers onto said first paste layer;    introducing a conductive paste layer onto said first paste layer, said conductive paste layer comprising a conductive paste formulation, said conductive paste formulation comprising a thermosetting resin and a graphite material;    introducing a second carrier film layer onto said conductive paste layer to form a sheet molding compound composite sheet;    compacting said sheet molding compound composite sheet to form a single ply of sheet molding compound; and    thickening said single ply.    
   
   
       88 . The method according to  claim 87 , wherein said graphite material comprises a graphite powder.  
   
   
       89 . The method according to  claim 87 , wherein said graphite material comprises a graphite flake.  
   
   
       90 . The method according to  claim 87 , wherein said graphite material comprises not less than approximately 20 weight percent of said paste layer.  
   
   
       91 . The method according to  claim 87 , wherein the said thermosetting resin comprises a polyester resin.  
   
   
       92 . The method according to  claim 87 , wherein said plurality of chopped reinforcing fibers comprises a veil, the method further comprising the steps of: 
 compression molding said ply in a mold having a surface;    flowing the fibers with the paste layers during the compression molding step; and    substantially covering the entire surface of the mold with said fibers in a substantially continuous form during said flowing step.    
   
   
       93 . A method for forming a composite part having electrical conductivity of less than 10 6  ohms per square along a visible surface, the method comprising: 
 forming a conductive sheet molding compound composite sheet, said conductive sheet molding compound composite sheet comprising a first paste layer, a plurality of chopped reinforcing fibers, and a conductive paste layer comprising a thermosetting resin and a graphite material;    compacting said conductive sheet molding compound composite sheet to form a single ply of a conductive sheet molding compound;    introducing at least one ply of said conductive heat molding compound to a mold such that said second paste layer is closely coupled to a surface of said mold; and    molding said at least one ply of said conductive sheet molding compound at a first temperature and a first pressure for sufficient time to cure said conductive sheet molding compound to form the composite part.    
   
   
       94 . The method of  claim 93 , wherein forming conductive sheet molding compound composite sheet comprises: 
 introducing a first carrier film layer;    introducing a first paste layer onto said first carrier film layer, said first paste layer comprising a first paste formulation;    introducing a plurality of chopped fibers onto said first paste layer;    introducing a conductive paste layer onto said plurality of chopped fibers, said conductive paste layer comprising a second paste formulation, said second paste formulation comprising a thermosetting resin and a graphite material;    introducing a second carrier film layer onto said conductive paste layer to form a conductive sheet molding composite sheet;    compacting said conductive sheet molding composite sheet to form a single ply of conductive sheet molding compound;    thickening said single ply; and    cutting said single ply into a plurality of moldable plies having a desired shape; and    removing said first carrier film layer and said second carrier film layer from said single ply.    
   
   
       95 . The method according to  claim 93 , wherein forming a conductive sheet molding compound composite sheet comprises forming a conductive sheet molding compound composite sheet, said conductive sheet molding compound composite sheet comprising a first paste layer, a plurality of chopped reinforcing fibers, and a conductive paste layer comprising a thermosetting resin and a graphite powder.  
   
   
       96 . The method according to  claim 93 , wherein forming a conductive sheet molding compound composite sheet comprises forming a conductive sheet molding compound composite sheet, said conductive sheet molding compound composite sheet comprising a first paste layer, a plurality of chopped reinforcing fibers, and a conductive paste layer comprising a thermosetting resin and a graphite flake.  
   
   
       97 . The method according to  claim 93 , wherein forming a conductive sheet molding compound composite sheet comprises forming a conductive sheet molding compound composite sheet, said conductive sheet molding compound composite sheet comprising a first paste layer, a plurality of chopped reinforcing fibers, and a conductive paste layer comprising a thermosetting resin and a graphite material, said graphite material comprising not less than approximately 20 weight percent of said conductive paste layer.  
   
   
       98 . The method according to  claim 93 , wherein forming a conductive sheet molding compound composite sheet comprises forming a conductive sheet molding compound composite sheet, said conductive sheet molding compound composite sheet comprising a first paste layer, a plurality of chopped reinforcing fibers, and a conductive paste layer comprising a thermosetting resin and a graphite material, said graphite material comprising not less than approximately 20 weight percent of said conductive paste layer, wherein said graphite material is selected from the group consisting of graphite powder and graphite flake.  
   
   
       99 . The method of  claim 93 , wherein molding said at least one ply comprises molding said at least one ply of said conductive sheet molding compound at between about 140-163 degrees Celsius and between about 5-10 MPa for about one-half to three minutes to cure said conductive sheet molding compound to form the composite part.  
   
   
       100 . The method according to  claim 93 , wherein said chopped fibers comprise a veil, the molding step further comprising the steps of: 
 compression molding said sheet in a mold having a surface;    flowing the fibers with the paste layers during the compression molding step; and    substantially covering the entire surface of the mold with said fibers in a substantially continuous form during said flowing step.    
   
   
       101 . A method for introducing a layer of sheet molding paste on a sheet molding compounding line comprising: 
 coupling a volumetric paste extrusion device to the sheet molding compounding line, said volumetric paste extrusion device comprising a paste tank fluidically coupled to a slit extrusion die, said paste tank having a quantity of sheet molding paste;    pumping said quantity of sheet molding paste from said paste tank to said slit extrusion die; and    volumetrically applying a portion of said quantity of sheet molding paste from said slit extrusion die onto the sheet molding compounding line to form a layer of sheet molding paste.    
   
   
       102 . The method of  claim 101 , wherein said slit extrusion die comprises a bulk molding volumetric slit extrusion die.  
   
   
       103 . The method of  claim 101 , wherein pumping a quantity of sheet molding paste to a slit extrusion die comprises: 
 fluidically coupling an input line and an exit line between said paste tank and said slit extrusion die, wherein said input line has a first volumetric pump and wherein said exit line has a second volumetric pump;    pumping a first quantity of sheet molding paste from said paste tank to said slit extrusion die through said input line using said first volumetric pump; and    pumping a second quantity of sheet molding paste from said slit extrusion die to said paste tank through said exit line using said second volumetric pump, wherein the difference between said first quantity and said second quantity represents the throughput of paste delivered onto the sheet molding compounding line.    
   
   
       104 . The method of  claim 101 , wherein volumetrically applying a portion of said quantity of sheet molding paste comprises volumetrically applying a portion of said quantity of sheet molding paste through a slit on said slit extrusion die onto the sheet molding compounding line to form a layer of sheet molding paste, said slit having a width W.  
   
   
       105 . The method of  claim 104 , further comprising coupling an Archimedes screw device to said slit extrusion die, said Archimedes screw device used to control the left-right balance of distribution of said portion of said quantity of sheet molding paste across the width W of said slit.  
   
   
       106 . The method of  claim 101 , wherein volumetrically applying a portion of said quantity of sheet molding paste comprises volumetrically applying a portion of said quantity of sheet molding paste through a slit on said slit extrusion die onto the sheet molding compounding line to form a layer of sheet molding paste, said slit having a width W, said slit having a deformable lip that allows control of the gap width of said slit in order to balance right-left linear throughput through said slit.  
   
   
       107 . The method of  claim 104  further comprising coupling a filter within said input line to prevent large particulate matter from entering said slit extrusion die.  
   
   
       108 . The method of  claim 101  further comprising the step of compacting a veil with said paste, wherein said veil comprises a binder substantially soluble in said paste.  
   
   
       109 . A volumetric paste extrusion device used to apply sheet molding paste to a sheet molding compounding line comprising: 
 a paste tank, said paste tank having a quantity of sheet molding paste;    a slit extrusion die having a slit, said slit having a width W;    an input line for fluidically coupling said paste tank to said slit extrusion die;    a first volumetric pump coupled to said input line, said first volumetric pump capable of pumping said quantity of sheet molding paste from said paste tank through said input line to said slit extrusion die;    an exit line for fluidically coupling said slit extrusion die to said paste tank.    
   
   
       110 . The volumetric paste extrusion device of  claim 109 , wherein said slit extrusion die comprises a bulk molding volumetric slit extrusion die.  
   
   
       111 . The volumetric paste extrusion device of  claim 109 , further comprising: a second volumetric pump coupled to said exit line, said second volumetric pump capable of pumping a first portion of said quantity of sheet molding paste from said slit extrusion die through said exit line to said paste tank, wherein a second portion of said quantity of sheet molding paste exits said slit across said width W, said first portion and said second portion comprising said quantity of said sheet molding paste  
   
   
       112 . The volumetric paste extrusion device of  claim 111 , further comprising an Archimedes screw device coupled to said slit extrusion die, said Archimedes screw device used to control the left-right balance of distribution of said portion of said quantity of sheet molding paste across said width W of said slit.  
   
   
       113 . The volumetric paste extrusion device of  claim 109 , wherein said slit has a deformable lip, said deformable lip allowing control of the gap width of said slit in order to balance right-left linear throughput through said slit.  
   
   
       114 . The volumetric paste extrusion device of  claim 109  further comprising a filter coupled within said input line.  
   
   
       115 . The method of  claim 109  further comprising the step of compacting a veil with said paste, wherein said veil comprises a binder substantially soluble in said paste.  
   
   
       116 . A single ply of a conductive sheet molding compound composite sheet used to make a composite part having surface conductivity comprising: 
 a first paste layer;    a preformed veil including a plurality of chopped irregularly shaped reinforcing fibers; and    a conductive paste layer, said conductive paste layer comprising a thermosetting resin and a graphite material.    
   
   
       117 . The ply of  claim 1  where said fibers or filaments comprise glass fibers or filaments.  
   
   
       118 . The ply of  claim 81  wherein said fibers or filaments comprise glass fibers or filaments.