POWERSANDING  WOOD  BOWLS      by  John  Franklin  We  have  all  been  taught  to  consider  sanding  a  less  than  desirable  function  when  turning  wood.  Although  skill  with   your   tools   will   normally   reduce   the   need   to   do   a   lot   of   sanding   on  most   turned   objects,   wet   turned  natural  edge  bowls  are  an  item  that  do  not  fit  into  this  category.  Why,  because  when  you  turn  a  wet  natural  edge  bowl   it   has   to   dry   before   you   finish   it.  When   the  bowl   dries   it   changes   shape   a   lot.  Where   it   started  round,   it  may  end  up  rather  oval.  Once   it   is  oval,   it  can  no  longer  be  turned  again  to  true  up  the  outside  or  inside  surfaces.      

So  how  do  you  finish  a  dried  wet  turned  bowl?  In  the  case  of  wet  wood,  power  sanding  allows  you  to  make  very  pleasant   looking  and   functional  bowls.  True,   they  are  not   really  perfect   circles  anymore,  but   they   look  nice  and  work  well.  Most  people  will  not  notice  that  they  are  actually  no  longer  round.      

Below  is  my  idea  of  a  functional  power  sanding  set  up.  Start  with  a  right  angle  drill  and  a  2  or  3”  hook  and  loop  disk.  Here   I  have  a  Grex   sanding  pad  extended  with  a  ¼-­‐20   coupling  nut.   The   coupling  nut  gives  me  better  reach  and   is  much  more   secure   in   the   chuck   than   the   screw  end  alone.     To   this   I   add  a   3”   x  ½”  or   1”   soft  flexible  pad,  then  a  5”  x  3/8”  flexible  pad,  then  a  6”  x  1/8”  flexible  pad,  followed  by  a  sheet  of  Abranet  open  mesh  sand  paper.    What  is  the  point  of  this  combination?    

 

First,  when  sanding  on  the  inside  of  a  bowl,  the  newly  removed  sawdust  created  by  the  sand  paper  is  trapped  between   the   wall   of   the   vessel   and   the   sandpaper   and   tends   to   stop   the   sanding   action   rather   quickly.  ABRANET  open  mesh  sand  disks  allow  the  dust  to  pass  through  the  paper  and  exit  the  sanding  surface.  You  get  much  faster  stock  removal  and  less  burnishing  caused  by  rubbing  the  wood  with  sawdust.      

Second,   when   sanding   the   inside   of   a   bowl   the   concave   surface   tends   to   cause   digs   in   eth   surface   when  sanded.  The  multiple  stepped  up  soft  backer  pads  allow  the  outside  edge  of  the  actual  sanding  disk  to  flex  and  not  dig   in  on   the  edges.   You   can   get   very   smooth   transitions.   You   can  work   the   sander   rather   aggressively  without  cutting  grooves  in  the  inside  of  the  bowl.    

 

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Although   power   sanding   is   by   far   the   fastest,   you   may   not   have   a   power   sander   to   do   the   job.   Another  effective  tool  is  a  hand  held  sanding  stick.  It  is  dangerous  to  hand-­‐hold  a  piece  of  sandpaper  inside  an  irregular  edge  bowl,  you  may  get  caught  by  the  waving  edge.  This  stick  allows  you  to  use  the  same  pad  combinations  used  on  the  power  sander  but  hold  them  safely  inside  the  bowl  while  the  lathe  runs.      

Shown  below  are  some  examples  of  various  uses  of  a  sanding  stick  with  different  sizes  or  shapes  of  sanding  pads.  Some  are  used  on  the  end  of  the  stick,  locked  in  place  with  a  set  screw.    

   

#1:   START   TO   BLEND   THE   INSIDE   SURFACE   :   The  important   thing   to   remember   when   power   sanding   a  out   of   round  bowl   is:   don’t   try   to  make   it   round.   Just  smooth   the   surface   and   blend   the   curves   into   a  pleasant  shape.    I  start  with  the  lathe  going  forward  at  about  48-­‐60  RPM.  The  sander  runs  clockwise  against  a  counter-­‐clockwise  running  bowl.     I  power  sand  against  the   rotation   of   the   lathe   so   the   sandpaper   is   actually  working   very   aggressively   on   the   wood.   Using   an   80  Grit  disk  on  clean  wood  will  make   for   fast  work.  Keep  the  unit  running  and  move  it  from  side  to  side  to  keep  it   from   cutting   into   any   area   more   than   another.    Always  use  a  dust  filter-­‐seen  in  the  background  to  pick  up  the  dust  you  create.      

POWERSANDING  WOOD  BOWLS      Page  3  Some  sanding  sticks  are  used  on   the  side  of   the  stick  by   threading   them   in   the  1/4-­‐20   tap   in   the  stick.  The  different  sizes  allow  you  to  handle  different  size  openings  in  eth  ends  of  hollow  forms.    

 

 

   

#3:  PUT  TOGETHER  THE  COMBINATION  SANDING  PAD:  As  you  did  with  the  power  sander,  combine  the  3”  pad  with  a  flexible  5”  pad  and  then  jump  to  a  6”  thin  pad  and  a  6”  ABRANET  disk.  This   combination  will  make  graceful   curves   inside   the  bowl.   I  thread   the  unit   into   the  upper   set   screw  hole   in   the   sanding  stick   tip.  The   sanding   stick   is  made  with  a  12”   IRWIN  drill  bit  extension   epoxied   into   a   Lufkin   File   Handle.   I   dip   them   in  Plastic  Dip   tool   coating   to  make   them  non-­‐slip.     Sometimes   I  bend  the  handle  to  get  a  more  flat  application  inside  the  bowl.  These   sticks   provide   great   leverage   and   keep   your   fingers  away  from  the  moving  irregular  edge.    

 

#2:   CREATE  A   THREADED   END  ON  THE  PAD:    Most   sanding  pads  are  smooth  shanks.  If  you  want  to  mount  it  on  the  side  of  the  stick  rather  than  the  end,  you  must  tap  the  end  with  a  1/45-­‐20   TAP   to   fit   in   the   set   screw   holes   in   the   side   of   the  stick.     The   shank   is   hard   steel   so   use   a   lubricant   and   be  patient  when   cutting   the   threads  with   a   die.     It   takes   some  time  to  thread  this  hard  steel.    

Another   option   is   to   purchase   the   Grex   pre   threaded   disks.  They  have  short  shanks  on  them  but  work  well   immediately.  They  cost  about  twice  the  cost  of  a  regular  sanding  pad,  but  they  are  very  well  made  and  designed  for  power  use.    

#4:   START   SANDING   THE   INSIDE:     Now   that   the   sander   is  assembled,   run   the   lathe   at   about   48-­‐80   RPM   and   start  sanding  the  bowl  with  80  grit  disk.    If  the  bowl  is  out  of  round,  a  high  RPM  will  make  the  sander  jump  off  the  high  spots  and  miss   the   low   spots.   Your   initial   object   is   simply   to   blend   the  surfaces   into   a   smooth   surface.   You   are   not   really   trying   to  make  the  bowl  round,   just  make  the  curves  consistent.  Move  the  sander  pad  constantly  to  keep  from  cutting  a  ridge  in  one  spot.  As  you  get  closer  to  the  outside  bark  edge,  roll  the  front  edge   of   the   pad   up   slightly   to   keep   from   catching   the   bark  edge.     On   some   very   irregular   bowls,   you   will   have   to   hand  sand  or  power  sand  the  edge  with  the  lathe  stopped.    

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#5:  CONTINUE  WITH  THE  FINER  GRITS:    When  you  are  satisfied  with   the   80   Grit   work,   dust   the   bowl   and   continue   with  120,180,220,320,  and  400.    

#6:  REPARING  BROKEN  OR  MISSING  BARK  EDGES:  Sometimes  you   may   have   a   piece   of   bark   break   off   during   the   turning  process.  Take  scraps  of  bark   from  another  piece  of  wood  and  glue  them  on  the  edge  of  the  bowl.  To  make  the  repair  appear  less  noticeable,   I   take  sawdust   from  the  same  bowl,  mix  with  thick  CA  glue,  apply  it  to  the  broken  area  of  the  bowl.    Add  the  bark  chips  and  then  clamp  the  bark  on  with  these  small  spring    clamps   that  grab  well  on  odd  angles.   Let  dry  and   then  power  sand  the  bark  back  to  the  correct  surface  .  

#7:   FLIP   THE   BOWL   AND   BEGIN   THE   OUTSIDE   SURFACE:    Mount   the   bowl   on   a   vacuum   chuck   or   a   hand   made   jamb  chuck  with  double  faced  tape.    

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#8:  ROUGH  SHAPE  THE  OUTSIDE:    Using  a  18-­‐24”  section  of  an  Abranet  sanding  belt,  rough  sand  the  outside  of  the  bowl.    

#9:  USE  PROPER  DUST  COLLECTION:    When  you  power-­‐sand  or  use  the  sanding  stick  you  will  create  a  great  deal  of  fine  dust.    

#11:   FINISH   SAND   THE   OUTSIDE:   Using   the   remaining  grits,  120  through  400,  finish  sand  the  outside.  You  can  use  a  hand  held  disk  on  the  outside  as   long  as  you  are  careful  with  the  edge.    

 

#11:  CLEAN  UP  THE  FOOT: