Replies

1. 
   Gabe | Apr 18, 2002 12:51am | #1

   We don't use jumping jacks anymore on our sites. They displace more than they compact.

   A plate is far more efficient and has more uses.

   Gabe

1. 
   timkline | Apr 18, 2002 04:47am | #2

   I'll agree that a Jumping jack used on crushed stone to try to get a solid base for concrete slabs is a waste of time, but to compact soil (clay and dirt), we find they work quite well. An experienced operator is a must.

2. 
   bearmon | Apr 18, 2002 06:37am | #3

   What is your intended use?  I have a plate compactor that works great.  Can't think of a situation (within what we do), where a jumping jack would work better.  But I don't know what you're picturing.

   Bear

1. 
   JTBelcher | Apr 19, 2002 04:34pm | #4

   I'm sure the plate compactor has a lot of uses, but I'm wondering if size could be a drawback.  Here's what I'm picturing - compacting a thin trench (i.e. for a water line) - or packing dirt behind a retaining wall where much of the hillside behind the wall is undisturbed earth.  I thought the thin footpring of a jumping jack might get into these tighter spots well.

   I'm also thinking about getting the tamper in and out of places.  Since most of these smaller tampers are only good for about 12-18" of depth, a deep area will have to be tamped in a couple different layers.  That means dragging the tamper down into the hole / trench with you.  Both weigh a ton, but I thought maybe a jumping jack would be a little more mobile for tight spots.

   Of course as the other guys said, if packing a gravel base under concrete is joke with a jumping jack, maybe the size advantage isn't all that meaningful.

   Edited 4/19/2002 9:36:56 AM ET by Jay

1. 
   Joe1225d | Apr 19, 2002 06:43pm | #5

   The only application i use a jumping jack is in a trench. Most utility trenches here are too narrow for a plate compactor.

   joe d

1. 
   JTBelcher | Apr 22, 2002 05:40am | #6

   Sounds like the plate compactor is more versatile overall.  I may just have to make do on those small trenches - rent or build up those back & shoulder muscles tamping by hand.

1. 
   bishopbldr | Apr 27, 2002 01:32am | #7

   Jay,

   We used to own a jumping jack but sold it. Our needs were mostly for compacting fill under floor slabs, not in trenches. A plate tamper works better for under slab work any day. If your needs vary, buy for the most often use and rent for the other.

   In our area most inspectors and architects call for compacting in 8" lifts, max. but depends a little on type of materials used.

   Bish

2. 
   mercer88 | Apr 27, 2002 03:39am | #8

   I have used both plate tamper and jumping jack.   Depends of where it is being used, tight areas I would use a jumping jack and if your displacing more that its compacting you need to add a little water.  On big areas we use a double drum roller.  Inspectors here require between 98% to 100% for compaction never had a failure yet.

3. 
   JTBelcher | Apr 29, 2002 03:59pm | #9

   Thanks to all for advice.  Doesn't sound like there is a best compactor - the two have very different pros & cons.  Well maybe the plate compactor is the best tool except where you can't fit it.