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View Full Version : Air Powered Post Driver... any experience


Lance
01-03-2005, 10:36 PM
Does anyone here have experience using air powered post drivers such as the one shown in the link below:

http://www.sunbeltrentals.com/catalog/EquipmentList.asp?id=13&sid1=228

Specifically, I am interested in driving a bunch of 4x4 posts into lake bottom as a foundation for a boat house / pier and am wondering if this tool and accompanying air compressor would be up to the task. The idea would be to sink about 200+ 4x4s to make a 48 x 48 boat house for mastercraft, pontoon, storage, bar, sundeck, and covered shelter. I just got word from the wife that our new pontoon would be off limits for this task but I am assuming I could come up with something as a workpad when driving the posts.

Also, for those that have built boat houses what size posts / pilings have you used and what is the spacing. At the lake I own property at most boat houses use 6x6s on about 8 foot centers. I have seen some that use 4x4s on 4 foot centers which would be what I am trying to do. Others use larger round pilings.

Lance

jimmer2880
01-04-2005, 06:04 AM
I never heard of such a thing. Looks cool though. How much is it? I imagine $200-300.

If you end up using one, pls post back here with how well (or not) it worked.

Lance
01-04-2005, 07:43 AM
Jimmer... I am not exactly sure how much they would rent for from Sunbelt from other sites that list their rental fee I get the sense the post driver would be about $40/day and the compressor would be about $60/day. To buy just the post driver I see there is on on ebay for $1200 at:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=46575&item=3864761851&rd=1

The compressor is the towable kind that is used for jack hammers so that would certainly be a rental item. The post driver would probably be a rental item as well as I wouldn't have much use for once the boathouse went up.

Mag_Red
01-04-2005, 07:50 AM
I don't know, but that thing looks sort of Rinky-Dink. I think if I was building a boat house, I would probably want a professional contractor sinking the piers for my foundation. Maybe our newest member Bongo would like to offer his perspective like he did in the Stump Removal Thread. :purplaugh

Dan K
01-04-2005, 08:23 AM
I have set a large number of 4 x 4 posts in for a seawall over the past few years. The way everyone here has done it is using water pressure to blast a hole and then quickly set the post. I rented a 5hp water pump that was fitted with a 2 inch fire hose. on the end of the hose I had a 6ft peice of pipe that acted as a nozzle. With this setup I could easily set an 8ft 4 x4 six feet into the ground. You need two people at least to mange the hose and the posts, it gets difficult to keep the post from floating out of the hole before it is filled back in completly. All the while you have to hold the post plumb and inline with all the others. Some of the posted I have set this way have been in for 5 years now and still look good and true.

MarkP
01-04-2005, 08:25 AM
Lance,


"Bar, sundeck, and covered shelter." You Go!!


I would agree with mag. (NOT speaking from experience), That looks a little light for the task. Can you find out what they used to sink others on your lake?

silk
01-04-2005, 08:43 AM
I have also used the water pressure method to install many perminent docks and sea walls ,it works great, but you do need the man power to set the posts and work the hose as there is a lot of water pressure

Lance
01-04-2005, 09:16 AM
To a certain extent I agree with Mag_Red that this would be a good item to contract out. The only problem is the people that I have talked to aren't interested in only doing the posts but would rather do the whole job (and the market is so hot here that they quickly move on... maybe in a slower market I could get just the pilings). When I explain what I want for boathouse I hear numbers in the $50K to $90K range. This seems really high to me so I throught I might try it myself since the job should be about as complicated as building a garage and a wood deck combined (well... with the added challenge of doing it over water... don't drop the tools).

Lance
01-04-2005, 09:21 AM
Dan K... can a 5 hp pump really do the job you describe? I have a trash pump which is a high volume / low pressure pump so I know it wouldn't be up to this task but I am suprised that 5hp on any pump could do what you describe. I am interested in more information on your experience to help with my "Underwater Stump Removal" thread. So my specific question is how big of a pipe did you use for the nozzle (1/2", 3/4", 1", larger?)? Also, where did you find the pump? Is this a rental item?

silk
01-04-2005, 10:20 AM
The pump we use is a 5hp also w/2'' fire type hose that reduces down to 3/4. our nozel pipe is about 4'. You get a guy or 2 to hold the piling on the bottom and put the nozel right on the base and she'll go down fast if the bottom is sand or anything but big rocks. We have also used this to loosen the roots around stumps it works really well. It's like how the sand washes out from under your feet when you stand on the beach when the big waves come in. Good luck.

G-man
01-04-2005, 11:10 AM
All the docks in our development are 8x8 primarly for the look. At our sister development they are on 6X6's. On the docks with and upper deck there is some side to side sway when your on top. Nothing serious but there is sway where the 8X8's don't have sway. On the distance between pilings I suggest 7'4" center to center. This way if you have a outer wrap board it will go to ends of the piling not to the center with an 8' wrap board.

east tx skier
01-04-2005, 11:14 AM
We set posts of the larger variety using the seven foot copper pipe and spray nozzle. We manually drove the posts, which given the number of cypress roots, was a chore. This was for the pier. The dock where the boat lifts would one day be was done by a professional who had a pile driver on pontoons.

This boat dock is the sturdiest thing I've ever laid eyes on. We refer to it as Fort Knox. I really should upload some pictures soon.

Dan K
01-04-2005, 11:36 AM
Lance,
5hp was plenty, it idled most of the time. our pipe was 1 1/2 or 1 1/4 I can remember. It is more volume of water not pressure that helps wash everything out.

jimmer2880
01-04-2005, 12:07 PM
My problem with setting posts is that nobody does it (professionally) where I'm at. I'm also working over the end of a 20' bank, so back-hoe's, etc aren't an option either. We always did the sledge-hammer or - a slide-pipe over the 4x4 method.


The hydro-pump method sounds real slick to me.

THANKS!

east tx skier
01-04-2005, 12:42 PM
We just hooked ours up to a garden hose and used the slide-pipe post driver. One guy holds the sprayer and steadys the post. The other guy sits on top of a ladder and pounds away.

phecksel
01-10-2005, 11:54 AM
Friend drove in 36 pipes on a few hours with one. Why 4x4? I'm using 3" diameter schedule 40 pipe.

jimmer2880
01-10-2005, 12:41 PM
Friend drove in 36 pipes on a few hours with one. Why 4x4? I'm using 3" diameter schedule 40 pipe.
Do you have any trouble with water freezing & breaking the pipe? That's my biggest concern with pipe.

jimmer2880
01-10-2005, 12:42 PM
We just hooked ours up to a garden hose and used the slide-pipe post driver. One guy holds the sprayer and steadys the post. The other guy sits on top of a ladder and pounds away.
awsome idea on the hose thing. I'll have to try that next time.

phecksel
01-11-2005, 01:05 PM
Do you have any trouble with water freezing & breaking the pipe? That's my biggest concern with pipe.
Many many years and no problems. Ice gets up to 24" think in front of my house