Have a pool fence that used steel 2" posts that are largely starting to corrode at the base.  Replaced a few that I could get to with a big demo bar (what a bitch) and shovel to dig the crap out.  Got smart for the last one and got a big sledge to break things up.  Still a cast iron bitch.

Have a few now that are somewhat buried in bushes where a good sledge swing would be about impossible.  Do any of the electric rotary hammers deliver enough impact to break things up?  Watched some manonry guys use one that looks like the $500+  DeWalt stuff.  Do not want to buy too much for something I might not use much in the future.  Got enough of that already.

Any good tools or technique recommends?  Going to be 69 next month, trying to do this with the least manual labor as possible.  Of course I would need to tackle this just when it really is starting to get hot. 

Did you try Hawaiian Rent all? I also discovered that Home Depot has an armory of large tools to rent.
I used a jackhammer to break foundations. Might be overkill. Or an engine hoist to pull the post out?

https://www.amazon.com/gp/aw/d/B00ET9OVW6/ref=pd_aw_sim_sbs_469_2?ie=UTF8&psc=1&refRID=SYKC806H745QP9KWJSJX
I've never used this stuff, but if you have a drill and some masonry bits to drill holes to pour it in it might work.

You could also try dissolving the concrete with concrete etcher if you have a lot of patience.

Did you try Hawaiian Rent all? I also discovered that Home Depot has an armory of large tools to rent.
I used a jackhammer to break foundations. Might be overkill. Or an engine hoist to pull the post out?

Will try HD again, think the first time I looked and saw the tool rental of the big electric hammers, unavaialble at the BI store.  Figures, everything else is.

Hoist might work, but cannot get in there for the same reason I cannot use a sledge, no room.  Dunno what I would connect it to if I could.  Post would snap off at the rusted area.

https://www.amazon.com/gp/aw/d/B00ET9OVW6/ref=pd_aw_sim_sbs_469_2?ie=UTF8&psc=1&refRID=SYKC806H745QP9KWJSJX
I've never used this stuff, but if you have a drill and some masonry bits to drill holes to pour it in it might work.

Saw a demo somewhere, still need a concrete drill.. Amazon will not ship it to Hawaii.

Did think about ordering this:
https://www.amazon.com/gp/product/B00IO3Z5MS/ref=nav_ya_signin?ie=UTF8&pd_rd_i=B00IO3Z5MS&pd_rd_r=VWGXW1EV1AKSJK7QR5PR&pd_rd_w=fwcJ1&pd_rd_wg=LPLki&psc=1&refRID=VWGXW1EV1AKSJK7QR5PR&

Never used one, but if it does slowly do the job, got to be easier than a sledge.  Seems renting the damn things runs up the bill fast, if you can find a place, so the price of this toy may be recouped fast.

Saw a demo somewhere, still need a concrete drill.. Amazon will not ship it to Hawaii.

Did think about ordering this:
https://www.amazon.com/gp/product/B00IO3Z5MS/ref=nav_ya_signin?ie=UTF8&pd_rd_i=B00IO3Z5MS&pd_rd_r=VWGXW1EV1AKSJK7QR5PR&pd_rd_w=fwcJ1&pd_rd_wg=LPLki&psc=1&refRID=VWGXW1EV1AKSJK7QR5PR&

Never used one, but if it does slowly do the job, got to be easier than a sledge.  Seems renting the damn things runs up the bill fast, if you can find a place, so the price of this toy may be recouped fast.

...
Awww it's non-explosive.
Where's the fun in that?

I say a 50 bmg might do the job.

...
Awww it's non-explosive.
Where's the fun in that?

The nosy old neighbors above us are already suspicious of me.   My airgun practice in the back yard got them going.

 A good concrete drill and some cherry bombs or m80 down the hole would be interesting, but those are unobtainable here, AFAIK.

https://www.amazon.com/gp/aw/d/B00ET9OVW6/ref=pd_aw_sim_sbs_469_2?ie=UTF8&psc=1&refRID=SYKC806H745QP9KWJSJX
I've never used this stuff, but if you have a drill and some masonry bits to drill holes to pour it in it might work.

+1 
Expansive grout is the way to go.
Used it once a  long time back but forgot where i got it.
Around Mapunapuna I think.
Place called Concrete products or something like that.

  Other option is "Rent-a-kid.
I find them quite useful/cheap.
And "It builds character" 

Pm sent

Used it once a  long time back but forgot where i got it.
Around Mapunapuna I think.
Place called Concrete products or something like that.

That is the rub with living on the BI, beside no shooting range: things that can be found somewhere on Oahu are nowhere here. 

That is the rub with living on the BI, beside no shooting range: things that can be found somewhere on Oahu are nowhere here.

"Rent-a-kid"

You could drill holes with a small hammer drill and split it with a steel wedge like this. 

https://www.amazon.com/Wedges-Shims-Pkg-Sets/dp/B003838VE8

Get smaller sizes if the concrete is not too large.


That would be a cheap way to do it.  A demolition jack hammer would be faster and less backbreaking work, you  might be able to resale it to recoup the cost after you are done using it.

That would be a cheap way to do it.  A demolition jack hammer would be faster and less backbreaking work, you  might be able to resale it to recoup the cost after you are done using it.

Went ahead and ordered that Amazon demo hammer,  For $137 and free shipping, it is cheaper than two days of a rental (assuming it was avaialble) and I have a bunch of awkwardly positioned rusting posts to get to.

The idiots that put in the posts evidently just dug large holes and poured a shiite load of cement in.  I am painstakingly redoing them with cardboard cylindrical forms.  Those vast seas of concrete are the pits, take forever to break up.

First one I did I could get to with a shovel and demo bar, ended up digging all around it and prying the damn thing out of the ground.  Could only chip off small edge parts.  Hauled 2-300 lbs cement mass to the dump as I had no way to bust it up.  Wife though I would drop a nut lifting that into the back of the SUV.

Too old for that, time to use technology.

Edit:  Oh yeah, thinking about ordering aluminum 2" square posts to redo this mess.  Shipping is a bitch, of course. 

Lowes steel posts will just rust out again.  With my luck, they would rust out before I kick the bucket, so maybe the expense of the aluminum will be worth it.

Went ahead and ordered that Amazon demo hammer,  For $137 and free shipping, it is cheaper than two days of a rental (assuming it was avaialble) and I have a bunch of awkwardly positioned rusting posts to get to.

The idiots that put in the posts evidently just dug large holes and poured a shiite load of cement in.  I am painstakingly redoing them with cardboard cylindrical forms.  Those vast seas of concrete are the pits, take forever to break up.

First one I did I could get to with a shovel and demo bar, ended up digging all around it and prying the damn thing out of the ground.  Could only chip off small edge parts.  Hauled 2-300 lbs cement mass to the dump as I had no way to bust it up.  Wife though I would drop a nut lifting that into the back of the SUV.

Too old for that, time to use technology.

Edit:  Oh yeah, thinking about ordering aluminum 2" square posts to redo this mess.  Shipping is a bitch, of course. 

Lowes steel posts will just rust out again.  With my luck, they would rust out before I kick the bucket, so maybe the expense of the aluminum will be worth it.

I've ordered small lengths from http://www.speedymetals.com/ with good experience.  Shipping, of course, is pricey to Hawaii, but for the size and pieces I wanted, it turned out to be the cheaper way to go.   I didn't have the need for a full length (20') which is what the metal suppliers over here carry. If you need a lot, price locally first.  Buying by the length locally and cutting down to the size you need may end up being the most cost effective choice, rather than shipping it here.

Also, aluminum may not be the best choice, as it will corrode if it is not coated with something or anodized somehow.  Galvanized steel (dipped) would probably last longer than untreated Aluminum.  Stainless steel would be the best choice, but millionaires we are not...  Lol.

Also, aluminum may not be the best choice, as it will corrode if it is not coated with something or anodized somehow.  Galvanized steel (dipped) would probably last longer than untreated Aluminum.

Very good advice.

There are metal fabrication shops on the Big Island that have components fabricated on Oahu and shipped over to them on Young Brothers. I would recommend having the steel posts cut to size and all holes predrilled, then hot dipped galvanized so all bare metal is covered. The only hot dip galvanizing plant in the state is Kloeckner Metals in Kapolei.

How old is the concrete? What condition? As in is it spelling or cracking at the surface? Or is the surface look pretty good?

When we spec concrete repairs, they typically use roto hammers. Sort of like a hand held jackhammer. 15 lb hammers are all you will need to break up concrete in good condition. It helps if the surface is cracked or spalled though. Gives you something to press the hammer on.

Eta: Oops. Just read that you already ordered a demo hammer from Amazon.

Very good advice.

There are metal fabrication shops on the Big Island that have components fabricated on Oahu and shipped over to them on Young Brothers. I would recommend having the steel posts cut to size and all holes predrilled, then hot dipped galvanized so all bare metal is covered. The only hot dip galvanizing plant in the state is Kloeckner Metals in Kapolei.

more amps...

For smaller jobs we use the Milwaukee version of the hammer you ordered and It works well.  Lighter more maneuverable in tight spots.  To split large pieces I may core / drill holes along a line that I want to crack, then come back with the larger spade chisel bit to "connect" the dots and create the fissure.  This method tends to be quicker than small chunks at a time.  If you want or need to get smaller more manageable chunks at a time then the smaller tip chisel works better. 

For bigger, more accessible jobs, we use a full sized hammer.  Heavier but effective and makes quick work of things.

Now that I have access to a "real" computer, here's the one that I see most often on concrete repair job sites.

https://www.amazon.com/11255VSR-BULLDOG-Xtreme-SDS-plus-D-Handle/dp/B000BB79Q6/ref=sr_1_1?s=hi&ie=UTF8&qid=1475175143&sr=1-1&keywords=bosch+roto+hammer

It's a lighter weight one (below 15 lbs) since it's intended to remove spalled and cracked concrete and hopefully leave the sound concrete behind, but it still works well for breaking up sound concrete.  As mentioned above, some drilled holes and "connect the dots" really helps that process.  A heavier hammer will work faster for sure, but I had assumed that the heavier hammers were MUCH more expensive.  Looks like you got a 45 lb hammer model, which should be much quicker than the 15 lb (or less) models. 

You mentioned replacing the posts with aluminum posts.  Are you going to embed those posts in concrete?  If you do, just be wary/careful of contact with anything steel, even rebar in the concrete.  Being dissimilar metals, the aluminum will accelerate corrosion of the reinforcing steel in the concrete, particularly if they are in contact. 

Cut the posts off at concrete height with sawz all.
Treat remaining post with Ospho.
Stick new post of smaller diameter in the interior of old post filling void between with your choice of "stuff" (post setting cement, epoxy, liquid nails).