# Air Spade?



## Keener (Aug 22, 2003)

I was hoping to get some input on the use of the air spade and some feedback on how effective it is for root excavation.
Any other info like how many cfm you need, cost of the tool, or if anyone has a home built version of it ect.
Seems the local tree authorities are soon to require it rather than the shovel and broom technique.
I'm all for it if it saves time, roots, and my back.
And it would be nice if it not priced like the first electronic calculators (new to market and outrageous in cost).


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## lhampton (Aug 22, 2003)

Very effective for root excavations, as well as a variety of other work. I have been on projects where it was used to trench through root zones for utilities, irrigation lines and drainage. To "till" in compost to ammend under trees for planting perennials. Bore holes for aeration, check for the prescence of living roots after construction or other disturbance. Excavate along foundations to check for roots prior to landscape and home renovations. Almost anything where dirt has to be moved or removed.

The drawback is the mess. On a single tree, or a few small trees you are almost better off doing the work carefully by hand. After you set up some containment, be it plywood or tarps, to help hold in the blown dirt, then cleanup, there are times when the old way is the best way. A great tool, but I wouldn't want to have to use it for every situation.

Neighborhood of $1100.00 US. The cost is in the nozzle. A specially designed venturi that creates a supersonic flow of air. Not easily duplicated in the DIY (Do IT Yourself) models, but I'm told that for $35.00 the DIY kicks butt. 185cfm, but there is a larger nozzle that needs greater flow. Check out the folks at Concept Engineering Group.

The Airspade seems to be all the rage here in Dallas. A few years ago, only one company had one. Now I know of five (probably a few I haven't heard about also), and everyone is talking about it. The company I work for is set to order one this next week.

I think the thing I like best is that it opens up another avenue of tree care that we have really been neglecting. In the Dallas area, most of the trees we care for are planted. Most are planted too deeply. After getting called out to "save" trees after its too late, it is nice to be able to do something proactive. Pruning, removals, sprays... Treating symptoms. Sure we can get down on hands and knees and scratch away the excess soil, but how any times do we really? Spend $1100.00 on the Airspade and $300.00 a week to rent a compressor and you can bet you'll sell some root collar excavations. You'll start looking at the base of the trees when you walk onto a property, and then look up, which really is what we should be doing most of the time anyway.

Louie Hampton


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## Keener (Aug 23, 2003)

Thanks for the input Louie, my concern over the price seems somewhat warranted when the exchange on the dollar makes it $1400 or so Canadian.
I am not doubting that it is a great tool, just out of reach for the small company.
Mind you if I sold my chip truck it might just pay for one with the freight included.
Do you know the outlet hole size on the model that you are familiar with?
And do the neighbors get their stucco covered in dust 3 or 4 houses away? This can be an issue when stump grinding during the summer especially. The guy next door has no sense of humor when he happens to be painting the exterior and the grinder is adding a dust topcoat.


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## Kneejerk Bombas (Aug 23, 2003)

If you go to the ISA webboard and look at a thread called "VerticalMulching/radial trenching/urbansoil repair " you will see a detailed discussion of a homemade tool.

I've used it in many situations and the mess is not a big deal. If the soil is moist you don't get any dust. Big particals don't fly very far, if there is a new car nearby, move it.


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## John Paul Sanborn (Aug 23, 2003)

Mkae sure windows near by area are closed. Especially down wind.

I've heard of people having a hose with a misting wand on hand...


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## Keener (Aug 23, 2003)

Thanks JPS and Mike the thoughts are appreciated.
I really think that the " if there is a new car nearby, move it" idea is a good one.
I think I will make it policy for any of the tree work I do.
Just have to figure a way to do the same with the house.


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## John Paul Sanborn (Aug 23, 2003)

I don't use my air tool very often, but when I do it saves my back (and finger nails)

Also have some old Felco's and a saw handy to get fine roots out of the way.

I've done a little work lately where I blow back all the soil around sprouts on Prunus and Malus, after having an NAA application several days prior. Then prune the sprouts back and reapply the ANN to ther fresh wounds.

I'll have to let everyone know how it turns out next year.


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## TREETX (Aug 24, 2003)

> _Originally posted by lhampton _
> *You'll start looking at the base of the trees when you walk onto a property, and then look up, which really is what we should be doing most of the time anyway.
> *



Amen. It is really an under emphasized practice. 

I have solved many an case of the declining post oak/cedar elm/planted live oak/etc by doing just that.


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## Kneejerk Bombas (Sep 5, 2003)

.


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## Kneejerk Bombas (Sep 5, 2003)

Holes filled with compost.


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## Kneejerk Bombas (Sep 5, 2003)

Area raked out.


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## Kneejerk Bombas (Sep 5, 2003)

No flair.


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## Kneejerk Bombas (Sep 5, 2003)

Down about 12", not much to do here, what a mess.


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## Kneejerk Bombas (Sep 5, 2003)

We left the grade down and dished the area out. This is an example of a tree not much could be done with, at least we removed the soil from the trunk.


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## Kneejerk Bombas (Sep 5, 2003)

This small pine was down about 6". The soil was very hard and compacted. Roots all around the trunk.


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## Kneejerk Bombas (Sep 5, 2003)

Area cleaned up.


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## Kneejerk Bombas (Sep 5, 2003)

The tow behind compressor was 375 cfm, but the 175 cfm and 185 cfm compressors that we used in the past worked just as well. Those are the only thre compressors we ever used. I suppose with the big one you could run two or three spades at once.
We made the holes about big enough to put one shovel full of compost in. You could make a small hole in the surface and twist the spade to make the hole cone shaped, to wreck less grass but hold more compost. They went down about 6" or 8".
One guy with the air tool went faster than two guys filling them back up and raking.


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## murphy4trees (Sep 6, 2003)

2 questions Mike

How do you sell that work?

How much do you charge? I would guess it's T & M.
Thanks,


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## Kneejerk Bombas (Sep 6, 2003)

We charge the same as our tree climbing rate, plus add a little extra for the compost. The stuff used was called potting soil, it's a mix of sand, sea shells, composted cow manure, and mushroom compost, and it costs about $30 a yard.

We sell the work so we can just come do the job when we have several jobs lined up, like stump grinding, so we have a whole day of it. Because we don't have our own compressor, the $100 rental fee gets spread out over several jobs.

How effective the hole method of adding compost is debatable, usually we spread compost on top and do the whole area that is compacted. This customer didn't want to redo his lawn.


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## Keener (Sep 12, 2003)

So I took Mikes input and built the airspade.
Used it today with 375 cfm compressor and had good results in two areas, moving the topsoil down to the hardpan and boring holes straight down ( 2.5 ft ) to check for bedrock.
Blowing away the hardpan was very slow and I would not want to trench any distance or depth with my version of the airspade.
Does anyone know just how well the commercial model works on clay type hardpan?
It seems to me the roots go to the hardpan level and run along at that depth, if you wish to undermine to place services you will be working largely in the hard stuff.
Feedback ?


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## John Paul Sanborn (Sep 12, 2003)

I've used a different home made "air drill" the "spade " name is registered after all. (_Andy from Concept wants it writen AIR-SPADE (R) or useing the code for the R whatever it is_) The actual AIR-SPADE (R) and the aluminum Air Knife (wich i own).

The comparison work we did showed the A-S to be maybe 25% better in compacted or very moist soils. many dont see that to be worth $1175. 

The A-K people also have a huge cannon thinggy that works 5 times faster.

One thing you can try on your Air-Drill is paly with the reducsers on the tip to see if you cna get any more efficiency.

Maybe a series of reducers so that the air is gradually restricted.


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## Kneejerk Bombas (Sep 13, 2003)

If you want to move more dirt, use that compressor and open up the size of the nozzle.


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## Keener (Sep 13, 2003)

I did experiment a bit with the outlet size and going larger did allow more airflow and moved more topsoil more quickly.
The main drawback with my attempt was that once the looser soil was gone the hard stuff was just too hard to move.
Regardless of the orifice size the hardpan was being removed very slowly unless I used the tip of the pipe to pick away at it as well. 
It may be that it was just to hard and glued together to be moved by any amount of air.
Now if you could get the same volume at say 500 to 600 psi I think you could cut concrete, the compressor I used seemed to be set at 150psi and dropped to 110 with the tool operating.


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## arborvor (Sep 13, 2003)

It's also a great tool for doing trenches in a lighting protection system. Especially when you have 27 to do in 100+ ft pines. As we did at Augusta National G.C. last week.


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## Keener (Sep 13, 2003)

How deep and what kind of soil?
Also how much time per foot of trench, roughly?


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## Kneejerk Bombas (Sep 14, 2003)

The type of soil is a factor, but how moist it is seems to make even more difference.

I'm curious about going down over two feet. The roots you have up there must be very different than those we have in my neck of the woods. Here the roots are mostly growing near the surface, about 95% in the top 12". Going down more than about 8" becomes a very inefficient.


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## John Paul Sanborn (Sep 14, 2003)

The ultimate form of soil aeration is mesic landscaping. Using plants that naturaly root deep. Sure it takes 5 years or so, but you get an 8 fold or better increase in an areas water handling capability.

I read a soil profile study that found tree roots 12 feet down in areas with old prarie maintained.

the thought is that this is a secondary root system for times of drought, when the upper layers crack and deeper soils get more air. The absorbative roots are ephemeral, where the woody roots go dormant during the wet cycles.


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## Keener (Sep 14, 2003)

JPS, it would be of interest to know the species that can root to that depth. My guess is that very few trees would have that ability.
Mike, the roots here are probably not much different but I was trying to see if we would hit bedrock if we decided to bore under the trees for the utilities.
Expensive to get the line bore set up and hit rock halfway through.


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