Air knife/air spade

How many of you have one of these handy little gadgets? How has it helped your business? How do you price this work? I was thinking of getting one of these. Seems like it would be easy to sell and one of the most beneficial treatments for compacted soils. I was curious about the pricing because a client of mine has 7 mature trees that have root issues and was wondering if a job like this would pay for one. Thanks for any info you can give me.

I try to price it a a bit over climbing work, since few people do it here.

If you do not do it often, then you can make one around 75% as good from pipe and fittings with a ball valve. Just use have a few different reducers for the tip and a chopped funnel as a "blast deflector".

I think people with gardens are the most amenable, since the basal flair can be an focal point.

Nice idea JPS, once you've built a wand, how many PSI do you need to operate it?

Do you need to cart around a generator and big air compressor, or is there an easier way?

I've used an Air Spade on many occasions. It's great for root pruning when dealing with construction damage and such. It's also great for improper mulching by landscaping companies. If you do alot of this type of work, it's invaluable.

From what I gather most price it by the hour, correct? If so, about how long does it take to radial trench and amend the soil on a mature tree 36" dbh out to the drip line?

kennertree said:

From what I gather most price it by the hour, correct? If so, about how long does it take to radial trench and amend the soil on a mature tree 36" dbh out to the drip line?

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If it is pretty tuff stuff it takes me a couple hours.

ddhlakebound said:

Nice idea JPS, once you've built a wand, how many PSI do you need to operate it?

Do you need to cart around a generator and big air compressor, or is there an easier way?

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Well I don't want to start an argument with JPS but those homemade airspades are not any good. What you need to cart is your butt to concept engineering and buy one if you want one, and yes, you need a big compressor. I don't know what you need the generator for unless you are air-spading in the dark.

mckeetree said:

Well I don't want to start an argument with JPS but those homemade airspades are not any good.

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I have an AirKnife, but know several people who have made effective airtools out of around $40 of standard pipe. Head to head they were not as effective as the AirSpade (R) I was using at the time, but to them the savings was worth it.

Like I said, 75% as effective

If you have a few jobs you can get started with, then rent a compressor (185cfm is my preferred). Once you have enough of the work lined up, then go with the real thing.

I've been running into bartlett lately, here's a good one: a friend of mine was trying to get me into this huge estate, bartlett got in and was there for like two months, must've been a phenominal bill-multiple crews too, anyway, they send their line guys up hacking away, after they airspaded the roots and left them exposed, bombing logs unto the basal roots blasting off chunks of cambium-oh yeah, they're "the best", lol.

Is Bartlett the best, they have an office about an hour from me.

md_tree_dood said:

Is Bartlett the best, they have an office about an hour from me.

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No.

Couple of comments:
1) The tool is the "cheap" part when you look at the cost of the compressor. Rental is at least $100 per day. You only need 100psi, but you need 185cfm. If you can find a worthwhile used one for less than $5500 you are doing well.

2) AirKnive or AirSpade? I have used both. On the surface, the AirSpade looks more ergonomic, but in use, I like the AirKnife a little better.

3) Pricing: I think I am close to loosing money if I charge less than $65 per hour. Time it takes to do the work depends on soil condition, make-up and moisture. Dry compacted clay -- forget about it, don't waste your time!

4) I certainly need to market it better, but the firms who do a good job marketing just about have a guy or 2 doing it full time in the spring and fall.

Thanks for the replies. I'm just trying to get a ballpark of how long it will take on 6 mature trees. From what i've learned I could get 3 mature trees done in a day, a long day. I will be pricing by the hour plus the cost of the compressor and soil ammendments. Another local tree company called us the other day and told us the guy from supersonic air knife is coming down to do a demo. I ill learn alot more about then.

John Paul Sanborn said:

I have an AirKnife, but know several people who have made effective airtools out of around $40 of standard pipe. Head to head they were not as effective as the AirSpade (R) I was using at the time, but to them the savings was worth it.

Like I said, 75% as effective

If you have a few jobs you can get started with, then rent a compressor (185cfm is my preferred). Once you have enough of the work lined up, then go with the real thing.

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Dan to Sally: Was I as good as your last boyfriend?
Sally to Dan: Well, I would say you were 75% effective.

More questions

What do you guys use for soil ammendments? I plan on using compost and I'm checking into worm castings. If there is anything better let me know. Also, when ammending the soil on a large mature tree aproximately how much compost does it take per tree if I'm radial trenching out to the drip line?

mckeetree said:

Dan to Sally: Was I as good as your last boyfriend?
Sally to Dan: Well, I would say you were 75% effective.

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I'm talking about time efficiency. If you have a handfull of jobs a season, then the $30 home job is worth it.

If you are a bigger company where $1300 for a tool is not a big outlay, then that is the way to go.

kennertree said:

What do you guys use for soil ammendments? I plan on using compost and I'm checking into worm castings. If there is anything better let me know. Also, when ammending the soil on a large mature tree aproximately how much compost does it take per tree if I'm radial trenching out to the drip line?

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A good turned compost with lots of mycillia running through it.

Rule of thumb is a 25% loss of fines due to drift, could be up to 30% with looser soils on a dry day. From there you do the math per job for volumes. If there is a big change of grade you are correcting, you may end up hauling some "native" soil away.

I've also seen tanks of week composted (!!!aseptic!!!) manure slurry drenched prior to backfill on a job with radial trenching and horizontal boring in between.

I emphasize aseptic because the stinkypoo tanked manure they spread these days from factory farms can be phytotoxic. Anaerobic decomposition makes higher alcohols, and other compounds. Anything we put around a tree should smell like good clean earth, something you would enjoy getting your hands into.

The other thing to consider in addition to compost for back fill is some diatomaceous earth (the bigger grains, not the powered stuff) or perlite. These increase and maintain pore space, but are (very close to) chemically inert.

ATH said:

The other thing to consider in addition to compost for back fill is some diatomaceous earth (the bigger grains, not the powered stuff) or perlite. These increase and maintain pore space, but are (very close to) chemically inert.

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True, a sandy loam with a coarse sand is good to.

Another thing to remember is that uniform ped size (ped = unit of soil) will lead to fast compaction. This is basic materials science. Larger peds will have more voids between them.

All this means is; you do not need to break the soil down into a fine shred like a gardener who tills regularly would want.

Had some time today to try out the air knife on a tree at my house. I'm real impressed with it. I did some radial trenching and between the trenches shot some holes in there for vertical mulching. Here are a few pics.

Did a root crown excavation to a poplar that is in decline. This damage was done a few years ago during the grading work on a construction site. This is why it's so important to do pre-construction planning to protect rootzones.