I’ve only used electric ROS’s, and have someone asking me about air powered ROS’s. I’m guessing some pro shops use these? Can anyone suggest some make/models I should look at?
Thanks
[OP]
Contributor
I’ve only used electric ROS’s, and have someone asking me about air powered ROS’s. I’m guessing some pro shops use these? Can anyone suggest some make/models I should look at?
Thanks
Contributor
Dynabrade is the main brand. Their 3/16 orbit is the one most used. 3/8 is pretty aggressive and hard to handle. The 3/32 is fine but I find the 3/16 leaves such a good finish I seldom need the fine one. You need about cfm to run them which equates to a full 5 hp ( real hp ) 80 gallon compressor. The larger the tank, the less likely you are to need a dryer. I use a dryer in humid weather to keep the sander from spitting. 3 m makes sanders almost identical. If you have the compressor, air sanders are hard to beat. Dave
[OP]
Contributor
Perfect David, thank you. I was going to help my friend buy a new compressor but needed to figure out what the sanders draw in terms of cfm.
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Since Dave gave what I think is a great answer I will add an aside. Mirka, in particular, is pushing their brushless electrical sanders into the markets that have been strictly pneumatic for decades. The power, longevity and form factor of brushless DC motors is starting to make a serious business case for electric. They are MUCH cheaper to run than pneumatic and I have a funny feeling pneumatic sanders days are numbered in industrial and commercial settings.
Of all the laws Brandolini's may be the most universally true.
Deep thought for the day:
Your bandsaw weighs more when you leave the spring compressed instead of relieving the tension.
Member
The problem with air-powered sanders is that they require oiling (preferably inline) and there's always an issue of residual oil spitting on the wood, which is bad mojo re finish contamination. I would never dream of using them for woodworking. This is not something you should be thinking about.Originally Posted by Matt Day
Contributor
Doug, your point is well taken. I've never had oil on the wood but dry air is important to reducing the amount of oil needed. A few drops every hour or two is about all I ever need as a hobby guy. You also need a vac attachment for any sander. Buying a compressor for sanding ( and a dryer ) screws up the economics compared to a Mirka type electric so you need to have the large compressor on hand. Like any tool, you have to learn how to use it correctly. Applies both to the sander and the compressor. A slow running compressor with a large tank, good filters, and some way to capture the moisture are critical. You can't go to Home Depot and expect a great result with a compressor. Dave
Member
You need oil _in_the_tool_. It doesn't matter how it got there upstream. I do a lot of automotive work, and I have an elaborate system for super clean/dry air, for painting, finishing, etc. But the tool needs the oil. If it doesn't get it, that tool is gonna die. Inline oilers (or the equivalent) are the way and the truth. And that's the point of contact with a sander and the wood, and there's no way around that.
Contributor
A good air-powered sander doesn't spit oil. They are standard in most commercial woodshops for good reasons; ergonomics, longevity and productivity. They do take a ridiculous amount of power vs electric ones and Mirka makes a very good sander, but I doubt the electronics will last as long as a minimally maintained Dynabrade at 1/3 the purchase price.
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There is no question that for the foreseeable future the cost of electric brushless sanders will far exceed the cost of pneumatic sanders both upfront and running costs but the cost of buying, maintaining and powering the compressors and refrigerated dryers in commercial and industrial settings is where the business case goes wonky in today's world. Using compressed and dried air to spin a sander is incredibly energy inefficient. I can see industrial settings where the power is rectified in a central location and only feedback load control is built into the individual tool reducing the need for the amount of miniaturized electronics onboard the sander. In a lot of settings, you wouldn't even need speed control onboard.
Of all the laws Brandolini's may be the most universally true.
Deep thought for the day:
Your bandsaw weighs more when you leave the spring compressed instead of relieving the tension.
Contributor
The economics are not always clear. I had the compressor and shopping CL and other sources I've accumulated about a dozen sanders of various sizes, orbits, round, square, orbital, inline, etc for less than the price of one new Mirka. Some used, some NOS, and even a couple new. I'll be dust before the energy cost becomes a deal breaker. I'm not advocating but I do like my Dynabrades. Dave
Member
The monetary cost/benefit analysis actually seems to become much more complex and murky for a hobbyist and why I only mentioned commercial and industrial settings. For the hobby guy a large relatively high volume compressor can be a multifuntion power source. It lets one buy high quality but much cheaper sanders, you can use a venturi vacuum system instead of a pump, you can buy a good gun instead of a 4/5 stage HVLP turbine and there are a ton of air tools that save a lot of money over electric especially if you do work other than woodworking. The energy costs can easily be outweighed by all the different things one can do with compressed air.
I really like air sanders, the feel in the hand and the control is amazing. Prior to the introduction of brushless sanders there wasn't really much of a discussion about air vs electric but the Mirka Ceros/Deros and Festool EC sanders which also bring noise and dust reduction to the mix add a lot of fuel for discussion.
Of all the laws Brandolini's may be the most universally true.
Deep thought for the day:
Your bandsaw weighs more when you leave the spring compressed instead of relieving the tension.
Contributor
In the past I used air sanders all the time (for bodywork). One of the things not talked about here is that the air coming out of the sander will blow dust everywhere. While my electric palm sander is bulkier it's easy to connect to the dust collector. I haven't looked at what's on the market now but I would make sure that it has some sort of dust collection capability.
Member
I've never had an issue and I know a lot of commercial ww'ing shops use them. If they spat oil, then body shops wouldn't use them either.
+1 on what Dave said. I use a 3M sander and very happy. Also like the Cubitron sanding disks a lot. Seem to last forever!
Biggest advantage I see is 1) they sand faster and 2)better dust collection. Yes you need a big boy compressor to handle the cfm.
Member
Which air sanders are you comparing to electric sanders?
Of all the laws Brandolini's may be the most universally true.
Deep thought for the day:
Your bandsaw weighs more when you leave the spring compressed instead of relieving the tension.
Contributor
"you need oil _in_the_tool_. It doesn't matter how it got there upstream. I do a lot of automotive work, and I have an elaborate system for super clean/dry air, for painting, finishing, etc. But the tool needs the oil. If it doesn't get it, that tool is gonna die. Inline oilers (or the equivalent) are the way and the truth. And that's the point of contact with a sander and the wood, and there's no way around that."
I worked in a shop with 5 or 6 Dynabrade sanders for 14 years. One was there when I started and was still going strong when I left. I don't remember any of them dying in service. All those tools got two drops of oil a day, if that, no inline oiler and no oil contamination on the work. Believe me, our finisher had no qualms about pointing out sanding problems.
That said, I am happy with my Festool EC-125. I don't care to invest in a big compressor and drier and run a 5hp motor to power a sander that only needs a few amps at 110 volts. The dust pickup is better with the Festool, but not a quantum leap (our air sanders were teamed up with Fein vacs). If my budget had been less squeaky I would have gone for a Mirka, they are a very good competitor to an air sander and my old shop has a couple of them now. Still, I doubt the electric units will outlast those Dynabrades.
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