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Dryer recommendationfor Miller 875 plasma cutter.

Overland

Stainless
Joined
Nov 19, 2017
Location
Greenville, SC
Just picked up a used one, WOW this sucker can cut.

The tip is in poor shape, however before I replace I'm told I should put a dryer on the air to protect the consumables.

What would be a good, economic recommendation please ?

Thanks
Bob
 
Overland

Old school science is your friend, make use of the gas laws (Robert Boyle circa 1662)... cheap!
High heat and high pressure gas (compression) holds lots of watter.
Low heat and low pressure not nearly so much entrainded water

So what you want to do is store air at as high a pressure as you can and draw it off at as low a pressure as you can.
Cooling of course helps greatly. But havng said that we cannot get a dew point in compressed air lower than the freezing point of water. with a regrigerated dryer In practice 40 degrees F / 4 degrees C is a practical limit

Which means that if you are cutting in the cold, a regrigerated dryer may do nothing for you.

Following that thinking in my shop the comressor cuts off at about 160 PSi. The wet receiver (drained ofetn) feeds throogh a coalessing filter and regulator at 125 PSI to a dry tank (40 gal) General shop air feeds right off that. The plasma cutter, air bearing on the grinders pass through a Milton Silica Gel bed the size of a coffee can and after that final filter to catch any escaping silica gel, mostly. Air tools seem to last way longer on dry air too!

I do have a IR chiller. In the winter it's too cold to do anything and in the summer it's too hot and dry to do much.

A guess at best. The combined gas laws let me catch the lions share of the mosture basically for free. The dessicant is icing on the cake with a dew point of something less than 0 degrees F. In the middle of winter doors open and 25 degrees ambient, my air would be in a practical sense really dry.

I get really good life out of the consumables on my 65A Hypertherm, at least with respect to water. IF I do someting stupid well that's another issue!
 
both links so far are to motor guard M-60s. I have been using one happily since about 1992. (actually, I am on number 3- eventually, the powedercoating fails, and then you have to buy a new one) Just click on the link. Black aluminum 2 piece, with a paper filter.
These days, most decent welding supply stores keep them in stock.
 
You specifically asked about plasma cutters. Just upstream of your plasma cutter, you should absolutely install an M60.
Personally, I have an electric programable drain on the main compressor tank- which acts as the first line of water defense- every hour or so, it is supposed to open a valve at the bottom of the tank and drain the water for 30 or so seconds- all adjustable.
Secondly, I have a cheap, off the shelf water trap on the air line as it comes out of the compressor head.
just something like this, with a clear cup, so you can see when it accumulates water.
1/2" Particulate filter water trap seperator moisture Compressed Air Compressor - - Amazon.com
Then, in several places on the air line, as it runs thru the shop, I have valves at the lowest point that I manually open, and drain water from the lines.
There are a variety of ways to lay out air lines, but all generally have drain valves.
Air Piping Layout

You really need all of this stuff.
And I live in an area where the general humidity/condensation problem is not that bad- in certain areas of the country, you will need even more than this, including a thousand dollar or so powered air dryer.

But for your plasma cutter, buy an M-60. Really. Its been proven to be a vast improvement, by thousands of users, over decades, and it increases tip life and improves cut quality.
 








 
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