Searched the forum for desiccant filters

Any recommendations for a large capacity bead type desiccant filer. Reasonably priced. To put on 3/4 copper air line.

I have this one.

It seems to work OK, I have it placed right before my Motorguard, so that can catch any dessicant particles that escape. It’s not easy to see when the beads have changed color, so I just open it occasionally and dump them into a tray for drying in the oven.

I made this one using an Aqua Plumb 9100 Water Filter Housing bought on Amazon. It’s been working well for me. It’s connected directly to the inlet of my plasma cutter.

I added a central tube of pvc with many holes drilled in it and a disc of Scotchbrite on top to keep the beads from dancing. After about 1 hour of torch time I’m seeing the top 1" turning pink from moisture absorption. I haven’t tried it yet but it’s supposed to take a couple of hours in a toaster oven to regen the beads when it’s time.


this does work but…

Do you feel that using this plastic water filter housing for compressed air is safe?

Compressed air is a thousand times more dangerous than compressed water when in a vessel.

Those things are only rated maximum for maybe 120 Fahrenheit and 125 PSI.

I know I’ve seen people use them in the past. At one time I even made one up for paint spraying.

But this is the question. if this is a good alternative why aren’t air filter companies making their housing out of this plastic considering it’s 1/5 the price?

I think the answer to this question is the reason you shouldn’t go this route.

I think you’d be pretty unhappy picking shards polycarbonate out of your face.

But you could save a good $70 so maybe the risk reward is worth it for some people.

IMO. The practice of using these polycarbonate vessels for compressed air is extremely dangerous. The risk might be low but the consequences are very high.

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That particular housing is rated for up to 125psi and since I keep my air set at 110psi it’s within the rated working range. It’s close but not over max and my air is cool and clean. In the summer a sheet of aluminum foil wrapped around it will minimize heat gain from the sun.

IMO it’s viable and no more dangerous than other things in my shop.


I like the idea of the re-purposed filter housings. Particularly if you are using an after-cooler to ensure that you aren’t pumping 250 degree (F) air through it. I went with an integrated solution made by Milton. Metal housing and 2 qt capacity (the little ones seem less than ideal for plasma cutting).

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I spread mine out on a cookie sheet and place them in the over (electric) on warm for about an hour…t


I think the desiccant dryer is a great solution but only if you have an after-cooler on your compressor. If your pump is running while the plasma is running you are forcing hot, super-saturated air into your desiccant and will overwhelm it pretty quickly. Here is my after-cooler build: Dry Shop Air - Step 1 (Compressor After-Cooler) | The Hobby-Machinist. Without an after-cooler I’d just run a refrigerant dryer with water/oil filters upstream.

I have 50 feet of 3/4" copper with 4 drop legs before it gets to the dessicant dryer and then the motorguard.

I have the Derale trans cooler and water separator between the pump and tank. Quincy QT-54. I ran the 1 hr. break-in with the tank drain wide open. No liquid came out of the tank. Maybe a half cup out of the water separator.

How much is that two quart desiccant dryer?

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I am thinking one large one on the main line 3/4" serving all drops.

Maybe I’ll rethink it and put small ones on the 1/2" drops where needed.

Check out the Milton line on Amazon. It is a little pricey but so are other larger format desiccant solutions (and by larger I mean not entry level - the commercial stuff is stupid expensive and gigantic).


I recommend you search on Google using “milton desiccant” rather than searching using Amazon’s totally useless search tool.

This looks nice. Price seems high for 1/2" port. 1 quart serving just just plasma could work.

I only use it on the line going to the plasma. Large dessicant dryers are expensive. $125 is cheap for a 1 quart size.

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so I a, now running a 60 gallon main compressor…it is going from the heads through a 5 leg x 5’ coppper cooler on the wall before going back into the tank…then it goes through a refrigerated dryer and stored in another 60 gallon tank…then it goes through a desiccant dryer and through a motor guard filter then into the plasma…overkill I know but it gives me sry air in my changing climate here in Canada’s Capital…

That’s quite the air supply
Behind every great man, air’s a great woman
Air’s more than one way to skin a cat

Sorry, just got in from celebrating with the dogs

Not so cheap, but I’ve got this system and it’s working well for me:

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I would love to get a big desiccant can like that.
4 quarts , amazing.

I have the MaxDry XXL in my shop after my passive copper dryer. It is one whole heckuva lot of dessicant, that’s for sure.