Homemade air assist

Hi everybody!

I was browsing some ideas for homemade air assist since the original air assist is a bit pricey. I do not have access to an air compressor, and it seems like the aquarium air pumps I have available to buy do not come close to the same amount of L/min as the original air assist can provide… Therefore I looked into something a bit different.

I saw a video of a guy making an air blower with a PC fan, so I was wondering if that could potentially work. Here is a reference picture:

So something in the same style with a smaller hose that fits the laser feeding tube.
I am a bit in doubt of whether it would provide enough air or too much air. The fan is 1300 rpm with 54.3 cfm, so technically it would provide too much air, but I am not sure what the number will be when it gets compressed into a smaller tube in a wooden box.

If you have tried something similar, I would love to hear your input, or if you have ideas I am open ears :slight_smile:

I very much doubt that you can make compressed air with an open fan system.

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What @bernd.dk said.

Also, balancing the fan blades will be a major PITA if done that way.
The blade shape and angle are also pretty much as far from correct as possible.
A marginally better solution would be to use the fan unit as-is, attached to a funnel to reduce the diameter.
If done correctly, it might keep the fumes off the lens and the laser path, but most likely won’t actually assist in the cutting.

The only easy DIY air assist alternative I can think of is a HVLP system made out of a vacuum cleaner turned into a blower.
Won’t be that silent either :wink: .

The best alternative to an air compressor I’ve found is a “Spira” compressor for inhalation applications.
Spira is only a company/brand name (derived from respiration), at least the older compressors are either piston or diaphragm types, not spiral as one would think from the name.
But those are somewhat hard to find, and if available, the airbrush folks will snag 'em up in a heartbeat.
The output is pulsed as-is, but I’ve found no problems with that in air-assist use.
And pretty easy to convert to constant flow if needed
The plus side is that the duty cycle is 100%, unlike in many other affordable compressors.



Re: duty cycle. Yeah. Lol. Something many overlook. I was pushing my assist pretty hard this weekend. 2.5 hours of continuous cutting, workpiece change (maybe 2 minutes), another 2.5 hours of continuous cutting, workpiece change (2min), and a final 45 min of cutting. My compressor was running approx 50% duty cycle for about 6 hours and the heads exceeded 212 degrees F well within the first hour. I put my hand on one and noticed it was a bit hot (I work in a weld shop, so “a bit hot” is relative). I sprayed it with some RO water and that quickly boiled off. I “had to” pull out a blower fan to move air over the head fins to keep them below boiling.

I’m running a small 2hp/5gal/5-6cfm compressor rated for 70% duty. It’s running well within specs but I still prefer to keep the head temps reasonably cool.

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