A $300 Versaflo powered air respirator

← Back to Kevin's homepagePublished: 2025 Aug 18

I wanted an integrated, minimal-faff PPE setup with ear protection, eye impact protection, and respiratory protection that I could use for woodworking while wearing my regular eyeglasses. So I paired a 3M Versaflo helmet ($225) with $50 worth of stuff from AliExpress and a bit of 3d-printing:

Read on for details, or just skip to the bill of materials for links to purchasable parts and 3d-printable files.

Background

Over years of woodworking, I’ve used all sorts ear muffs, safety glasses, and respirators, but always found them to be a hassle — especially using them together.

For example, 3M’s 7500-series ($35) half-mask respirator has a strap that goes across the back of your head (rather than your ears) so it can make a tight seal to your face:

Unfortunately, if you’re wearing this together with ear muffs (e.g., while power sanding), this means every time you want to drink some water you’ve got to take the earmuffs off first, then the respirator.

If you normally wear eyeglasses (like I do), it’s even worse: earmuffs, glasses, and respirator off, drink water, then respirator, glasses, and earmuffs back on.

If I know I’ll be working for a while, I’ll wear contact lenses instead of eyeglasses, but in many cases eye protection is needed anyway. These ski-style goggles ($12)

work OK, though in my experience the “anti-fog” features are, uh, somewhat aspirational. These anti-fog ventilation holes also allow dust and vapors through, so while the goggles will protect your eyes from blunt trauma, they won’t help with blinking/crying.

If you don’t want stuff getting to your eyeballs, you’ll need a full-face respirator like 3M’s 6800-series ($125), which definitely increases the faff-factor:

There’s also step 0: Don’t have a beard or glasses, since these keep the mask from properly sealing to your face.

Luckily, our Minnesota Mining and Manufacturing friends have a great solution to all these problems: Their Versaflo line uses a belt-mounted battery and fan to blow filtered air into a helmet with attached earmuffs.

This solves all of the aforementioned problems:

• It’s fine to have glasses or a beard, as you don’t need a tight seal to your face (dirty air can’t get in if enough clean air is flowing out).
• You can put everything on / take everything off all at once, though you don’t even need to do that for a quick break as the visor flips up and the earmuffs “snap open” away from your ears.
• It doesn’t fog up, since clean air is always blowing across the inside of the visor (and your sweaty face).

Unfortunately, it’s a bit spendy: $1,650 for the starter kit on Amazon. (If you’re made of money or hate DIY, though, please do feel free to use that affiliate link!)

However, 3M sells all of the components separately, which got me wondering — how hard could it be to make a battery-powered filtered fan unit?

DIY Versaflo

I decided to throw together my own system:

• Standard Versaflo helmet for the flip-up face shield, air handling channel, elastic face seal, ergonomic adjustment mechanisms, and earmuff attachment points
• USB-C power bank
• 12V centrifugal blower fan
• USB-C fan controller
• 3D printed adapters for everything, reusing 3M’s “bayonet-style” filters (e.g., the $3 P100 particle filters and $6 organic vapor cartridges; PDF overview of 3M cartridges/filter)

For the Versaflo helmets, there are a bunch of different model numbers flying around. You’ll want to look at the PDF to get an overview, as somehow it’s 2025 and web designers still haven’t figured out information design. Here’s the tl;dr:

Although the 300-series looks way cooler with its two-tone color scheme, I don’t actually need a hard hat for woodworking, so I opted to save $100 and got an M-206 helmet for €194 from PBMDiscounter.nl (I live in the Netherlands; Amazon.com has the M-206 for $297, though you could probably do better on EBay or some other supplier).

I purchased Peltor X2 earmuffs with hard-hat mounting points (€23 from PBM or $33 on Amazon.com)

Unfortunately, despite 3M marketing copy like:

3M™ Versaflo™ M-Series headtops can help protect your workers from a variety of respiratory and impact hazards while maintaining comfort. Now able to be used with 3M™ PELTOR™ headsets

when I had everything in-hand I discovered that I’d made two mistakes.

First: there are Versaflo-specific Peltor earmuffs ($75), which have a different mounting hole pattern than the standard hard-hat version I’d purchased:

I found that 3M does sell an the hole mounting plate (Z3Af/2), but I couldn’t easily find it for sale in the Netherlands.

My second mistake was that the earmuffs are officially only compatible with the M-100 or M-300 series helmets, and I’d purchased an M-206.

Luckily, 3M seems to have used the same mold for the inside of the M-200 series helmets, as they have cylindrical plastic bosses in exactly the same place where the M-300 Peltor installation video shows the Official Divots you’re supposed to screw the earmuffs into. I just used a light from the inside to locate where to screw in a 3d-printed adapter:

Here’s what it all looks like put together:

Here are the individual pieces:

The assembly consists of:

• a 10,000 mAh power bank with integrated display and cables ($20)
• a centrifugal blower fan ($16)
• a USB-C power delivery adjustable speed fan controller with dial ($10)
• a CPAP hose ($5)

These are all integrated via a few 3d-printed pieces:

• A holder box contains the power bank and fan controller (dial sticking out the bottom of the box), an integrated belt clip, and two captive M3 nuts.
• A filter adapter, with one side containing a groove for an NBR O-ring that mates with the input face of the fan and the other side having a boss which holds a gasket and mates with a 3M bayonet-style filter or cartridge; two 45mm M3 screws go through this piece, through the fan, and into the captive nuts of the holder. I copied the bayonet geometry from a 6800-series mask, the only change being chamfering the bottom face of the three barbs to make them printable.
• A fan output to CPAP hose adapter; since this is under positive pressure the seal is not crucial — I just friction fit onto the fan and designed groves to match the (left handed!) plastic threads of the CPAP hose cut end. (My CPAP hose came with squishy connectors on both ends, which turned out to have the right outer diameter to make a good connection to the Versaflo helmet, but I cut the hose to shorten it.)

The belt assembly (without hose and filter) weighs 480 grams.

Testing / future improvements

The fan controller takes about 10 seconds to negotiate from 5V USB up to 12V, at which point a green lightning bolt shows on the charger and the fan audibly speeds up. I used an FNB58 inline USBC tester to measure the power draw, which fluctuated between 5–10W while the fan was at max speed. According to the seller, the fan controller can use up to 36W with USB-PD (3A @ 12V) or 18W with QC fast charging (1.5A @ 12V).

I roughly tested the airflow by measuring how long it took the fan to inflate a garbage bag. The flow was about 2 liters/second (4 CFM) when pulling through an organic vapor cartridge and about 3 liters/second (6 CFM) without the cartridge.

This is pretty far off from the nominal ratings of the BFB1012H fan I used (25 CFM, 1 inch H2O static pressure). I have no idea if it’s an issue with the fan, the controller, or my testing methodology. (If I really cared about the ratings, I’d be buying from Mouser or Digikey instead of AliExpress =D)

I’ve ordered a more powerful BFB1012UH fan (37 CFM, 4.6 inch H2O static pressure) which has the same form factor and should be easy to swap out.

As for actually using the setup, I’ve found it to work well thus far. I can fog the visor by strongly exhaling through my mouth, but it disappears in 2 seconds.

Last weekend I used the setup for sanding and finishing a tabletop, which consumed about 10% of the powerbank over an hour’s work.

However, part way though the finishing I started to smell the oil, which could indicate insufficient airflow or a stale vapor cartridge. If this issue persists with the more powerful fan, I’ll likely redesign to use two larger, lower RPM (quieter) fans and two filters.

In that case, I’d probably also switch from a belt-clip design to a small backpack, as I suspect that’d be easier to take on/off than a larger belt contraption.

The CPAP hose is quite lightweight but seems to be made of a delicate plastic film. It’ll be fine to use in my wood shop, but if I were crawling around underneath a house or something I’d probably replace this with a harder plastic vacuum hose.

Bill of materials

Disclaimer: I threw this together for my comfort as a hobbyist woodworker. If you are working with actually dangerous shit, just pay 3M $2k for the proper setup (or have your employer do so, as OSHA requires). Use your judgment here, and definitely don’t sue me because you got hurt following an Internet rando’s blog post about assembling junk from AliExpress with plastic noodles from a 3D printer, because then my lawyer will point to this paragraph and you will look like a dumb dumb.

3D printing

I printed all of the parts from PCTG filament using a 0.6mm nozzle on a Bambu Labs P1S printer with the following settings:

• 0.3mm layer height
• 2 walls with 150% line width, which maximizes the “squish” and thus layer adhesion
• 15% adaptive cubic infill
• 250°C filament temperature
• 80°C build plate temperature (textured PEI plate)
• 16 mm^3/s max volumetric speed

This was my first time printing PCTG and I found it worked great — no failures and much less stringing compared to PETG. Nothing here is really under serious stress, so I’m sure printing with PLA (especially a more flexible “tough PLA”) would also be fine.

No supports are required when printing in this orientation:

The parts took about 2.5 hours to print and consumed 140g of filament, for a total material cost of $4.

The files are:

• fan adapter.stp
• filter adapter.stp
• peltor adapter.stp
• housing.stp

They are also available on Printables.

Other resources / prior art

• This Australian metalworker has several nice YouTube videos comparing the Versaflo with alternatives like a $150 Chinese PAPR and the Trend Airshield.

• Gerard Hughes does comprehensive testing comparing PAPRs, including airpods call audio while wearing the helmets!

• I ran across a few similar DIY battery-powered fan + filter projects (They were quite fashionable in 2020 for some reason). Most seem to be powered via drill batteries, though I feel like using a USB-C power bank is both cheaper and safer (as some power tool brands have all the protection circuitry in the tools rather than the battery packs).

  • Large 3d-printed design with box filter
  • A dual-fan design in a laser cut box
  • Smaller 3d-printed design for NATO 40mm filters