How to build a PAPRa Fan Box

A video on how to build the BNC connector:

Strip the red wire on the fan:

Connect the smaller brass component to the red wire:

Crimp the brass component to the wire:

Test that the crimp went well by tugging on the brass component:

Make sure to put the wires through the ground cylinder before connecting the brass component to the connector:

Push the brass component into the center of the connector.

Since the wire is braided, this step can be tricky, and a small item like a paperclip can help push the component into the middle of the connector:

Check that the brass component is visible and flush with the interior plastic column in the connector:

Tugging on the wire should not have the component pull out:

Strip the black wire:

Crimp the ground cylinder to the back of the connector with the black wire:

Another angle of the crimp:

Place the waterproof seal around the edge of the BNC:

Place the bottom gasket (P-TET-000146) into the fan box (P-TET-000140):

You may need to use a tool to get the edges of the gasket down:

Place the Fan Outlet Spacer (P-TET-000145) into the fan:

Place the Fan Outlet Spacer (P-TET-000152) into the fan:

Note the orientation:

Begin taping the Fan Outlets into the fan:

Be sure to cover all of the gaps with dryer tape:

Place the Fan Outlet Gasket (P-TET-000) inside the Fan Outlet Spout raised edge (P-TET-000144):

Place the Fan Outlet Gasket (P-TET-000) on the outside of the fan outlet:

Place the gasket and outlet spout into the fan box:

Place the BNC connector into the slot in the fan box:

Make sure to seat the BNC into the hexagonal space properly:

Place the fan into the box, holding the gasket in place:

Pull the BNC connector in place:

Finger tighten the hex nut in place:

Then tighten with a wrench:

Place four square nuts into the Filter Interface (P-TET-000141):

Place four of the 20 mm m4 bolts into each of the holes in the Filter Interface:

Place the Fan Gasket (P-TET-000147) on to the Filter Interface:

Flip the Interface/Gasket combination and put it onto the Fan Box:

Screw all four corner bolts into place:

Place filters into the Filter Box (P-TET-000142):

Make sure you get the orientation correct, and don’t touch the filter directly.

Place the four 30mm bolts into the Weather Guard (P-TET-000143) and then slide the Filter Box (P-TET-000142) in place:

Place the Filter Gasket in place (P-TET-000148):

Once again, flip the entire complex onto the currently assembled fan box and then screw the four corner bolts in place:

Screw the MOLLE Strap (P-TET-000153) in place:

Thread the prongs of the MOLLE Strap part through the straps:

Put the MOLLE Catch (P-TET-000154) in place:

Congratulations! You’ve now built a Tetra PAPRa Fan Box!

Changing the filter depends on how much you use the device. If you’re using the device where there are a lot of particulates in the air (such as a construction site or a woodshop), you may want to change every month or so. If you’re using the device where there are less particulates, every two to three months should be fine. HEPA filters just get dirtier and eventually the fan will have a hard time pulling air through the filter, and the filter should be swapped before that happens.

This particular box was built around the Klein Tools p100 filter. Off-brand filters may not be as effective, so be sure that the filter is NIOSH certified.

No, the fan box is not water proof. With the weather guard in place, water should not get into the filter directly, but increased humidity could decrease the effectiveness of the device.

It is important to periodically check that the nuts are tight on the fan box, to ensure that the box is properly sealed against the elements. Hoses should also be cleaned periodically as well.