Shop Vac Blower mating with NPT air hose connections?

[JamesDean]

Hey everyone,

My shop vac has a detachable motor segment that can be used as an electric blower. I was wondering if anyone has any experience with that apparatus to a standard air hose 1/4" NPT stuff.

That might sound odd but here's why I want to do it:

I bought a sand blasting chamber for use with my cruise control re-work business. Part of the process is stripping off the old polyurethane coating. This is messy work and previously I'd just been blowing around the particles and rather making a mess.

So in comes the sand blasting chamber...

I've got a 30 Gallon portable air tank hooked up to it right now with a standard blow off gun. It works merely OK.

I figured if I could get the shop vac connected up I'd have some decent pressure and infinite supply of air.

I think the shop vac hose opening is maybe 2-3" in diameter.

Anyone have any solutions? Aside from raiding the plumbing section of Home Depot and making some god awful massive reducer with like 12 steps?

[kmaysob]

problem is, that shop vac isnt making any real pressure. cup a hand over it and you notice it stops flowing air. now set your air compressor to 10 psi and try to plug it with your thumb.

[SwampYankee]

Originally Posted by kmaysob

problem is, that shop vac isnt making any real pressure. cup a hand over it and you notice it stops flowing air. now set your air compressor to 10 psi and try to plug it with your thumb.

That would be my concern too.

I think you'd be far better served with a small pancake compressor. You can find one at Harbor Freight for $60.

Probably not a whole lot more than you'd spend raiding the plumbing section of Home Depot and making some god awful massive reducer with like 12 steps. Which I would totally do first before realizing the error of my ways!

[cmbdiesel]

Where are you getting the compressed air now?
Sand blasting is pretty air intensive...

Another issue you would likely find is that the blower fan is not designed to push air into a pressured environment. Would likely overload the motor fairly quickly and burn it out.

X2 on a compressor. Very useful to have regardless, and like so many other tools, once you have one, you will wonder how you ever survived without.

I have a little Porter Cable pancake that I got at the HD about 6 years ago when I needed something smaller than my Emglo. Still works great, but it's a noisy little bastid. Plan on having enough hose to put the compressor as far away as possible if you are going to be using a lot of air.

[Air&Road]

James,

Think of this in terms of Ohms Law. Think of the pressure as voltage, volume as current and resistance to flow as resistance.

Now, think of the vac as able to produce very low voltage(pressure,) but high current( flow volume.)

When you choke that 2 1/2" hose down to 1/4", you have raised the resistance. With the pressure being the same, there is not enough pressure (voltage) to push any volume (current) through the circuit.

Hope this helps.

[JamesDean]

Thanks for the responses!

I have an air compressor in the garage that I use to fill up the 30 gallon portable tank then use that in the sand blasting chamber. Keep in mind that I'm not actually sand blasting, I'm just using the chamber to contain the stuff that gets blown off the circuit boards.

[cmbdiesel]

Ah... so it's really a low flow blowing off the pieces kind of operation...
How about actually vacuuming rather than blowing?

Could probably glue a PVC cap on the end of the shop vac hose and drill a hole in it for a 1/4" NPT fitting.
That would probably work either direction, pressure or vacuum.

[JamesDean]

Originally Posted by cmbdiesel

Ah... so it's really a low flow blowing off the pieces kind of operation...
How about actually vacuuming rather than blowing?

Could probably glue a PVC cap on the end of the shop vac hose and drill a hole in it for a 1/4" NPT fitting.
That would probably work either direction, pressure or vacuum.

Yep that's all it is. I apply a stripper agent to the PCB and then dust it off with the blow off gun.

Not sure about vacuuming, there is a residue that is on the board from the process and the blow off gun does a good job of..blowing it off.. Not sure about vacuuming.

[JB3]

Id probably get a PVC pipe cap and glue it to the end of my shop vac pipe I was using, then id drill and tap that for my NPT fitting

[TnBob]

or 2" to 1" to 1/4"