Glitchy air sander

[Alan R]

Hey Guys, I have a Snap-on 6" random orbit air sander that just started acting up. It now slows down for no apparent reason - I will then hear a "pop" and it will scream to the max as if something had been restricting the air flow, but was then blown out. I don't know how better to describe it. No problem with the air supply itself and I oil the unit daily. Any ideas what I'm up against?

Many thanks. Alan

 

[Hammer1963]

I have the same issue with my 3" Snap-on DA. I've taken the plunger air valve apart and changed the o-ring, flooded it with PB blaster but no luck as it still has the same issue and at times will only run at low speeds. When it is stuck in the low speed mode, the exhaust has a totally different sound. I bought a Cornwell to CAT325 to replace it till I figure the Snap-on out.

 

[Greatbear]

This can happen if there's moisture in the lines causing localized freezing somewhere in the tool, but the signs would be there as you're using it, water mist coming from outlet, very cold tool body, etc.

 

[Alan R]

I have the same issue with my 3" Snap-on DA. I've taken the plunger air valve apart and changed the o-ring, flooded it with PB blaster but no luck as it still has the same issue and at times will only run at low speeds. When it is stuck in the low speed mode, the exhaust has a totally different sound. I bought a Cornwell to CAT325 to replace it till I figure the Snap-on out.

Thanks for the input as I was about to try the same thing. And yes, my exhaust also sounds different as well. Was hoping to avoid replacing it. Will let you know if I come up with a better answer.

 

[Alan R]

This can happen if there's moisture in the lines causing localized freezing somewhere in the tool, but the signs would be there as you're using it, water mist coming from outlet, very cold tool body, etc.

Last winter I did have very similar problem, but found out it was ice that had formed in the air outlet. That was fixed easily enough by my just removing the air diverter. This problem seems more "internal", though I will now check to see if the same is occurring somewhere else in the tool (or will just warm it up to see if that makes any difference).

thanks

 

[Jswain]

If it's not working correctly there's no harm in taking it apart/cleaning it up and throwing it back together. That's my theory anyways, I've saved a few air tools at work doing that.

 

[Alan R]

If it's not working correctly there's no harm in taking it apart/cleaning it up and throwing it back together. That's my theory anyways, I've saved a few air tools at work doing that.

I will be doing that next. Didn't know if there was a common problem with these with a specific solution. thanks

 

[Hammer1963]

Since I posted my first reply, I since revisited my Snap-on DA issue and found it to be a clogged exhaust issue. Somehow and I suspect since day one, the exhaust packing had a plastic disc floating about and got lodged causing the loss of performance. It's now running at full speed

 

[Alan R]

Since I posted my first reply, I since revisited my Snap-on DA issue and found it to be a clogged exhaust issue. Somehow and I suspect since day one, the exhaust packing had a plastic disc floating about and got lodged causing the loss of performance. It's now running at full speed

Thanks for the follow-up. That's what was happening to me last winter due to frost clogs in the exhaust packing. I've done some more homework (lot's of "experts" out there) and tried a combination of solutions (literally), as nothing seemed to want to come apart very easily. Made sure tank was free of moisture. With the 4612 tool I cleaned/blew out all I could from the outside, then flooded it (several ounces) with WD-40 and blew that through 2-3 times (NOT to be used as a lubricant I hear, but a good cleaner). I then lubed it with Marvel Mystery Oil for Air tools. Seems to run as good as ever, but it has been warmer here. Will have to see how it performs through the season. Glad you got yours running. Luck

 

[Greatbear]

I've discovered that tools which throttle the exhaust of the tool for speed control tend to ice up even if the air supply is pretty dry. The expansion happens on the outlet of the tool almost exclusively so it gets pretty cold. I have a couple die grinders that have an exhaust throttle max speed control, they can sometimes get frosty on humid days. Those same tools will spit solid little ice chunks when I use them with one of my big portable compressors.

 

[Alan R]

I've discovered that tools which throttle the exhaust of the tool for speed control tend to ice up even if the air supply is pretty dry. The expansion happens on the outlet of the tool almost exclusively so it gets pretty cold. I have a couple die grinders that have an exhaust throttle max speed control, they can sometimes get frosty on humid days. Those same tools will spit solid little ice chunks when I use them with one of my big portable compressors.

Thanks - that answers another one of my questions as I have had icing problems even on dry days with a clean tank. I run a 2 stage 5 hp compressor (and probably run the psi a bit higher than I should), so I'm definitely moving some high pressure air out of the exhaust.