Question reg makes vibrating noise

[Lorenzoid]

I have a HOG D1 (diaphragm first stage) that makes a sort of vibration. Any idea what is the likely cause? When I inhale normally on the second stage, the vibration is a few Hz (like "tat-tat-tat"), and when the LP inflator is used, the vibration frequency increases--makes sense, but what causes this?

It's sort of an academic question, as I'm going to do a complete service on the reg, and I'm sure that will fix the issue. But if it could be a damaged part, it would be educational for me to look for it as I disassemble the reg.

 

[axxel57]

'Harmonics' are quite common in 1sts. I'm not familiar with Hogs but as other diaphragm 1sts they also sometimes show that behavior.
Up to now nobody, AFAK, could completely explain why it gets to those harmonics.
I had the feeling that sometimes the slight movement of the main spring when compressed could cause the sound and after just turning the spring and lubricating the base the sound sometime was gone.
Unfortunately that doesn't work always.
Please let us know if you find a possible cause of that vibration during or after your service.......

 

[Nemrod]

On a diaphragm reg first stage the spring will sit on a pad against the diaphragm. Sometimes that pad welds itself to the diaphragm and I think that this can be the cause of the vibration which excites the spring or is amplified by the spring. Same with the pad on the push rod that lifts the seat. I will put just a dab of silicone grease under the pads, not say it a good idea, but it prolongs the time before the pad sticks to the rubber. You might flip the spring. Piston regs make weird noises also. In both cases it might mean a cleaning and proper lubrication is in order. More is not better usually. I dunno :/ .

James

 

[GF99/99]

'Harmonics' are quite common in 1sts. I'm not familiar with Hogs but as other diaphragm 1sts they also sometimes show that behavior.

Yup this will happen especially on all the Apeks style knock offs. Usually an easy fix is to just adjust the IP either up or down just a hair of a turn and if this does not do it pull the HP seat and put a little extra lube on the shaft and the little o-ring it rides in

 

[Lorenzoid]

Thanks, all. I had heard of the harmonic vibration issue, but I wasn't sure if that was what I was experiencing because I had in my mind that harmonic vibration would be higher frequency. If I breathe in very slowly, it's more like a tapping sound--in other words, it goes down to a surprisingly (to me) low frequency. I wish in my HOG service course they had been able to demonstrate a reg exhibiting this problem so we could have heard what the vibration sounds/feels like.

The HOG D1 has two soft plastic isolation washers that abut the ends of the main spring. In the HOG service course it was explained that these washers are intended to address harmonic vibration. It was also stated that if for some reason the reg we were working on was missing these washers, the workaround was to substitute a bead of lube. These washers are very thin, made of transparent plastic, and therefore difficult to see and easy to lose. At least one of my regs is missing at least one of these washers, and when I have serviced them I remembered to substitute the bead of lube. I am willing to bet the reg in question is one of those that is missing a washer. Maybe I didn't use enough lube? I have no idea where to source those washers, or even if the washer actually works any better than the bead of lube.

 

[Nemrod]

Is any part of the spring(s) becoming coil bound? If so the spring may have gone soft and you need a new spring.

Have you polished the ends of the springs? When a spring compresses and relaxes there is a torque generated, that could be the tic, tic, the spring slipping and then binding without the washer to allow easy slip?

Could you get the washers from Hog? Ace Hardware has Mylar washers but you might have to cut and trim to fit. McMaster-Carr?

James

 

[Lorenzoid]

I'm not familiar with the term "coil bound."

I have not done anything to a spring. Should I polish the ends? I got some wonderful Micro-Mesh from @rsingler 's reg service course.

I have not found any washers of the right size and thickness at McMaster or from any other source, and moreover, I'm not confident in my ability to measure them. My micrometer is a piece of junk. I wish I had the manufacturer's spec. I'm sure they could be cut from a Mylar sheet with a punch kit for making washers, but I really don't want to buy that.

 

[Nemrod]

Coil bound is when the coils begin to touch one another when compressed. Then the spring acts as a solid column, no longer a spring. As a spring goes soft it might over time need repeated adjustments to keep IP at spec. At some point the coils begin to touch one another. A spring can go bad if not heat treated properly or materials or compressed beyond working range.

Is the spring bowed? Such that it touches the side of the first stage body?

You could polish the ends with 600 and then 1000 wet/dry paper with water or oil for lubricant to give a finer finish.

The tic, tic you describe is a bit odd, which is why I am sort of guessing. I have not heard it so it is hard to make a good diagnosis.

Diaphragm regulators usually do not use shims to adjust IP as do some piston regs, they have an adjustment screw/barrel instead. Those washer are in there for slip to allow the ends of the spring to move as it compresses and returns and for isolation. That is why they are saying to use a bead of lube.

James

 

[VikingDives]

I have no idea where to source those washers, or even if the washer actually works any better than the bead of lube.

What's the part # on the washer? I'll look and see if it's normally available... If it's not it's probably only a phone call away.

 

[Lorenzoid]

What's the part # on the washer? I'll look and see if it's normally available... If it's not it's probably only a phone call away.

The HOG D1 schematic calls it's a Spring Washer, item number P-01-002-03.