Gear driven diaphram pumps

I don’t like the idea of jacking around with 12v stuff. They just seem underpowered and janky. I’ve got a friend who has in 3 years replaced 5 or 6 pumps, and then on top of that has now invested in a booster. Just seems like a lot of money invested in equipment that doesn’t last long. Others seem to have better mileage out of the 12v diaphrams, but I have a hard time looking past all the reports saying they break often.

I was considering assembling a large air compressor and then going with an aodd as I am intimately familiar with them already, but I recently discovered gear box driven diaphram pumps and though that might be a cheaper option with a smaller foot print for similar performance to an aodd.

Anyone using this? Anyone want to defend the 12v route? Anyone want to convince me the air operated option is the best?

Follow up question: how does one keep from blowing a diaphram? Is there a bypass plumbed or what?

12v pumps are a cheap expense compared to the wads of money you can make with it. It’s not meant to be something you buy once and use for years to come. Expect to replace every 6 months atleast with heavy use sometimes even sooner. Rinsing well after makes them last longer but it’s a meant to be replaced often just like pump up sprayer.

I mean fair enough regarding expense : earning potential being good enough to justify the purchase of a 12v pump, but when there’s better ways, there’s better ways. That’s why I’m asking after the gear driven diaphrams. I know aodd can put up with some pretty gnarly stuff, and rebuilding them isn’t very expensive, especially if you are conscious of the rebuild kit costs when selecting a model. Just sort of polling the collective to get some thoughts.

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Post a link to the gear driven diaphragm rig would ya

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Gear driven diaphragms are pretty common.

I can think of two and one would not be suited. I’m just trying to find out what the guy is looking at.

Ok @MuscleMyHustle on second thought answer his question with no additional information since you seem to know so much lol. I however am trying to figure out what exactly the guy is talking about.

Well big D, from what I can gather he thinks 12v pumps are janky and wasteful and is looking for an alternative, he was looking at a booster pump until he discovered gear driven diaphragm pumps witch he says have a smaller foot print and are cheaper but hasn’t done any research on how they work or why they might not be the best option for what he is after. The way I read your comment was that you didn’t believe there was a gear drive diaphragm pump to witch I replied to that they are pretty common.

Yes I was here for all that but thank you for the play by play


I got you son! Leave the thinking to me :joy:

Lol, well you mostly got it right, but it’s my fault ultimately. I’m not excellent at making myself understood.

Ok, yes, I don’t like 12v pumps. Sure, they are better than a pump up sprayer for lots of things, but I’ve never seen one used to near it’s capacity for long periods of time day in and day out and not fail quickly. I’ve seen 12v pumps die in a single day before. I have a friend who is mentoring me in power washing and his experience is more or less what my expectation would be imagining using a 12v pump to wash houses and roofs. Between deep cycling batteries, low pressure restrictions (adding a booster would help that, but then you have yet another pump to power and maintain, not to mention the booster itself is expensive), and lack of longevity, I would rather use something else.

Air operated double diaphram pumps (aodd) are great. I’ve used the mess out of them in other industries for a myriad of different applications. You can bull head the pump (no unloader or need to divert a portion of the flow back to suction). You can find chemical resistant air operated diaphrams for just about any liquid or slurry you need to move from one place to another in a hurry and are very adjustable for different situations. But they require a) a large amount of air and b) a pretty hefty up front investment because air compressors capable of really pushing that pump aren’t cheap. However, even when you “break” them, you can scoop up rebuild kits for a very reasonable cost. An example of a suitable AODD: Now I am pretty good at finding equipment on the cheap so I feel confident I could get a diesel powered air compressor slapped together that would produce enough air, and buy the pump, and everything else somewhere to the tune of about 2000-3000 depending on my luck at auction.

Then I was cruising a FB equipment site and saw one of these: for sale. I did some digging and it would handle the SH. And I’ve seen it sold cheaper elsewhere, but that link was handy. It got me thinking of a little honda gx engine I have hanging out without a current purpose. If you’ll notice, the specifications on these two pumps are quite similar. And a little honda engine with this bolted directly to it would be a much smaller footprint than a 2-3 cylinder diesel, plus the air pump, plus the tank, plus the AODD and would ultimately cost a lot less to set up. It would be suitable for washing and transferring chemical just like i was going to use the AODD for.

However, I’m really not intimidately familiar with the ins and outs of gear driven diaphram pumps. In fact I can say that I’ve only seen 1 with my own two eyes and used it only the once. The application I used it for was not one where the flow would need to be cut on and off. When you cut the flow off from an aodd, the pump stops because the air you are feeding the pump isn’t enough to continue to pressure up the fluid/diaphram until failure. I was a little confused about what happened when you cut the flow off to this pump (let go of the trigger). I have since read that there is a bypass function, so that means some sort of rudimentary unloader set up. I have been assuming that the unloader is internal, but I would like to find more information on that. I would also like to hear from people who have used something like this. It looks like rebuilds are reasonable, and I would imagine a person would get lots of life out of this little guy as well before needing to rebuild it, but expectations and reality don’t always line up. I was also hoping someone who uses an AODD for soft washing would chime in with reasons to do the same or reasons why I should consider the gear driven alternative.

Thanks for the interest, gentlemen.

Sorry for the novel.

Good lord, I twice fell asleep reading that :confused: lol


Oh come now. It’s long, but not that long. I :joy:

Oh your done? I’m still reading.


Nope, I only made it to the 18th sentence. :sleeping:

I think it’s your prose, it’s like a sedative and laxative combined. Hahaahahhaa

I’ll try to sexy it up for you next time. Maybe throw in a couple jokes.

In all seriousness, we run the Harbor Freight truck mounted air compressor and 1/2" kynar allflow, it’s bulletproof. Hundreds of roof jobs per season and had to replace a diaphragm 1 time, took all of 15mins.

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Lol I just knew if I interacted with you long enough I’d get a real answer. Yeah…aodds are so nice. What model air comoressor are you running to feed that diaphram pump? I’ve always felt like the consumption specs on a diaphram pump was exaggerated.

It’s the only hf truck mount they carry, things been purring for yr and half.