(Not as boring as it sounds!) Pressure washer inlet 1" barb to 1/2" NPT homemade fitting for $1.42

NOTE: it’s been brought to my attention that installing plastic fittings on the pump head is a bad idea, for a number of reasons:

1. Vibrations will cause leaks and cracks
2. You cannot fully tighten plastic into metal
3. Broken plastic in a pump will chew up check valves

I recommend that you do not attempt this project. I’m leaving this here for the sake of anyone else searching for info on the use of plastic fittings on pressure washing pumps.

I wanted to run my 1 inch supply line directly to the inlet of my pressure washer. But there is no reasonably priced fitting that goes directly from a 1" barb down to the 1/2" pipe thread on the pump. So I improvised.

All of this was done with a soldering iron in about ten minutes:

  1. Cut the barb portion off the 1"x1" fitting
  2. Melt down the barbs slightly on the 3/4"x1/2" fitting
  3. While the plastic is still soft, quickly slip the 1" barb piece over the 3/4" barb
  4. Weld the pieces together by running the soldering iron around the inside of the barb end. You want the inner piece to melt outward and fuse with the outer piece
  5. Weld the back end of the fitting by carefully running the point of the soldering iron in the joint where the two pieces meet, and then smoothing over the plastic. Make sure to leave enough flat space on the hex portion so you can still grip the fitting with a wrench
  6. Last, but certainly not least, take a small file to the inside of the fitting to smooth out the opening and get rid of any loose chunks of plastic. They won’t play nice with the inside of your pump!

Total cost: $1.42. And I think this is a better solution than anything available off the shelf at the hardware store.

Ok ok it’s not that boring Alex! :wink:

I wonder how it will hold up over time…

Haha, thanks. I guess that’ll depend on the quality of my welds. Since polypropylene is solvent resistant, the only accepted method of fusing it is with heat welding.

Your welcome :smile:

Interesting never thought about that before now…

Do you think heat welding wfp clamps would be the same?

I think welding clamps would be a much trickier job. Probably someone with the right equipment and some experience could weld a broken clamp back together. But I wouldn’t really trust any repair I did myself with a soldering iron.

This little project with the fittings is kind a unique situation where using the soldering iron actually works. Lots of contact area and plenty of excess material to be spread around. Plus this won’t be experiencing the same stress loads as a wfp clamp; just some vibration from the pump.

Yeah just fyi i tried it after i saw the message this morning, if “someone” with the right tools and experience maybe…but not me! :stuck_out_tongue_winking_eye:

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1/2" ? Mine is 3/4". I. Got a brass barb.

3/4" to 3/4 barb


Why wouldn’t this work with the 3/4" MPT an 3/4" barb
3/4" FGH Swivel with 1/2" MPT Threads - Pressure Tek

Some good ingenuity though :grin:

I could have definitely found another way of adapting stuff. I had this style inlet filter on my pump:

But I wanted to ditch it because I already have two big Y-strainers in my setup. One before the buffer tank and one before the machine. So removing that left me with the 1/2" fpt on the pump.

I also didn’t want to reduce down from a 1" ID hose to 3/4". I wanted to run the 1" straight to the pump. If I ever upgrade machines, I want to make sure there are no restrictions in my setup to pull more gpm.

What you did is genius. I was just shocked that he inlet was 1/2". Usually it’s 3/4" for a regular hose connection, but I’m use to 4 GPM I’m assuming because it’s 5.5gpm it ls different

Anyway I’m almost postive the polypropylene hose I use to connect to my 3/4" barb is 1" ID. I use a clamp to tighten it snug. I could use 2 clamps if it was permanent connection , but it comes on an off at each job.

Thank you for that. I got a much different response when I posted this over on PWR. I’m beginning to think that prolonged exposure to bleach fumes causes a shift in personality. Either that, or the power washing profession just attracts a lot more jerks.

Either way, I’m going to be careful to keep our business at least 51% window cleaning. I don’t want to become a power washer that also does windows… :smirk:

I also had a 3/4" garden hose thread on my inlet. But it was all integrated with that strainer assembly. So off it came.

I’m betting that the actual inlet on your pump is 1/2" npt, as well, but there’s a 3/4" fgh adapter installed there.

If you’re only using 4gpm, my approach of using 1" supply line right to the pump is way overkill. It’s probably huge overkill for my 5.5 machine, as well. I mostly wanted to see if it could be done.

I’ll try and update everyone on how this holds up. I’ve been so crazy booked with window cleaning, I’ve had hardly any time to really work on this trailer. I need to learn how to pace myself a little better instead of cramming my schedule as full as possible :unamused:


Now thats funny! :laughing:

Please note: I’ve just been informed that plastic fittings on a pressure washing pump head are a bad idea. I’ve updated my original post with a warning.

Hey Alex…how’s the pressure washer working for you? I saw some where on the forum that you have a 5.5 2500psi unit. I think it’s the same one I’m thinking of getting.

That is correct. Still setting the whole thing up. I’ve had very little time between window cleaning jobs to work on it.

I’m looking forward to washing a lot of houses with it. I had been using a 3.5gpm rental machine before this. So that means I should be able to rinse about 60% faster, right? :wink:

Having my whole trailer setup correctly is going to be a huge time saver, as well.