Power Washer

[JimJa]

The thread concerning the use of a power washer against wheel well trim brought to mind some comments about power washers in general. Please allow the following.

A family friend invented the power washer concept in the early '50s. I've been using them since my father was a test business since then. The company was called Britt Tech and located in the small community of Britt, Iowa. The inventor has passed away, the company has been sold (adsorbed) by a larger company and is no longer around. Here's the best advice I can provide based on year's of experience and information from engineers in the former company.

- Best cleaning pressure is 670 PSI. The 1,000, 2,000, 3,000 PSI is purely a marketing sales pitch. High pressure does have use however, under fender cleaning, the deck on your home and so on, but not for auto finish.
- Water volume goes hand in hand with pressure. The higher the water volume, the better cleaning. 4 gallon/min is excellent. Unfortunately, higher volume costs more,
- Cheaper units advertise high pressure but volume is typically limited to around 2 gallons/min.
- Cheaper units also use "wobble" pumps. These are fine for the casual use, but the better pumps are piston pumps with ceramic cylinder liners. I have two units both with Cat piston pumps. I've been using these units for 25 years with out pump leakage or failure.
- The very best units heat water but these typically have a starting price around $3K.
- The tip at the end of the wand is pretty much standard and not an issue for any brand.
- A 50' hose is almost a requirement. Cheaper units are 25' and you will find that is just a little too short for most uses.
- Soap is another issue and I have the very last of Britt Tech brand soap and have no experience with today's soap, which is normally liquid.

I currently have two machines, one gas and one electric.. I like the gas unit better. I have no connection with the company I purchased my gas unit from but they have a nice selection of various units; at various price levels and that company is Northern Tool in MN. Northern Tool is a nice starting point just to see what is out there. Good luck to all.

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[Allfor]

This is awesome! I read the same post and thought to myself "I've been wanting to get one of those" and then your post was right below it! Screenshotted for later reference, thanks!

 

[JimJa]

Most all units use a low-pressure soap application. This is turned on/off by a short in/out movement of the wand. This induces soap flow by changing the pressure near a soap supply orifice. This has a name, but my physics of years ago escapes me - Bernoulli's Principle (?).

I installed a diaphragm on the low pressure side (inlet) of the pump and once adjusted provides soap to the incoming water using an adjustable on/off valve in the soap line. This allows soap to be applied at high pressure. 40:1 is the normal soap to water ratio. Unlike typical machines, the soap mixture then goes through the pump and is applied at pump pressure enhancing cleaning action. The addition of soap increases abrasion within the pump and cheaper units, without ceramic piston liners will wear faster than those with. This is not normally a problem for the casual user.

My biggest complaint about machines today is the lack of a soap container attached to the power washer itself, forcing the user to haul around two containers.

Soap/water cleaning solution should be applied using 40-45 degree wand tip and at approximately a 45 degree angle to the cleaning surface. The soap solution then acts like a cutting edge between the dirt and the finish of what is being cleaned, providing the best possible cleaning.

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