Pressure washers - can you adjust the PSI?

[Autark]

I've been trying to figure out moss control for the roof. Had a roof guy quote me nearly 2k for their special wash treatment that was supposed to only be good for a year or two. I told him where he could stick that. That was in the winter, most of it is dried up now. Just have to get up there to treat it. I've been advised against everything, including sweeping and especially pressure washing. Going to try the zinc powder.

 

[ilikegunspdx]

I've been trying to figure out moss control for the roof. Had a roof guy quote me nearly 2k for their special wash treatment that was supposed to only be good for a year or two. I told him where he could stick that. That was in the winter, most of it is dried up now. Just have to get up there to treat it. I've been advised against everything, including sweeping and especially pressure washing. Going to try the zinc powder.

Baking soda or moss be ware works. I like baking soda. Costco sells in 13 lb bags. Just sprinkle it one when it's rainy season. Works excellent.

 

[MikeInOr]

For decks, cars and the house I prefer an electric pressure washer.

For washing concrete with a rotating head wand you really need the power of a gas powered pressure washer. I use my electric pressure washer 90% of the time.

When pressure washing it generally works a lot better to spray at a 45 degree angle to the surface. At an angle the water will lift and remove the dirt. At 90 degrees (perpendicular) to the surface the water will just be pushing the dirt into the surface and it will take a lot longer to get the job done with more surface damage.

 

[ilikegunspdx]

Wow. Did a test on a many decades old fence. It was literally falling down and held up with wire before I took it down. It would not accept new screws or nails in many places cuz too rotten.


I wet it down then sprayed on 1/2 cup oxyalic acid per gallon and let sit 30 min. Then pressure washed. No scrubbing.


This other test fence was built about 15 years ago and never cleaned. It was dirty and a pale light green color from algae but nowhere near as bad as the other fence. Same method.

Pressure washer I ended up with is this one. I figure I'll just baby the pump and keep it cool and see how long it lasts. I woudl have ended up buying the wand extension and turbo nozzle separately so I'm glad it came with those. Gonna change to redline or molygen oil after about 4 hours or so of break in.

https://www.costco.com/be-power-3400-psi-24-gpm-gas-pressure-washer.product.4000279100.html

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[teflon6string]

I have all the common colors of quick-connect tips with my fixed-pressure 3,000 psi Honda. 0°, 15°, 25°, 40° and 65°. I've not had much luck with swapping them out as they all seem to blast a very focused central stream and merely wet a wider swath depending on their respective numbers. There's no stopping halfway through a job, ever, because the target surface is either clean as a whistle or not.

Not to drift the thread, but it's somewhat relevant. I'm thrilled with the Nexan aluminum deck I had installed 5 years ago. It's waterproof, dry underneath (where I store my power washer) and requires minimal maintenance to keep it looking brand new. No stripping, sanding, re-staining or any of that time-consuming, labor-intensive silliness. One hour once a year with the power washer and I'm done.

Back to power washer pressure, I use the green 25° nozzle for everything and simply adjust my height above the surface that I'm blasting.

 

[Bacchus]

I finally went and bought an inexpensive washer. I used it on my patio and it did a great job of removing the accumulated dirt, but it also "spotted" the patio by lifting off some of the brick-colored stain that was applied about ten years ago. Now I have to find a more durable stain. I had power washed that patio a few years ago with a borrowed washer, with no problems.

Then I power washed my driveway and the new washer did a great job there also, except for a large oil stain. My driveway had a 2-foot diameter oil stain, about three weeks old, and the washer wouldn't budge the stain.

Next from YouTube videos I bought Goof Off Concrete Cleaner and Oil Stain Remover. There were several videos that tested multiple products and this did the best in those videos.

Also from one of the videos I skipped the first cleaner instructions where you mix it with water, and went to the heavy duty instructions where you cover the stain about 1/8 to 1/4 inch thick with undiluted cleaner. Maybe I should have tried the diluted instructions first, because I used a whole 32 oz bottle covering my stain. I let it set for most of a day, came back and brushed it off, hosed it off, let it dry.

This worked great! I can't tell where the stain was.

 

[ilikegunspdx]

I finally went and bought an inexpensive washer. I used it on my patio and it did a great job of removing the accumulated dirt, but it also "spotted" the patio by lifting off some of the brick-colored stain that was applied about ten years ago. Now I have to find a more durable stain. I had power washed that patio a few years ago with a borrowed washer, with no problems.

Then I power washed my driveway and the new washer did a great job there also, except for a large oil stain. My driveway had a 2-foot diameter oil stain, about three weeks old, and the washer wouldn't budge the stain.

Next from YouTube videos I bought Goof Off Concrete Cleaner and Oil Stain Remover. There were several videos that tested multiple products and this did the best in those videos.

Also from one of the videos I skipped the first cleaner instructions where you mix it with water, and went to the heavy duty instructions where you cover the stain about 1/8 to 1/4 inch thick with undiluted cleaner. Maybe I should have tried the diluted instructions first, because I used a whole 32 oz bottle covering my stain. I let it set for most of a day, came back and brushed it off, hosed it off, let it dry.

This worked great! I can't tell where the stain was.

Great info! I've got some of those oil spots to tackle also. Re stain I've just been using semi transparent concrete stain from Home Depot. Here's a shot from this mornings staining. This patio was laid down 13 years ago as one color. I stained individual pavers at that time. Most of the color has worn off and after pressure washing just traces of color remained. I should restain every 5 years instead of every 13! Foreground is not done yet I still need to do some grey stain.

 

[hongkong2]

I finally went and bought an inexpensive washer. I used it on my patio and it did a great job of removing the accumulated dirt, but it also "spotted" the patio by lifting off some of the brick-colored stain that was applied about ten years ago. Now I have to find a more durable stain. I had power washed that patio a few years ago with a borrowed washer, with no problems.

Then I power washed my driveway and the new washer did a great job there also, except for a large oil stain. My driveway had a 2-foot diameter oil stain, about three weeks old, and the washer wouldn't budge the stain.

Next from YouTube videos I bought Goof Off Concrete Cleaner and Oil Stain Remover. There were several videos that tested multiple products and this did the best in those videos.

Also from one of the videos I skipped the first cleaner instructions where you mix it with water, and went to the heavy duty instructions where you cover the stain about 1/8 to 1/4 inch thick with undiluted cleaner. Maybe I should have tried the diluted instructions first, because I used a whole 32 oz bottle covering my stain. I let it set for most of a day, came back and brushed it off, hosed it off, let it dry.

This worked great! I can't tell where the stain was.

I've had good results with removing oil stains from concrete by putting straight Dawn dish soap on them and letting it sit for a few hours then pressure washing.

 

[Bacchus]

I've had good results with removing oil stains from concrete by putting straight Dawn dish soap on them and letting it sit for a few hours then pressure washing.

That definitely sounds cheaper! Maybe I'll try that, but I hate working on my driveway so much that I am reluctant to invest time trying something new once I've found somewhat works. This doesn't seem like too big a time investment, since I have to set up the washer anyway, but I might forget by the time I get around to power washing again. Good tip!

 

[Bacchus]

Great info! I've got some of those oil spots to tackle also. Re stain I've just been using semi transparent concrete stain from Home Depot. Here's a shot from this mornings staining. This patio was laid down 13 years ago as one color. I stained individual pavers at that time. Most of the color has worn off and after pressure washing just traces of color remained. I should restain every 5 years instead of every 13! Foreground is not done yet I still need to do some grey stain.
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Whaddaya mean, "semi transparent concrete stain"? I have some brick red brick-type pavers expanding the perimeter of the patio, and the original idea was to stain the patio to match the color of the brick-red pavers. Are these "transparent" stains available in solid colors (e.g., brick red) ? I can go to Home Depot and look for myself, but if you know the answer off the top of your head that might save me a trip. Thanks.

BTW, your patio looks way nicer!

 

[Bacchus]

I guess I should also try using a less aggressive washer nozzle, as suggested by some folks here.

 

[ilikegunspdx]

Whaddaya mean, "semi transparent concrete stain"? I have some brick red brick-type pavers expanding the perimeter of the patio, and the original idea was to stain the patio to match the color of the brick-red pavers. Are these "transparent" stains available in solid colors (e.g., brick red) ? I can go to Home Depot and look for myself, but if you know the answer off the top of your head that might save me a trip. Thanks.

BTW, your patio looks way nicer!

They make solid color stains and semi transparent stains. The semi transparent are sort of a milder coloring and I believe the solid is more like a paint look (just guessing). I've never tried the solid color so perhaps check YouTube reviews on that first. Behr brand. They have standard colors including red but I think they can also mix up any color (have to ask them but I think that's what I did for the charcoal color- I can't recall for sure). The semitransparent soaks into the pavers. No prep at all as long as it's clean.

 

[Bacchus]

The stain I washed on my driveway was a brown oil stain from a spill of less than three weeks ago. Today I tried washing the garage oil stains, using the new power washer and Goof Off, and it did a good job on the recent oil spill in the garage but not the nickel-sized black spots that have been in my garage for more than a year.

I'm trying the Goof Off on the black spots again, with a heavier coverage. If that doesn't work I'll try the Dawn and if that doesn't work I think I saw a "Pro" version of the Goof Off somewhere.

 

[ilikegunspdx]

The stain I washed on my driveway was a brown oil stain from a spill of less than three weeks ago. Today I tried washing the garage oil stains, using the new power washer and Goof Off, and it did a good job on the recent oil spill in the garage but not the nickel-sized black spots that have been in my garage for more than a year.

I'm trying the Goof Off on the black spots again, with a heavier coverage. If that doesn't work I'll try the Dawn and if that doesn't work I think I saw a "Pro" version of the Goof Off somewhere.

I've been researching this a bit and xylene plus brake cleaner seems to work. Also baking soda plus acetone and cover with plastic and let it sit all day. My issue is I don't want to use anything I have to rinse cu I don't want it to move to the freshly cleaned pavers. I haven't tried either of these methods yet. Oh yea also one guy squirted toilet bowl cleaner and let sit 3 hours and rinses off. That seemed to work good also. Just some info from what I researched fyi, not personal experience.

If I had any of that oil dry powder stuff I woudl soak that in acetone and cover it to suck the oil out. I have diatomaceous earth maybe I'll try that with acetone. If I recall the oil dry is caliche or diatomaceous earth, I can't remember. Or it could be just some absorbent clay. Now that I think of it I bet kitty litter plus acetone plus cover woudl work awesome. I'll try that.

 

[Bacchus]

One of the videos I watched included a test of cheap kitty litter, with its clay composition. It didn't work well for the established stains, but I think that is probably a great product to soak up fresh oil.

 

[ilikegunspdx]

One of the videos I watched included a test of cheap kitty litter, with its clay composition. It didn't work well for the established stains, but I think that is probably a great product to soak up fresh oil.

Agree I'm using it only to pull up the acetone (and the oil with it). In theory sawdust, oil dry, baking soda, diatomaceous earth should all work. I'm gonna test the kitty litter but if it is too coarse to pull much up then I'll try baking soda. Test is fermenting now ha ha. I know acetone will move even old oil stains, it just has to have somewhere to move to. Also it evaporates fast, thus the plastic cover (garbage bag). We'll see tomorrow how it does.

 

[ilikegunspdx]

FYI acetone plus kitty litter plus cover with plastic for a day works good. Probably a 6 out of 10.

Acetone plus baking soda + cover for a day works really, really good. Probably 8.5 out of 10.

Baking soda can be reused up to a point where it is too saturated to pull more acetone.

I tried the toilet cleaner and leave for 3 hours then pressure wash and I would give that a 1 out if 10.

I might also try a spot of brake cleaner plus baking soda plus cover for a day to see if that works better than acetone. Acetone is cheap though vs brake cleaner.