Pressure washer question....

…seems off-topic, but I will use it occasionally to clean boats. I have a Karch (Karcher?) home model, and the manual insists I should use their detergents in it. I presume they’re just trying to sell product, but has any one here had experience with using other, cheaper detergents in home pressure washers other than the manufacturer’s brand? I suspect they all come from the same factory with different labels anyway.

I used all sorts of chemicals
thru my pressure sprayer with no problems.

Used Others and Homemade
When I had a Travel Trailer I used all sorts of “store bought” stuff, including vinyl siding cleaner from Lowe’s. Finally ended up mixing my own bleach and water compound (with a wee bit of dish soap) and it worked just as well - and costs pennies for gallon instead of dollars. Sill use the mixture today - home, boat, PU camper, car.

Stay safe on the water,


Don’t blast the gelcoat too hard or
direct … you might not like what happens … and it could. Many boats have small micro-pockets just behind the gelcoat and gelcoat can get blasted off.

I have used a water-vinigar mixture to clean stuff sometimes. Makes great window cleaner and I think I used it once in a carpet shampooing machine I rented. No guarantees but a thought.

Maybe borrow some one elses boat and try it out.


– Last Updated: Jan-07-06 9:43 PM EST –

I agree withy cal3san. For every gallon water, one cup bleach and about two drops of dishwashing detergent. Don't know about vinegar, but heck, if matmac says it works, dump some of that in there too. Mix and spray, and I have a Karcher 5 hp too. I use it on my pool cover, my cedar siding, and my kayaks. Watch the oil level in that baby; if it gets low at all the machine automatically shuts off. Once. The second time you say, "hmm. Wonder why she shut down?" and you start the engine again... boom. Freezes up. Like, permanently.

No No No
Do not add vinegar to anything with bleach. You will produce chlorine gas!!!

Any specific recommendations for…
…car & boatwashing? Would car detergent from the parts store work?

Don;t know, talgapin
When I wash my cars, I put car wash soap in bucket, scrub vehicle, and then spray off with pressure washer (well, mostly I just use the hose and the spray gun without pressure washer). Did I mention watching the oil level in the pressure washer carefully to prevent a total non-warrantied frozen engine? Oh, yeah, I did. Trust me, it is one of those sick to your stomach feelings when it happens. How do I know? Well, let’s just say I thought the thing came from Lowe’s full of motor oil.