Mobile Power Pressure Wash Procedures & Chemical Usage Guide

Rahsco Cleaning Systems
2513 Warfield Street, Fort Worth, Texas 76106-7554
Phone: 800-433-2113, 817-625-4213; Fax: 817-625-2059
email: rahsco@dcs1.com, URL: http://www.dcs1.com

Washing Techniques:

  • Always fog or presoak items being washed with detergent, degreaser, or chemical presoak. Presoaking will reduce your wash time and cut your chemical cost. It is just like washing your dishes, heat, soaking (dwell time), and detergent all make the job easier. Commercial contractors generally use 4 to 6 GPM at 1500 to 3,500 PSI for most cleaning applications except for wood cleaning where 500 to 2,000 PSI is used with chemical cleaning to reduce the furring of the wood. Water flow rates of less than 4 gallons per minute are generally considered as consumer (home owner) flow rates and not high enough to be competitive with. In other words the increased time of cleaning will make you non-competitive because of increased labor cost.
  • Hot Water is a better solvent than cold water. Remember that clothes and dishes come cleaner faster and easier if they are presoaked and washed in hot water! The same is true in High Pressure Washing.
  • Always rinse detergent off before it dries.
  • Chemical Dilution is largely a matter of personal preference. For most Mobile Power Washing Chemical Cost will be between 3% to 5% of Gross Sales, Labor Cost will be 30% to 45% of Gross Sales, and Fuel for heat will be 2% to 4% of Gross Sales. Soap and Heat are cheaper than Labor! i.e. A slight increase in chemical and fuel heat cost will reduce your labor cost. Generally saving on chemical and fuel for heat are less than your increase your labor expense because of minimal heat and chemicals.
  • Washers with chemical injection before the pump start out with the metering valve open 1/4 turn. Then adjust as needed.
  • W-200 Spray Wax is similar to spray wax that you are familiar with in Coin-op Car Washes. Wax should be applied hot and followed by a cold rinse on fine surfaces like cars and pickups. On heavier surfaces like like homes and trailers the cold rinse is not necessary. The application of wax will extend the life of your wash job, make subsequent cleaning easier, and enhance appearance. Note: Because the application of wax will extend the life of your wash job some contractors choose not to use wax because they prefer to wash more often. The use of wax may reduce your income because of the extended life of your cleaning while other contractors use wax because of the enhance appearance and extended life of the cleaning!
  • For Fleet Washing, Wax in the rinse water will reduce dirt adhesion and reduce subsequent washing time. In heavy concentration will reduce cement adhesion on Concrete Trucks.
  • Using the techniques described in this report brushing will only be required about 5% of the time. Contractors typically will only brush in the spring or the fall, or only as needed. If the brushing is done one or twice per year at a specified time then extra help can be scheduled for those times only (like High School Students for brushing).
  • For Environmental Power Washing Techniques read Report 507.
  • Nozzle Selection:

    There are two selections that need to be made in choosing the proper nozzle: the nozzle orifice size and the spray angle. This is normally expressed at 25055 or 2505 where the first two digits are the spray angle and the last 2 or 5 digits is the nozzle size. The Spray Angle obviously the angle of the spray width and the nozzle size determines the gallons per minute at a particular pressure that a nozzle will pass. Therefore in order to determine a nozzle size you need to know the GPM (gallons per minute) and PSI (pounds per square). To make this determination it is necessary to look up the information in a nozzle chart like on page 8 of "The Rahsco Wats Blaster".

    By increasing the size you will reduce the PSI of your pressure washer and the flow will remain the same. If you reduce the pressure of your washer with the unloader you will decrease both the PSI and GPM. Knowledgeable contractors reduce the PSI of their pressure washers by increasing nozzle size in order to keep the GPM at its maximum. To make this determination it is necessary to look up the information in a nozzle chart like on page 8 of "The Rahsco Wats Blaster".

    Choices for spray angle are 0, 15, 25, 40, and 65 degrees. 25 degrees fits the natural wash pattern of most contract cleaners. However, some contract cleaners prefer a 40 degree spray angle because they can hold the nozzle closer to the surface and obtain the same width of contact. The advantage of this is that greater impact pressure and higher temperature is delivered to the surface because the nozzle is closer to the point of contact. However, you have to learn to keep the nozzle equal distance from the surface, its like using a broom.

    A zero degree nozzle concentrates all of the cleaning power in a very small area with a high degree of cleaning power at the center of impact. This causes streaking similar to chicken tracks. Sometime you can see the entire track of your wand wash pattern. The zero degree rotating nozzles like the ST-58 or Rotomax solve this problem. They have the power of a zero degree nozzle and the coverage of a fan nozzle and when used properly do not leave wand marks (tracers).
  • PSI (Pounds per Square Inch):

    The Pressure that contractors use varies a great deal. With a fan nozzle there is almost no pressure (cleaning power) greater than 3 feet from the nozzle. The pressure and temperature drop rapidly with the distance from the nozzle. You can test this by placing placing your hand in a fan spray 3 feet from the nozzle then slowly moving your hand toward the nozzle. As a result of this rapid drop off in cleaning power a lot of contract cleaners will use 3,000 to 3,500 PSI to wash things that cannot stand that sort of pressure. They do this by varying the distance of the nozzle from the surface being washed. For less pressure they hold the nozzle back (increase distance from the surface being cleaned), and for increased pressure they hold the nozzle closer. Most larger contract cleaners will have washers that produce 4 to 6 GPM at 3,000 PSI, with 200 F. This much power is really needed for concrete cleaning while 1,500 to 2,000 is satisfactory for washing of vehicles. Heat has a great advantage where grease and oil are concerned. A few Vent-a-hood cleaners will use 310 F steam but these are mostly operators over 50 years old who learned to do Vents when that was the only thing available. Younger Vent Cleaners (under 50 years old) will generally use 3,000 PSI 200 F units. However, some vent cleaners use electric 1,000 PSI cold water washers hooked up to hot water (they hand scrape more). At the present time 3,000 PSI units are sort of the standard of the Contract Cleaner Market. A big reason for this is that there is not much price difference between 2,000 PSI and 3,000 PSI washers and there is a big difference in cleaning power.

    The PSI for decks (wood) varies from 200 to 3,000 PSI. Too much pressure will cause the wood to fur. If this happens you will need to sand with fine sand paper or steel wool to knock off the furred surface. A lot of Deck Cleaners use a variable pressure wand (like the ST-54 36" Double Lance Wand) so that they can adjust the pressure as necessary. Using low pressure and letting the chemical (like Rahsco's DSR-49 Deck & Siding Restorer or DSR-50 Deck & Siding Restorer plus Stripper) do the work will avoid furring the deck. Hint: use the under side of the deck to test the PSI. For more information go to http://www.dcs1.com/del/deck.html
  • Wet Sandblasting:

    A Wet Sandblasting attachment to a 4 GPM at 3,000 PSI pressure washer will use about 50 pounds of sand every 20 minutes of continuous usage. Also it is only about one half as effective as a commercial air sand blasting unit. That makes the market for wet sand blasting only for small jobs where the Pressure Wash Contract Cleaner is already at and environmental jobs where wet sand blasting is required. Also wet sandblasting is done on some Building Restoration jobs in area where chemical cleaning does not work.
  • Soda Blasting:

    Baking Soda Blasting is done as an Environmentally Friendly type of sand blasting not requiring any clean up because of the media being used. Also is a milder type of blasting where paint for example can be removed from a coke can without hurting the can. There are several Industrial Applications of this technology. Monument and statue cleaning is a common use of this technology.
  • Painting after Paint Stripping:

    Most coatings need to be applied to a neutral surface. Most Paint Strippers are high in Ph therefore the surface needs to be neutralized before a coating is applied. This will require you to apply an acid which is low in Ph. You will need Ph paper to tell you where the Ph is. Oxalic acid, phosphoric, and aluminum brighteners are commonly used for this.

    For concrete, masonry, and used equipment A-400 Aluminum Brightener Etching, followed by Washing with R-109 to neutralized the A-400, then clear water rinsing has successfully been us as a paint prep.
  • Stain Removal:

    Stains are difficult and there is not one product that will do all stains. The source of the stain, how long it has been there, and what surface is all effect what it will take to remove the stain. For concrete or masonry surfaces start out with Aluminum Brightener, like A-400 or A-40X. Also Scale Away De-liming Acid Coil Cleaner is a good stain remover.

    For stains on painted surfaces try DNB-1430 undiluted (caution: undiluted DNB-1430 can remove some paints) then A-400 or A-402 Aluminum Brightener. 
  • Cleaning Copper Trim:

    About any over the counter toilet bowl cleaner cleaner will restore copper trim.
  • Spider Webs

    Nothing will dissolve spider webs without also dissolving paint and wood Etc. D-limonene based cleaners and ammonia work fairly well but may streak the the paint, test before using. 15 degree and zero degree nozzles (like the X-jet) work good for removing spider webs with your pressure washer. Also Grocery Stores and Janitorial Supply Stores sell "Spider Web Brooms" for removing spider webs. And fabric softener towels will drive the spiders away, so if possible leave fabric softener towels scattered around.
  • MATERIAL SAFETY DATA SHEETS for the above chemicals can be found at http://www.dcs1.com/msds/

Mixing Instructions:

Mix all powders 1/2 pound (8 oz.) per gallon of water to make a liquid concentrate. Mix W-200 Spray Wax 2 cups of wax to 5 gallons of water to make a liquid concentrate. Mix DNB-1430 Mix Kit in 55 gallon of water to make a liquid concentrate.

Chemical Selection Guide:

  • Car Washing:

    Cut R-109 Liquid Concentrate 100 to 1. For a wax like sheen cut R-111 Concentrate 100 to 1. (Note: R-111 is also an excellent hand wash detergent)
  • Pickup, and Van Washing:

    Cut R-109 Liquid Concentrate 75 to 1. For a wax like sheen cut R-111 Concentrate 75 to 1. (Note: R-111 is also an excellent hand wash detergent)
  • Tractor/Trailer Washing:

    Cut R-109 Liquid Concentrate 50 to 1. For very dirty rigs boost with 1/3 R-202 or use DNB-1430 presoak cut 5 to 1. Some fleets clean up very well just presoaking with DNB-1430 then followed by a hot water rinse.
  • Heavy Equipment Washing:

    Cut R-109 Liquid Concentrate 40 to 1. For very dirty rigs boost with 1/3 R-202 or use DNB-1430 presoak cut 5 to 1. Or use DNB-1430 cut 40 to 1 as the detergent.
  • Engine Steam Cleaning:

    Cut R-109 Liquid Concentrate 30 to 1. Presoak with a liquid Concentrate cut 5 to 1 of: R-109, DNB-1430, or V-500.
  • Aircraft Washing:

    Cut R-109 Liquid Concentrate 50 to 1. Scrub heavy carbon exhaust areas with DNB-1430 cut 30 to 1.
  • Building Fire Damage Washing:

    Prespray a Liquid Concentrate of R-109, V-500, or DNB-1430 cut 10 to 1. Wash with a Liquid Concentrate of R-109 or DNB-1430 cut 40 to 1. You will be able to kill the smell and remove the smoke but you will not be able to remove the char from the brick, masonry, or wood. In a normal fire clean up after you remove the smoke everything close to the heat source will be charred and your will be able to see the heat gradient in the walls and flooring.
  • House Washing:

    Cut R-109 or DNB-1430 Liquid Concentrates 50 to 1. To kill mold and mildew add 1/4 bleach to your liquid concentrate. (Note: There is a lot of controversy about using bleach to kill mold and mildew, however approximately 50% of the Contract Cleaners use bleach because of availability, price, and effectiveness). Another method of using bleach is not to use it as a cleaner but only to retard the growth of mold and mildew and the residual effects ends as soon as you rinse. A ratio of 1 to 8 works well. This is something that the home owner can also do to extend the life of your cleaning job.

    To remove black spots and black streaks from gutters and siding cut DNB-1430 (5 to 1) to undiluted. Caution: Undulated DNB-1430 can remove some paints and coatings. Be sure and test a hidden area to determine the strength required to remove the spotting without removing the paint.

    Adding wax to your rinse water will extend the life of your wash job and enhance the appearance. See notes of W-200 Wax above.
  • Boats and Ship Washing:

    Cut R-109 or DNB-1430 40 to 1. For mossy areas pre-spray A-400 Aluminum Brightener cut 20 to 1.
  • Aluminum Siding Washing:

    Cut R-109 or DNB-1430 50 to 1. Some Contractors pre-spray with DNB-1430 cut 10 to 1 and follow with a hot wax rinse. The wax reduces the amount of cleaning needed and makes the next cleaning easier. The cost of the wax is about 20 cents.
  • Vent-A-Hoods--Non-Oriental Restaurants-- Washing:

    Pre-spray with V-501 Liquid Concentrate cut 5 to 1 on heavy build ups, the wash with V-501 Liquid Concentrate cut 40 to 1. Caution: V-501 may etch some Aluminum Hoods if contact time is too long.

    Heavy Carbon Deposits pre-spray with OD-100 cut 10 to 1. Wash with V-500 cut 10 to 1.
  • Vent-A-Hoods--Oriental Restaurants--Washings:

    Pre-spray with OD-100 cut 10 to 1. Wash with V-502 cut 20 to 1.
  • Asphalt Road Washing :

    Cut R-109 or DNB-1430 Liquid Concentrate 40 to 1. Pre-spray oil spots with R-109 or DNB-1430 cut 5 to 1. Caution: Asphalt is a petroleum based product and high concentrations of R-109 and DNB-1430 can cut the asphalt. In order to cut the oil and grease and not the asphalt you have to have the proper strength and the correct time. This takes a little practice to achieve the desired results.
  • Concrete Washing:

    Wash with R-109 or DNB-1430 Liquid Concentrate cut 40 to 1. Pre-spray with R-109, DNB-1430, or R-202 Liquid Concentrate cut 10 to 1.

    Note: Some contractors like to sprinkle R-202 dry powder on the concrete then fog lightly with water, brush, then High Pressure Hot Water Rinse.

    Another technique is to boost the power of R-109 with 1/3 R-202 in difficult cleaning situations.

    see asphalt and tire removal below
  • Asphalt and Tar Removal:

    Prespray with R-103LX mixed 10 to 1 with diesel fuel. Soak time may be from 2 to 12 hours depending on the thickness of the Asphalt or Tar. Dwell time during the heat of the day in direct sunlight also helps. Wash with DNB-1430 or R-109 Liquid Concentrate cut (10 to 20) to 1.
  • Aluminum Trailer Brightening:

    Cut A-400 20 to 1. Apply from the bottom up then wash with R-109 or DNB-1430 Cut 40 to 1 from the top down (the detergent neutralized the acid in A-400). Rinse with clean water.

    Repaired Trailers (with welding) use A-40X to remove the black welding marks. Cut A-40X from (10 to 20) to 1 depending of the age and amount of welding to be removed. Several applications can help blend in old aluminum with new aluminum.
  • Graffiti Removal:

    Apply DR-2100 paint remover. (Coverage: 100 SqFt/gallon for brushing and 200 SqFt/gallon spraying). Wash with R-109 or DNB-1430 cut 40 to 1.

    For High Graffiti areas apply Graffiti Guard to a clean surface at 400 SqFt/gallon. This forms a wax like barrier to keep the paint from penetrating the surface and can be washed off with hot water and detergent the next time graffiti is applied to the surface.
  • High Pressure Wax Rinse:

    Cut W-200 Liquid Concentrate 75 to 1. It is best to apply hot and follow by a cold rinse on fine surfaces like cars and pickups for an even application and spotting reduction. On heavier surfaces like homes, and trailers the cold rinse is not necessary. This will reduce dirt adhesion, enhance appearance, and extend the life of your wash job.

    Cut W-200 Liquid Concentrate 20 to 1 to reduce surface adhesion on Ready Mix Concrete Trucks and Heavy Equipment.
  • Carbon Deposits (smoke) from Engine Exhaust:

    Pre-spray with V-500, DNB-1430 Liquid Concentrate cut 5 to 1. Then wash with R-109, DNB-1430, or V-500.

    Alternative method is to pre-spray A-400 Aluminum Brightener cut 20 to 1 then wash with R-109 or DNB-1430.

    Brushing also helps on heavy carbon deposits and smoke.
  • To Stop Spotting:

    Try the following procedures in this order, the least expensive is first.

    1. Add W-200 Spray to your rinse. See Wax techniques above.
    2. Add RA-130 to your rinse water. Cut RA-130 Liquid Concentrate 50 to 1.
    3. Add a water softener.
    4. Add de-ionized or RO Water Rinse. Call Culligan to see which option is least expensive in your area. This always works but can be expensive.
  • Masonry Cleaning:

    Masonry Cleaning is a hunt and peck type of work. One chemical or procedure does not do all jobs. Testing is required on all jobs and it is not unusual for each side of the building to require a different technique. To start with testing should be done with and without heat, with and without detergent (R-109, DNB-1430, V-500, or R-202), and Rotating Zero Degree Nozzles (Rotomax or ST-58). With Environmental Concerns a lot of Contractors changing to cold water and Rotating Zero Degree Nozzles so that the runoff can go down into the storm drain.

    If none of the above work try Aluminum Brightener as the next step. Cut A-400 40 to 1. Caution: A-400 can etch glass and some architectural aluminums.

    If the above does not work you will have to do sand blasting, soda blasting, or use Restoration Chemicals. For Restoration Chemicals we recommend Diedrich Products, Phone: 800-323-3565, Fax: 414-764-6993
  • New Masonry

    The bricklayers have a lot of control over whether this type of job can be profitable or not. Sloppy work by the masons can greatly increase the cost of doing this type of work. The most common acid used by bricklayers is muriatic acid. Muriatic Acid is a harsh acid that will react with the oxides in some brick and turn the brick a different color. A test with muriatic acid should be done allowing the acid to dry for 24 hours then inspecting for discoloration. SureKlean and Diedrich Chemicals have commercial acid cleaners with buffers in them to avoid this problem.

    The basic procedure is to remove all the heavy build up of mortar with a scraper or chipping hammer. Then wet the surface just before applying the acid. This keeps the acid on the surface. The work needs to be done while the mortar is still green (fresh). The longer the mortar cures the harder it is to remove. The acid will only remove a thin layer (scum) of mortar. After applying the acid use your high pressure washer for cleaning. Most contractors use 2,000 to 3,500 PSI. Zero degree rotating nozzles like the RotoMax, and ST-457 will add greatly to your cleaning ability. Care must be taken to avoid blowing out the joints.

    The acid is normally applied with special acid sprayers or special acid brushes like Tampico brushes.
  • Paint Stripping:

    Chemical Coverage: Normally paint strippers will cover 100 SqFt/gal when brushing or 200 SqFt/gal. when spraying. When using airless spraying equipment you will need units with Stainless Steel Pick up parts and Teflon Packing.

    For Paint Stripping Buildings the time is usually one hour per layer of paint. There are a lot of environmental disposal problems with paint including whether or not it contains lead. For more information call Diedrich Products, Phone: 800-323-3565, Fax: 414-764-6993.

    For Truck, Pickups, Cars, and Heavy Equipment Paint Stripping use DR-2100 Trailer Decal and Truck Paint Remover.
  • Trailer Decal Removal:

    Use DR-2100 Trailer Decal and Truck Paint Remover. Most decals are on Aluminum or Stainless Steel Tanks. The DR-2100 Decal Remover will not effect most Aluminums or Stainless Steels, but testing is required. With skill a decal can be removed from a painted surface by just applying DR-2100 to the surface of the decal.
  • Fabric Awning Cleaning:

    Use AC-12 Awning Cleaner cut 5 to 1.
  • Vinyl Awning Cleaning:

    Use AC-22 Awing Cleaner cut 10 to 1.

Last Update: September 25, 2009

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