The Complete Bilt Hamber Guide
Every Bilt Hamber dilution in millilitres, Panel Impact Ratio explained in plain English, and a calculator that does the maths for you.
Bilt Hamber make some of the best chemistry in car care, and some of the most confusing instructions. Percentages, "1 part in 100", "PIR at the panel, not in the bottle". This guide turns every Bilt Hamber figure we could find into millilitres you can actually pour.
Every number on this page is Bilt Hamber's own, taken from their product pages, technical data sheets and published FAQs. Where Bilt Hamber give two different figures for the same job, we show you both and say where each one comes from. Where they give no figure, we give none. For what each product is and what its safety data sheet declares, see our Bilt Hamber product guide.
A percentage is millilitres per litre, times ten. 1% is 10 ml, 2% is 20 ml, 4% is 40 ml, in every litre of finished mix. Product in first, then water to the line.
Bilt Hamber's "1:100" means 1 part in 100. That is 1%, or 10 ml per litre. Not 1 part to 100 parts of water.
PIR is the strength that lands on the car. In a foam lance, your pressure washer dilutes the bottle again, so the bottle must be much stronger than the target.
One five-minute bucket test fixes it for good. Discharge a litre of water through your lance, measure what comes out, multiply. Bilt Hamber's own method, step by step below.
Everything else is simple. Korrosol, Auto-Wheel, Trace-Less, Cleanser-Fluid and Ferrosol are used neat. Auto-Wash is one teaspoon in a 10 litre bucket.
Two kinds of dilution, and why Bilt Hamber confuse people
Most brands give you one number: how much goes in the bottle. Bilt Hamber often give you a different kind of number: how strong the liquid should be when it reaches the paint. They call that the Panel Impact Ratio, or PIR. In Bilt Hamber's own words for Auto-Foam, the strength "is needed at the panel not in the detergent bottle or reservoir".
When you mix in a bucket, trigger bottle or pump sprayer, the two are the same thing. Nothing dilutes your mix after you make it, so 2% in the bottle is 2% on the car. That is just millilitres per litre:
When you use a foam lance on a pressure washer, they are not the same. The lance draws your bottle mix into a much bigger stream of water from the machine, and every machine draws differently. Put 40 ml of Auto-Foam in a litre bottle and it might land on the car at a fraction of 1%. That is why people say Bilt Hamber "doesn't work" in their cannon: the product is fine, the dose at the panel is far too low.
Bilt Hamber use the term for Touch-Less (0.5–2%) and Auto-Foam (1–5%, typically 4%). They use the same "at the panel" idea, without the name, for Surfex-HD as a pressure-washer shampoo (4% "onto the surface") and Atom-Mac ("2% Atom-Mac strength from the pressure washer nozzle").
The bucket test: Bilt Hamber's own method
You only do this once for your machine and lance. It tells you how many litres of water your lance pushes out for every litre in the bottle, and from then on the maths is one multiplication.
Fill. Put exactly one litre of plain water in the lance bottle. Set the lance to its usual setting.
Discharge. Spray into a large bucket or tub until the bottle is empty.
Measure. Measure the water you collected, in millilitres. A kilogram of water is a litre, so bathroom scales work.
Multiply. Multiply by the strength you want: × 0.04 for 4% (Auto-Foam, Surfex-HD), × 0.02 for 2% (Touch-Less on a dirty car, Atom-Mac), × 0.005 for 0.5% (Touch-Less maintenance). That is how much product goes in the bottle. Top up to one litre with water.
Worked example. Your lance empties its litre into 15 litres of water. For Auto-Foam at 4%: 15,000 × 0.04 = 600 ml of Auto-Foam, topped up to 1 litre. For Touch-Less at 2%: 15,000 × 0.02 = 300 ml. For a light maintenance wash at 0.5%: 75 ml.
What if the answer is more than a litre? Bilt Hamber cover this. Some machines don't draw from the bottle fast enough to reach 4% even with neat product. Their advice: fill the bottle with neat Auto-Foam and see what results you get, because it "can clean reasonably well at rates as low as 1-2%". Or apply it with a garden pump sprayer at 4% (40 ml per litre), since the bubbles don't do the cleaning, and pressure-wash it off with plain water.
For Touch-Less we have already done the maths for the common Kärcher, bigboi and studio machines in our Touch-Less dosing chart and calculator.
CalculatorWork out any Bilt Hamber dose
Ranges (1–2%, 5–10%, 2–5%) are worked at the middle of Bilt Hamber's range. Start there and adjust within it.
The full Bilt Hamber range, in millilitres
Grouped the way you use them. The figure on the right is the amount of product. Where it is a percentage, it is per litre of finished mix: product in first, then water to the line.
Apply to cool panels in the shade, soak 1–5 minutes, never let it dry. Bilt Hamber say a litre of diluted product should last 4–5 washes. In a pump sprayer nothing dilutes the mix further, so the bottle strength is the PIR.
Use on a cool surface. At 4% Bilt Hamber say it typically dwells for five minutes. "Auto-Foam is alkaline, but importantly it is non-caustic." From a pump sprayer, don't expect foam; Bilt Hamber advise pressure-washing it off.
Teaspoon in the bucket first, then up to 10 litres of fast-flowing warm water. Bilt Hamber put it at up to 100 washes from 500 ml.
Car cool and out of direct sun, pre-washed with Touch-Less. Rinse immediately after the lance; it is not a high-foaming bucket wash. Bilt Hamber prefer demineralised or deionised water in the trigger, and the car must not air-dry or it may water-spot. Dry with microfibre or a blower.
Shake the bottle for 10 seconds, then shake your dilution vigorously for 20 seconds. Panels no hotter than 50 °C. The weaker mixes must not dry on the car. Bilt Hamber say it cannot be used on soft furnishings.
Use on cool surfaces. Saturate greasy surfaces and leave one to five minutes, then rinse. Always spot test first.
Cool surfaces only, test a small hidden area first (for wheels, the rear face). Korrosol turns from clear to deep purple and works faster when warm. Keep both off chrome-effect plastics and films. Bilt Hamber suggest Korrosol every six to twelve months.
Must never be used dry. Bilt Hamber put one bar at about four or five cleans on an average-sized car. If you want a lubricant, Phat-Neut at 1–2% is Bilt Hamber's own.
Cleanser-Fluid goes on cool panels only and should be followed straight away by wax or sealant. Re-View is not for aftermarket or plastic tinted film or textured glass; mist with water if machine polishing.
Bilt Hamber put a 250 ml tin of Double Speed-Wax at up to 50 applications. If Hydra-Wax has gone solid, stand the bottle in about three inches of hot water for five to ten minutes. The Finis-Wax guarantee applies only when it goes on after Cleanser-Fluid.
Bilt Hamber say 5% or 10% "are very effective even for heavy corrosion", and the best concentration is 5%. Results are slow around 10 °C. Plastic or stainless vessels only, and never immerse zinc, lead or tin. The bath is spent when it turns very dark yellow or black.
Bilt Hamber say two applications are normally enough.
Dilute in deionised or distilled water, not tap water. From a pressure washer, aim for 2% at the nozzle: the bucket test × 0.02.
Warm Dynax S50 in a room at about 15 °C for 24 hours before use, and leave cavities unclosed for 48 hours. Dynax UC can be driven after 30 minutes and reaches final firmness in 24–96 hours. On tar, Ferrosol is left 10–20 seconds; on seized fasteners, a few minutes.
Where Bilt Hamber give two figures
Bilt Hamber publish a lot, across product pages, data sheets and FAQs, and in a few places the numbers don't quite agree. None of these differences is big enough to hurt a car, but if you have read one figure and we print another, this is why.
Surfex-HD, light work. The product page says it stays active at "1 part to 200" (0.5%). The how-to-use tab and the data sheet say 1 part in 100 (1%). For upholstery and carpets their FAQs say 1–2%, which is what we print.
Surfex-HD, brake callipers. One Bilt Hamber FAQ says the best dilution is 10%, another says 10–20%. Start at 10%.
Auto-Wheel, reaction time. The product page says normally 3–5 minutes; the data sheet and FAQ say 1–5. Either way, rinse once the colour change has happened and before it dries.
Five rules that matter more than the number
Cool panels, nothing dries. Almost every Bilt Hamber instruction starts with a cool surface out of direct sun. Pre-washes, Touch-On and the weaker Phat-Neut mixes must never dry on the car.
Calibrate the lance once. The bucket test is the difference between Touch-Less and Auto-Foam working and not working. Do it once and write the number on the machine.
Use the right water. Atom-Mac goes in deionised or distilled water. Touch-On in a trigger prefers demineralised or deionised water. Auto-Wash wants fast-flowing warm water.
Shake. Phat-Neut is shaken in the bottle for 10 seconds and again for 20 seconds once diluted. Touch-On and Trace-Less are shaken before use too.
Neat means neat. Korrosol, Auto-Wheel, Trace-Less, Cleanser-Fluid and Ferrosol come ready to use. Don't water them down.
Bilt Hamber's own Dynax test
The full Bilt Hamber range, used in our studio
Every product on this page is in stock in Heidelberg West, Melbourne, and ships Australia-wide. Free shipping over A$95 (A$200 for WA, TAS and NT). Stuck on a dose? Ask us, or walk in and we'll calibrate it with you.
What does PIR mean on Bilt Hamber products?
PIR is Panel Impact Ratio: the strength of the product in the liquid that actually lands on the car, after your pressure washer has diluted the bottle mix. Bilt Hamber use it for Touch-Less (0.5–2%) and Auto-Foam (1–5%, typically 4%). In a bucket or pump sprayer the bottle strength and the PIR are the same.
How much Touch-Less goes in a foam cannon?
It depends on your pressure washer. Bilt Hamber specify 0.5% PIR for maintenance washes up to 2% for very dirty cars. Do the bucket test: discharge one litre of water through the lance, measure what comes out in millilitres, and multiply by 0.005 for 0.5% or 0.02 for 2%. If 15 litres come out, that is 75 ml to 300 ml of Touch-Less, topped up to one litre.
How much Auto-Foam should I use?
Bilt Hamber's typical figure is 4% at the panel, within a range of 1% for light cleaning to 5% for heavily soiled cars. Through a foam lance, multiply your bucket-test result by 0.04. In a pump sprayer, 4% is simply 40 ml per litre.
My calculation says I need more Auto-Foam than the bottle holds. What now?
Some pressure washers can't draw enough from the bottle to reach 4%. Bilt Hamber's advice is to fill the bottle with neat Auto-Foam and judge the results, since it can clean reasonably well at 1–2%, or to apply it at 4% with a garden pump sprayer and pressure-wash it off with plain water.
How much Auto-Wash goes in a bucket?
One 5 ml teaspoon in up to 10 litres of fast-flowing warm water, a dilution of about 1:2000. Bilt Hamber put a 500 ml bottle at up to 100 washes.
What dilution of Surfex-HD should I use?
Bilt Hamber give 1–2% for upholstery and carpets, 5–10% for wheel arches and tyres, 10% for brake callipers, 4% at the surface as a pressure-washer shampoo, and neat for heavy grease and oil. Use it on cool surfaces and spot test first.
How strong should a Deox-C bath be?
Bilt Hamber say the best concentration is 5%, one part to 19 parts water, so 1 kg makes a 20 litre bath. They give 5% or 10% as very effective even for heavy corrosion, with 20% (one part to four) the strongest mix they list, and the bath warmed to no more than 70 °C.
What does 1:100 mean in Bilt Hamber's instructions?
One part in a hundred of finished mix, which is 1%, or 10 ml of product made up to one litre with water. At these strengths the difference from "one part to 100 of water" is tiny, but thinking in millilitres per litre avoids the confusion altogether.
Every dilution, dwell time and caution on this page is Bilt Hamber Laboratories' own, from the product pages, technical data sheets and FAQs at bilthamber.com, read in November 2026. Millilitre conversions are ours. Safety data sheets for every Bilt Hamber product are linked from each product page and our data sheet library. For the chemistry behind each product, see our Bilt Hamber product guide and the Bilt Hamber Australia page.