Auto-Wash Powder Coating Pre-Treatment Machine

The Auto-wash is our fully automated, pre-treatment machine for use in the powder coating industry. It can be used for both Aluminium and Steel (the process is different for each, see below). Successful powder coating involves more than spraying powder and curing in an oven. The pre-treatment process can determine the difference between an average job and a first class one. Quality standards are inexorably rising in all aspects of industry and no more so than in powder paint finishing. More and more customers are demanding a phosphate conversion coating. The days of wiping products down by hand are becoming limited and it is no coincidence that the most successful powder coaters have decent pre-treatment systems.

Powder coating pretreatment
Powder Coating Pretreatment

0ur standard Auto-Wash is a three tank system and is suitable for most steel and aluminium processes. It is very simple to operate, economical to run and completes its cycle quickly. After loading the parts, which can be done using a trolley system, the machine heats the chamber to 40°C to soften any oil or dirt residue, and then washes the parts with a detergent and phosphate solution. This is followed by a cold water rinse and a polymer sealant before drying with a gas fired hot air system.

The chamber, tanks and various other parts are made from stainless steel.

The whole process is automatically controlled via an on board Siemens PLC computer.

An acidic solution of around 1.5pH is required along with multiple rinses. The pre-heat process, chemical and chamber temperature, rinse cycles, sealant application and dry off are all critical to the success of the process. All are easily adjusted on the central control panel and consistent and verifiable. Results are easily obtained by following simple guidelines.

Features of our Auto-wash:

  • Fully automated sequence
  • Choice of front or side loading
  • Very low running costs
  • Typical cycle time of 20 minutes
  • Dry-off facility
  • Multi-metal solutions now available to treat both steel and aluminium
  • Proven design – our machines are currently in use worldwide
  • Our UK manufacturing plant produces high quality machines, designed and built to last.
  • CE mark
  • Fully guaranteed
  • Service contracts available
  • Training and help with chemical selection
Video showing Auto-Wash in use
Animation of Auto-wash workings
Powder Coat Steel and Aluminium Pre-treatment

The Chemical Process

Aluminium Pre-treatment

Treating aluminium to ‘exterior’ or ‘seaside’ grade is far more complex than the treatment for steel.

To prepare aluminium prior to powder coating, oxides have to be removed from the surface of the metal. If not removed they react with airborne pollutants, for despite appearances, a powder coated finish is actually porous. The reaction results in degradation leading to flaking and chalkiness.

The accepted standard, covering the amount of removal, is 1gram per m2 of surface area for “External “grade and 2 grams for “Seaside” grade. Seaside grade is required where the products will be exposed to harsher conditions, for example in coastal areas or on high rise buildings.

After this stage is complete the product must be thoroughly cleaned before a polymer solution is applied to seal the surface.

Steel Pre-treatment

The treatment of steel is different in that weight is added rather than subtracted. This is achieved by using a phosphate, either iron or zinc, immersed in a slightly acidic solution. This produces a slight etch and removes the surface whilst at the same time depositing a phosphate coating. Testing is done as follows:
A test panel is weighed (A).
and then treated in the machine after which it is weighed again (B).
The panel is now immersed in an inhibited acid for a short time and weighed again (C). The weight (C) is subtracted from (B).
This is the conversion (weight).

A properly applied conversion coating offers far greater rust protection and much improved adhesion. We have our own laboratory standard test equipment that provides fast and precise results.

Loading the Auto-Wash
Loading the Auto-Wash
Phosphate pretreatment
Phosphate Pretreatment


Our standard Auto-Wash machines all have a chamber size of 1.25m wide and 1.5m high. Our standard Auto-Wash machines are a three stage process.

3m – £18,500

4m – £21,000

5m – £24,000

6m – £26,500

Prices exclude VAT.

All chambers are 1.25m wide x 1.5m high. Choice of front or side loading (the price is the same).

We can also custom make larger sizes to suit individual requirements, please contact us for more details using the form below.

Phosphate powder coating pretreatment
Phosphate Powder Coating Pretreatment

Delivery and installation by agreement. We can arrange for our machines to be shipped worldwide; we charge for shipping at cost.

Our Auto-Wash machines are available to view in our manufacturing premises in Glossop – SK13 6LG (10 miles South East of Manchester – 5 minutes from the end of the M67).

For further details please contact Tony Bowker on 01457 868888 or get in touch using the contact form below.