Application Technical Report ATR-1898
Activity:Repair & Maintenance Cleaning
Industry:Manufacturing - Paint & Coatings
Widget:Piping, Mixing Tools
Soils:Surface Prep Primer
Method:Agitation Parts Washing
Key Features:Safety, Performance
Improve safety in a paint stripping application.
Mirachem’s environmental services partner, Heritage-Crystal Clean, was asked to assist with an evaluation of this paint and coatings manufacturer’s production maintenance processes. The company’s product, a high-solid, solvent-based primer, needed to be cleaned from mixing tools, piping, and other equipment and surfaces associated with the manufacturing process.
The incumbent process utilized a typical aliphatic hydrocarbon / methylene dichloride based paint removal product, and involved extended soak times to remove the primer. Parts typically required a soak time of 40 - 60 minutes at ambient temperature.
Based on the inherent worker and environmental safety risks associated with the cleaning chemistry in use, replacing that material with a safer technology quickly became the focal point of the project. Successful conversion to a Mirachem aqueous paint stripper could deliver significant benefits including reduced fire risk and VOC emissions, less worker exposure to chemical hazards, and decreased cost of waste handling and exposure.
Crystal Clean representatives also noted the high-solid, almost clay-like nature of the soil being cleaned. Unlike many paint formulations, the primer material did not come off surfaces as shoots or become readily suspended in the cleaning solution. While not part of the customer’s original mandate, Crystal Clean also identified product performance as an opportunity for improvement in the customer’s process. If the customers parts could be cleaned more productively, the maintenance cleaning processes would require less labor, and improve uptime for the manufacturing line. Agitation cleaning equipment was identified as a potential means of providing this increased efficiency.
It was also important to evaluate the cost effectiveness of a new process. Generally speaking, aqueous paint stripping products are more expensive on a purchase cost per-gallon basis when compared to riskier solvent formulations. However, on a use cost per-gallon basis, properly diluted water-based formulations are nearly always competitively priced, particularly when the reduced costs of risk management and waste handling are taken into account.
The success measurement for the project would be an appreciable improvement in the cleaning processes’ safety factors, without significant reduction in efficiency of cost effectiveness.
With the substrate materials consisting primarily of stainless steel and PVC, Mirachem QX-490 Paint Stripper was selected for evaluation. 1
The Crystal Clean Model 2778 agitating parts cleaner was selected as the equipment for testing. Ultrasonic parts cleaning was considered, but was not selected for testing based on the determination that initial equipment costs would not be justified by whatever increases in performance over agitation cleaning that the ultrasonic method could deliver.
Because QX-490 is a water-based technology, heat could be introduced into the process to improve performance. QX-490 is recommended to be used at an operating temperature of 105-160 ºF. For the purposes of this evaluation, it was decided to test at the Model 2778’s default temperature of 130 ºF.
The standard dilution recommended for QX-490 in agitating parts washers is 50%, which was selected for the test.
A health and safety review of the Safety Data Sheets for the incumbent solvent product and Mirachem QX-490 demonstrated significant reductions in risk in the areas of fire danger, worker safety, and air quality compliance. While not quantified at this initial review stage, reductions in regulatory compliance costs and waste management were determined to be likely if the proposed aqueous process were adopted.
The results of the performance testing were positive, with a noticeable reduction in cleaning time. Most parts cleaned in a 10-20 minute cycle, representing a time savings of up to 50% versus the existing protocol.
It was also noted that the primer product removed by the QX-490 / Model 2778 process was more effectively held in suspension with the cleaning solution. While no statistical analysis was performed to attempt to quantify the benefits of this result, operators were of the opinion that this left parts cleaner and made machine cleaning and maintenance easier.
Based on the results of the performance evaluation, the customer elected to adopt the proposed aqueous process without an in-depth cost analysis. They concluded that whatever increases in purchase cost for the Crystal Clean aqueous service program versus the incumbent process were more than offset by the time saving delivered. .
It is worth noting that since this evaluation, the customer has monitored labor, risk management, compliance, and waste management costs, and has validated the overall costs savings to their satisfaction. They have since adopted QX-490-centered processes in similar applications removing other soils, including latex and oil-based paints.
1. While this application was originally tested using QX-490, subsequent improvements in Mirachem’s aqueous technologies have led to the development of additional paint stripping products. While QX-490 is compatible with stainless steel, it is usually not the preferred product for use on this substrate material. If this application were to be evaluated today, we would recommend testing Mirachem QX-494 Paint Stripper for Non-Ferrous Metals, or Mirachem’s newest paint stripping technology, Mirachem QX-495 Paint Stripper for Multi-Metals.
2. Temperature is an important variable in any water-based cleaning protocol. In general, higher operating temperatures deliver better results, but can also contribute to increased fluid loss due to evaporation, increased risk of burns, or potential for damage or deformation to temperature sensitive parts. Care should be taken to find the proper balance between product performance and safety and material compatibility concerns.
3. Dwell time is also a factor in the success of a cleaning process. Again, longer soak times will typically deliver better performance. However, excess cleaning times are also a major contributor to corrosion and substrate damage issues. Cycle times should be kept to the minimum necessary to achieve desired performance.
4. Proper corrosion management steps should always be taken when cleaning with water-based products. This includes use of correct products(s), maintenance of proper dilution ratios, management of dwell time, and where necessary, using corrosion protection additives such as Mirachem Rust Inhibitor Liquid.
5. Galvanic corrosion is metallurgical reaction caused by dissimilar metals coming into contact with one another in the presence of an electrolyte, such as water. Exercise caution when stripping different metals in the same cleaning solution, particularly aluminum and yellow metals like brass or bronze.
6. Cleaning of magnesium substrates with water-based products can present significant material compatibility challenges. Always test parts with a high magnesium content carefully when developing an aqueous cleaning protocol.
7. When left unused for periods of time, usually in excess of 48 hours, new, diluted solutions of the the QX-400 Series Paint Strippers may experience separation, and/or the fluid may turn a milky white color. This is an expected behavior of the formulations and does not compromise product quality. Normal agitation, from stirring or simply activating the cleaning equipment, should be sufficient to restore normal product appearance. This behavior is not typically seen in solutions that have been in use.
8. Appropriate personal protective equipment (PPE) should also be used by personnel working with or near hot materials, including parts recently removed from hot cleaning solutions.
1. At the time of this evaluation, Mirachem offered only one paint stripping product, QX-490. Since then, the QX-400 Series product line has expanded to include Mirachem QX-494 Paint Stripper for Non-Ferrous Metals, and Mirachem’s newest paint stripping product, QX-495 for Multi-Metals.