When deciding to remove paint from metal parts, using a hot chemical paint stripper is a common method. However, understanding the associated costs is crucial for determining whether this process is economically viable for your operations. The costs involved in paint stripping are categorized into two main types: Operating Costs (OPEX) and Capital Investment Costs (CAPEX).
Operating Costs (OPEX)
The operating cost can fluctuate depending on the type of paint stripper used and the surface area of the metal parts. Generally, if you're using an alkaline paint stripper (suitable for steel only), the cost is around USD $0.15 per square foot. On the other hand, if you opt for an organic paint stripper (which can be used for multiple metals), the cost tends to range between USD $0.75 and $1.00 per square foot.
A key guideline to remember is that the operating cost should always remain lower than the value of the part you're reclaiming. If the cost of stripping exceeds the value of the part, it might not make financial sense to continue with the stripping process.
Types of Costs in Paint Stripping Systems
There are two primary categories of costs to consider when operating a paint stripping system:
Operating Costs (OPEX)– This category includes all the recurring costs necessary for day-to-day operations, such as:
- Chemicals: The cost of the paint stripper solution.
- Labor: Wages for employees handling the stripping process.
- Utilities: Expenses for electricity, water, and other services.
- Waste Disposal: Costs related to the disposal of used chemicals, sludge, and paint residue.
- Space Utilization: Rent or overhead costs for the space occupied by the paint stripping operation.
Capital Investment Costs (CAPEX)– These are the upfront costs associated with setting up a paint stripping system, which includes:
- Equipment: The cost of purchasing the machinery and tools required for stripping, such as strip tanks and hoists.
- Renovations: Any facility modifications or improvements needed to accommodate the equipment.
- Amortization: The process of spreading out the capital costs over time, typically over 3 to 5 years, based on the number of parts processed.
Example: Stripping Aluminum Sidings
Let's consider an example to understand these costs better. Suppose you need to strip 100 aluminum sidings per day. The sidings are 0.5 feet wide, 6 feet long, and coated on both sides.
Step 1: Surface Area Calculation
The total surface area of each siding is 6 square feet (0.5' x 6' x 2 sides).
Since the siding is made of aluminum, an organic paint stripper is selected with a using cost of USD $0.75 per square foot.
Step 2: Operating Costs (OPEX)
- Chemical Cost: The stripping chemical costs approximately $0.75 per square foot. For a 6 square foot siding, the chemical cost is $4.50 per siding (6 sq. ft x $0.75).
- Labor Cost: The labor time required per siding is approximately 0.1 hours (6 minutes), with an hourly wage of $30. This results in a labor cost of $3.00 per siding.
- Utility Costs: Utilities such as electricity, water, and waste disposal contribute $1.00 per siding.
Thus, the total Operating Cost (OPEX) per siding is:
OPEX=4.50 (chemical)+3.00 (labor)+1.00 (utilities)=7.50 per siding
Step 3: Capital Investment Costs (CAPEX)
The capital investment costs associated with setting up a fully integrated paint stripping system include:
- Heated Strip Tank (Agitated): $21,750
- Rinse Station: $5,000
- Ventilation System: $14,550
- Hoisting System: $9,000
- Initial Chemical Charge: $6,570
- Facility Renovations: $15,750
Total CAPEX: $72,620
Step 4: Amortization of Capital Investment
If you plan to strip 100 sidings per day for 250 working days per year over 3 years, the total number of sidings processed is:
100 sidings/day×250 days/year×3 years=75,000 sidings
To calculate the amortized cost per siding:
72,620 (CAPEX)/75,000 sidings=0.97 per siding
Thus, the total cost to remove the coating from one siding (including both OPEX and CAPEX) is:
7.50 (OPEX)+0.97 (CAPEX)=8.47 per siding
Conclusion: Is Reuse Worth the Cost?
With an acquisition cost of $20 for a new bare aluminum siding and a paint stripping (reclaiming) cost of $8.47, it is economically beneficial to reuse the part instead of discarding it.
In other scenarios, the decision to reuse can be even more obvious. For instance, if a titanium part worth $100 can be stripped for just $4, reusing the part makes perfect sense. Conversely, if the stripping cost for a basic steel fixture is $0.10, but the part itself is only worth $0.05, recycling might be the only feasible option.
Key Takeaways
- Calculating OPEX and CAPEX is of utmost importance when determining if you should invest in a paint stripping system. If CAPEX + OPEX of stripping the part is lower than the price of a new part, the investment should be made.
- Reusing is often more cost-effective than recycling, especially when dealing with high-value parts. Given the various value-added processes (such as cutting, welding, machining) that a metal part undergoes before being coated, reusing the part after stripping is often a more attractive option than starting from scratch.
Understanding these cost components helps in making informed decisions when considering the use of paint strippers for metal parts. By weighing OPEX, CAPEX, and the potential for part reuse, manufacturers can optimize their processes and reduce waste.
By: Martin Pageau, P.Eng. – Greensolv inc.
April 2025
