Choosing the proper brush for inside coil cleaning can be complicated with the variety of brushes available. The purpose of an inside coil brush provides a cleaning solution that can reach hard-to-reach areas of the curved and confined interior of coils or tubes that a flat or straight brush cannot access. With so many specifications available, how does a buyer make a good decision? This guide breaks down the important considerations that experienced operators and purchasing teams should take into account when ordering internal cleaning brushes.
Why Brush Selection Matters
The incorrect brush type may create low cleaning output, reduced brush lifespan and use up unnecessary funds. In industry, it is essential that the brush matches the workpiece’s geometry as well as its materials. If the brush is too big, it will get stuck within the coil and if it is too small, there will be no contact at all. By specifying correctly initially, you will save time, reduce the amount of time not in use and increase the length of time before your next service, all of which will be of benefit to any maintenance manager.
Key Factors When Choosing an Inside Coil Brush
1. Coil Inner Diameter and Pitch
The most important measurement is the inner diameter of the coil or tube. The brush outer diameter should be slightly larger than the coil inner diameter to ensure that the bristles have constant contact as they compress. The coil pitch also affects how the brush moves through the inside of the coil. For this reason, tighter-pitch coils require more flexible brush designs.
2. Fill Materials
Different fill materials contribute to different levels of aggressiveness and durability in regards to cleaning. The following is a quick comparison of different fill materials with their common attributes:
| Fill Material | Level of Aggressiveness | Best Use | Durability |
| Nylon | Low | Polished surfaces, light dusting | Moderate |
| Brass Wire | Medium | Soft metals, non-sparking areas | Moderate |
| Steel Wire | High | Heavy scale/rust deposits | High |
| Stainless Steel Wire | Very High | Corrosive areas; food grade | Very High |
| Abrasive Nylon | High | Deburring surfaces | High |
For the majority of heavy duty coil cleaning, steel or stainless steel wire fill is the preferred fill choice. Operators who operate in non-sparking environments prefer using brass wire fill rather than steel wire fill.
3. Wire Diameter and Trim Length
A brush with a thicker wire will give off a more aggressive cutting action as opposed to having more flexibility with the wire being thinner allowing it to conform easily to irregular surfaces. The trim length (exposed bristle length) from the core of the brush is what determines the depth of your brush working in grooves & cracks. A common guideline within the industry is:
- Short Trim: Offers good stiffness for use on hard deposits.
- Medium Trim: Offers a balance of flexibility and cleaning ability.
- Long Trim: Offers maximum reach for use on irregularly shaped surfaces or very deep recessed areas.
4. Core Construction
The core of the brush is the component that “holds everything together”. Inside coil brush products typically use the most common type of core construction, which is twisted wire cores, due to their ability to flex, allowing them to follow curved paths. Tube-style (also called tube cores) or channel-style cores offer the most rigidity; therefore if you need high torque, tube or channel cores would be the best choice.
5. Application Environment
The application environment is the primary factor influencing all other decisions. This includes:
- Temperature Range – High temperature applications require tempered steel or stainless steel filling.
- Chemical Exposure – Corrosion-resistant material must be used in both acidic and alkaline environments.
- Speed/Rotation – The brush will need to be rated for the RPM at which it is to be used.
- Surface Sensitivity – Softer fill should be used when working with precision-machined surfaces to avoid scratching.
Those requiring additional detail on this product category can reference the detailed overview of what is inside of a coil brush. This overview contains information on construction, types, and how they work.
Consider Related Applications
The use of an internal cleaning tool similar to an inside coil brush may be complemented by products that would also work equally as well in completing a job; however, depending on the type of work being performed, their ability to help to do the job may vary.
Wire Rope Maintenance
Wire rope cleaning brushes are specially designed to clean and lubricate wire ropes by wrapping around the outer surface of the wire rope and scrubbing between the strands while the wire is passing through. Although their design/configuration is different than that of a coil brush, they are often used by the same crews. Facilities with wire ropes and coiled components often buy both types of brushes together. More information about wire rope cleaning brush products can be found in the article titled What is a Wire Rope Cleaning Brush?
Chain Cleaning
Like the 360 chain brush, these brushes are used to clean the entire surface of a chain link at the same time. Typically, they are used in a variety of applications including conveyor systems, motorcycle repair, and industrial chain drive applications. Although the use differs from internal cleaning of coil, the same material selection principles apply: type of wire, aggressiveness of the brush, and corrosion resistance. A detailed discussion is provided in the guide on what is a 360 chain brush.
How to Order the Correct Brush from a Supplier
When you contact a manufacturer or distributor, having the following information available to them will help to streamline the quote process and minimize the likelihood of making mistakes when placing an order:
- The inner diameter of the coil and the coil’s length.
- The type of material used to create the coil and its surface condition.
- The fill material and wire gauge you want (e.g., nylon and 0.005” wire).
- How the brush will be applied (i.e., with a manual tool or power tool).
- The quantity of brushes you need and when you need to receive them.
A great resource when searching for suppliers for brushes are companies like Fortex Brush, who are able to create customized inside coil brush solutions for OEMs and bulk buyers that have application-specific requirements (i.e., multiple items with different specifications).
Quick Selection Checklist
To help ensure that your purchase is correct, use the following checklist before making your final decision:
- Accurately measure the outside diameter of the coil.
- Identify the type of deposit on the coil (rust, dirt, grease, scale).
- Select the correct fill material for that cleaning application.
- Verify the operating conditions of the coil (temperatures, chemicals, and speed).
- Determine if you are using a manual or power-driven tool.
- If ordering in bulk for the first time, request samples before placing your order.
Frequently Asked Questions
Can I have a custom inside coil brush made to fit my non-standard coil size?
The majority of professional manufacturers of inside coil brush products provide custom sizing options as well as non-standard diameter and length sizes, materials, etc. to meet specific requirements.
How many do I need to purchase wholesale?
MOQ varies by supplier, but generally manufacturers of brushes for wholesale will accept orders of 50-100 pieces, with larger price breaks at greater quantities.
Will these brush products work in automatic cleaning systems?
Absolutely. Inside coil brush units with reinforced cores and power-drive shanks integrate well into automated or semi-automated industrial cleaning lines.