RC Threadlocker Guide: When to Use It and When to Avoid It
Use threadlocker only where your exact RC model’s instructions call for it. Use the product they specify, and follow the cleaning and assembly steps. Do not add it to every screw.
A metal screw can thread into metal, plastic or a metal insert inside another part. Check which material the screw goes into before adding threadlocker.
If a screw keeps coming loose, check the screw, the parts around it and the manual first. This guide explains what to look for before you choose a product or order replacement hardware.
What does threadlocker do?
Threadlocker is an adhesive that helps keep a screw from working loose. Many common liquid products for metal threads set and build strength when trapped between close-fitting metal surfaces, away from air.
This process is called curing. It does not work the same way for every product. Some threadlockers use a different type of adhesive or are made for different materials.
Read the instructions for the exact product. Do not assume that two bottles work the same way because they look alike.
1. Check what the screw threads into
Look at where the screw’s threads grip the other part. The metal screw head alone does not tell you what that material is.
| Where the screw threads go | What to check |
|---|---|
| A threaded metal part or nut | Does the manual call for threadlocker here? Which product and strength does it require? |
| A plastic part | Do the model and adhesive instructions allow that product in this location? |
| A metal insert inside a plastic part | Check the insert’s instructions and whether the adhesive is safe around the nearby plastic. |
| A part you cannot identify, or one that has been changed | Identify it before applying anything. |
A metal insert is a small metal piece fitted into another part to provide threads for a screw.
For example, one screw may pass through a plastic bracket and grip a metal nut. Another may thread directly into the plastic. Similar-looking screw heads do not make those connections the same.
Some common threadlockers for metal threads can cause small cracks in certain plastics. Products made for plastic also exist, but you still need to check the exact product and location.
If the instructions do not confirm a suitable product for a plastic connection, do not apply one until you have checked.
2. Read the manual’s instructions for that location
Find the manual for your exact model and version. Read its threadlocker notes and the steps for the part you are working on. If you have fitted an upgraded part, check its instructions too.
Do not copy another owner’s method for a motor screw, set screw or driveshaft screw without checking your own model. Even a small set screw, also called a grub screw, needs the instructions for its own location.
Write down:
- The model, version and any parts that have been changed.
- The assembly step and original screw part number.
- The material the screw threads into.
- The required threadlocker, cleaning steps and tightening instructions.
If you cannot identify the screw, our RC screw sizes guide explains how to record its size and special features.
3. Check the product and strength, not just the color
“Blue threadlocker” is not a full product description. Check the maker, product number, materials it can be used on, strength and removal instructions.
Threadlockers come in different grades, or product types. Their strength and other features can differ:
- Low strength: designed for easier removal in the uses listed by the maker.
- Medium strength: helps hold a screw in place where the part also needs to be taken apart for repairs.
- High strength: provides a stronger hold for the uses listed by the maker. Removing it may require a different method.
These descriptions do not tell you which product belongs on a particular RC screw. Use the one required for that location.
A stronger product is not always a better choice. Think about the next repair as well as the next run. If you cannot identify or find the product named in the manual, check which replacement is suitable instead of choosing by color.
4. Follow the cleaning and application steps
Once you have confirmed the screw connection and product, follow both the model’s instructions and the adhesive maker’s directions.
Check how to clean the threads, where to put the adhesive, how much to use and how to fit the screw.
Do not copy the amount listed for a large bolt onto a tiny RC screw. There is no single “one drop per RC screw” rule that covers every product and location.
Avoid spreading adhesive onto nearby parts. Before using a cleaner, check that it is safe for the materials it could touch.
Some products also call for an activator. This is a separate product used to help the adhesive cure. Use it only as directed, and check that it is safe around nearby parts.
Read the product’s handling instructions before use. Follow the model’s tightening instructions too. More adhesive or more force will not make up for the wrong screw or a damaged part.
5. Allow the required cure time
Fixture time is not the same as full cure. Fixture time is an early stage when the adhesive has enough strength for handling. It does not mean the connection has reached full strength or is ready for driving.
Cure time can change with the product, the materials it touches and the temperature. Stainless steel and plated metal can behave differently from the materials used in a product’s example tests. Plated metal has a thin layer of another metal on its surface.
Follow the exact product’s cure instructions for your materials and conditions. Note when you applied it and how long you need to wait. A screw that is fitted is not necessarily ready for use.
What if the screw still comes loose?
Stop and check the parts instead of repeatedly adding adhesive.
Check that you have the correct screw and that its threads fit the other part properly. Inspect the nearby parts and anything the manual uses to keep the screw in place.
A screw that spins without tightening may have a different problem from one that gradually works loose during use.
Do not use threadlocker as a repair for damaged threads, a rounded screw head or the wrong screw. Follow the model’s repair instructions and fix the problem before running the vehicle again.
If you need replacement hardware, compare the parts you need with the exact listing’s contents. Our RC screw kit buying guide explains how to check what a kit includes and leaves out.
Keep a simple repair record
A few notes can make the next repair easier:
- Location: model, assembly step and screw part number.
- Materials: what the screw and the threads it goes into are made from.
- Threadlocker: exact product and required strength.
- Cleaning: the approved cleaning and application steps.
- Assembly: the model’s tightening instructions.
- Timing: when you applied the product and how long it must cure before use.
- Questions: anything you still need to confirm.
Mark uncertain details as uncertain. A clear question is more useful than a guessed screw size or product.
Common questions
Should I put threadlocker on every metal-to-metal RC screw?
Follow your exact model’s instructions. A product may work on metal threads, but that alone does not tell you whether this screw needs it or which product to use.
Can I use ordinary metal-thread threadlocker on plastic?
Do not assume it is safe for plastic. Some products can damage certain plastics. Use one only when the model and adhesive instructions confirm that use.
Do stainless steel replacement screws change the answer?
The material name alone does not decide it. Check the replacement screw’s instructions, the material it threads into and the threadlocker’s cure guidance. Do not assume that every stainless screw needs the same product or wait time.
Leave a comment