Acri-Bond 502

Signage System for Channel Letters

1. Cleaning

Before gluing it is always recommended to clean and degrease both the acrylic and aluminium surfaces. This removes any contaminants and oils prior to applying adhesive for the best results. We recommend using either Acri-Bond Cleaner or Isopropyl Alcohol for this step as these cleaners have shown to not damage Acrylic and increase the surface adherence of aluminium.

 

2. Tacking

The next step in building channel letters is “tacking” the letter together. This step was developed to speed up the production line and remove the need for using tapes to hold the letters together whilst applying adhesive. We recommend using our thick cyanoacrylate adhesive for this step Acri-Bond 501 with our instant cyanoacrylate activator Acri-Bond Cyanoacrylate Accelerator.

 

Set up your channel letter for gluing by placing the aluminium into the channel slot on the acrylic. Apply a small bead of Acri-Bond 501 and once happy with the position apply a small droplet of Acri-Bond Cyanoacrylate Accelerator. Hold the joint for a couple seconds until it is firm and your first tack is complete. Now about every 5cm or any area that has tension on it apply another bead of Acri-Bond 501, then apply a small droplet of Acri-Bond Cyanoacrylate Accelerator. After the first 1-2 tacks you can apply multiple tacks at the same time to speed up this process.

 

If you did not position the joint correctly don’t worry simply apply some pressure and separate the acrylic and aluminium in that area, reposition and re-apply Acri-Bond 501 and Acri-Bond Cyanoacrylate Accelerator next to the tack you just separated not on top.

 

This product is only holding the job together as the glue is only on the surface level it is almost like taping the job and why we call it “tacking”. It is Acri-Bond 502 that provides the strength of the joint for the channel letter as it penetrates through and wicks into the routed edge of the acrylic giving it more surface area for a reliable bond.

 

Acri-Bond 501 is a thickened cyanoacrylate adhesive which makes it very easy to put tacks down right where you want without the adhesive running everywhere. Due to having this thickener in it the glue will take a very long time too set on its own when it is not in between two surfaces. This is why we apply the activator on top to instantly set the glue off when you have positioned the joint.

 

This adhesive is not designed for the sealing step as it will not “wick” into the joint it will only stay surface level due to its thick viscosity this is where you will need to use Acri-Bond 502.

 

3. Preparing for Sealing

When your whole letter is tacked together before moving to the next step of sealing the joint you must clean the surface with Acri-Bond Cleaner or Isopropyl Alcohol. This is best practice to ensure no residue of Acri-Bond Cyanoacrylate Accelerator is left on the surface of the acrylic or on the aluminium, it will not damage it however due to Acri-Bond 502 also being a cyanoacrylate it will instantly set off if it comes into contact with any residue of Acri-Bond Cyanoacrylate Accelerator. We don’t want this as we need Acri-Bond 502 to fully wick into the joint to provide the strongest possible joint.

 

Simply apply some cleaner to a cloth and wipe around the inside of the completely tacked channel letter.

 

4. Sealing

This is the final step in our channel letter system. There are two different ways to seal the letters, and it depends on your environment and workshop needs to which you choose. Both offer the same strengths and using the activator as advised does not negatively affect the product in anyway.

 

4.1 Acri-Bond 502 without Acri-Bond Cyanoacrylate Accelerator

This is the easiest, quickest and cheapest way to produce strong reliable bonds for your channel letters. Simply apply the product around the whole inside of the letter. Acri-Bond 502 is much less viscous than Acri-Bond 501, so it is able to wick/ capillary effect into the joint, similar to how Acri-Bond 105 works if you are familiar with using that product.

 

There is no need to apply too much you should only see a small bead around the whole edge on the inside. This adhesive when fully cured is extremely strong and durable. It is also rated to retain up to 30% of its strength at 100 deg C (the acrylic becomes the weakest point at 70-100 deg C as it softens not the adhesive), which is plenty for the rugged Australian climate.

 

If you are finding Acri-Bond 502 without Acri-Bond Cyanoacrylate Accelerator is taking a while to set on the surface level this has to do with the humidity levels of your location, workshop conditions or techniques of applying. Here are some tips to help.

 

Troubleshooting

Ventilation – This is by far the easiest to check as all you need to do is place a fan down to circulate air around. Cyanoacrylates cure through a polymerization process triggered by moisture. Without airflow, fresh moisture cannot reach the adhesive, slowing or preventing proper curing.

 

Applying too much adhesive – When it comes to cyanoacrylate adhesives, more is not better. Applying an excessive amount of glue does not improve bond strength, in fact, it can significantly slow down the curing process. Cyanoacrylates cure through a reaction with moisture in the air or on the bonding surfaces. Using too much adhesive restricts airflow and reduces the available surface area for moisture contact, leading to delayed setting times. For optimal performance, a thin, even layer is all that’s needed to achieve a strong, reliable bond.

 

If you have tried these two steps and it is still taking too long to set, the issue is likely related to the humidity of the working area. If the humidity is not at a satisfactory level (typically below 40%) the cyanoacrylate may struggle to cure efficiently. In such cases, it is recommended to also use Acri-Bond Cyanoacrylate Accelerator with Acri-Bond 502, which is explained below.

 

4.2 Acri-Bond 502 and Acri-Bond Cyanoacrylate Accelerator

This process is very similar to applying Acri-Bond 502 on its own. Simply apply Acri-Bond 502 around the whole inside of the channel letter, same as above you don’t need to use too much just needs to have a small consistent bead going around. Give it a 30-60 seconds to allow the adhesive to penetrate through the joint. Now apply one droplet of Acri-Bond Cyanoacrylate Accelerator every 5-10cm, when you drop it the Activator will spread to cover that distance. Acri-Bond 502 will cure almost instantly when in contact with Acri-Bond Cyanoacrylate Accelerator. As long as you give Acri-Bond 502 enough time to penetrate through the joint, there is no mechanical negatives to using the activator, it doesn’t make it weaker or less temp resistant.

 

4.3 Acri-Bond 502 and Acri-Bond 204

Acri-Bond 502 on its own provides a strong, reliable bond for most standard applications, including everyday signage assembly. However, for larger letters, high-temperature environments, or projects requiring enhanced mechanical strength, Acri-Bond 204 can be applied over the bead of Acri-Bond 502 to provide additional reinforcement. Acri-Bond 204 is a clear, structural two-part methyl methacrylate adhesive that adds extra strength and flexibility, making it ideal for bonding materials that may expand or contract at different rates. This dual-layer approach combines the fast-setting convenience of 502 with the structural resilience of 204, ensuring peace of mind in more demanding conditions.

 

5. Tooling

Below is the recommended tooling and set up that is recommended for the best job.

Acri-Bond 501 – 65mL Applicator Bottle with 1.4mm Needles (dark green) or 100mL Applicator Bottle

Acri-Bond 502 – 65mL Applicator Bottle with 0.6mm Needles (pink)

Acri-Bond Cyanoacrylate Accelerator – 65mL Applicator Bottle with 0.5mm Needles (blue)

Acri-Bond 105 – can be used to clean out the applicator bottles and needles after a days use. This is maintenance to ensure a good life out of your equipment and stop the bottles and needles clogging up.

If they do clog up simply empty out the contents of the bottles into its respective larger container, pour about 5-10mL of Acri-Bond 105 into the applicator bottle, cap it off and shake it. Give it a couple seconds to soften the cyanoacrylate then dispense contents onto a cloth through the needle, this will unclog your bottles and needles.