October is national manufacturing month — an opportunity for manufacturers everywhere to celebrate the important things we make, do and deliver for applications around the world. It’s also an occasion to help shepherd new young professionals into the field, where there are plenty of rewarding, lucrative careers to be made.
When I think about manufacturing in the commercial fenestration industry, I tend to focus on the craft of it. Making high-performance insulating glass (IG) that must stand up to the rigorous demands of forward-thinking architecture is no easy task. It requires precise attention to every part of the process, and everyone involved in production on your shop floor should be familiar with the proper best practices. Their ability to understand both how and why certain elements of production can lead to unit failure is important.
With all of this in mind, I thought it was worth casting some attention to what our teams at Quanex frequently see as pain points in the fabrication process for commercial IG of all edge seal construction types. And while all parts of IG manufacturing are important, uncompromising quality on the following three points can best help you prevent unit failure:
Ensure a Good Primary Seal
A good primary seal, which acts as your unit’s main moisture/gas barrier, starts with a good sealant profile. Make sure your primary sealant is properly placed and not over- or underfilled. Avoid skips or voids in the primary sealant.
After you have a good seal profile, it’s essential to close the start/stop points or joints. If these are not joined/sealed properly, you’re creating a potential path for moisture/gas — and potential for desiccant to get into the air space. After you’ve pressed the unit, verify that the primary sealant is fully pressed out and wetted to the glass and spacer. Fully wetted PIB should be a solid, flat black. Checking these criteria on the first few units out of your press should indicate whether you need to make any adjustments to your processes.
Properly Applying Your Secondary Seal
Your secondary seal ensures the structural integrity of the unit, helping it to withstand the inherent temperature fluctuations and dynamic pressure changes of demanding commercial applications. First, the spacer should be consistently inset to allow for a proper secondary sealant depth. Work with your sealant supplier to identify proper sealant depth recommendations to meet structural performance standards. And remember that thicker glass, larger units or units intended for highly demanding applications may require more sealant depth.
Next, be sure that your inset is properly filled — structural effectiveness is at stake. Avoid slumping or dishing in the center. Sealants can sometimes flow up the sides of the glass, making the inset appear fully filled when the center might in fact be too shallow. Once the proper depth is achieved, check for and close any joints or gaps, and fix any bulges that extend past the glass edges.
Finally, good racking can help protect your units while the sealant cures. Your racks should be clean and free of dust, debris and old sealant material that can become embedded in a freshly applied secondary sealant, compromising performance. Support strips should be firm and wide to fully support the weight of your unit without compressing. If your unit sinks into the support, the strip can displace the secondary sealant. Poor racking can cause an otherwise good unit to fail earlier than expected.
Protect the Desiccant
Desiccant prevents moisture accumulation within the unit’s interior. Even a perfectly sealed IG unit can begin to show condensation in the air space shortly after it’s been assembled if the desiccant has been compromised.
Whether your desiccant is a separate, powdered component or is incorporated into the spacer material, its job is to adsorb moisture from its surrounding environment. Molecular sieve is the most common desiccant used in IG, which has a very strong affinity for moisture even at very low humidity. A desiccant-filled spacer left out and exposed long enough, to even a modest 20% relative humidity, can potentially adsorb up to 80% of its total moisture capacity before it even makes it into your IG unit.
What to do? Protect the desiccant from exposure to fresh air as much as possible at all stages of production. Storing it properly when not in use limits its potential to waste desiccating capacity before it’s applied, helping it to deliver proper performance once sealed into the unit.
These are some things to keep in mind throughout your manufacturing processes. Keeping a keen focus on the craft of IG fabrication can help ensure high-quality units that will last. Happy manufacturing month!
Joe Erb is national account manager for Quanex.