Adhering Kraft or primed paper to a substrate during door manufacturing offers multiple benefits. It can give a smooth finish, balance veneers, and eliminate the necessity of priming the door’s surface before painting.Â
If you want to reap these advantages, browse this guide, where Adkwik will detail how to achieve this bonding technique. We’ll also highlight the adhesive and application equipment needed, demonstrating how to get your production process working faster, safer, and more cost-effectively.Â
Using Kraft or Primed Paper in Door Manufacture
Bonding primed or Kraft paper is a regular step during door manufacturing, from creating regular internal doors to critical fire doors. Below are two of the most common applications and the benefits they provide.
Balancing Veneers:Â
Kraft paper is an excellent balancer for specific veneers as it is relatively inexpensive, lightweight and does not impose as much stress on the substrate as a wood veneer. This balancing technique is vital as it helps prevent warping or distortion on the door, particularly during changing humidities.Â
Priming the Door’s Surface: Â
Manufacturers can also benefit from opting for white Kraft paper facing, as it provides a smooth, ready-to-paint surface to which water—and solvent-based paint will adhere evenly. This technique allows workers to skip the regular, time-consuming priming procedures and transition quicker to the final painting stages.
Additionally, these white pre-primed doors are valuable assets. At this stage, manufacturers can sell doors to customers and clients, providing them with a solid door base.
Achieve Successful Bonding of Kraft Paper and Primed Paper
Learn how to attach the paper to the substrate using our recommended adhesives and application methods.
Suggestion 1: Urea Formaldehyde ResinÂ
One option is to reach for a traditional UF resin, such as Prefere 4152 Resin. This adhesive is versatile and ideal for all veneering work on panels or shaped timber components.
Mix the resin with a suitable hardener to adjust the bond, assembly and setting times. For this task, we recommend the 5664 Hardener, a filled powder hardener including an extender, perfect for counteracting adhesive penetration through thin or porous veneers. You can find more information about these products in their relevant datasheets.
Surface Preparation:
Before applying UF resin, ensure the surfaces are smooth, thoroughly cleaned, and entirely free from dust or other debris. This preparation is critical as debris can build up and wreak havoc on your work.Â
Witness a real-life example of this problem in our ‘Improving adhesive bonding processes increases production for specialist manufacturer’ case study and how Adkwik helped to resolve this issue.Â
Application:
This particular resin is a two-part system that requires mixing, and the quantities depend on the hardener used. For the 5664 Hardener, follow the recommended ratio of 30 to 50% hardener by weight. Mix the resin, hardener, and, if required, water, then stir thoroughly.
To apply the adhesive, ensure an accurate coat weight using a brush, a glue spreader, or a mechanical glue roller for bulk application. Generally, it’s enough to apply the mixture to just one of the surfaces.Â
Finally, clean your tools after use; any excess adhesive should wash off easily from your equipment.
Suggestion 2: Ubabond 30 Resin
While UF resin is a reliable choice, it does contain formaldehyde. If you’re looking for a safer alternative with just as impressive results, Ubabond 30 is a great solution. This resin is formaldehyde-free and eliminates the risk of VOC emission – ideal for protecting your working environment and delivering a safe final product.Â
It’s also water resistant, tackles adhesive bleedthrough, and rapidly reduces hot press times. Addressing these issues ensures production efficiency, durability, a professional finish, and overall confidence in your work. Request a datasheet from Adkwik for further technical details about this product.Â
Surface Preparation:
As with the previous adhesive, the substrates must be clean, dry, and free from grease and dust. The Ubabond 30 datasheet also recommends that the wood be conditioned for several days in the factory before bonding (15-200C) and that the wood moisture be 6 to 12%.
Application:
Since no mixing is required, you can use Ubabond 30 directly from the container. We recommend using one of our 25-litre Metal Drum Tippers for easy dispensing before applying U30 with a handheld or automatic glue spreader.
For the best results, apply a low coat weight of around 80 grams to 100 grams/m2. Once spread, clean all equipment with lukewarm water to keep your tools in good condition.Â
Turn to Adkwik for Expert AdviceÂ
This guidance should help you to fine-tune your glue, preparation process and application techniques, leading to improved results. However, please contact us if you still need assistance or wish to review your production process.
At Adkwik, we’re far from a faceless company. We’re eager to understand the details of your production process and provide tailored solutions to help you move forward. To get in touch, call 01223 412373 or leave a message via our convenient online contact form to speak with our trusted technical team.Â
Alternatively, delve further into our blog, where you’ll find articles addressing specific concerns and helpful industry insights.