UV Bonding technology is being used by glass processors across a wide range of applications. This 10-step guide from Bohle explains the basics.
A cursory search for future trends in interior design is telling. In almost all the top ten Google search returns, glass is tipped as a defining design trend for the coming year. From boardrooms and offices, to hotels and homes, glass is being employed in a diverse range of applications, with demand for glass furniture, in particular, greater than ever.
“The scope to add-value to product through glass bonding is a real area of opportunity for glass processors,” says Amanda Carr, UV Bonding specialist, Bohle.
“We’re not just talking about traditional applications – jewellery and shop displays, museum cabinets, office furniture and shower screens – but a far wider range of furniture applications.
“This is driven by the interior design sector, which is incorporating glass in increasing volume into the design of our homes and workspaces and the furniture within them.
“It means the ability to reliably bond glass to other materials is generating significant opportunity for glass processors and the interior design sector more widely.”
The technology to do this is one of Bohle’s particular areas of strength. Offering an extensive range of pre-treatments, primers and adhesives, plus an extensive range of UV bonding lamps, UV bonding tables and clamping devices, Bohle has an established reputation as industry leader and has been highly influential in its development.
So, what do you need to get started in UV bonding? The guide below walks you through the steps to create an entry level piece of glass furniture:
Check with your H&S officer and follow your company’s procedures. You will need the following basics:
- Clean glass
It seems obvious but any contamination left on the glass as part of the process can impact on the strength of the bond. To start, clean all bonding surfaces with Bohle UV Bonding Glass Cleaner (BO 5107910) to remove dust, grease and light contaminates.
- Establish a secure fix
In order to achieve a high precision cure, you need to be able to hold the bonding parts stable, making sure that they don’t slip or that the bond isn’t weakened through vibration, something done using fixation devices.
Bohle offers three distinct solutions:
- The Verifix Pro 90° set of two suction holders (BO639.1)—ideal for high quality workshop production, having superior protection against vibrations as well as exact adjustability for creation of the bondline gap.
- The Verifix 90° Angle Suction Holder (BO 630.2), which uses two suction pads to hold the glass in place plus easy height and positioning adjustment of +/- 12mm to support accurate positioning
- The Verifix Pump-activated Angle Suction Holder (BO 638.0), which is specially designed for box constructions including showcases and glass cabinets
Bohle supply a range of specialist clamping technologies. These include the Verifix clamping device for 6-19mm glass (Bo 636.1) and Verifix Eccentric Suction Stoppers (BO637.0 and BO637.4), specially designed for use in shelf construction.
“Glass bonding is all about precision,” continues Amanda. “End-users want that high precision, almost clinical finish, which is what gives glass furniture its contemporary appeal. To do that you need a high level of stability plus the scope for accurate adjustment. That means the right tools.”
- Dry bonding surfaces
Having cleaned bonding surfaces use a hot air fan to remove invisible residual moisture (humidity).
- Pyrosil pre-treatment
“Technically, you can bond glass without using a pre-treatment but if bonding dissimilar materials, such as glass and aluminium, or if the bond will be under stress, for example, hinges, then it’s best to pre-treat the bonding surfaces to increase connective strength,” says Amanda.
The Bohle Pyrosil Pre-treatment Professional Kit BO5209491, includes a piezoelectric gas burner, coupling agent and application brush, suitable to pre-treat 10,000cm2 of bonding surface.
As part of the first stage of the pre-treatment process, the light blue part of the flame is run along each surface to be bonded, before primer is applied thinly with a brush. Once this has evaporated, adhesive can be introduced.
- Choose and apply adhesive
“In the same way as there are different tools for different jobs, there are also different adhesives,” says Amanda. “These will be defined by the materials being bonded, for example, glass-to-glass; metal-to-glass; or glass-to-stone.
“The other determining factor is the scale of the project. For example, a low viscosity glass to glass adhesive like Bohle Verifix LV740 will be suitable for a wide range of furniture applications and is straightforward to apply, entering the joint through capillary action.
“If you’re working on a larger project you might want to choose a medium viscosity adhesive like MV760, which can be supplied with spacer granules to prevent the adhesive from being forced out from the bond under pressure and can achieve a sheer strength load capacity of 25 newtons/mm2 .
“It’s simply about making the right choice because the technologies are there.
- Establish Pre-curing time
Pre-curing delivers an initial ‘fix’, holding bonded materials in place, allowing you to clean away any surplus adhesive before the final cure. This is done by exposing UV adhesive to UV light, generated by a UV lamp.
Pre-curing times are defined by the surfaces being bonded. A good way to establish pre-curing time, according to Amanda, is to run a test bond, applying the adhesive between thin glass lenses. Hold these lenses beneath the light with a sample of the glass you will be bonding that day between and rub the surfaces together, recording the time from first contact to the point that they no longer move, to establish the pre-cure time.
Having worked out your pre-curing time you need to expose all surfaces which are to be bonded to the same levels of UV light.
Bohle is again at the forefront of UV lamp technology. Its industry leading UVA Star tube lamps (BO5500380-90), deliver higher quality UV bonding cures .
A new high-intensity lightweight UV LED Hand Lamp (BO 5500358) is now available, which significantly cuts bonding times, making it ideal for industrial production while also delivering increased flexibility in bonding of metals to glass.
“There’s no transformer so it’s far more mobile but it also delivers an exceptional output. There’s no warm-up time, it delivers immediate high-outputs, significantly cutting pre-curing and curing times. This is something which clearly has the potential to deliver significant time savings when used in batch production.”
- Remove excess adhesive
Once pre-curing is complete, you can remove excess adhesive with Bohle UV Bonding cleaner, single-edge blades or fine-grade steel wool ahead of the final cure with the lamp.
- Final cure with the lamp
With pre-curing complete and excess adhesive removed, you can carry out the final lamp cure. This will vary depending on materials being bonded, the adhesive used and the lamp selected. As a rough guide, most bonds require 3-5 minutes light exposure with a tube lamp and 1-2 minutes with a high intensity hand lamp.
This means that the bond is now almost at full strength and will be ready for full loads after a further 24 hours. It is good bonding practice to build one day and ship the next.
“Glass furniture is very much on trend and with the right tools, the production process is straight forward,” says Amanda. “The value-add that UV bonding delivers, is what’s so significant, representing a major opportunity for glass processors, shopfitters and metal workers.”
For more information or to join one of Bohle’s UV bonding seminars please email email@example.com or call the customer services team free on 0800 616151 for more information.