How To: Epoxy pumps: when bigger is better
Gary Thompson was visiting the famous Red Sky Craft boatyard in Kotka, Finland, when he came across a simple but ingenious solution to dispensing large volumes of WEST SYSTEM® G/flex epoxy.
Allan Savolainen and his team at Red Sky are big fans of WEST SYSTEM G/flex 655 epoxy, using it for all their bonding applications. In fact, the epoxy was used throughout their extensive four year restoration of ‘Blue Marlin’, the 12m sailing yacht including replacing every plank fastening with G/flex 655 epoxy.
The thickened epoxy adhesive has all the great physical characteristics of a conventional epoxy, such as moisture exclusion, high tensile and compressive strength but it is much more flexible. This malleability causes the epoxy to behave more like wood, so Allan uses as much as possible in order to keep his restorations ‘semi-traditional’. In other words, he makes sure the boat’s behaviour is as close to a traditional boat as possible – whilst still using modern adhesive technology to preserve it for the future.
Another important factor in the decision to use G/flex epoxy can be seen as soon as you walk through the boatyard door.
I have seen a lot of impressive restoration yards, particularly in Scandinavia, but Red Sky tops them all. The workshop is temperature and humidity controlled and is ordered like a hospital operating theatre. Allan likes to keep dust to a minimum, so the cleanliness of G/flex 655 epoxy is perfect for Red Sky. Its simple 1:1 mixing means there’s no need to thicken by adding dry fillers as both the resin and hardener are pre-thickened.
Allan’s only problem, then, was that he couldn’t use the G/flex 655 epoxy fast enough. He required a higher volume dispenser to get it out of the tubs quicker.
G/flex epoxy is typically a high-viscosity adhesive, so the only way to effectively dispense it is through a pressurised twin cartridge gun but this style pump isn’t traditionally manufactured. Unfortunately for Allan, positive displacement pumps for lower viscosity epoxies are widely available on the market but high-volume pumps are far more rare.
So, Allan decided to take matters into his own hands and build himself a giant, vertically hung, twin 1:1 syringe pump. In his design, both plungers are moved simultaneously by a single action lever, delivering the heavy glue via gravity and pressure. The best ideas are always so simple! It took a bit of time to cobble together but Allan is sure that the time saved in dispensing G/flex 655 epoxy has long been overtaken.
Discover more about Red Sky’s favourite WEST SYSTEM product.