WHY USE HOT VAC ?
- Reduce drying time to days, even with long term “hopeless cases”
- Remove osmosis and the causes of osmosis
- Restore structural strength to the hull
- Post-cure of new hull builds or hull repair work
How is the process better than heat lamps?
- Moisture combined with the residues from the breakdown of polyester resin may only be evaporated at very high temperatures.
- These are at least 140°C higher than can be safely achieved with heat lamps. However, the extremely low pressures of a HotVac enclosure allows evaporation at temperatures that are safe, closely controlled and also beneficial for ‘post curing’.
- A second aspect is that the heat pattern generated by lamps is highly non-uniform, there are hot and cold spots and hence treatment will be irregular. HotVac manages to control the temperature of the hull being treated to ± 1°C in a very uniform manner across the heater area. If you are cost conscious, then take a look at your electricity charges for operating heat lamps continuously for three or four weeks.
- HotVac’s intimate application of heat can show up to a ten fold reduction in energy consumed; and that’s good for the environment too!
Will HotVac damage my boat?
- No! HotVac has never been known to have damaged a boat. The slight colour change during treatment has occasionally revealed defects that were previously hidden. These include whitening of fibres through strain damage, impact crazing, areas of de-lamination through the stress reversals of normal service, or stress cracks at bulkheads. Discovery of these defects allows effective repairs to be made. Polyester resins, even when of poor quality, should not be adversely affected at temperatures below 130°C. Good quality resin should be safe at temperatures far higher than this. When taken beyond the glass transition temperature (the temperature after which the resin becomes increasingly plastic) the laminate will become less stiff. With moisture absorption into the hull over the years, this transition temperature at which the material changes from its hard glassy phase into the softer plastic phase, may have actually reduced by as much as 20°C. When the laminate cools down again, it is typical for the laminate to have become stiffer than when newly moulded, and recovered its structural strength. In the process the glass transition temperature will have increased back to near its original value. This is why some boat manufacturers are now curing their hull mouldings in ovens.
Gallery of few projects: