TJ Bear
15-03-2010, 12:30 PM
Noticed that their are a few boat builders in Australia using closed moulding to manafacture boats and after a number of PM's asking questions about the process I will attempt to explain the two processes.
I use Vacuum Infusion to build my little 445F based X15, at Riviera I was responsible for the 44ft Sports Yacht and 58ft Sports Yacht both of which where vacuum infused. I was also involved in the development and production of the RTM Lite parts at Riviera. At Riv we manafactured everthing from hard tops for most of the flybridge boats down to the anchor hatches, if I remember rightly over 150 different RTM Lite mouldings.
Vacuum Infusion or Vacuum Infusion Process (VIP)
Vacuum infusion is a process where dry glass is placed into a mould, the mould ussually has a quite large flange so a vacuum line can be run around the outside of the mould. It is possible to install all the dry glass and longitudinal and transvers frames at the one time. Once all the dry glass is in place resin lines are run thoughout the part. Once this is completed a sheet of infusion grade plastic is placed over the mould and affixed to the outside of the flange using tacky tape. 1 bar or close to 1 bar of vacuum is then applyed to the part. When vacuum integrity has been established and there are no leaks from the bag resin lines from a central drum are plumbed into the mould. Resin is then drawn into the mould starting at the keel and all the way up to the flange wetting out all the glass. This takes approximatly 15 minutes on my little X-Boats X15 and up to an hour on a Riv 58ft Sports Yacht. When all the resin has gone off the bag and resin lines are removed and building goes on as normal. Of course there is more than outlined above to being able to succesfully infuse a part but its an overview of the process. Boats that I know are being Vacuum Infused include the boats metioned above plus the new Markham Cat, new Mustang Cruisers, a new 26ft Trailerable Game boat in Cairns and many of the high end US sportfishing boats. Most composite parts for the aerospace industry are vacuum infused from commercial airlinner wings to the newest helicopters and fighter plane fueselages.
Advantages of Vacuum Infusion
Low resin to glass ratio. As the strength in a composite laminate comes from the glass fibre not the resin you can build a lighter stronger product. Typical vacum infused laminates have a resin to glass ratio of between 0.6:1 to 1:1 where typical hand laminates vary from the very best at 1.5:1 to many production boats sitting at between 2:1 to 3:1. High resin content produces a laminate that is heavy and prone to cracking with repeated loading.
Quality - As the glass is layed in by hand before the resin is introduced so it is possible to ensure that glass goes exactly where it needs to be every time. The hull can be engineered to a higher standard and a greater use of higher quality multiaxiale cloths are used than with traditional hand laminates. Every boat will use the exact same amount of resin and have finished weights consitantly the same. As you can bond the tranverse and longitudal frames in the primary infusion you have far more strength as you do not need to worry about secondary bonding in these areas, the entire hull structure is manafactured at one time ensuring a complete chemical and mechanical bond.
Through the use of peel ply the hull does not need to be groud before installing bulkheads etc. This has a quality and enviromental advantage.
When using cores wether they be foam or timber you get a 100% wetout and do not have to worry about air voids or dry spots in the core that can lead to future failure and rot problems.
Due to the bag no volitile ommissions are produced during the process which creats a much nicer working enviroment and you are not emitting large amounts of styrene into the atmosphere.
very flexible process well suited to custom top end manafacturing on a reasonably low volumeDis-advatages
Vacuum infusion cost more due to the consumanles used and more expensive glass and resins used in most instances.
Higher trained staff, to get the process right in a production enviroment you need quite highly trained staff, with hand lay you can put a roller in a guy off the streets hands and have him going in a couple of days, not so with VIPRTM Light
The only boat that I know being built in Australia using RTM Lite is the new little Haines Signature 485 (think thats what they cal it). Haines call the process RIVA I think but it is RTM Lite. A number of US mass produced smaller trailer boats are manafactured using RTM Lite.
RTM Lite is very similar to VIP however instead of placing a plastic sheet (called the bag in VIP) over the dry glass you place a light weight flexible glass mould over the top of the dry glass. The light glass mould can be gel coated first to give you a finished part with gel coat on two sides. The two moulds come together on the flange where 1 bar of vacuum is applyed to clamp the top and bottom mould together. When the flange vacuum is established and not leaking 0.5 bar of vacuum is applyed to the part through a catch pot. When the 0.5 bar vacuum has been established and there are no leaks resin is introduced under preasure (in most instances) around the flange. The resin flows from the flange through the glass and comes out at the catch pot in the centre of the part totaly wetting out all the laminate. When the part has gone off the top light weight mould is removed and the boat can be built as normal.
Advatages of RTM Light
All the quality advantages of Vacuum Infusion
Quick cycle times due to faster setup than VIP, great for larger volumes
Two sided gel coat finish
Does not require as high a level of training of staffDisadvantage of RTM Light
High tooling cost as you need to build an accurate male and female mould
High cost of additional resin infusion pump and vacuum machines
Not suited to custom building as it is very difficult to modify the laminate, cores etc
Not possible to build undercut parts using multi piece moulds as you can with VIPHope this has been of help to someone and ask away if you have any questions.
There are a number of videos on Youtube if you do a search under vacuum infusion boat hull
I use Vacuum Infusion to build my little 445F based X15, at Riviera I was responsible for the 44ft Sports Yacht and 58ft Sports Yacht both of which where vacuum infused. I was also involved in the development and production of the RTM Lite parts at Riviera. At Riv we manafactured everthing from hard tops for most of the flybridge boats down to the anchor hatches, if I remember rightly over 150 different RTM Lite mouldings.
Vacuum Infusion or Vacuum Infusion Process (VIP)
Vacuum infusion is a process where dry glass is placed into a mould, the mould ussually has a quite large flange so a vacuum line can be run around the outside of the mould. It is possible to install all the dry glass and longitudinal and transvers frames at the one time. Once all the dry glass is in place resin lines are run thoughout the part. Once this is completed a sheet of infusion grade plastic is placed over the mould and affixed to the outside of the flange using tacky tape. 1 bar or close to 1 bar of vacuum is then applyed to the part. When vacuum integrity has been established and there are no leaks from the bag resin lines from a central drum are plumbed into the mould. Resin is then drawn into the mould starting at the keel and all the way up to the flange wetting out all the glass. This takes approximatly 15 minutes on my little X-Boats X15 and up to an hour on a Riv 58ft Sports Yacht. When all the resin has gone off the bag and resin lines are removed and building goes on as normal. Of course there is more than outlined above to being able to succesfully infuse a part but its an overview of the process. Boats that I know are being Vacuum Infused include the boats metioned above plus the new Markham Cat, new Mustang Cruisers, a new 26ft Trailerable Game boat in Cairns and many of the high end US sportfishing boats. Most composite parts for the aerospace industry are vacuum infused from commercial airlinner wings to the newest helicopters and fighter plane fueselages.
Advantages of Vacuum Infusion
Low resin to glass ratio. As the strength in a composite laminate comes from the glass fibre not the resin you can build a lighter stronger product. Typical vacum infused laminates have a resin to glass ratio of between 0.6:1 to 1:1 where typical hand laminates vary from the very best at 1.5:1 to many production boats sitting at between 2:1 to 3:1. High resin content produces a laminate that is heavy and prone to cracking with repeated loading.
Quality - As the glass is layed in by hand before the resin is introduced so it is possible to ensure that glass goes exactly where it needs to be every time. The hull can be engineered to a higher standard and a greater use of higher quality multiaxiale cloths are used than with traditional hand laminates. Every boat will use the exact same amount of resin and have finished weights consitantly the same. As you can bond the tranverse and longitudal frames in the primary infusion you have far more strength as you do not need to worry about secondary bonding in these areas, the entire hull structure is manafactured at one time ensuring a complete chemical and mechanical bond.
Through the use of peel ply the hull does not need to be groud before installing bulkheads etc. This has a quality and enviromental advantage.
When using cores wether they be foam or timber you get a 100% wetout and do not have to worry about air voids or dry spots in the core that can lead to future failure and rot problems.
Due to the bag no volitile ommissions are produced during the process which creats a much nicer working enviroment and you are not emitting large amounts of styrene into the atmosphere.
very flexible process well suited to custom top end manafacturing on a reasonably low volumeDis-advatages
Vacuum infusion cost more due to the consumanles used and more expensive glass and resins used in most instances.
Higher trained staff, to get the process right in a production enviroment you need quite highly trained staff, with hand lay you can put a roller in a guy off the streets hands and have him going in a couple of days, not so with VIPRTM Light
The only boat that I know being built in Australia using RTM Lite is the new little Haines Signature 485 (think thats what they cal it). Haines call the process RIVA I think but it is RTM Lite. A number of US mass produced smaller trailer boats are manafactured using RTM Lite.
RTM Lite is very similar to VIP however instead of placing a plastic sheet (called the bag in VIP) over the dry glass you place a light weight flexible glass mould over the top of the dry glass. The light glass mould can be gel coated first to give you a finished part with gel coat on two sides. The two moulds come together on the flange where 1 bar of vacuum is applyed to clamp the top and bottom mould together. When the flange vacuum is established and not leaking 0.5 bar of vacuum is applyed to the part through a catch pot. When the 0.5 bar vacuum has been established and there are no leaks resin is introduced under preasure (in most instances) around the flange. The resin flows from the flange through the glass and comes out at the catch pot in the centre of the part totaly wetting out all the laminate. When the part has gone off the top light weight mould is removed and the boat can be built as normal.
Advatages of RTM Light
All the quality advantages of Vacuum Infusion
Quick cycle times due to faster setup than VIP, great for larger volumes
Two sided gel coat finish
Does not require as high a level of training of staffDisadvantage of RTM Light
High tooling cost as you need to build an accurate male and female mould
High cost of additional resin infusion pump and vacuum machines
Not suited to custom building as it is very difficult to modify the laminate, cores etc
Not possible to build undercut parts using multi piece moulds as you can with VIPHope this has been of help to someone and ask away if you have any questions.
There are a number of videos on Youtube if you do a search under vacuum infusion boat hull