Vaccum Infusion and RTM Lite Boat Building

[TJ Bear]

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 volume

Dis-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 VIP

RTM 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 staff

Disadvantage 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 VIP

Hope 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

[TJ Bear]

Some pics of the X-15 being vacuum infused. Placing dry glas into mould, bag on the mould with vacuum and finished parts ready for the gunwale rubber to go on. I have also included a pic of a cored carbon fibre and epoxy panel that is being infused.

[Chimo]

Interesting stuff, me thinks Riviera should have kept you!

Cheers
Chimo

[TJ Bear]

Thanks Chimo I wish Riviera kept me too. I was made redundant in the last round of redundancies and still have not been payed out by Riv which has made it hard to get x-boats up and going, you don't know anyone with a shed I could use for a couple of months ;-) have completed all the moulds, bought all the equipment, built the web site, have boat one just about finished and have heaps of interest but need a shed to start production, if Riv paid me what they owe me Id be sweet but the recievers have said no chance of that until atleast the 28th of April. Bastards have owed me for nearly a year.

[sharkcat one]

Hi TJ,

Nice looking boat, I like you have infused offshore race boats to production boats and busses. the infusion process does make a lite weight boat , good for reducing weight in race boats and large boats , but maybe not so good in small boats that you want to fish off shore in , Be carefull you don't make the boat to lite , because it will float like a cork.
A friend of mind with more money than sense, got made a 6m off shore fishing boat ( not telling which brand ) and had the hull and deck infused.
I have a 23 sharkcat , another friend has 21 savage , both boats are built old school laminates and are heavy. The three of us go out fishing alot together in our own boats , The sharkcat and the savage punch through the waves , the infused boat goes over every wave , sharkcat & savage very smooth ride - infused boat very bumppy ride because it goes over everything, when we are drift fishing and the wind picks up , fishing from the sharkcat and savage we can still hold the bottom , but the infused boat cannot , he has to use extra lead and sea anchor to hold bottom and sometimes he justs gives up, when at rest at sea the sharkcat & savage are stable platforms , the infused boat is not .

All I am saying from my experience be carefull on making the boat to lite , if you want to use it in rough weather.


cheers

[Chimo]

So given the weight saving and strength an infused top would be a proposition to replace sunbrella bimini, and increase the eyebrow length while at it, ?

Mine has the usual short front section and then the rest goes all the way over the cockpit on a SS bow. (see pic on left)

If so what would such an animal cost particularly, if a few Vagabonds were fitted with them?

Cheers
Chimo

[TJ Bear]

Your 100% correct sharkat one thats why when we designed the hull laminate we way over engineered it to get some weight into the bottom of the hull. The hull bottom has a 600g chopped strand tie lay then a layer of 800g double bias and then 2 layers of 3600g combi mat that is 8600g of glass on the bottom and 8000g of the 8600g are stitched multi axial. The combi is so thick the only way to wet it out is to infuse it. Your typical trailer boat would be luck to have 1600g of stiched multi axial on the bottom with about with 1800g of gun roving chopy, for a total glass weight of 3400g. The hull sides are cored with 15mm closed cell foam with 1600g of glass on each side. Finished weights are about the same as a hand layed boat but far more glass in the boat and the weight has been kept below the water line to make foe a very stable boat at rest.

[TJ Bear]

Not sure of cost of the top of my head as would need to make a plug and mould so would have to know how many where required to spread the cost. Infusion though is perfect for hard tops. Im going to make a Carbon Fibre, epoxy and foam cored t- top for the X15 that will weight about 5kg but you could use it for a chin up bar is will be that stiff.

[TheRealAndy]

Thanks Chimo I wish Riviera kept me too. I was made redundant in the last round of redundancies and still have not been payed out by Riv which has made it hard to get x-boats up and going, you don't know anyone with a shed I could use for a couple of months ;-) have completed all the moulds, bought all the equipment, built the web site, have boat one just about finished and have heaps of interest but need a shed to start production, if Riv paid me what they owe me Id be sweet but the recievers have said no chance of that until atleast the 28th of April. Bastards have owed me for nearly a year.

MAte do a google for geers. If you were laid off and the receivers wont pay you may be able to make a claim for the money owed via GEERS. Its a government scheme, independant of the receivers.

[sharkcat one]

Sounds like you have done the research.

Just interested in how you are going to price this boat with all the work going into the construction side of things ( infusion , carbon , etc. ) ?

Because I do own a small boat company and I have looked at infusing our hulls , but just cannot justify the extra cost ( just yet )that I would have to pass onto the customer .
I have been taking our boats to the boat shows for the last 5 years . And I have found that about 90% of people just don't care if it is infused or not , all they care about is -- top of list --- how much they can get for their money
---- what extras you will give them free of charge
---- how much bling is on the boat
---- they want a 4-stroke for a 2-stroke price
last question is how thick is the hull ?

Five years ago the questions were different , they asked about and were interested in the construction , but now days it is all about what bang they get for their buck.
Today people just don't care because they have a thing called "warranty".

Times have changed.

You and I know how fast you can build a boat with a good gun opperator . This is the reason why I still haven't converted to infusing, The way things are at the moment to compete against imports you have to keep costs down and still build a good boat.
Very hard thing to do.

cheers

[TJ Bear]

If you setup correctly you can get an infused boat out at the same price as a chopper gun boat and we proved it at Riv with the 44 Sports Yacht, from gel coat to stage 1 engineering in 6 days. Cheaper to build than the identical hull as a 44ft Offshore Express which is hand layed. In production I will move to CCBM and a resusable silcone bag that is custom built for the hull. If the customers focus is price over value Im not really interested in building them a boat. I will only build high quality low volume custom boats and if that means I only build 2 a year so be it. I wont use cheap fittings, shitty poly resin, miles after mile of cheap gun rovings, I wont fit cheap wiring, low volume bilge pumps, cheap lights etc etc. If you want a cheap boat there is a heap of them out there. Id prefer to stack shelves at night and build 2 boats a year that Im proud of.

TheRealAndy Been through the GEERS thing they will only pay if the company goes bankrupt. Riv is going to pay but not before the 28thof April only taken a year to get what Im owed.

[JB]

Good attitude there TJ, nice to see boat builders taking pride in their boats. Good luck with the business.

Jas

[TheRealAndy]

Any plan for a boat in the 6m+ range?

[Steeler]

TJ

I think your approach to building a boat and pricing it accordingly rather than building one to a price is just super.

Wish you all the very best.

Steve

[TJ Bear]

Thanks for the positive comments, I know its not the way to get rich but I build boats cuase I live building good boats, as for a bigger boat I have plans for a 5.6m and 6.5m when funds allow.