Wraping hi density foam into tight places without using heat and makingthe foam hard

[tunnels]

Who said it cant be done ?? where there's a will there is a way! Took all of 5 minutes of thinking to solve this problem ! Heating was impossible and 3 people had already tried and walked away shaking there heads ! so cutting part way through was the answer but how much to leave that was the question , we did not want print through onto the shiny gel coated finish out side and with a very thin glass skin !
This was similar to another job I had done a couple of years before so cut a sample and wrapped right in the bow where the tightest radius was and behold it worked !! with the cut inside they closed up but gave us channels for the resin to fill and there was no visible cut inside once the peel ply was removed ! the first hull was the trickiest getting a methods sorted and after that it was a breeze !
Photo 3 shows what had to be cut port and starboard for each boat ! It was such a tight area to work inside of only one person as able to fit !
Photo 4 shows the base adapted to angle grinder to give the right depth and the guide for each cut ! The width if the actual teeth on the saw blade was another key to making it work ,The finer the cuts the more had to be made !!,with the 18 MM hi density foam getting the right depth was another factor to making this work properly and allowing the foam to bend and not break so we settled on just 4 mm of uncut foam at the bottom the groove ! The cuts at bow end were close together and as the radius increased so the spacing of each cut increased as well !
As can be seen in photo 2 whole sheets had to be cut similar to achieve a nice gentle bend ! Hi density foam was only used in the hi stress area and above the waterline the density dropped to H65 and the thickness went down to 15 mm These hulls had just one skin of 0/90- 600 gram each side but continuous strand 400 mm wide unidirectional glass was laid only where rigging would be putting huge strain on the hull ! under the core in strategic places and over the top of the core before the inner skin was laminated .

[olboatman]

As you said its all about thinking it thru.... useful info! Question How much stronger is the foam now that it has resin in the cuts? Thanks Gary

[tunnels]

As you said its all about thinking it thru.... useful info! Question How much stronger is the foam now that it has resin in the cuts? Thanks Gary

Adding strength was not an issue as the foam was hi density H80 any way but longitudinally it was really ridged !
Was amazing we made some samples and it was really quite strong to tryand flatten out !
I showed this to a guy on Boat design who was trying to vacuum infuse a big whole catamaran hull in one piece and it worked wonders for him stem to stern each hull with a vac bag inside and outside By memory the hulls were about 30 foot long ! ! The principle is easy to understand and its the fact of having the cuts inside that gives a smooth outer curve without any ridges and doesn't leave any print though marks out side against the gel coat as the resin is filling the small voids is inside the foam ! The narrower the saw blade the finer the cuts so all in all there's only a very small amount of resin gets used within each saw cut And because the saw cut is closing together on the inside edge so no filling required any where ,Its also a good place to use peel ply and make a neat job of laying every where !specially over all the edges !

[FUJIMO]

What are you bedding the foam in? What catalyst? What percentage? What temps are you doing this in? Any retardant?(Cumene Hydroperoxide, 2-4 Pentandione, etc.)

[tunnels]

What are you bedding the foam in? What catalyst? What percentage? What temps are you doing this in? Any retardant?(Cumene Hydroperoxide, 2-4 Pentandione, etc.)

The whole hull was foamed from gunnel to gunnel stem to stern apart for the keel stub and the rudder bearing area and where the sail drive was mounted ! The sail drive unit was mounted onto solid glass !and the core stepped away 80mm around the bases perimeter !THe area from the waterline down was all H80m foam and water line up H65 !Foam
A single layer of very wet 450 gram Chopped strand matt was used extensively to bed all the core panels in place ! everything was vac bagged the forward area was all precut and fitted in place from the bow first, then bagged onto the wet glass ,two people worked in this are as the hull was narrow !
All resin for the whole boat was Vinylester ! And catalyst was just the standard off the shelf And no retardants were needed or used at any time ! Temperature was +25c all the time as the glassing area was completely tented over with air conditioners going 24 hours of every day while glass was being done !!Even at night temperature was maintained 7 days a week .
When I first arrived in Korea the project was already 3 month behind and because it was beginning of winter with temperature's down to minus -15c and two foot of snow outside most of the time to get and maintain a tight production schedule each day with no failures of any kind and for any reason so we had to have a 100% controlled air conditioned environment to work in!

[olboatman]

Still wondering if the resin lines make the foam stronger? We use sheets of plywood cut like that for making curved stairways in some of the houses I build.

[XstreamVking]

You could also use 2 thinner pcs of foam to make the curve w/o all the cutting.....

[tunnels]

Still wondering if the resin lines make the foam stronger? We use sheets of plywood cut like that for making curved stairways in some of the houses I build.

Same principles apply to foams as there are in working with wood !

[tunnels]

You could also use 2 thinner pcs of foam to make the curve w/o all the cutting.....

Have tried that before and was a waste of time !, there's just to much work involved ,and its no where near as strong ! the boats the company are making to this day they haven't changed the system

[One Oldman]

Great post! Just like curving wood!

[FUJIMO]

The whole hull was foamed from gunnel to gunnel stem to stern apart for the keel stub and the rudder bearing area and where the sail drive was mounted ! The sail drive unit was mounted onto solid glass !and the core stepped away 80mm around the bases perimeter !THe area from the waterline down was all H80m foam and water line up H65 !Foam
A single layer of very wet 450 gram Chopped strand matt was used extensively to bed all the core panels in place ! everything was vac bagged the forward area was all precut and fitted in place from the bow first, then bagged onto the wet glass ,two people worked in this are as the hull was narrow !
All resin for the whole boat was Vinylester ! And catalyst was just the standard off the shelf And no retardants were needed or used at any time ! Temperature was +25c all the time as the glassing area was completely tented over with air conditioners going 24 hours of every day while glass was being done !!Even at night temperature was maintained 7 days a week .
When I first arrived in Korea the project was already 3 month behind and because it was beginning of winter with temperature's down to minus -15c and two foot of snow outside most of the time to get and maintain a tight production schedule each day with no failures of any kind and for any reason so we had to have a 100% controlled air conditioned environment to work in!

...All sounds good. Working with what you have is hard enough in the U.S., let alone, where you are... Nice job.

[tunnels]

Great post! Just like curving wood!

Yip exactly the same principle !!