one bang ployester resin layout ???

[newo eloc]

I intend to hand layout 12 mtr long sleek elipse shaped cat hull( more like a pontoon or long pipe) at their widest point they are 900ml x 600ml , 2.4 mtr circumfrence. surface area 30 m2. I use a male mold that revolves around a point bow and stern.highest point bow to stern is a straight line horizontal to waterline.Nothing is proud of the surface area. On a 3mtr (1mtr circumfrence) model I built, I laid out the matt( just one of duo matt) on a table next to the mold, wetted out then slid it over to starting point on mold then revolved mold 1 complete turn bringing matt with it .It worked well. Question 1/ could it be done with 6 milimtr's of laminates at the same time or will it cook ( 90 kg's resin in one bang)? q/2 how can you slow down gel time ? q/3 down side of one bang layout ? q/4 incorperating vinyl-ester in final laminate as protective coat over poly-ester laminate can that be done ?

[nero]

Interesting idea. How do you keep the mold from sagging in the middle? Will it support the load of resin and glass and still not sag?

No nothing about polyester. Do you plan on doing this by yourself?

[newo eloc]

I dont want to do it myself. I have built 12mtr GRP hulls and I swore never again Ill probably get a local shop to do it. Ill support the guts on adjustable rollers as its going over then sit it down upside down on its straight back Ill have to talk to whoever will be doing it. I dont even know if it can be done it worked on a smaller scale.

[yokebutt]

Eloc,

You can buy un-promoted resin and add the cobalt and DMA yourself to get the right cure-rate. Most shops used to do it themselves as a matter of course a couple of decades ago, but do beware, they're nasty chemicals, and if you mix the wrong things together undiluted it can explode, but other than that, it's easy.

(Cobalt is cobalt naphtalene, and DMA is dimethylaniline)

Yoke.

[newo eloc]

thanks yokebutt, what about wetting out all the lamenates one layer at a time but all in the same session ( total 6ml thick 90 kg resin over 26m2) and let it all go off together is that advisable .

[yokebutt]

Eloc,

How about making a smaller test-sample by adding each layer a few minutes apart? But you'll have to space out the time between layers to mimic the time it takes to do the full-size layup.

Yoke.

[newo eloc]

thanks Yoke ,I will do that ,I'll do a bulkhead and time it to match main layout and see how it behaves.

[IHeartFRP]

I just want to echo (for your safety) the health hazard that comes along with working with Cobalt and DMA. DMA is extremely poisonous, Cobalt not as much but I still wouldnt go licking it off your stir stick.

Get yourself some gloves that state on the box that they are impervious to chemicals. The regular old latex cheap-o gloves let some chemicals right on through so I recommend nitrile gloves. Also make sure you work in a heavily ventiliated area because the DMA can easily be inhaled too, not just absorbed through your skin. Wear safety glasses or goggles as well to protect your eyes from any splashing that may occur.

And yes... these chemicals can be explosive if mixed together undiluted. The best thing to do is to take out one chemical, measure it out, mix it into the resin and then put it away. Then take out the next one and use a different measuring device than you used for the first, mix in, and put it away. Also- keep catalysts away from the Cobalt... yet another dangerous explosion hazard.

Good luck- sorry to be so lengthy but I am a stickler for details when it comes to your health!

[newo eloc]

thank you Iheart , I wont be mixing chemicals, the poly ester already knocks me around enough as it is. I'm not set up for it. Long term exposure to these resins must cause neurological damage. Vacum baging sounds good but I mainly do one off's. Ill certainly take your material handling procedure recomendations on board. I have a shop pricing a 30 m2 180 kg job for me but they want to lamenate 1 at a time using 1.2mtr width w/roven. the pontoons are cylindrical and have a 2.35 mtr circumfrence it will take 6x1.2x12mtr lengths of r/roven can someone suggest a more efficient manufacturing process .