I'm going to be bagging a 20' hull 30" wide. The layup will be 7/16 H-60 foam strips edge glued cove and beaded. FiberGlass lay-up on each side, I will bag one side at a time using West System epoxy. I plan on using peel ply, batting, and bagging plastic.

I have not purchased the equipment yet but need to soon.

Basically if you don't already have a very good mould, then don't bother, any weight savings will be minimal ( about the 4 pints of beer you had last night ) and you run a real risk of distorting the foam sufficient that you can't fair the outer surface. Far better to follow John Lindahl's LR3 or LR2 build method, it produces a fair product quickly.

Another trick particularly if you plan to use carbon is to put a very light weight glass cloth on the top surface, you can see instantly whether you have added enough resin or sqeegee off excess.

Best of luck

Mike,

Two local small boat builders in the Chesapeake Bay are Mr Kevin Cook and MR George Saunders .... they are known to frequent the BoatBuilders Forum. Between them they have built Tornadoes ... IC's .... A-Cats .... 33' Carbon Tri ... etc

I would put a "shout-out" to them.

Harry

Hi, I have a question.
Do you have a mold or planing to build one?
You might check out the Farrier Marine site http://www.f-boat.com/pages/trimarans/F-22.html or some of the blogs that their customers are writing, http://ballard-f22.blogspot.com is a good spot to start. Also you did not mention "release film" in your vacuum bagging stack.
If you don't use it the Breather/Bleeder will bond with the peel ply and it will be a real mess getting it off!
I have been doing this on and off for 25 years and when everything work right it can be a real joy to pop out a new part.

run a test bag with a gauge. listen for leaks in the foam. have lots of bag, get it to start to go down and then smooth it off the laminate. use a 'p-3' perf film between the peel ply and the bleeder. take your time to get the peel ply right, use a dry brush to apply it in smaller (non roll width) strips. make sure you have a good spot to seal the bag to. take your time. use ultra slow hardener. add heat. dont make a mess.

I have to second the motion for "ultra slow hardener" the part I did yesterday took 4 hours to layup. You don't want the part the "pop off" while you are still working on it!
My molding room is 8' X 22' in size, so I just seal it up and turn on a heater and set it for 130 F.
8 hours later turn it off and pop the part 36 hour later.

I always thought that a 40' shipping container would make a good area to do layup work in. You could close it and turn it into a giant metal oven basically with some space heaters.

That sounds pretty good.

Make sure that your foam surface is airtight and a couple of inches oversized.

Make the bag oversized - better than too small! Wrinkles in that won't matter. get the peel-ply nice and flat tho'

Put plenty of resin on the foam 1st. Any excess will always get drawn through, but less likely to go the other way if foam is abit dry

make sure that foam is secured in shape well as distortion may happen under pressure [As previouly said]

take a look at the farrier builders, many of them do it this way. Myself,seeing as Farriers only use one skin of glass, i didn't find it worth the effort/money. You can't beat a good man on the squeegee that is also paying for the resin! Always use peel-ply tho.

I'd recommend you not vacuum bag that hull. Here's why.

Vacuum bagging works best when you have a complete, fair male or female mold. Since you are using stations, its going to be next to impossible to get the vacuum to seal, at least until the foam strips are glued together and even when they are, its going to be hard to get a good seal. Any leak between the foam strips will ruin the vacuum and the entire hull will be a mess.

Take a look at Tony Arends build of his Acat hull, he uses push pins to hold the foam in place until the epoxy dries between the foam strips. He pulls out the pins and then he puts on the cloth.

The benefit of vacuum bagging is that it holds all the layers of your hull in a mold and presses everything together, so you get good adhesion and a more dense part, and everything follows the curves of the mold.

Since you will need to pin the foam down, you are missing one of the big benefits of vacuum bagging, having the vacuum suck everything down into the mold. And since you need to do that step by hand, you might as well squeegee the cloth on by hand too.



http://www.usaca.info/index.php?option=com_content&view=article&id=173:inner-skin-a-skim-coat&catid=51:predator&Itemid=104

Another thing that I thought of;

Put a band of epoxy where the seal tape for the bag is going to go, put on peel-ply and let it harden. This will make sure that the tape has a nice surface to stick/seal to. it doesn't like raw foam too much.

it is quite possible and easy to bag to the foam in the situation you are in. it is worth it not for the bleed out of excess resin but for the fibre consolidation.
like teamvmg says, add a band of epoxy to seal to, but have the foam large around the perimeter of the boat.

Agree with Basket Case. I have vacuum bagged a lot of hull sides and parts up to 34 foot trimaran hulls - singlehanded. There are a lot of tricks to make things easier - send me a private message and we discuss further if you want.
Kevin Cook

Kevin,

learning your tips and tricks would be wildly interesting for others as well. Or at least for me.. I want to try my hand at foam sooner or later, and learning from a "master of tricks" will surely shorten the learning curve.

I'd advise you to talk top this guy:
http://www.fram.nl/

Hennie used resin infusion on a Farrier F39. He was probably the first to do so.

Dennis

I'll try to write an occasional post on the boatbuilding forum concerning one aspect or another.
Kevin

Dennis,
I have visited this website and was totally impressed with the resin infusion project. It takes a lot of work up front to get this method to work right. Are the hours worth it for a one-off building project? Certainy the results are better than any wet layup method and rival prepreg quality but it's a huge investment in hours for the planning. But, for pushing the envelope for home builders, this person dererves our respect.
Kevin

Thanks for the advice. From what I've read the NA says the foam can be lifted slightly once the strips are glued to slide the bagging material under the foam between the foam and wooden mold stations. I've been a bit under the weather and have not replied sooner. I have a bum shoulder and I'm looking at going under the scope so it has slowed me down some. Take a look at my website to follow along with the construction method and progress www.themanshed.net then click on the TMS-20 link on the right.

Kevin I sent you an Email on yopur offer.

Hope that you get that shoulder sorted before you start filing and fairing!

Did some fairing on the mold Sat and spend all day Sunday sore! Going in the tube this afternoon to see what the damage is to the rotor cuff.

I have been using peal ply on lay ups with and without bags with good results on carbon cloth. One of the headaches with carbon is knowing if it is wetted out since it doesn't go clear like FG and squeeging off the excess without distorting the weave. Peal ply solved both of those problems for me I can squeegie over the peal ply remove air bubbles, add resin to dry areas thru it and remove excess resin. It leaves a nice surface like it was bagged ready for a single fill coat without a lot of sanding thru the weave like a plain layup leaves and can be pieced on with overlapping with only a small line to sand away. Getting the results of a vacuum bagging without the extra steps or material. Resin infusion is fun you can spend all day making a bag perfect and completely sealed under vacuum before mixing the resin.

This is a hatch lip I cast under my deck after removing the peal ply no vacuum.

Hope the test in the tube goes well, those things usually need cutting on something to get better.