Wahoo ATV

is the epoxy heat activated as aposed to chemically? I ask because I thought you needed an autoclave for prepreg.

DPT MOTORSPORTS

Yahoo,

Not sure if I have it right but isn't an Autoclave an oven? If so they bake all the OL's they build in an oven.

Sean H

they are post curing the epoxy in the oven. it's a straight oven, not autoclave, an autoclave has the ability to attain a high pressure and heat, the oven is basically a paint booth used for curing paint.

DPT MOTORSPORTS

Thanks for clarifying Sean. I have never seen an Autoclave up close so that would be the reasoning for my mistake. Everyday you learn something new. Very, very cool though.

Wahoo ATV

If they are simply post curing the epoxy, wouldn't infusion be a better method than vacuum bagging? Afterall, they are already investing in CF and a premier boat. Just asking because I really don't know and find this stuff very interesting.

Sean H

You could, but you are still vacuum bagging it, you are just drawing the epoxy through at the same time. It may save you a little weight, but it takes longer. You have to still layup the the outer skin the convential way also. The guys I have asked about it say it probably is an ideal way to do it, but not always practical.

The biggest drawback I have heard from the 2 guys I have asked is, you have to lay all your fabrics, spray adhesive down all the coring, lay more fabric, put all the bags on and tubes and hope nothing has moved in the process. That is a lot to chance to save a few pounds over a quality bagged epoxy hand layup.

Keith Atlanta

Autoclaving will result in a stronger and more dense end product. Only problem is an autoclave is about 20x more expensive than a heat booth. Think of something that looks and is designed like a submarine that draws down to multiple negative atmospheric pressures as well as heat. Vaccuum bagging on the other hand is a pain in the ass weather you are laying up a boat, a plane or a bicycle. In which case a leak or air being drawn into the bag is a disease and leaves the infected area looking discolored and porous. Although its labor intensive, its still far cheaper than an autoclave. If you are interested in the topic GOOGLE Boeing 787 or Lockheed JSF35. These aerospace processes are highly technical and the marine industry essentially leaves out a piece here or there.... its not really that easy but it is easier to start complicated and go backwards. As Sean H mentioned, its only worth a few pounds but in aviation that is 100's of pounds and it makes a BIG difference. Realistically the 787 fuselage is only about 1/4 thick carbon between you and 500 MPH and 30,000 feet. A hull such as an Outerlimits or Mystic or whoever can build a carbon fiber hull that is 30% lighter due to significantly less mass than their fiberglass counterparts.

http://www.star-telegram.com/Multime...dreamliner.swf

Step by step carbon fiber process. (click on Voughts tail for actual pictures)

animalhouse

Tuesday Progress, Stringers are going in, building the carbon dash's, and finishing the cockpit structure.

glassdave

iTrader: (1)

Autoclaves work on positive pressure not vacuum. When combined with a vacuum bagged laminate the part is first layed up, completely bagged and vac'ed of any air voids then placed in the autoclave and kept under full vac pressure until the autoclave reaches its peak positive pressure or vented to the outside atmosphere. When pressure is applied the process kind of works in reverse of the original vac bagging. If that makes any sense

Also think of this. How would you heat it if it were a vacuum?

that a cool website on the 787 by the way. Its amazing the fuselage parts are built all around the world then brought together in WA. Thanks.


great thread by the way.

jayboat

iTrader: (1)

Just curious, if you can tell us without divulging trade secrets-
how hot and how long do you cook it?

I'm really enjoyin this thread- thanks for taking the time to post the pix.