| Re: Free Autoclave for Masts/Spars
[Re: Kevin Cook]
#142346 05/07/08 11:56 AM 05/07/08 11:56 AM |
Joined: May 2003 Posts: 4,451 West coast of Norway Rolf_Nilsen
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Posts: 4,451 West coast of Norway | I would like to show a picture/drawing embedded in a message (in addition to as an attachment). The picture/drawing is on my pc as a .gif-file, I do not have website with an url for it. I have seen some messages display an attachment picture embedded in the text. How does one do that? just upload the file as an attachment to the message. Then go back and edit your message. You can then cut and paste the URL to the image uploaded to catsailor.com in your message. Any clearer, or worse? | | | Re: Free Autoclave for Masts/Spars
[Re: Kevin Cook]
#142347 07/12/08 12:33 AM 07/12/08 12:33 AM |
Joined: Jan 2004 Posts: 196 Arkansas, USA CaptainKirt
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Posts: 196 Arkansas, USA | Kevin- I am interested and in the process of building a 40 x 54' building so would house it fairly easily. My problem is I am in Little Rock- any idea what the weight is and dimensions of the two pieces? I could not see photo- I actually have a cat trailer of mine at a friend's in Chattanooga, TN that might hold it- Any chance you could meet me somewhere inbetween or deliver to Chatanooga if I covered your costs? Or??
Thanks!
Kirt
Kirt Simmons Taipan, Flyer
| | | Re: Free Autoclave for Masts/Spars
[Re: Rolf_Nilsen]
#157148 10/15/08 03:32 PM 10/15/08 03:32 PM |
Joined: Dec 2001 Posts: 5,590 Naples, FL waterbug_wpb
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Posts: 5,590 Naples, FL | Autoclave processing is the most common method used for curing thermoset prepregs. The curing of thermoset composites involves both mechanical and chemical processes. Mechanically, pressure is applied to remove trapped air and volatiles, and to consolidate the individual plies and fibers. Chemically, a crosslinking reaction must be initiated and taken to completion to form a rigid matrix. Crosslinking is most commonly initiated through the application of heat, though it also may be initiated by exposure to ultraviolet light, microwaves, or high-energy electrons (e-beam curing). In the autoclave process, high pressure and heat are applied to the part through the autoclave atmosphere, with a vacuum bag used to apply additional pressure and protect the laminate from the autoclave gases. The cure cycle for a specific application is usually determined empirically and, as a result, several cure cycles may be developed for a single material system, to account for differences in laminate thickness or to optimize particular properties in the cured part.
The typical autoclave cure cycle is a two-step process. First, vacuum and pressure are applied while the temperature is ramped up to an intermediate level and held there for a short period of time. The heat reduces the resin viscosity, allowing it to flow and making it easier for trapped air and volatiles to escape. The resin also begins wetting the fibers at this stage. In the second ramp up, the temperature is raised to the final cure temperature and held for a sufficient length of time to complete the cure reaction. During this step, the viscosity continues to drop, but preset temperature ramp rates and hold times then stabilize viscosity at a level that permits adequate consolidation and fiber wetting, while avoiding excessive flow and subsequent resin starvation. These control factors also slow the reaction rate, which prevents excessive heat generation from the exothermic polymerization process.
Jay
| | | Re: Free Autoclave for Masts/Spars
[Re: waterbug_wpb]
#157149 10/15/08 03:37 PM 10/15/08 03:37 PM |
Joined: May 2003 Posts: 4,451 West coast of Norway Rolf_Nilsen
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Posts: 4,451 West coast of Norway | Yeees, thank you But how is the laminate consolidated without something physical pressing on it? Like it is in vacuum bagging. Still hope Kevin (or others) have pics of parts ready for 'cooking' in the 'clave. | | | Re: Free Autoclave for Masts/Spars
[Re: Rolf_Nilsen]
#157157 10/15/08 03:58 PM 10/15/08 03:58 PM | Anonymous
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Unregistered | Rolf, the parts are in a vacuum bag inside the 'clave. using the 'clave lets you achieve more than 1 atmosphere of pressure. | | | Re: Free Autoclave for Masts/Spars
[Re: Anonymous]
#157187 10/15/08 09:40 PM 10/15/08 09:40 PM | Scarecrow
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Unregistered | Rolf, the parts are in a vacuum bag inside the 'clave. using the 'clave lets you achieve more than 1 atmosphere of pressure. Sorry that was me. | | | Re: Free Autoclave for Masts/Spars
[Re: ]
#157209 10/16/08 03:56 AM 10/16/08 03:56 AM |
Joined: May 2003 Posts: 4,451 West coast of Norway Rolf_Nilsen
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Posts: 4,451 West coast of Norway | Thanks for all the replies! I am looking to scrounge parts as good steel is quite expensive. Might find most or all of in the scrapheap at work as high quality tubing goes in and out of the plant here all the time. What kind of bags can be used when heating? Regular polyethylene would probably melt? I am also curious how you set up the bags with the venting valve?? One pic probably say more than a thousand words at this stage. How much pressure can you use if doing a wet layup? More than 2 bars and I was told the part would be resin starved. I am not saying we are going to do this, but the idea is ricocheting around the inside my skull. I am a bit wary about having a homebuilt pressurized autoclave in my basement, but as long as my wife dont know.. | | | Re: Free Autoclave for Masts/Spars
[Re: Kevin Cook]
#157243 10/16/08 09:02 AM 10/16/08 09:02 AM |
Joined: Oct 2007 Posts: 199 Constanta, Romania isvflorin
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Posts: 199 Constanta, Romania | Kevin, what are the advantages of using the autoclave with wet layup and not prepregs ? Faster cure for sure but is it worth it for wet layup ?
Florin
| | | Re: Free Autoclave for Masts/Spars
[Re: Kevin Cook]
#157303 10/16/08 03:22 PM 10/16/08 03:22 PM | Scarecrow
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Unregistered | I agree with Kevin, you don't need an autoclave for wet laminates. If you want to get fancy with these try resin infusion.
Suitable bagging materials for pre-preg work should be available from who-ever you buy the pre-preg off. Typically the bagging film is green and quite crisp. In my experiance Aerospace autoclaves operate at about 7 atmospheres, but this will be unnecessary for your projects. Aerospace 'claves are also pressurised with inert gases to minimise the chance of them turning into bombs, however this might be a bit complicated for a home build. | | |
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