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Old 07-29-2017, 03:15 AM   #10
spearq8
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Join Date: May 2009
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Re: Pre Preg Carbon Wrap

Quote:
Originally Posted by kavachi View Post
Majd, what sort of actual vacuum time required with the 209 hardener?
Looking at cheapest/most compact option for bagging sleeve and handle here, something small but with sufficient run time.
Got plenty of pressure here with Bauer and tanks, but no SUCTION…….
Time is totally dependent on the ambient temperature. If it is cold, I might have to leave the vacuum on overnight ... and maybe a little more. In our hot summers, I just leave it on for about an hour or two. Of course if it is cold then I would just use 206 as it still gives enough time. Lately I have been using epoxy from easycomposites in the UK and their stuff is incredibly liquidy and has even longer cure time than 209. My last few CF wraps, I actually just put the CF sleeve over a dry stock ... makes things much much easier. I apply the epoxy after the sleeve is on ... since it is so liquidy it wets out the CF extremely well. I also don't use the typical vacuum bags any more. I bought some new vacuum bags that are shaped into sleeves ...this avoids the typical hassles of sealing a typical vacuum bag. I just seal one end of the tube ... push the CF wrapped speargun inside and then just seal the other end. I keep that tube longer than I need as this way I can re-use the bag again and again ... I just cut the edge to allow me to remove the gun after cure, and with the added length I can re-seal it and thus re-use it several times. My latest CF wrap protocol is actually extremely easy to do and takes only a few minutes of work. Using the thin epoxy allows the vacuum to really suck up any extra epoxy ... thus keeping additional weight to an absolute minimum. I do keep a peel ply layer that gives the surface a nice rough finish to allow a final coat of epoxy. This also helps as it keeps the need for sanding to an absolute minimum ... which also makes things easier and faster. I always keep sanding CF to an absolute minimum ... and if I have to sand I always use heavy grit like 100 or to file off the zip tied ends I just use a file ... this keeps sanded particles large and thus avoids them floating all over the place. CF dust can be extremely irritating to your skin and you should take precautions against that ... a mask and gloves is a must if you are sanding. I even use a Tyvek suit to make sure no dust gets into my clothes and have a Hepa 13 vacuum cleaner on to suck up as much debris as possible if I work indoors. I did a lot of research regarding the hazards of CF dust, and somehow it seems that it is not hazardous like say asbestos as it is carbon and we are carbon based ... but it can really be irritating to your skin especially if it has curing epoxy on it. What is extremely hazardous is the new nano carbon fiber that is being introduced. That stuff is dramatically stronger than normal CF ... but I will never touch that stuff as it just isn't worth it.

If you don't have a vacuum pump you can get away with a compressor and add a special valve that allows the compressor to suck up vacuum. Of course a compressor is not designed to be left on over night ... so I would just use faster cure epoxy and have a setup which the seal is very good where I can just turn off the vacuum without having the bag leak. With sleeves that is pretty easy to do but with a typical vacuum bag it is more difficult to have a 100% leak proof bag ... so maybe you would need to keep an eye on the bag for a while as you seal of the leaks. Personally I just leave the vacuum pump on as this allows me to forget about it and do something else.

Last edited by spearq8; 07-29-2017 at 03:39 AM.
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