Re: Resin volume placed on foam


Eugen Pilarski
 

Wow. Great story and pictures!! Did not think that so many composite experts are here in this group. Great. 

When I look at what you have worked with in your career in the field of composites, especially with these large furnaces, I feel really small with my little vacuum bag and the electric blankets.  :-))  I think the Q1 would fit entirely in one of these ovens and many more......

Eugen 

Am 31.03.2021 um 02:01 schrieb Jay Scheevel <jay@...>:

That’s a cool discovery, Charlie. Also, glad you are going to get the “Milk Stool” back in the air soon. 
 
Cheers,
Jay
 
From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of One Sky Dog via groups.io
Sent: Tuesday, March 30, 2021 5:36 PM
To: main@Q-List.groups.io
Subject: Re: [Q-List] Resin volume placed on foam
 
Vern,
 
You cannot use a vacuum bag for a repair on orbit. No consolidation without a column of air pushing on it. We discussed on orbit composite repairs with Thiokol and Scotty Horowitz after the second shuttle loss. The silicon carbide / carbon leading edge had a hole in it from ice impact. It would take a lot of development but Space shuttle is gone.
 
 
<image001.jpg>
 
I found two of my composite Filament Wound Case segments in Tucson a couple of weeks ago while visiting the museum. The forward 3 segments are 1/2” D6AC steel but the back two are what we produced at Hercules 1985-1986 RIP Challenger.

Charlie
 
P.S. found a replacement engine for the Tri-Pacer and working on installing.



 

On Tuesday, March 30, 2021, 3:28 PM, smeshno1@... wrote:

 The ideal is zero void. Q.A. has to have some standard for acceptance or rejection. Engineering margin calculations take into consideration that zero void is not possible, although in zero G/ zero atmosphere manufacturing we might be much closer to the ideal. I probably will not live long enough to see it but most M.E. have already thought of what limits would be revised in such an environment. Perhaps some of you in your twenties could..I hope so!!   
 
 Theoretically.. glass fiber would be nearly infinitely strong in tension if there were no surface stress risers on the fibers. Not possible in todays world of course. 
 
 As I mentioned once before..nano techs were in the works to really make some advancements but the almighty Euro/Dollar/Yen or whatever money exchange chosen stepped in and made "no joy" for those events to happen.
 
 Check out "bucky balls" on the Net if your curious. Anyone that ever made this actually happen would be wealthy beyond imagination.     
 
Vern

From: main@Q-List.groups.io <main@Q-List.groups.io> on behalf of Rob de Bie <robdebie@...>
Sent: Tuesday, March 30, 2021 4:35 PM
To: main@Q-List.groups.io <main@Q-List.groups.io>
Subject: Re: [Q-List] Resin volume placed on foam 
 

Thanks for the explanation! I never did autoclaving myself, although I prepared some fiber-metal 
laminates to be autoclaved.

A related question: AFAIK, a low percentage of voids (below 3-4%) has hardly any effect on the 
material properties. Would it be right to say that it is then more an indicator for quality control?

Rob

On 30 Mar 2021 11:57, One Sky Dog via groups.io wrote:
> Rob,
> 
> In an auto clave the usual cure cycle begins with full vacuum to expand the air bubbles so they move 
> laterally between the plies. The pressure is applied to reduce the size of any voids left and drive 
> remaining gases into solution in the resin.
> 
> Blender scheduals are calculated to not remove to much resin.
> 
> 
> Charlie
> 
> My you tube channel
> https://www.youtube.com/channel/UCr3x6bkHUw1UUQ96ATcRFfg 
> <https://www.youtube.com/channel/UCr3x6bkHUw1UUQ96ATcRFfg>
> 
> On Monday, March 29, 2021, 1:30 PM, Rob de Bie <robdebie@...> wrote:
> 
>     I really like this as a thought experiment. And I see some parallels with autoclave processes.
>     In an
>     autoclave you can apply pressure without the vacuum turned on. Therefore this is sort of similar to
>     what you propose. I haven't figured out yet whether this leads to different amount of resin flowing
>     into the bleeder - but my gut feeling says it will have a considerable effect.
> 
>     And now that I'm thinking about it, a typical autoclave pressure *could* make the resin absorb
>     small
>     air bubbles. At least that's what I see in resin casting, using polyurethane resin. In that process
>     one can take one of two very different routes: vacuum casting or pressure casting. In former you
>     'pull out' the air bubbles, in the latter the pressure makes the resin absorb the air bubbles.
>     Until
>     tonight I hadn't seen the parallel. But it has nothing to with building a Q1 or Q2 :-)
> 
>     Rob
> 
>     On 27 Mar 2021 21:40, Bruce Crain wrote:
>      > Just a thought.  Would it help to vacuum bag parts and then put sand or lead on top of the
>     outside
>      > bagging material to use weight to press the resin and glass together tighter into the weave?  It
>      > would be messy and you would have to keep the mold from creeping but what does the group
>     think and
>      > does any one have any experience to share about that?  Just thinking outside the box.
>      > Bruce Crain
>      >
>      > ---------- Original Message ----------
>      > From: "Stuart Grant" <smgrant@... <mailto:smgrant@...>>
>      > To: main@Q-List.groups.io <mailto:main@Q-List.groups.io>
>      > Subject: Re: [Q-List] Resin volume placed on foam
>      > Date: Sat, 27 Mar 2021 07:18:37 -0700
>      >
>      > Here is a link to a YouTube video where Cozy Girrl Randi explains about how Cozy Girrls make
>      > composite parts, including mixing epoxy, mixing micro, using gloves, low pressure vacuum
>     bagging,
>      > peel ply, sanding etc. The video was recorded at Sun-N-Fun 2019 and the beginning has a lot
>     of noise
>      > from the air show but Randi has great tips. https://youtu.be/fmuDOWTr_3c
>     <https://youtu.be/fmuDOWTr_3c ><https://youtu.be/fmuDOWTr_3c <https://youtu.be/fmuDOWTr_3c>>
>      > If the link doesn't work search YouTube for
>      >
>      >
>      >          Cozy Girrrl's LoVac Composite Tools & Tricks
>      >
>      >
>      >
>      >
> 
> 
> 
> 
> 
> 





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