Laminate Sample #36: Vacuum Infused E-glass / Epoxy with Low (Not Enough!) Vacuum
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- Опубликовано: 1 авг 2024
- This Laminate Sample #36 is about vacuum level and how little vacuum you need to do a successful infusion. Short answer: probably more than this!
Laminate - wise this is an almost-symmetrical balanced 2.5mm e-glass / epoxy plate. The resin is Proset INF-114/210. It is infused at only 10inHg - which is roughly 1/3 of the potential max vacuum level.
The video touches briefly on Darcy's Law - which shows how flow rate is linked to permeability, resin viscosity and the pressure differential created by the vacuum. I try to see if by reducing the vacuum, the permeability can be higher because the laminate stack is less compressed. Of course, this yields a more resin-rich (thicker) laminate with a lower fiber volume fraction. This isn't great! Let's stick to more vacuum in the future!
Check out the EC! article "Introduction to Vacuum Infusion" at:
explorecomposites.com/article...
Also "Troubleshooting Vacuum Infusion" at:
explorecomposites.com/article... 
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I am happy to have found your channel, very cool stuff, I did a vacuum infusion test back in 2009, from watching a one Sf. panel I learned alot., I will be subscribing
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It would be interesting to see this experiment replicated at different vacuum settings, and with possibly other post-infusion steps like rolling on top of the bag while still drawing a vacuum.
Unfortunately to do that would an inordinate amount of time and materials.
Yes! I had similar thoughts putting this together. Would be fun to do tests with the same part over and over with only one variable changed. Wouldn’t be too big of a deal to do...
I have a problem with changing all the variables every time!
I do infusion for my Hobby Sail Boats. I can now get perfect results for my needs using 30 inches of mercury. I had noticed that when cutting off the resin and leaving the project sit, there would be some degassing of any pooled resin such as at the end of the inlet hose and tee inlet fitting I was using. It really did not make any difference in the result of the boat hull as it came out pristine as always. I was curious about the degassing and decided to drop the Mercury Vacuum by one Inch at the end of my infusion process. The result was a less than pristine finish on the mold side and a small amount of resin pooling in various places in the Hull. Like you, this was just a curiosity and will not be ventured again.
That's a strange result from my perspective but infusion has got so many variable going on it's never 100% clear why something is happening unless you do a bunch of testing... and even then! Do you have resin breaks between the part and the vacuum side?
You should be able to avoid pooling by clamping off slightly before its filled or by playing with the height of the feed bucket. Not sure why there would be porosity in a surface unless there is a vapor issue or a leak... but again - too many variables.
But if you have something that works - that's not a problem!
@@ExploreComposites Thanks for the reply. Question 1 answer, Yes I use a resin break and it works consistently.
Question 2 answer, yes I do clamp before the finish and have no problem there.
I just wanted to contribute the result of my adjustment to the vacuum pressure after the job was finished. I can promise you I am not going there again. I can live with some bubbles in the inlet line after the job was finished. As I said, the finished product comes out really fine. Thanks again for the response.
very good exeperiment. what you could do to remove that air is maybe reduce a lot more the flow, slower cure resin and bigger resin brake, so after infusion, you can add more vacuum pressure and try to remove all the air. i only infuse poly and ver on low vacuum. and just because the panel will recive primer and paint.
I think you are onto something with slower flow and raising the vacuum once infused... sort of the opposite of my go-to method where the infusion happens at high vacuum and this is reduced as the part fills and kept lower for curing to prevent volatilization. Worth exploring further for sure.
@@ExploreComposites Also when reducing the vacuum, any bubbles will shrink in size. I've done infusions at full vacuum at the outlet, just clamping the outlet after infusion without clamping the feedline, but just lowering the feed bucket by 1m. This seems to nicely equalize the compaction and collapse any the bubbles or dry spots, especially on wood cores as it tends to suck the bubbles (and resin) inside. 1m head, is just ~10% vacuum though, I'm considering feeding from a vacuum chamber for a little more back pressure and compaction.
Apa yang terjadi jika tidak menggunakan kain flow ?
Do you use spiral wound tubing on the outlet as well as the inlet ?
Yes, my arm kind of hides it but it the spiral is fit over the tube for the last foot or so. It is probably overkill here but is a good inexpensive solution when you have room for a decent sized resin/vacuum break to keep resin from just rushing into the vacuum outlet side.
would this be a more viable method when say building honeycomb or foam composite panels as to not force the honeycomb or foam down to hard and potentially have a crush happen?
Thanks as always for the great videos !
Certainly low vacuum is good for core bedding and some wet layup situations. Infusion doesn’t seem to be the place for it though!
You will never crush foam or honeycomb (as long as edges are beveled) with vacuum alone.
I agree - was more concerned with overbleeding core bonding resin than damaging core. Core crushing not likely in most cases. Honeycomb - not sure - don’t have much data on wet-bonding honeycomb but it probably benefits from more vacuum than less - the bondline being more the sides of the cells than just the tiny edges that make contact...