Composite Testing: Vacuum Resin Infusion Fast Flow Test

Many people say that you have to have a slow resin flow rate during vacuum resin infusion in order to have a good mold side finish. In this video we do an experiment to try compare a slow flow rate to a fast flow rate during Vacuum Resin Infusion to see if there is a difference.
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[@itsDjCaliKid]

Just commenting to show some love. Just came across your channel and now I’m going to binge watch all your videos. I’m surprised you don’t have massive amounts of viewers...yet. Thanks for everything!

[@Designer103]

Thanks for the comment! I wish more people were interested in engineering and airplane design and construction.

[@JoelArseneaultYouTube]

I've been watching a bunch of your videos and I really enjoy all of the testing that you have done. Lots of great info for beginners and experienced folks alike. I'm a huge believer in learning hands on. One of your videos, you mentioned your vacuum gauge was reading off after you let air in quickly and you suspected epoxy in the valve. I had a similar thing happen to me, except, by some fluke I saw a rubber cap on the top of the gauge and thought it may be a calibration screw or something... In an attempt to remove it with my finger, I heard a hiss noise and the gauge went to zero. Not sure if this is a fluke, or if this is a way to calibrate the gauge to elevation by equalizing pressure. Maybe it was a total fluke, but I thought I would share the story with you.

[@Designer103]

You are correct about the purpose of that black rubber plug on the top of the gauge. You peel it up a little to equalize the outside and inside pressure. You are correct that this will usually zero a gauge. Unfortunately for me the gauge still had an offset after I equalized the pressure. Gauges are relatively cheap though. Thanks for making the suggestion. I love to hear them.

[@JoelArseneaultYouTube]

@@Designer103 It's good to know my reasoning worked out to be correct this time around. Thanks for the response.

[@marcocochran]

Hi Leon, just found ur series of vids on carbon laminates. Love ur methods for testing infusion, sandwich, finish and strength! Haven't seen them all yet so u might have tried this already, but have a couple of thoughts. Have u tried glass tissue as ur first layer on the mould? Maybe it will give an internal flow medium to fill the last pin holes on the surface making that a bit more resin rich without adding too much weight. And u probably won't see it as the tissue refractive index will make it 'disappear' in the laminate. I wonder if that might work if u used it as an additional internal flow medium across the foam core? I saw another comment somewhere to put a layer of resin on the mould before u lay it up and bag it but that might be risky as the clock is ticking before u start bagging it. Have u tried hand laying it up, then bagging it and vac out the excess resin? I'm like u, worked with grp many moons ago and have a rekindled interest in carbon and vac. When I can get back to Europe then I'll go through a similar process u r going through. Interested to keep following what u r doing and what u do when u get into elec motors, and batteries! Keep up the good work!

[@Designer103]

Thanks for the comment. I have not tried the glass as the surface layer. I need to save all the weight that I can so I'll only do that as a last resort. I think that I can now get a good surface finish so hopefully it will not be needed. I've thought about the hand layup first but time could become an issue. It might be possible though. I'll try it if I need to. Thanks again!

[@mtraven23]

Thanks for the great video, I found it very helpful. I am just learning how to infuse composites...I don't have any peel ply, wondering if I could substitute something else? The peel ply must be porous to allow epoxy to flow through it, right? how does it not also become infused in the layup? what are the purpose(s) of peel ply? Ive read its to even out vac pressure & help release, is that it?

[@Designer103]

Assuming that you have flow media in the setup, without the peel ply the flow media would be difficult to remove (it would be encapsulated in the resin) and if you managed to remove the flow media you would have a VERY rough surface with excess resin chunks still stuck to the surface (the chunks would be the spaces in the flow media that filled with resin). I accidentally did this one time. The flow media is pretty much impossible to remove from the part. You get the same effect with peel ply but since the holes in the peel ply are small the surface is closer to being smooth when the peel ply is removed. But the surface is not completely smooth so it also provides a great surface to glue other parts to. You don't want to try to glue to a glassy smooth surface. And yes the peel ply does become encapsulated in resin BUT the pores in the cloth are small so the resin is then thin columns through the peel ply and easy to break as you pull on the peel ply to remove it.

[@mtraven23]

@@Designer103 thanks, that was very helpful in confirming a bunch of things I thought to be true, but wasn't sure. Specifically that the peel ply allows resin to flow & has small enough holes to easily break the columns. I don't have any of the "proper" materials, and I am actually using fiberglass to repair some holes in my pool. My flow media is the plastic mesh that the local pizza place puts under the pie in the box and I am currently trying to 3d print an all in one, peel ply & flow media & inlets. I think its gonna end up locked together, but as long as the cloth is @ the btm, I can just sand it all down until its gone.....i think. care to venture a guess on the outcome of my little experiment?

[@JoelArseneaultYouTube]

I also have a question, and thought I would post it separately. I have never done infusion before, and am jumping in some what recklessly. I am attempting a 6mm (1/4"ish) lamination with 16 layers of 6 oz 3k 2x2 twill and 2 layers of unidirectional 22.3 oz. Layers will be 5 twill, 1 UD, 5 twill, 1 UD and 6 twill. From what I have seen your testing has all been with thin laminations, but I think your experiments with core material may have some parallels to thicker laminations. I have watched many of your videos several times... so I'm not asking this in ignorance, but because I value your hands on experience. I'm concerned about the material not wetting out completely. My thoughts are that I should use a restrictive flow media (media substitute) to encourage flow through the cloth. I remember you saying that you had issues with UD not flowing well as the flow path is through the tows. The end product will be carbon fiber, but I intend to attempt this part first in fibreglass with similar cloth. The resin viscosity I intend to use is 920 cps and has a pot life of about 75 minutes in the required volume. Any advice would be appreciated !

[@Designer103]

Not sure what your intended use of the laminate will be but your part will be stiffer if your unidirectional layer's are closer to the outside. You need to consider your viscosity with the hardener mixed into the resin. Hardener will usually lower the viscosity a lot. For infusion you typically want a mixed viscosity in the 250 to 300 range. As for the flow media. I've always had to experiment to find out what works. Try infusing a small part first to see if it will work. You may very will have to try a more restrictive flow media with the unidirectional. Good luck. I'd be interested to know how your project works out. Feel free to send me an email using the email address you can find at the bottom of the "About" section of the channel's main KZbin page.

[@JoelArseneaultYouTube]

@@Designer103 Thanks so much for the response ! It seems so obvious, now that you have said it, to put the UD close to the outside of the parts. It is going to be a engine mount for a Jet Ski, so it needs to be fairly stiff and strong. The size of the completed part is 17" x 11" at the widest and longest sections, so the size is working to my favor. Wow. I had no idea that infusion resin was so thin. I have been told by several people to just use West System with the slow hardener, but even their extra slow is 650. I'm glad I didn't run out and purchase Aeropoxy before rewatching your video about it. I will keep looking for a low viscosity infusion resin, and in the meantime, I may do wet a layup and vacuum bag. I really appreciate your help and email offer.

[@illla]

When you have leak it will reduce the pinholes sizes because of more pressure on the resin.

[@carbonkid7557]

Anyone could u tell me if it might happen degassing processes in the vacuum bag during vacuum infusion proces (gaugein 30 inch hg) that can make aerating the resin. Or we have to lower down the prsure to 27unch hg.

[@Designer103]

If you degas your resin in a vacuum chamber where you can watch it, you'll be able to see at what vacuum level your resin will degas. There is no single answer. Each resin is different. Most infusion resins should be OK at 27"hg. The resins that I have would still degas at 30"hg.

[@carbonkid7557]

@@Designer103 thanks for the answer it helps me well.

[@ilhamcputra6550]

Sir can you show calculation of resin needed

[@Designer103]

For carbon fiber you can assume that the weight of the carbon fiber will be equal to the weight of the epoxy that fills it. For the epoxy that will fill the flow media you will have to look up the data sheet of the flow media. I ignore the epoxy that will fill the peel ply. I just take a guess at the amount of the epoxy that will be in the tubing. No complicated calculation needed.

[@WereAllThatBored]

Stretchlon 800 is much “safer” then the 200 when trying to avoid punctures from the flow media.

[@Designer103]

Thanks for the tip!

[@ramjayanor1238]

How to make perfect finish without pinhole? After infusing. Thank you

[@alvaroapache]

As long as you restrict fluid inlet just a bit is enough