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Hanaldo
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+xHow long did it take you for this infusion? I disagree, that it was mat's fault. He shows, that the inlet was that resin rich, he could easily lift the bag. So the soric obviously had more than enough resin to feed from. Still, the flow front was almost frozen. And my results totally back that up. Pet core is a different story. The flow channels are wider and far more stable. Especially for the thicker ones. Still, no comparison to a flow mesh. Less than an hour, around 40 minutes or so. You have to understand that the resin will only flow as fast as the slowest point, it cant speed up. The resin doesn't get 'sucked' through the stack, it gets pushed through from the feed end by ambient pressure. By not having his inlet on the flow media (in this case, the Soric), the resin flow was choked. It then doesn't matter how much resin is inside the bag, it can still only flow as fast as the entry point. If you were using flow mesh, the same thing would happen. If you place the inlet off the flow mesh, the resin will not flow, even once there is a heap of resin in the stack. 3D Pet core flows slower than Soric... Soric has small cells and large channels (which is why it's compressive strength is so good, but it is heavy). 3D core has large cells and smaller channels, which makes it a fair bit lighter, but resin flow is marginally slower.
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andy47
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My part will be 2 meters long and 60cm wide, so it's pretty large. This video tutorial shows how to build a bonnet with Soric and no infusion mesh: https://www.easycomposites.co.uk/learning/make-a-carbon-fibre-bonnet-hood-part2The bonnet is pretty large, so I suppose that my 2m x 60cm part should work using the same method. If I put the spiral along the middle, it's only 30cm to the edge.
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Hanaldo
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If you infuse across the short direction and run spiral along the length, it will work fine. Shouldn't take any longer than 15-20 minutes, less if you do a centre feed infusion and run the spiral down the middle of the laminate stack and have spiral around the perimeter connected to your vacuum outlet. I had a bit of spare materials and time, so I did a trial infusion and shot a video to prove the theory. Just uploading it to YouTube now, so I'll link it when it's done.
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andy47
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I am wondering why don't you just run the infusion spiral multiple times for large parts? For example, if the part is 1m x 1m, I would put the spiral 30cm from all edges, so the infusion would be as fast as with 30cm x 30cm part and also the risk of issues is reduced. If the part is 2m x 2m, you can place the spiral in a way that the infusion process takes the same time. You can always use as long spiral as you want.
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oekmont
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+xä You have to understand that the resin will only flow as fast as the slowest point, it cant speed up.
exacly. And the slowest point was obviously the soric, otherwise the resin would not have been pushed from the feed line to the soric, to a point where you can easily lift the bag. A good flow media has a low resistance for the resin to flow through. This means, if you think about it, that the pressure difference between the flow front (zero pressure) and the feed line (full pressure) will be transfered smother, resulting in an more even pressure over the part surface during the infusion. A bad flow media (wich I think soric is) will even out the pressure less good, resulting in a sharp pressure gradient behind the resin front, and a larger area of high pressure behind. And this is exactly what you can see in mat's video. He could easily lift the bag around the feed line and a good way up the soric. This shows, that there must be a high pressure area in the resin, which obviously means, that the connection from feed line to the soric was not the problem, as the soric had more than enough resin to feed from, but was unable to transfer it to the resin front. Keep in mind that mat could not lift the bag (that easy) near the resin front. So there is clearly a steep pressure gradient over the soric area (low pressure at the resin front, high pressure down the first third of the soric area), and almost no pressure gradient from the feed line to the soric (both high pressure). If you think about it as resistors in line, and you measure the current over both resistors, your result will tell you, that the second resistor (soric) is much greater than the first one (feed line to soric).
Wich kind of soric did you use exactly? I used sf and lex in 3mm and 1.5mm.
From my experience an hour seems very fast for that setup (although I would prefer it much quicker, around 25min)
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oekmont
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+xI am wondering why don't you just run the infusion spiral multiple times for large parts? Because that might trap some air pockets. If you got an area with an infusion line (almost) all around it, the resin front will trap an poket. The pressure in the poket is very low, but there is still air in it, so if the poket is to large, it will result in an visible defect, when atmospheric pressure is reached.
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Hanaldo
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+x+xä You have to understand that the resin will only flow as fast as the slowest point, it cant speed up.
exacly. And the slowest point was obviously the soric, otherwise the resin would not have been pushed from the feed line to the soric, to a point where you can easily lift the bag. A good flow media has a low resistance for the resin to flow through. This means, if you think about it, that the pressure difference between the flow front (zero pressure) and the feed line (full pressure) will be transfered smother, resulting in an more even pressure over the part surface during the infusion. A bad flow media (wich I think soric is) will even out the pressure less good, resulting in a sharp pressure gradient behind the resin front, and a larger area of high pressure behind. And this is exactly what you can see in mat's video. He could easily lift the bag around the feed line and a good way up the soric. This shows, that there must be a high pressure area in the resin, which obviously means, that the connection from feed line to the soric was not the problem, as the soric had more than enough resin to feed from, but was unable to transfer it to the resin front. Keep in mind that mat could not lift the bag (that easy) near the resin front. So there is clearly a steep pressure gradient over the soric area (low pressure at the resin front, high pressure down the first third of the soric area), and almost no pressure gradient from the feed line to the soric (both high pressure). If you think about it as resistors in line, and you measure the current over both resistors, your result will tell you, that the second resistor (soric) is much greater than the first one (feed line to soric).
Wich kind of soric did you use exactly? I used sf and lex in 3mm and 1.5mm.
From my experience an hour seems very fast for that setup (although I would prefer it much quicker, around 25min)
The drag car body I did used 2mm SF. I've just recreated a similar test to the one that Mat did; 2mm SF Soric around 30x10cm. One layer of 450g biaxial fibreglass on either side of the Soric. With the feed line positioned directly over the Soric, the infusion completed in around 5 minutes. With the feed line placed off the Soric like Mat had it, the infusion didn't finish before the resin gelled (around 90 minutes).
Soric is a good flow media, it works just fine when setup correctly. As I said before, there are differences between using an internal flow medium like Soric and an external flow mesh, and you need to account for those differences in your setup. If you do, then it works perfectly. If you don't, then it can go wrong. It's simple though, your resin feed must always be placed over whatever flow medium you are using, whether it is mesh or Soric or PET Core or anything else - the resin inlet needs to be in direct contact or you choke the flow.
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oekmont
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Your almost there. I am starting to have a slight doubts about my experiments. But what I said about mat's infusion is undoubtedly true. That's university knowledge.
There is only one solution: more experiments. Sadly i've got no sf in stock atm, as it usually to heavy for my taste. In 90min we will know it for sure.
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oekmont
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Ok, finished with experiments. I'll come up with details later. First I need to do some actual work. But I have to admit: hanaldo was right. Soric is a reasonable good flow media.
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Hanaldo
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When you get a chance, I'd be interested to know what you changed in your test, Oekmont? This is my little experiment. Forgive the video quality, my filmography skills aren't up to Mat's level! http://www.youtube.com/watch?v=kRKxrxNhbUwFairly obvious, but to be clear: The stack on the left is with the resin inlet directly on top of the Soric, the one in the middle is with the inlet in front of the Soric, and the stack on the right is with 3D PET core. The 3D PET core stack should have been the same size to be worth noting, but I didn't have any similar sized off-cuts, so really it is only worth looking at to note how it works having flow mesh on the edge of the core just to initiate the resin flow. Another point worth making is that usually I would use a silicone through-bag connector rather than just having the hose through the bagging tape, as this causes bridging around the hose which is why the resin tracked backwards so quickly on the first stack. Layup is as I mentioned above and is the same for each panel, 450g biaxial fibreglass > core > 450g biaxial fibreglass.
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