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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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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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+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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oekmont
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Group: Forum Members
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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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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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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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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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+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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oekmont
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How 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.
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Hanaldo
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+xIf the part is larger, I would not rely on the flow propertys of the soric. During my own experiments I didn't see any flow advantage compared to the same laminate without soric. A guy named Matthieu libeert made a YouTube video about that, backing my results. He basicly failed an feet long infusion, just relying on the flow propertys of soric An important point to make about Mat's infusion is that he did not have the resin inlet on top of the Soric, he had it in front of the Soric with no flow media. I'm a big fan of Mat's, I love his videos and he makes some great posts on here. But he made some mistakes in that Soric infusion that led to the failure, it wasn't the Soric that caused the problems. I use Soric and 3D PET Core as flow media all the time, and have done infusions as large as 1 piece bodywork for a GTO Monaro door slammer (so roughly 3m x 1.5m) without any flow media. You just need to be aware that it does flow a bit slower than green infusion mesh, so you need to account for this in your feed setup. If possible, it's always better to infuse from the middle of the part out to the edges, rather than across the distance of the part. If you aren't going from the middle or directly on top of the Soric, then you do need flow mesh on the edges of the part to facilitate resin flow into the Soric. If you are concerned about your pot life, then you need to mix smaller batches rather than trying to do it all in one hit.
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