I had to go back and watch the video since it had been so long ago. Once the resin reaches the output side of the composite part, the vacuum on the input side is pretty low and you can even get siphoning action that pulls too much resin into the input side of the part. I clamp off the resin cup input and then open up the Tee that bypasses the composite part so that I can then get full vacuum on the input side to pull out any excess resin. You do not needed it but it is a faster method to remove the excess. Otherwise excess resin has to be pulled all the way through the part and that can take a while.
@@Designer103 that makes perfect sense. Thank you for your reply. Can I ask if you would do something different if there was a layer of plastic between your bottom carbon fiber layer and your mold bottom? Part of me thinks that extra sandwiching of the carbon fiber might present issues. thanks for your videos.
Do you mean the grid for the holes on the foam core? If yes than I can't remember. That was many months ago. It was most likely 1 1/4" ( about 3cm). 1 1/2" seems too much (although it can work) and 1" works but is closer then really needed. But this is for my specific configuration of foam thickness and carbon fiber fabric layup plus the flow media that was used. You will have to experiment for the layup that you use.
A few thoughts: 1. The final weight of the part doesn't tell the story. I'd suggest that you weigh dry reinforcements before infusion and then weigh finished samples in order to obtain the resin-to-fiber ratio. 2. I suggest that you'd better use a high quality flow medium, such as Enkafusion. 3. You have just a little bit of peel-ply resin break, seemingly just half an inch wide. It should be significantly wider, let's say - 4 inches. The thing is that in such a low permeability reinforcement you have multiple flow fronts propagating inside your laminate. The slowest one is at the mold surface, you have to give it a chance to catch up. The resin break serves two purposes: it slows down the flow front significantly before the resin outlet tubing/connector so that the whole stack is fully infused; and it also draws that first portion of highly aerated resin out of the laminate. 4. This good old vacuum infusion has long become such a pedestrian technology . Consider employing semi-permeable membranes, for example MTI-hose: th-cam.com/video/oXf6YsVJ8w4/w-d-xo.html 5. Just making a grid of circular perforations in the foam core would normally be insufficient. There should be a system of grooves and scores that form resin flow channels. Take a look at products like Divinymat and Lantor Soric: www.fibreglast.com/product/DIVINYMAT_01024_A/Foam www.fibreglast.com/product/lantor-soric-xf 6. Consider this: a high quality infused composite sandwich is good for building boats but incompatible with the very name Ultralight airplane. That's because a proper infusable core itself takes up to 3.5 oz extra of resin per sq. ft. For a light airplane/glider with 15 sq. meters wing area that's about 80 lb of dead weight. It's hard to justify. I believe that a better choice would be to build a sandwich laminate in sequence, and bonding of the core to the outer skin should be done by a good old wet layup/ vacuum bagging technology.
Denis, Thanks for the comment. TH-cam had blocked your comment and I had not noticed. I think that it was because of the web links but it was claiming "blocked words". I did not see any unacceptable words so I approved it. You are correct about those "proper" cores added extra weight and I will not be using those unless I run into some unusual situation where they might make sense. At the moment I can not think of one though. I've been having success with just the holes in the core after a bit of fine tuning. I have considered using MTI but at the moment I can not justify the expense. I'd like to play with it in the future though. I've seen it used before so I am a little familiar with it. I even have a small sample of it in my shop. It is possible that a sandwich hand layup with vacuum bagging is the way to go. That is also a good idea for a video so compare with the resin infusion. Thanks!
@@Designer103 perhaps it just didn't like a lengthy comment? I don't know. Anyway it's literally one of just a few comments I ever made on youtube, so I have no experience. I don't know where you buy you spiral tubing from, but MTI hose from German Compposites is $1.99/ ft and the spiral tubing from Fiberglast is $1.99/ ft, so there's virtually no difference, unless you buy your spiral tubing for much less than that. Did you post a video of a successful sandwich infusion yet? If so, could you please shoot me a link, I can't find it myself. Thanks!
I second Denis's comment on the resin break - the extra peel ply at the end. You should also cut your flow media back 50mm or so from the end of the part that will be last to fill. This will keep the resin front from overflowing the dry fiber and blocking off the path for the air to escape.
Hi! I got the fibers very very sticked to the peelplay. When I try to dissamble is so tought because both the peeplay and the cured textiles are very linked. When would you recommend me? Thanks in advance.
If you have a foam core then this can be a problem since you may de-laminate your face sheet. If you are worried about that then you need to get a peel ply that has a release coating on it. The peel ply that you see in this video has a green tinge to it because it has a release coat/sizing.
Sir how do i select my pump for the composite i want to make....the hight is 5ft and 4ft width sir...i just want to know how much cfm i need at psi to get a best result?
You really did not provide enough information to give you a full answer. The vacuum needed will depend on weather you are doing infusion or just vacuum bagging. For just bagging 25 inches of Hg would be enough. For infusion you will want at least 28.5 inches of Hg. The CFM is not really that big of a deal. If you have a low CFM it will just take a little longer to reach the full vacuum. I would say in the range of 2.5 to 5.0 CFM would be fine. For a part the size you are talking about you will probably need to feed the resin into a line that runs down the middle in the 5 ft length. That way you only need to flow the resin 2 ft. in each direction from the line. That is still a long distance to flow for some resin systems and cloth though. You may have to experiment.
With the timelapse it was difficult to see but I had opened the inlet valve just a little bit. The darn thing is very finicky. It let far more flow through than I had wanted. I like to have about 1" per minute flow rate until the epoxy gets near the end of the core and then I slow it down a little bit to allow the mold side to catch up. This particular combination of fabrics is very difficult to infuse so I was experimenting with different hole patterns in the core to see what would happen. I have had success with a different fabric on the top side that infuses easier. Spread tow and tight biaxial don't seem to like infusion.
What is the point of the "T" junction that brings the hose back around to the outlet side of the part? I can't seem to make sense of that in my head.
I had to go back and watch the video since it had been so long ago. Once the resin reaches the output side of the composite part, the vacuum on the input side is pretty low and you can even get siphoning action that pulls too much resin into the input side of the part. I clamp off the resin cup input and then open up the Tee that bypasses the composite part so that I can then get full vacuum on the input side to pull out any excess resin. You do not needed it but it is a faster method to remove the excess. Otherwise excess resin has to be pulled all the way through the part and that can take a while.
@@Designer103 that makes perfect sense. Thank you for your reply. Can I ask if you would do something different if there was a layer of plastic between your bottom carbon fiber layer and your mold bottom? Part of me thinks that extra sandwiching of the carbon fiber might present issues. thanks for your videos.
Also I would like to know the width of grid you used. Could you tell me? Thanks again! 😃
Do you mean the grid for the holes on the foam core? If yes than I can't remember. That was many months ago. It was most likely 1 1/4" ( about 3cm). 1 1/2" seems too much (although it can work) and 1" works but is closer then really needed. But this is for my specific configuration of foam thickness and carbon fiber fabric layup plus the flow media that was used. You will have to experiment for the layup that you use.
A few thoughts:
1. The final weight of the part doesn't tell the story. I'd suggest that you weigh dry reinforcements before infusion and then weigh finished samples in order to obtain the resin-to-fiber ratio.
2. I suggest that you'd better use a high quality flow medium, such as Enkafusion.
3. You have just a little bit of peel-ply resin break, seemingly just half an inch wide. It should be significantly wider, let's say - 4 inches. The thing is that in such a low permeability reinforcement you have multiple flow fronts propagating inside your laminate. The slowest one is at the mold surface, you have to give it a chance to catch up. The resin break serves two purposes: it slows down the flow front significantly before the resin outlet tubing/connector so that the whole stack is fully infused; and it also draws that first portion of highly aerated resin out of the laminate.
4. This good old vacuum infusion has long become such a pedestrian technology . Consider employing semi-permeable membranes, for example MTI-hose: th-cam.com/video/oXf6YsVJ8w4/w-d-xo.html
5. Just making a grid of circular perforations in the foam core would normally be insufficient. There should be a system of grooves and scores that form resin flow channels. Take a look at products like Divinymat and Lantor Soric:
www.fibreglast.com/product/DIVINYMAT_01024_A/Foam
www.fibreglast.com/product/lantor-soric-xf
6. Consider this: a high quality infused composite sandwich is good for building boats but incompatible with the very name Ultralight airplane. That's because a proper infusable core itself takes up to 3.5 oz extra of resin per sq. ft. For a light airplane/glider with 15 sq. meters wing area that's about 80 lb of dead weight. It's hard to justify. I believe that a better choice would be to build a sandwich laminate in sequence, and bonding of the core to the outer skin should be done by a good old wet layup/ vacuum bagging technology.
Denis, Thanks for the comment. TH-cam had blocked your comment and I had not noticed. I think that it was because of the web links but it was claiming "blocked words". I did not see any unacceptable words so I approved it.
You are correct about those "proper" cores added extra weight and I will not be using those unless I run into some unusual situation where they might make sense. At the moment I can not think of one though. I've been having success with just the holes in the core after a bit of fine tuning.
I have considered using MTI but at the moment I can not justify the expense. I'd like to play with it in the future though. I've seen it used before so I am a little familiar with it. I even have a small sample of it in my shop.
It is possible that a sandwich hand layup with vacuum bagging is the way to go. That is also a good idea for a video so compare with the resin infusion. Thanks!
@@Designer103 perhaps it just didn't like a lengthy comment? I don't know. Anyway it's literally one of just a few comments I ever made on youtube, so I have no experience. I don't know where you buy you spiral tubing from, but MTI hose from German Compposites is $1.99/ ft and the spiral tubing from Fiberglast is $1.99/ ft, so there's virtually no difference, unless you buy your spiral tubing for much less than that. Did you post a video of a successful sandwich infusion yet? If so, could you please shoot me a link, I can't find it myself. Thanks!
I second Denis's comment on the resin break - the extra peel ply at the end. You should also cut your flow media back 50mm or so from the end of the part that will be last to fill. This will keep the resin front from overflowing the dry fiber and blocking off the path for the air to escape.
Hi! I got the fibers very very sticked to the peelplay. When I try to dissamble is so tought because both the peeplay and the cured textiles are very linked. When would you recommend me? Thanks in advance.
If you have a foam core then this can be a problem since you may de-laminate your face sheet. If you are worried about that then you need to get a peel ply that has a release coating on it. The peel ply that you see in this video has a green tinge to it because it has a release coat/sizing.
Sir how do i select my pump for the composite i want to make....the hight is 5ft and 4ft width sir...i just want to know how much cfm i need at psi to get a best result?
You really did not provide enough information to give you a full answer. The vacuum needed will depend on weather you are doing infusion or just vacuum bagging. For just bagging 25 inches of Hg would be enough. For infusion you will want at least 28.5 inches of Hg. The CFM is not really that big of a deal. If you have a low CFM it will just take a little longer to reach the full vacuum. I would say in the range of 2.5 to 5.0 CFM would be fine. For a part the size you are talking about you will probably need to feed the resin into a line that runs down the middle in the 5 ft length. That way you only need to flow the resin 2 ft. in each direction from the line. That is still a long distance to flow for some resin systems and cloth though. You may have to experiment.
👍🏻
when the infusion speed increase it didnt give time for the resin to infuse properly ( under the core)
Why did it speed up out of nowhere??
With the timelapse it was difficult to see but I had opened the inlet valve just a little bit. The darn thing is very finicky. It let far more flow through than I had wanted. I like to have about 1" per minute flow rate until the epoxy gets near the end of the core and then I slow it down a little bit to allow the mold side to catch up. This particular combination of fabrics is very difficult to infuse so I was experimenting with different hole patterns in the core to see what would happen. I have had success with a different fabric on the top side that infuses easier. Spread tow and tight biaxial don't seem to like infusion.
Mhmmm ....sad to hear but il take your word on that ..great job
@@samiam3087 Well, I could be wrong. I've been wrong before. I'll be wrong again I'm sure!
Дядя, смолу попробуй хорошую купить)
When I start making parts for actual flight I will upgrade the resin that I use. While I'm still learning I'm using a mid range resin.