MTI hose question

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MTI hose question

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Kacordy	K Kacordy posted 4 Years Ago HOT Topic Details
K Group: Forum Members Posts: 17, Visits: 341	I would like to try MTI hose. Out of curiosity I took a 2 foot section of MTI hose, added an elbow at one end, sealed it with yellow sealant tape, at the open end I wrapped and sealed it with sealant tape, then applied vacuum. The MTI Hose holds at 20 very well. I thought the white covering was supposed to be porous and let the gasses seep through while blocking the resin? I’m I supposed to take a fine needle and poke holes through the membrane to get it to work? Thanks, Allen
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Hanaldo	Hanaldo posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	+x Kacordy - 9/22/2020 4:35:13 PM I’m I supposed to take a fine needle and poke holes through the membrane to get it to work? Thanks, Allen Certainly not! I'm not sure what youve done wrong here, but something is wrong. Can you post a picture of what you tried? Have a look on YouTube for MTI Hose, DD-Compound themselves and lots of others have some good videos where you can see how to use the hose correctly.
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Kacordy	K Kacordy posted 4 Years Ago HOT Post Details
K Group: Forum Members Posts: 17, Visits: 341	+x Hanaldo - 9/23/2020 12:18:24 AM +x Kacordy - 9/22/2020 4:35:13 PM I’m I supposed to take a fine needle and poke holes through the membrane to get it to work? Thanks, Allen Certainly not! I'm not sure what youve done wrong here, but something is wrong. Can you post a picture of what you tried? Have a look on YouTube for MTI Hose, DD-Compound themselves and lots of others have some good videos where you can see how to use the hose correctly. Check this out. I hooked up vacuum to one end of the MTI hose and plugged the other end. Apply vacuum and the MTI hose is sealed and holds vacuum perfectly. So how is the MTI hose used under the vacuum bag to remove air and draw resin into the mold? Look closely and the white outer liner is wrinkled because the vacuum has drawn the material in. Here is a picture. The white material is not porous. If it was porous it would not hold vacuum. Check out the gauge at 20. Allen
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Lester Populaire	L Lester Populaire posted 4 Years Ago HOT Post Details
L Group: Forum Members Posts: 311, Visits: 13K	+x Kacordy - 9/23/2020 2:45:45 AM +x Hanaldo - 9/23/2020 12:18:24 AM +x Kacordy - 9/22/2020 4:35:13 PM I’m I supposed to take a fine needle and poke holes through the membrane to get it to work? Thanks, Allen Certainly not! I'm not sure what youve done wrong here, but something is wrong. Can you post a picture of what you tried? Have a look on YouTube for MTI Hose, DD-Compound themselves and lots of others have some good videos where you can see how to use the hose correctly. Check this out. I hooked up vacuum to one end of the MTI hose and plugged the other end. Apply vacuum and the MTI hose is sealed and holds vacuum perfectly. So how is the MTI hose used under the vacuum bag to remove air and draw resin into the mold? Look closely and the white outer liner is wrinkled because the vacuum has drawn the material in. Here is a picture. The white material is not porous. If it was porous it would not hold vacuum. Check out the gauge at 20. Allen does it hold this vacuum level when you turn off the pump? there is obviously some restriction with the MTI hose. I usually pull the initial vacuum through the resin feed side to get all the air out quickly. cheers
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Hanaldo	Hanaldo posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	+x Kacordy - 9/23/2020 2:45:45 AM The white material is not porous. If it was porous it would not hold vacuum. Check out the gauge at 20. Allen I can not tell from the photo what you are doing, but you are jumping to conclusions here. I can assure you the white material is a semi-permeable membrane, and it works as intended when used properly. Not only have I used it personally, but it is an award winning internationally used product. DD-Compound post on here semi-regularly, so they will probably be along in a bit and reply themselves. In the meantime, this is a very strange test. 20mm/Hg is no where near full vacuum, which indicates that you are pulling against a major air leak - likely the MTI hose. It is very difficult to see any wrinkles in the hose in that photo, but to me that looks like the hose when it is not under vacuum. Watch this video, this is how you use the hose:
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Warren (Staff)	Warren (Staff) posted 4 Years Ago HOT Post Details
Group: Administrators Posts: 2.5K, Visits: 7.9K	Hanaldo probably has the right answer here. The hose is naturally a restriction by design. The holes in it need to be small enough to restrict and stop resin flow. However air will still pull through them albeit at a slower rate. That of course doesn't matter as the air flow when infusing is not high flow anyway. IT needs to be able to allow the trapped air in the laminate an air path out into the vacuum line while stopping movement of resin. It does this very well. Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant
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Kacordy	K Kacordy posted 4 Years Ago HOT Post Details
K Group: Forum Members Posts: 17, Visits: 341	+x Warren (Staff) - 9/23/2020 2:05:37 PM Hanaldo probably has the right answer here. The hose is naturally a restriction by design. The holes in it need to be small enough to restrict and stop resin flow. However air will still pull through them albeit at a slower rate. That of course doesn't matter as the air flow when infusing is not high flow anyway. IT needs to be able to allow the trapped air in the laminate an air path out into the vacuum line while stopping movement of resin. It does this very well. I just wanted to test a piece of the MTI hose before I set it up on a cowl project. I only pulled it to 20. It holds at 20 forever. I cannot thank everyone enough for your input. I completely new to vacuum bagging. I’m starting with a relatively small 25 by 10 inch wide cowling. My focus is learning this process thoroughly before I attempt a much larger 46 by 18 inch RC boat hull project. I spent the last year building the new boat and it’s complete. I will pop a mold off the bottom of the new boat this weekend. The cowling is an item for me to learn the vacuum bagging process. I discovered the CF seat video on YouTube a month ago. That’s why I ordered the MTI hose because I believe it will be the best way to infuse the much larger hull. I will set-up the MTI hose on a large piece of glass and make a CF flat panel. Thanks for your help, Allen
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DD-Compound	DD-Compound posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 25, Visits: 1.1K	Hello, with a short piece of MTI the airflow is restricted quite a lot so you will always see high numbers at the gauge when pulling vacuum. The 20 inch HG means it still lets air pass. I am wondering it holds the 20inch when you shut the pump off or clamp the vac line. What you should do is pull vacuum and fold the vac line, you will the the vacuum in the MTI hose will be gone immediately because the air goes into the MTI hose. The prosity is big enough for infusion. Often people are worried that the airflow is not big enough but it only slows down the evacuation time. During infusion there is vacuum and only the air out of the resin that is little degassing has to be evacuated. The porosity is always big enough for that. The MTI hose is used to infuse 85m wind blades so it works, don't worry. By the way it is interesting thet German Advanced Composites has copied our clamps and sells them unautorized and under our name and brand.
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