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fibernoob
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Group: Forum Members
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+x+xIm not sure its your case... but I have had similar problems when I used too much (wax based) release agent and did not polish it into the mold. Hello fibernoob, we also used wax based release agent in the area of the sealing cord, so that we can use it again if resin reaches the sealing areas of the tool. So yeah, im pretty sure this can be the reason. We are going to clean the tool again and wont use the wax release agent anymore. If somebody has another idea though, please tell me  Maybe it can help. Thank you for your help! Nik After getting some information, i discovered that wax based release agent has to be applied and thoroughly polished and left for some time for the solvents to evaporate and leave just a thin film of wax (invisible chemical barrier). Remember that your part will replicate the texture of your mold... if its smooth and well polished (shiny surface) with release agent it will come out perfect. In my case, I thought that the more release agent i would cover the part with ... the easier it would demold! That was my mistake. The part then showed similar white residues on many places. Check if those white spots have a similar greasy texture to make sure its release agent. You can use Water Based release agent (PVA) but it is not as easy to polish or spread uniformly. If the problem is not release agent related, it can be what the other comments are suggesting. There are valid points being made... Humidity , Resin Ratios etc. Good Luck !
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oekmont
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what type of pump are you using? what do the specifications say how much pressure it can reach?
30mbar happens to be the boiling point of water at room temperature. If you got a moisture problem, the pressure stops at this point during evacuation. Because of this, I degas at least down to 6mbar, at wich the boiling point is at 0°C. And during infusion, I try to maintain a slightly higher pressure, around 6-7 mbar, to prevent further degassing.
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tsombnik
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+xstill, there is a vacuum inside the mold, and the resin front is under vacuum. What kind of pump are you using? Are you using the same pump for the evacuation as for the degassing? What negative pressure do you reach? Ah okay, yes you are correct. We are using the same pump for evac and degassing. We reach a value up to 30 mbar remaining pressure
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oekmont
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Group: Forum Members
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still, there is a vacuum inside the mold, and the resin front is under vacuum. What kind of pump are you using? Are you using the same pump for the evacuation as for the degassing? What negative pressure do you reach?
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tsombnik
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Group: Forum Members
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We are not directly doing an infusion. We close the tool, pump out all the air and therefore create a vacuum. Then we have a resin storage which is set under a pressure of 0,7 bar. After the vacuum is created inside the mould, we open the vents and the resin gets pumped into the tool. So we have both, vacuum inside of the mould and the resin gets pumped inside with a pressure of 0,7 bar.
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oekmont
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Group: Forum Members
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during infusion, the outgassing happens where the pressure is the lowest, which is at the flow front. At bridging areas, this gas can accumulate, and stay there during the solidification. This gas consists of trapped air and physically soluted gasses, wich contains h2o. After the impregnation this moisture diffuses back into the resin, but can't get very far.
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tsombnik
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Group: Forum Members
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+xI've had similar effects caused by moisture. the storage of the resin might be too cold, so that water condense on the resin, once it's in the mixing pot. Do you degas your resin before the process? This can be a countermeasure against moisture. Additionally the degassing foam wich occurs without pre-degassing might cumulate in bridging areas, and produces this opaque resin after the compression. Do you have the access to a microscope for a mircosection? Hi oekmont, yes, we use an Exicator for degasing. Something like this: ( https://goo.gl/images/W822mS)So i guess the degasing foam cant be the reason? For future experiments we will degas way longer to be sure! Nowadays we only degas for around 5 minutes. But if you would be right, wouldnt all the resin be opaque, not only in the bridging areas? If you look closely at the bottom of the picture, just below the fibers, you can see the resin of the ring gate being clear. I dont have access to a microscope. And even if i had, i dont have the skills to see anything 
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oekmont
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Group: Forum Members
Posts: 550,
Visits: 27K
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I've had similar effects caused by moisture. the storage of the resin might be too cold, so that water condense on the resin, once it's in the mixing pot.
Do you degas your resin before the process? This can be a countermeasure against moisture. Additionally the degassing foam wich occurs without pre-degassing might cumulate in bridging areas, and produces this opaque resin after the compression. Do you have the access to a microscope for a mircosection?
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tsombnik
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Group: Forum Members
Posts: 6,
Visits: 147
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+xIm not sure its your case... but I have had similar problems when I used too much (wax based) release agent and did not polish it into the mold. Hello fibernoob, we also used wax based release agent in the area of the sealing cord, so that we can use it again if resin reaches the sealing areas of the tool. So yeah, im pretty sure this can be the reason. We are going to clean the tool again and wont use the wax release agent anymore. If somebody has another idea though, please tell me Maybe it can help. Thank you for your help! Nik
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fibernoob
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Group: Forum Members
Posts: 34,
Visits: 134
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Im not sure its your case... but I have had similar problems when I used too much (wax based) release agent and did not polish it into the mold.
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