Hi guys,

quite a while ago I came across the MTI hose, developed in Germany. A regular spiral tube (albeit a larger diameter) covered in an air-permeable membrane that is impervious to resins.

Question is, are any of you familiar with this product? They promise cosmetic, pinhole-free surface, without the need for catchpot and continuous vacuum. Was just curious if easycomposites or some of the other pros out there have any experience and if its worth giving a try, looks interesting.

Cheers

its a molecular debate

if the pores are small enough to stop the relatively long epoxy molecules from passing through, yet small enough to let the various air molecules through then it might work, however from what i understand, the bigger epoxy molecules will just block up the pores making it impossible for air to get through.

Sure vacuum will pull on any bit of hose where its not wet, but as soon as it is wet, how can a vacuum pull any more? you would have to rely on the bag naturally evening out the vacuum all over (which it will do) once the resin feed is clamped.

but the excess resin around the resin feed isnt going to distribute itself as theres no force pulling it. hence resin rich towards the resin feed of the part and a uneven laminate.

probably fine for more cosmetic and non-critical structural parts though.

I guess with practice you could calculate your theoretical resin uptake for the layup and then clamp the resin feed a little early as some do with normal infusion allowing the excess to flow to the edges. However that only works on normal infusion because in reality you have an excess of resin that will go into the vacuum line/catch pot so in practice you dont have to be too precise, just make sure you havent got too little resin.