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

any pics or links?

Dave.

http://www.hp-textiles.com/shop/product_info.php?info=p873_mti--hose-5m--roll--hp-mti-08.html&XTCsid=e5d3492143709a9d36c10975cb293465

http://www.youtube.com/watch?v=8C0DkROWsiE

I've used it and you can request a sample from the supplier. It does away with the need for a catch pot as no resin is drawn out of the layup so similar to VMS2 resin barrier.

They say to surround the mould with the hose and feed resin from the centre. I've not done it this way yet and have only had resin inlet on the left and MTI hose with vacuum on the right.

I've got pinholeless results from it so far.

surely as soon as the resin reaches the hose, the pores will block and any trapped air will stay in the laminate?? ie resin flow will stop as will vacuum pull.

Surely this will lead to resin rich parts??

As we all know, during infusion, the vacuum on the resin feed side of the mould plummets as its only the viscosity of the resin stopping the vacuum going completely back to ambient pressure.

So you are going to have to be very careful in timing when you clamp off the resin feed to ensure there is enough vacuum head on the resin to pull a vacuum again by the resin feed and even out the laminate before it gets to the hose all the way round.

Sure it might give pin hole free parts and might be useful if the resin isnt flowing right to edges far from vacuum port, but surely it does nothing that cant be achieved with proper planning and placement of resin feed, spiral, mesh and vacuum ports. 

to add, surely a better design would be to have such a hose with slightly bigger pores to slow down the resin going into the vacuum line rather than stop it.  Then you would have the advantages of the resin flow being pulled to the edges all round on a complicated part (path of least resistance is through empty laminate rather than wet laminate) but still be able to ensure an even vacuum all over as the small resin flow into the vacuum line would still mean an even vacuum can be pulled all over and still allow any tiny bubbles from the resin to be drawn out.

I agree totally with the Supreme Being.

In fact, I would think it an unwise choice to disagree with a Supreme Being.

LOL how did i end up a supreme being?

it states that against your name on here.

Maybe you've posted a lot of advice that us mere mortals like

Hi Warren,

I have no experience with this particular product myself, thus wanted to get some opinions. Thanks for your input!

I discovered the hose on another forum (yes im having an affair hahaha) and many people there have said very good things about it.

I may try it, although i'm happy with my current setup.

You stated it would be difficult to gauge the ammount of resin going in resulting in a way overfilled part. I totally agree, although I dont know how they gauge it but i will find out shortly.

What I imagine is that the hose being around the perimeter draws uniform vacuum, then when the resin reaches the hose everywhere, it stops being drawn in and the uniform vacuum doesnt allow oversaturation. That would be the ideal case. As for the remaining air in the resin, I think it does get drawn out when vacuum is left running, of course provided the bag is air tight.

If it wasnt the case, then the product would be pretty much useless. I watched the clip and it looks pretty good, I may try some and post my results.

cheers