Hi Sebgron, 

Have you actually tried this product or is this just theory?
I've received a sample a few month ago and have ordered more since.
Never had any problems with pinholes or resin rich areas. It's a truly remarkable product, such a shame easycomposites.com don't sell it (the guy I spoke to actually said that he tried to contact these guys but never got any answers)

Hi, I´m new to this forum but I can tell you something about my experiences with the MTI-hose. I`ve been working on motorcycle parts since 2003 just for private use. These parts are e.g. an airbox seat monocoque, gas tank, fenders etc. and consists of carbon fibre. During that evolution period of nearly 10 years I digged deep into the process of how to produce perfect carbon fibre parts. Starting with open moulds and a wet layup turning to the closed mould process and resin infusion I was never able to produce absolute pinhole free parts. So rework was necessary all the time. Especially the sharp edge design of the new parts I`ve been working on since the beginning of this year forced me to reassess the manufacturing process. I came across the MTI-hose and gave it a try. With amazing success. Since I learned how to make a 100% tight vacuum bag I`m able to produce perfect cosmetic parts. I`m happy with that product since the produced parts are now 100% pinhole free and no rework is necessary. I also use a clear PU inmould coating wich is UV resistant.


Regards

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.

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

it states that against your name on here.

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

LOL how did i end up a supreme being?

I agree totally with the Supreme Being.

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

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.

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.