internal flow media???

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#1

is there a type of flow media that can be used internally for resin infusion?

i am infusing helmets and am finding that without something to promote resin flow my resin gels before the parts are fully infused.

i tried laying peelply, then green flow and then infusing and it worked well. the only problem is because my parts are small and have so many complex curves it is an absolute bitch to rip the peelply out.

i am looking for something that i can put within my laminate like green flow that will help me get the resin flowing and not have to rip anything out after. because my parts are only 3mm it would need to be something relatively thin.

thanks in advance guys…appreciate the help!!

#2

There are several options:

Rovicore type of materials, normally used in RTM Light or LRTM processes can be used, Enkafusion can be used (but then you can just as easy toss in greenflow, more drapable as well)

Another option is CFM, continuous filament mat, aka unifilo. Get a very light one, 150 gr/m2 is more then plenty. Not so drapable, though…

#3

A helmet size part can be infused with no flow media, simply use resin with low viscosity and long enough work time to do the job maybe heat it up some, then you don’t have to put anything extra in and rip anything out afterwards,

#4

+1 I’ve done 18" parts with no media. Takes longer, but it has it’s benifits like sychrovsky said.

#5

Totally depends on laminate schedule. What do you use for your helmets now?

#6

im sure that if i decrease the gel time of my resin the part will become saturated given enough time. im worried that if i do that my demoulding time will go up.

im trying to infuse sglass and kevlar.

14 oz sglass
5 oz kevlar
9 oz sglass
5 oz kevlar
14 oz sglass

the part that was fully infused is awsome. i was hoping i could just through a layer of something inside the part in order to promote resin flow instead of adjusting the resin.

the resins i am toying with are in the 300 cps range. i heat them to about 32 degress celcius but i find the heat makes it gel faster.

what is an appropriate viscosity for the resin? i find that epoxy resins tend to be higher then the vinyl i tried although both seem to have the same results.

#7

That is a pretty dense pack. Lightweight, but hard to infuse without any medium.

You could try the CFM150 if you can get some (hard to source, although I have 8000 kgs of it…) and see if the part does not get overweight.

Another option is to infuse from the sides, and have the vacuum line in the centre. You might end up sourcing or making a special fitting to be able to connect a vacuum line in the center (basicly a piece of tube with a flange) or fiddle with a (thin) vacuum line (nylon pneumatic airline will do) which you place in a crease in the bag, and position the end of it in the middle of the helmet.

Ring infusion basicly cuts infusion time in half, compared to line infusion, or even by 75% if you compare it to point infusion.

As for resins, if you want to get a reasonable mould time, stick with esters. Epoxy tend to be fluid much longer. Unless you can immediately cook the part, your mould times are high.

Viscosity: You could source a thinner vinylester, although this one should be OK.

#8

I am going to just say, you need a better resin. lower viscosity and longer gel time. I do caul plated panels that are thick and 24"sq without any media. The resin I use has a 24hr pot! I worry more about race tracking than I do my resin curing too quickly :slight_smile: