Understanding the Purpose of Flow Media

[CatBuilder]

I am getting ready to start infusing. There is still one nagging thing in my mind that I can't seem to understand.

Flow media.

My planned stack of materials will be:

-Dahar Release Film (used as vacuum bag)
-Green Mesh flow media
-Peel Ply
-Various layers of fiberglass
-Corecell

My question is regarding the flow media. Is the purpose of the flow media to hold the bag off the peel ply to allow the vacuum to develop nicely and evenly, or... is the purpose to allow resin to flow over the top of the peel ply between the peel ply and the bag?


Anyone?

[AndrewK]

Flow media is to speed up resin flow, without it you would have to place your resin distribution lines very close.
Also you should use perforated release film between the flow media and peel ply.
If you dont you have no choice but to strip the flow media with the peel ply the next day before the resin cures. No release film is OK for very small parts but for larger jobs its just too hard. Also you run the risk of damaging the laminate and you no longer have peel ply there to keep the laminate clean and protected.

Search the BD as there have been a number of good discussions regarding infusion, some were part of vacuum pump sizing.

[jim lee]

Don't you have some more glass on the other side of your core?

Corecell makes a wonderful flow media itself. I's what we use, mostly.

-jim lee

[CatBuilder]

Originally Posted by jim lee

Don't you have some more glass on the other side of your core?

Corecell makes a wonderful flow media itself. I's what we use, mostly.

-jim lee

Yes, I already have glass on the other side of the core. I have plain Corecell, which isn't a flow media at all, but just a flat surface, as you know.

I need to flow the epoxy through the heavy triaxial (nice, because now I can put the rougher 0 deg side down against the foam). I think the 0 deg side of 34oz (1150g) triax will make a nice flow media itself. I have the real, green flow media on its way as well for on top of the triaxial. The foam, being plain, won't help the flow a bit, but it's nice to stick a bag to.

[Releaseagent]

I would use a core that has been made for infusion, scored at least. I was at a training session last week and we tried to infuse a sheet of scored balsa with some epoxy resin. The resin fast tracked along the sides and locked off the vaccum and it all stopped. Using a flow mesh over the release film on the second go helped it work a lot better.
Richmond Aerovac now have a wonder product called VMS2 which means no one should have a failer due to resin flow or vaccum lock off. It enables vaccuum flow on top of wet impreginated zones through out the entire curing process web site www.aerovac.com