What went wrong

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#1

Okay guys, as you can see from the pics the mold would not allow me to use infusion mesh over the entire mold surface due to some of the complex shapes.
The resin started okay but when the laminate was around 1/3 way I started losing vacuum on the inlet side, the bag became loose and resin flow slowed.
I may have saved the part, basically i waited until the laminate was saturated then switched the vacuum to the inlet side to obtain bag pressure once again.

what would cause me to loose vacuum pressure? how would I infuse with flow media around complex shapes?
Any advice on how to infuse this bad boy?

I have included one picture of the plug.

#2

Dang, that sucks. I would imagine there would be a number of things that could’ve caused that. Hopefully someone who has had a similar experience but knows what the cause was will chime in. Interested to see.

#3

In my opinion you should use all around mesh, i always use mesh and complex shapes has nothing to do as long as vacuum will do the job

#4

I’m not familiar with that mesh. The mesh I use and have seen would easily conform to those shapes. Still looks like your piece is saturated though. If I can help please let me know.

#5

okay… he we go :slight_smile:

used mesh all around, and cut the peel ply into strips in an attempt to prevent bridging…still couldn’t get the peel ply to lay down into the small radi corners. (there has to be a trick behind it) next time i will cut a hole around the boss’s then lay another patch of peel ply over the top.
vacuum…as soon as the resin hit the laminate, everything behind the resin line (wet area) I lose vacuum, everything in front (dry) retains vacuum pressure.
Flow stalled once again, and another one bites the dust…,lol

I’m certain now, its something to do with the infusion mesh not distributing the vacuum correctly.

#6

One problem I see after looking at your pics some more is your bagging material. Looks like stretchlon, not great for infusion. Also the mesh should be over the part not the edges. Vacumn hoses need covering too, especially if that is stretchlon. I suspect the stretchlon has been perforated by the mesh and or spiral wrap.

#7

A little confused on what is going wrong really, but from what you are saying, after the mesh is filled, the resin slows down and fills with resin? Well…yes, the mesh is tehre to allow a faster flow of resin, so it will slow down. Also, if you think the resin inlet side is filling with resin…where is your resin bucket? Do NOT have it above the part…have it below the table the mold is on. Else, you are, in essence, flooding the mesh area with resin, and causing a higher pressure in that area…with no flow media in the middle of the part, it takes awhile for that pool of resin to suck through.

Remember, the resin inlet side is kind of atmospheric pressure after letting the resin in. You can equalize the pressure (vacuum) gradient by keeping the resin under the mold, and allowing the resin to flow evenly though the part.

ps: a stalled inlet indicates a leak. Vacuum is being drawn, but once a leak happens, all the air is being sucked from the hole, NOT the resin!

#8

Hummm i’ll place the resin under the bench next time. thanks for the tip!

The resin doesn’t really stall as such but slows down significantly, to point where the epoxy gels before it reaches the other side. I had around %80 coverage on the second attempt before the resin cooked off.
I use the slowest hardener, but the 90 deg temps are tough to deal with…I do cool the resin in the fridge down to 70 deg.

Its appears the vacuum is having a hard time pulling through the laminate in time.
I’m now believing its the combination of not meshing the entire part and using strechelon bagging material.

Next attempt will be with mesh over the entire part, except the high boss areas.

I’ll report back after this weekends attempt

#9

True story. Cant tell you how many times I punctured stretchlon with the cut edges of flow material.

#10

Aye, there ya go. You can get a finer mesh and use that as well, so your flow front isn’t too fast. That media you have looks giant. but in short, yes, if your resin isn’t being pulled through quickly, is because of it having no media to flow through. Granted, i just did a no-media carbon part this week, but my gel time is 10hr, and it was only a 5" sq cored panel.