Vinyl Ester degassing under infusion

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#1

How can I fix this? Ive tried so many things and am running out of patience.

The parts are either made of 5 layers of 6oz carbon or 1 layer of 11oz and 1 layer of 20oz with 2mm core material in between, depending on the parts purpose.

I am infusing with MVER I believe its called from innerplastics. Or is it interplastics? Anyways, its a VE / Poly blend and I add 1.5 - 2% mekp-925. The 9 gasses off worse.

Infusions go perfectly fine and always with 0 air. After a few min when I clamp off the resin inlet line is when tiny tiny air bubbles start to form in no pattern, everywhere. Then after I demold there is usually air on the surface… I’m losing thousands of dollars no joke.

Any ideas? I’m getting ready to stop clear gel coating the molds and post gel coating all parts, but that doesn’t prevent the parts having air in them, just makes a pretty airless surface…

#2

I think a professional told me the answer to this before but I didn’t pay attention because I never thought I’d be using anything but epoxy…

But if you find out how to fill those pin holes in between the tows an EASY way other than flood coating please PM me or post it here. I have a part that got air in and I have a ton of surface bubbles… I think I’m going to smear epoxy on and spray some light mists of acetone on the surface to break the tension and see how that works…

#3

By the way. The part is 5 ft long and 1.5 wide. The center 2 inches has two layers of green flew and enkafusion. The two layers of green flow cover the center two feet. The rest has one layer. There is no break between the flow media and the edge of the part. However there was a 1" break between the edge of the parr and the spiral wrap.

Also, rhe part required 22oz of resin exact but I infused 24oz. The inlet was clamped about 30 seconds after the part was infused. Could I be clamping too soon? Could I be infusing too fast? The areas where I have more flow media have the most air.
Before I infuse I allow the resin to sit for 20 min to allow all the foaming to subside abs air to rise out of the resin. Then I hover a heat lamp over the finished infused part. Kicking the resin to gel sometimes seems to help the resin by shortening the time allowed to degass under vac.

#4

My problem is I have a layer of duratech over the pin holes. That turns them into into air bubbles. I coat my molds with clear resin before I layup. I might have to stop.

#5

Have you degased your resin?
Is it an infusion resin?
Wich vacuum do you apply?
Do you use MTI hose?
Do you infuse enough resin? (maybe it is only saturated on top but not the lower layers)
What bagging film do you use?

#6

It’s probably your peroxide, ask your supplyer for another one for infusion. Herman can tell you more, I haven’t done a VE infusion in years, but had the same problem. something with the o2 levels in the peroxide if I remember correctly…

#7

Degassing the resin is the first place to start. Also, with some resins a CHP initiator will reduce foaming and peak exotherm, check with the resin mfg. I would not put heat lamps on the infused part before it gels because it may cause the bubbles to increase or grow larger. Last, are you using an adequate brake between flow media and end of part and end of part to vacuum line?

#8

try using 925 H. i have been infusing for a few years daily with a ccp ve resin. when i started i used 2% 925 and the resin would foam like crazy. after switching to 925 H the problem went away. i also extended my gel time from 15 mins to 40 mins which helped as well. i dont really understand the science but the extra gel time and the other catalyst seem to work for me.

#9

Vinylester + Hydrogen Peroxide (H2O2) = gas.

I like to use Andos / Norac / Syrgis / Performance Initiators (don’t you hate it when companies change names more often than the CEO changes underwear?) peroxides:

MCP: slow, slight gas, but only in the beginning. Can be degassed out.

MEKP-925: has H202 (see datasheet)

MEKP-925H: low on H2O2 (see datasheet)

For long open times and stress free parts, I really like the MCP peroxide.

A lot of technology goes into peroxides.

#10

I let the resin sit for 10 min. The gassing off carries all the air out of the cup of resin. I can’t even see air with a lens.

Its a VE / Poly blend resin.

I get below 34 hg. That’s what my gauge says.

I don’t use mti. I have 400 Ft of spiral tubing I need to fi ish first haha. Then I will stock up on mti.

Maybe I don’t infuse enough. After the part is finished I let it sit for about 1 min before I clamp the hose. I believe I might infuse too fast and I think its infused 100%.

I use the 120" wide green Airtech bag.

I’m going to try a cup blend with 925 and have a larger break between the end of the part and the flow media. I will report back in a few hours.

#11

Is the mold flat or vac line located at a low point? We just talked about air bubbles “wanting to go up” here a week ago. Perhaps making sure the vac is located at the highest point will help?

#12

Most of the molds have flanges that are bigger than the trim line. I always vac from the highest point by default.

#13

I used to have that problem until I change to Red Flow Media, stop using green flow media years ago.

Resin Flow Speed for GreenFlow 75 and Resinflow 100 from Airtech is meduium and very high. Some stage there resin when using Greenflow.

http://www.carbonfiberglass.com/Vacuum-Bagging-VARTM-Infusion-Materials/flow-media

#14

The Red flow might do the trick.

I did an infusion today. Instead of 1.5% mekp-925 I did 1% 925 and .5% CHP. I also cut the infusion flow media 10% from the edge of the part so that way it forced a slower infusion towards the end.

Lastly I shut the pump off and clamped the part a min after I clamped the inlet tube. I didn’t see the dry spots I would usually see around the spiral tubing.

So far 1 for 1 today. I have a few more infusions to do so I will keep everybody updated.

#15

Check the following
1.Degass your resin
2.Don’t use heat lamps too close to the part because you may bowling the resin and creating bubbles
3.check your flow media…it might be too fast and as a result not all the fibers to get wet
4. leave a resin braking area or reduce the amount/speed of resin entering in the laminate while infusing

#16

How much is your absolute pressure?
The first thing to stop burning further money will be change to working materials.

#17

And do not mix peroxides. Some peroxides are more tolerant for additives, some are less tolerant. Chances are you are mixing a non tolerant peroxide into a peroxide which has a bunch of additives.

Mixing yourself is a big gamble…

#18

34" of hg???..absolute vacuum is around 29" of hg. Get a new gauge. Are you checking inside the bag pressures or reading at the pump. Styrene boils off at around 20" of hg…this may be your problem.

#19

could it be moisture on the carbon due to humidity? Maybe put it in the oven before your layup.

#20

Do you keep your fabrics inside where and cut them where it is climate controlled , and then bring them out to be infused ? Its been hot and humid on this side of the state and I haven’t been having that problem .

Are your resins new or 6+ months old ? If i’m not mistaken , MEKP consists of 20 different chemicals . Over time , some evaporate that can lead to undesirable outcomes .Neither may be the case with your situation but i am trying to brainstorm possibilities . The Florida climate can make mountains out of mole hills . Whatever it is , I’m sure it’s a small yet critical detail . Good luck .