I've just infused my first test piece, a carbon/foam sandwich using your IN2 Infusion Resin and I am seeing *a lot* of outgassing from the resin under full vacuum. Small bubbles are visable within the within the resin transfer mesh and continue to form/appear as long as there is a hard vacuum. Will this compromise the strength or the cosmetic finish of the finished part? (I haven't de-molded yet.) Is there any way to elimitate outgassing?

Thanks,

Phil.

Hi Philip,

I moved this thread to the Easy Composites Technical Support forum since it's an Easy Composites product you want support on and the Easy Composites support staff (myself and Paul generally) will prioritise support for our own products if you post them in this forum.

Depending on the size and amount of these bubbles, from what you're describing this sounds perfectly normal. You'll always see very small bubbles forming around the mesh and peel-ply at the very front of the resin's progress. A few mm's back from this line the bubbles should fade away. If it is just this then it's simply a function of the resin foaming slightly as it's forced through the laminate and also, to a small extent, degassing slightly (simply from any airation when you mixed it) as the bubbles of air expand under vacuum and make their way out of the resin.

We've tried to get a close up of this on our resin infusion video (take a look at the part where we actually run the infusion). If it looks like this then you're fine. There will be no trace of these bubbles once the infusion is finished.

Best regards, Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

The pump runs at 30 psi. When making a small part "like my seatbelt hinge cover" I noticed 30 PSI just squeezes the livng sin outta the part and mold. I did one at 20PSI and I liked it.

Are the situations you guys prefer to lower the psi of the pump? could this help the flow?

Even when making my slightly larger part seems the over pressure issue is gone.



If Brute Force Isn''''t working your not using enough...

To get the air out of the mixed resin, just put it under a light vacuum and slowly increase the vacuum. This will helps to get as less air in the part as possible, when you let the resin flow into the mould. This is important if it`s a structural part.

Hi Matt,

I observed the line of bubbles you described along the front of the advancing resin as it infused, but the bubbles I was describing appeared to evolve all over the surface of the part (in the mesh layer) *after* I had clamped off the resin supply (particularly near/around the vacuum connector) - and continued to evolve as long as the vacuum line was un-clamped. There were no leaks in the bag. From what I have read elsewhere, it appears that infusion resins can 'boil' under hard vacuum. I guess the answer is to clamp off both the resin feed and vacuum lines, once the infusion is complete, at the first sign of bubbles forming.

The video demonstration of vacuum infusion suggests clamping off both lines, while the instructions in the EC-TDS-Guide-to-Vacuum-Infusion.pdf document suggest leaving the vacuum line open until the part is cured! I'll clamp off both lines for my next piece.

I have another question, about post curing, but I'll post that under a topic.

Thanks,

Phil.

Hi Philip,

Epoxy infusion resin (such as our IN2) will not boil, even under a total vacuum. Polyester, acryllic and vinylester infusion resins can and will boil but epoxy will not. If you're getting air bubbles forming away from this 'front line' of the resin then something is wrong somewhere. When you say there is no leak in the bag could you let me know how you confirmed this - did you perform a 30 min drop test?

Regarding clamping off both lines or only the resin feed line (and the difference between the text guide and our video tutorial), both of these methods are correct but will yield different results. In the video we're trying to show something very specific which is how to do a resin infusion specifically for a *perfect surface finish*. To get this purfect surface finish you actually have to perform the infusion slightly resin rich (which is to say slightly more resin that the minimum that the reinforcement can support). By having a slight (maybe 5%) amount of resin above the minimum you should not get any pin-holes on the surface (where the nodes of the fabric intersect). This was the trick we wanted to show in that particular video.

In the text guide, we describe the traditional infusion process where the vacuum line is never clamped off (and in fact keeps pulling at the bag for the duration of the cure). This method will result in the lowest resin-to-fibre-ratio but will almost always result in tiny pin-holes on the surface of the laminate (which most people have always accepted).

Like I say, neither is wrong or right, they're just targetting different priorities. For the lightest possible laminate, keep the pump running and never clamp off the vacuum line. For the best surface finish, clamp off both lines at approximately the same time, which will leave the laminate slightly resin-rich, and then switch off the pump.

--Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

I've just been out to the workshop and the vacuum gage has dropped from -1bar to around -.8 overnight... so I do have a leak after all. I only did a short (5-10min) vacuum check before introducing the resin (impatients I guess.) Lesson learned - I'll perform a full 30min vacuum integrety test in future.

Apologies, mea culpa!

Phil.