Hello friends,

i am currently working on a project where we are manufacturing CFRP Parts with vacuum assisted RTM process. We are using infusion resin with infusion hardener (HP Textiles (HP-HE3000RI-30) / HP Textiles (HP-HTE300RI-9)) and Semiperm Monofilm R&G Release Agent. We are experiencing weird white spots inside of the part after curing of the resin and arent able to fix them. The wierd thing is, that we have these white spots very concentrated at a few positions of the part. The rest of the resin inside the resin pot is clear!  What could be the problem? This is how the process looks like:

1) Inserting preform into the tool
2) Closing of the tool
3) Vacuuming of the tool
4) Injecting of the resin with 0,7 bar injection pressure
5) Wait 2 days until resin is cured
6) Open the tool

I have added a picture inside of my post. I hope you can help.

Thank you very much for your potential help,

All the best, Nik

I've had similar effects caused by moisture. the storage of the resin might be too cold, so that water condense on the resin, once it's in the mixing pot.
Do you degas your resin before the process? This can be a countermeasure against moisture. Additionally the degassing foam wich occurs without pre-degassing might cumulate in bridging areas, and produces this opaque resin after the compression. Do you have the access to a microscope for a mircosection?