Resin Infusion 101

Pros:

• Better fiber-to-resin ratio
• Less wasted resin
• Very consistent resin usage
• Unlimited set-up time
• Cleaner

If done right, this process saves materials and creates a stronger layout with less work during the layout and we can be more careful on layering throughout the setup process.

Cons:

• Difficult to set up
• Trial and error
• Difficult to keep dry materials flush to sides prior to infusion

The process can be complicated as it requires a precise set up of vacuum tubes and resin inlets to pull resin all the way through the shell and once the dry materials are set there is no way to really adjust them.

Equipment:

• Vacuum pump
• Vacuum tubing - Vinyl tubing, ½” diameter to allow for maximum flow
• Resin trap - traps excess resin, for larger projects multiple are recommended 
• Spiral tubing - standard for resin infusion, is ideally suited for in-bag for vacuum line extenders or resin feed lines
• Resin distribution mesh - helps spread resin
• Clamps- to clamp off resin pump

Step-by-step guide

1. Step 1: The Mold
   1. Prepare the mold and select type of reinforcement and flow media
   2. Lay reinforcement in mold
      1. Use an adhesive spray to secure the fabric down
         1. Put only a light amount spray on the first layer as to not have any visible adhesive spray on the face of the part when completed
2. Step 2: Resin and Vacuum lines
   1. Select and install resin feed lines
      • From a source, usual resin in a bucket
      • The line for getting the resin into the laminate will have to be installed before closing the bag
      • Same tubing that is used for applying vacuum is fine for getting the resin to the bag
3. Step 3: Assembling Stack, Vacuum Bag, and Attach Your Resin Line 
   1. Place down Peel ply - This gives a better finish to the part and allows it to release from the rest of the stack *Use spray adhesive to tack down
   2. Place down Infusion mesh (also known as flow media) - Allows for resin passage through the part *Should be cut slightly smaller, tape this on to the tacky tape as spray adhesive doesn't work on this
      1. If it still doesn't attach well, use a few beads of hot glue to tack it down
   3. Place Spiral Tubing *Spiral tubing should be placed in a manner such that the resin does not need to flow more 500mm
   4. Build Your Vacuum Bag - same as normal 
   5. Attach resin and vacuum lines 
      1. Vacuum lines should be cut at a 45 deg angle and then inserted
      2. Put a piece of tacky tape on the lines in order to make sure bag remains sealed
   6. CLAMP OFF RESIN LINE BEFORE VACUUM IS SWITCHED ON
      • Vacuum should be tight before resin is drawn in
        • Preform a drop test to ensure there are no leaks in the bag, if there are, then find and fix them or else the infusion will not work as planned
      • Can use a flow regulator 
   7. Use Resin trap to prevent resin from entering vacuum
      • When set up properly, the vacuum tubing will flow out of the laminate and connect directly to the resin trap
4. Step 4: Vacuum Pump *Vacuum should be 
   1. Attach vacuum line to pump
   2. Switch on vacuum and ensure proper seal
5. Step 5: Prepare for Infusion
   1. Select resin, does not need a specific resin- just need to watch for viscosity. Lower will allow for more infusion
      1. When mixed, the resin should have a viscosity of under 300 cps
      2. Pro-Set Infusion 114 is an epoxy which could be used
   2. Resin Bucket-set up
      1. Have to be careful as air in tube will ruin process, so make sure resin line is staying in resin and staying straight and not curling
6. Step 6: Resin Infusion 
   
   1. Catalyze resin  *Note, resin does not have to be MEKP based, regular 2 part systems can work as well AS LONG AS THEY HAVE THE RIGHT VISCOSITY WHEN MIXED
   2. Place resin line in resin and unclamp the resin line and allow to flow into laminate 
      1. There will be air in the infusion, but these are just the bubbles in the epoxy expanding, and should not be an issue, but can be negated by degassing the epoxy
   3. Clamp off resin line
   4. DO NOT turn off pump yet until resin is completely gelled *A good way to check if its cured is to bend the resin in the tube leading to the resin trap, if it snaps, then its cured, if not, wait a few hours

Related articles

• Page:
  2022-2024 Composites Layup Process
• Page:
  Brief Overview of Composite Materials
• Page:
  Resin Infusion 101
• Page:
  Aeroshell Wet Layups for Dummies
• Page:
  (WIP) Canopy 22-24

https://compositeenvisions.com/document/the-many-ways-to-layout-your-infusion-setup/

https://www.provac.com/blogs/news/vacuum-pumps-for-resin-infusion

https://www.fibreglast.com/product/vacuum-infusion-Guide

https://media.easycomposites.co.uk/datasheets/EC-TDS-Guide-to-Resin-Infusion.pdf