Infusion tech – history

Vacuum resin infusion is considered a relatively recent process; it was filed in 1959 in U.S. for the production of swimming pools made in fiberglass (GRP, Glass Reinforced Plastic), using a system of distribution of the resin. In the early 80’s Lotus Cars used a similar process for the production of car body parts. In the same years, one of the first applications in the water was a series of RORC One Design yachts, produced by Jeremy Rogers in Lymington, England.


Main aspects of infusion:

infusion process

Achievements of vacuum resin infusion

  • Process with low emissions of styrene and acetone
  • Standardized and repeatable process and pieces
  • Excellent composite’s mechanical characteristics
  • Weight reduction
  • Time and costs reduction

Infused Composite’s Quality

  • Excellent resin / fiber ratio (35%-65%)

  • Constant thickness

  • No use of putty or bonder for fixing the core

  • Absence of interlaminar air bubbles

  • Excellent mechanical properties of the laminate due to uniform compression exerted by vacuum.


  • Low emissions of styrene in the air
  • Cleanliness
  • Reduced costs for PPE and flue gas treatment equipment
  • Ergonomics
  • No contact with resin by workers
  • Reductions occupational diseases (carpal tunnel, etc …..)

abiente lavoro infusione

Comparison with the main processes:

Lenght's limitation of the piece++++++--
No limitationsNo limitationsNo limitationsMedium sized partsSize limits depending on the size of the autoclave
Waiting time for polymerizzation of the resin for each layer placedWaiting time for polymerizzation of the resin for each layer placedAbility to work on shifts whithout waiting for the polymerizationHigh industrializationUsed for limited production
Mechanical properties---+++++
In general, poor and dependent on the human factorSlight improvement for the gluing phase of the core but same features as the handly lay-upExcellent propertiesDependenton the amount of fiber inserted into the moldexcellent properties
Fiber/Resin ratio----+++++
Resin: 65%Resin: 65%Fiber: >65%Depending on the amount of fiber inserted into the moldFiber: >65%
Fibers' workability--+++++
Once impregnated layers lose their stabilityOnce impregnated layers lose their stabilityGoodGoodGood, but in short time
VOC emissions---+++++
High emissions (open mold)High emissions (open mold)No emissionNo emissionLimited emission
Masks, sults, gloves.Masks, sults, gloves.No special precautionsNo special precautionsGloves
High cost to treat the air at the workplace to comply with regulationsHigh cost to treat the air at the workplace to comply with regulations
Material fee+++++---
Possibilty of using various productsPossibilty of using various productsMedia and multi-axial flow to enhance the features mechNeed to purchase specific fabricsPrepreg fibers (high cost)
Facilities fee++------
No specific facilitiesNo specific facilitiesVacuum pump and resin infusion machineVacuum pump and RTM machineAutoclave and refrigeration to stock materials
Molds fee+++++----
Existing molds can be usedExisting molds can be usedExisting molds can be used with minor modifications to widen the perimeter flangesNecessary to carr out a controlled plece to produce mold and counter-moldAluminium molds (in general)
not usedTakey tape, peel ply and various in the gluing phaseSpray adhesives, peel ply, pipes and channels to convey the resinPipe to ingect the resin the moldTakey tape and nylon for high temperatures