Hi Wizard ,
Sorry to confuse you , I figured someone wanting to build a carbon gantry may have a broad understanding of the process and components . That said , I will explain .
Hybrid laminates are a mix of various materials like carbon/kevlar or carbon /S or E glass . There are many different hybrids and these address various aspects where for instance carbon /kevlar would be used where both stiffness and impact resistance is needed . Remember these cloths are a mix of properties , so do a little of each .
The different weaves where developed for lay or how the cloth drapes on a plug or in a mold , say for instance unidirectional cloth does not like to take a tight turn in length ,but a twill weave at 0/90 or +45-45 would lay much better . These weaves can also add to the stiffness of the component being fabricated .
Cross linked resins are not that new and in the case of polyester resin it's the isopthalic polyester where non cross linked is orthopthalic polyester . A cross link is a much stronger bond on a molecular level so makes for a stronger resin .
This cross linking has been used in epoxy development where the molecular chain has been altered in a way that it betters certain properties .
Proset epoxy is a Gougoen Brothers product ,the makers of West Epoxy and is a cross linked epoxy . It is used by a lot of high end custom boat builders these days because of its broad properties ,like it makes a very good infusion resin with a 9 hr pot life and it can be used for wet layup with a brush and roller with the use of a different hardener . The various other manufacturers have their own take on these various resins including System Three .
For something like a self built gantry ,using prepreg or high temp cure resins is cost prohibitive and the amount you win by going this route is not the same as the substantial investment made in the purchase as these components can cost substantially more .
Post curing helps remove any volatiles left in the resin after the initial cure . These components are usually solvents or plasticizers which can soften the resin if left behind making for a weaker bond . The post cure process is usually a uniform heating up of the component to help the off gassing of the volatiles . Most components continue to off gas over its lifespan and some polyester race boats that where post cured 15 years ago still offgas the strong MEK smell if drilled or cut into . The same for some of the solvent based epoxy boats built years back .
Post curing can distort a component if it is not properly supported so a lot are post cured in a mold or on a plug under vacuum .
A lot of the low temp cure resins are being used now for less distortion and will cure at temps between 160 -180 Fahrenheit which is attainable with a propane space heater in a plastic tent or a hotbox made from polyiso insulating foam sheets like sold at Home Depot .
The best way to go is to actually call all the various suppliers and tell them what you want to achieve and ask what product they would suggest you use . These guys work with all these component daily and most are aware of what works and what doesn't . Collect as much info as possible ,then make a decision which way you want to go . If this is not your everyday job ,I suggest to do a test patch first to get familiar with the process and the workability of the components . Do a small section in the mold with the full layup you have calculated to work and see what it takes to do the job . If possible work in an air conditioned room and use slow set hardener for a longer pot time , so you have ample time to fix any holidays or wowies you may make .
The use of a vacuum bag will also help hold things together and can be set up prior to laminating , so it's easy to pull over and seal , then start to pull a vacuum and check for bag leaks . A bag leak will introduce an air source into the laminate and can pull enough resin out of the area to form a dry spot which would destroy the component . Let the resin kick off and while that is happening build your tent or hotbox around the component ready for post cure . Most of the new resins only need a 24 hour post cure with a cold shut off at the end , unlike some of the older resins that required a slow rise and fall with a 48-72 hour cure, this can use a lot of propane if you don't have an efficient oven .
If you intend to secondary bond anything onto the component , it is a must to use a material called peel ply which is a woven polyester cloth that is draped over the component before the bag goes on . What this peel ply does is pre prep the surface so you don't have to abraid the surface and solvent wipe which can trap solvent in the adhesive . It also allows the amine blush to come to the surface of the peel ply and is removed when you pull off the peel ply .
Amine blush is a waxy layer created by the reaction during the epoxy cure that floats to the surface ,and needs removing before anything else can adhere to it . It can be removed by washing with soap and water and a light abraiding with a Scotchbrite pad or the use of peel ply .
Most fabricators will leave the peel ply on until they need to bond as it keeps the component surface isolated from dirt ,they will then mix a batch of adhesive ,pull the peel ply and apply the adhesive and whatever they are bonding . Any masking or setup work can be done around or through the peel ply if necessary.
I hope this explanation helps you understand a little more and answers some of your question
Regards Roc