SO YOU WANT TO MAKE FIBERGLASS BLADES
The Word Fiberglass can be construed to have many meanings in the plastic business also known as F. R. P. Fiber Reinforced Plastic.
1.) Fiberglass products contain fibers and a resin (binder).
A. glass fibers
B. Kevlar (expensive)
C. Carbon fibers (very expensive)
D. Polypropylene
E. Nylon
F. Others such as burlap among others have been used (not so good)
2.) The Resin (Binder) contain a binder which is known as resin usually polyester resin that uses a catalyst that interacts with a promoter to cause a molecular action which enables the product to cure also known as polymerization. Cure (not to be confused with drying) Drying depends on solvent evaporation into the atmosphere order for the product (usually paint) to dry. Curing can take place in a vacuum but is fairly temperature sensitive with the best temps ranging from about 72to 77 deg.
However most will cure at about 65 to 100 deg but with some unpredictable cure times and low or high peak exotherms which low exotherm (low curing temps) may cause a part to not achieve full strength . High peak exotherm will some times cause the part to get to hot (and on rare occasions spontaneously combust) to crack and split causing the part to be unusable. Note when using polyester and it is very hot above say 85 deg the recommended amount of catalyst must be cut by about 40/50%. When the temp is about 100 deg then the catalyst must cut by about 70%, this is all of course based on the amount of promoter the manufacture added to the Polyester resin . Also be knowledgeable there are summer and winter formulations of polyester; obviously the winter grade has much more promoter.
A. Epoxy which will bind to steel much better than polyester but more expensive
B. Vinyl Ester which when used in connection with fibers yields a higher strength. Popular usage is in Race Boats Hulls and Round Track Parts.
FOAM CORE
WHAT TYPE OF FOAM ?
Types of Foams to Consider
1.) Polystyrene, which is mostly styrene monomer that has been formed by a gas.
Formerly freon gas was used but has been abandoned because of being linked to damaging the ozone layer.
A. When considering polystyrene AKA Styrofoam Use Epoxy as it does not dissolve the foam. Styrofoam dissolves when polyester is applied, because polyester one of polyesters main ingredients is polystyrene.
B. Like chemicals (chemicals with similar makeup) will attack and most frequently dissolve the other.
C. When Using Polyisocyanurate foam AKA urethane foam you may use Polyester, Vinylester or Epoxy, as it will not dissolve, because of it chemical composition is totally different from Styrofoam.
D. Both types of foam are manufactured in different densities the higher the density the heaver the weight per cubic foot.
Lower density foams are lighter, contain more air/gas and have less strength.
E. Regardless of what type foam is used the mounting base of the blade has to be strong enough not to collapse when they are attached together. No lightweight foam will meet this requirement.
Surfboards are usually made of Styrofoam, fiberglass cloth (not stranded mat) and epoxy resin. Each board the foam is formed and then made in reverse of the typical female mold process used in Manufacturing FRP, boats, bath tubs, swimming pools, etc.
Would it really be cost effective to make a female mold to make Blades?
Disadvantages
It would require at least two molds, one for the front side and one for the back side, then there is the problem of bonding the two pieces together and getting a perfect alignment, and then there is the balance to consider. Another factor is the Mock up or prototype that you must have to make the female mold from. In theory your mold can be only as good as the part you are pulling it from.
Then with the two-piece mold you can only make one blade at a time and from that molds life you can only pull that exact shape, pitch and size from that mold.
To make fiberglass molds is a field of it own even requiring more skill than laying up the fiberglass part?
Making the prototype and the mold is very time consuming and expensive and must be done to exact tolerances.
Advantages
Onc't you have the molds, let's assume close to perfection you can pull several hundred parts from them. That is if a part does not stick to the mold and also considering you know how to keep from damaging the mold when your are trimming the part and demolding it . Demolding means, removal from the mold.
Fiberglass manufacturing has several trade skill within.
- ) Design of the desired part and ability to draw a scale drawing.
- ) Ability to produce a 3 dimensional mock up from that drawing
A. From wood
B. Clay
C. Wood,Screen,and Plaster,
D. Shaped Foam covered with Resin
E. And numerous other possibilities.
3.) The Skill to be able to understand the negative and positive draft angles
Which will enable the part to be easy to remove from the mold.
- ) The skill to lay up the part, which the poor mans way is open contact lay up, commonly known as hand lay-up.
- ) The Knowledge of which resins, fibers (glass cloth or stranded mats, etc)
- ) What weight of cloths or mats to use then how many layers to lay up to achieve the desired strength, weight, of the finished part.
- ) The number of lawyers laid up for each blade half and the weight of the resin is critical when the balance is to be held in tolerance even where the part can be balanced after assembled.
What Do I Consider to Be the Best Choice for Performance/Cost Efficiency .
With all this said if you want a blade that has some of the properties of fiberglass superior strength, foam core is not feasible. The best choice is probably to coat a good designed tested wood blade. Then you would kind of have the best of both worlds. Strength of the wood and the weather proofing of the fiberglass.
But a word of caution here the wood humidity level must be at about 8% or less
And you must apply enough fiberglass to overcome the expansion (strength) factor of the wood. For instance in the morning the Wood Blade temp might be 35 deg. And by noon could be 75 deg this continued cycling of expansion and contraction over a period of time will split the fiberglass coating if enough layers are not applied to become the dominant strength factor to reasonably restrain the wood. Also all the wood must be sealed from the ambient atmosphere or it will take on moisture which will cause expansion of the wood when it heats up. In other words for the fiberglass/wood to work synergistically the wood must be totally encapsulated!
JerryD Manufactured fiberglass products for more than 33 years, making one piece bath tubs, dune buggy's, jeep bodies, water slides, satellite dishes among numerous other parts. He has been a consultant to numerous fiberglass and cultured marble companies for the past 25 years
Is any one familiar with what is known as verticell honey comb ?
It is made in cardboard, plastic, and even aluminum and when a great strength to weight ration is desired it is used. Like in some aircraft wings.
What man can conceive he can achieve. But you must work very hard at the achieving part. Any one can conceive ideas but until there are applied, tested and proven , only then do they benefit society.
Even though I have the skill to build FRP Molds then Blades I am looking to purchase them, because making Blades that are exactly the right shape, angle etc, which people have already proven to work on their Gens is a total different skill
Can you imagine if each person on the discussion board used his field of experience and we all worked together how many high quality Wing Gens we could put out each week!
Make Clean Electricity and save the world !
JerryD. Hall