Resin Infusion of carbon fiber with balsa core

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Resin Infusion of carbon fiber with balsa core - any experience?

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Fasta	Fasta posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	I am also a balsa hater. Being this natural material it has these mentioned variations and is typically heavier. You can use a thicker foam for greater stiffness and still be lighter than Balsa. The foam do come is many weight grades too, 80kg, 100kg, 130kg, 200kg and upwards. The balsa can also suck up a lot of moisture depending on your place of work or storage and that in turn can lead to your resins not curing properly, hence not bonding properly either. For larger projects it is too much of a risk to take when a product is so valuable to build. If it soaks more resin out of a laminate then that that will also affect the bond and strength. I always feel it just a risk not worth taking, for me especially in boats where wood and water should be avoided. Fastacraft Facebook page
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oekmont	oekmont posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 550, Visits: 27K	I have done balsa infusion/wet lay setups for my laminate/material library. With infusion grooves and holes, like solid foam infusion preparation. I used polyurethane coupling spay coat to seal the wood. In the end the weight of the three pieces varied significantly. After mathematically taking away the carbon skin, the difference was about 30%. And the weight wasn't pleasing either. It was about the same as 3d pet core/soric lrc. Wich are easier available, better in terms of handling, storage, reliability and were ready to use right of the roll. Both aren't what I would call ultra lightweight. For me that are bread and butter sandwich materials, because they are infusion ready. Wet layed rohacell is less than a third that weight. For 3mm. For thicker sandwiches even less. Wet layed, balsa would be lighter than both materials, but solid airex would be still lighter. And for stiffness: as long as you aren't using insulation foam or solid metal, the stiffness is just the same for every core material.
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John Hansen	J John Hansen posted 6 Years Ago HOT Post Details
J Group: Forum Members Posts: 42, Visits: 232	+x oekmont - 3/8/2019 6:34:03 AM That's the core of the problem. You will not find much data for the resin uptake, because it varies more than 100%. No two pieces are the same. I have had balsa, wich was almost like birch, and I had balsa, wich was like xps foam. I have seen balsa wood with fine structure, and wood with a sponge like structure. The small influence of the core to the bending characteristics results directly out of the principles of mechanics. And the pressure resistance of a sandwich is proportional to the pressure resistance of the pure core material. It's as easy as that. Have you ever had airex or rohacell in your hands? Maybe you picturing it like insulation eps. Real core foams are incredibly solid. You can drive your car across an airex board without damaging it. I am not saying you should not use balsa. I am just saying that it seems to me that you are glorifying for some reason. And your image of it being an top end ultralight option ("as light as possible") and much stronger than foams doesn't correspond with my experience. And resin uptake is a tricky beast itself. other than the used wood, it depends on your resin, the thickness, the surface preparation, infusion aiding preparation and many more. If you want to seal it, use a quick setting epoxy, or a 2k laquer. @oekmont, When you say: "I have had balsa, which was almost like birch, and I had balsa, which was like xps foam" what are your sources for the balsa? I see claims of suppliers that their balsa is pre-sorted or graded by density. I am preparing to buy a sheet of the lightest available balsa that I can find. I am most interested in Baltek. Have you ever used it? A Lifelong Learner
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