Discussion in 'Composites' started by proppastie, May 8, 2018.
Aluminium walking sticks are a possible mandrel. Removable with acid.
Also removable with Saran Wrap wrapped around the mandrel first, no acid, no hazmat, no CIA body disposal accusations, no Homeland Security knock on door
Acid is so yesterday. The modern way to dispose of a body is with a woodchipper.
If you can pressurise your mandrel before wrapping, it's a lot easier to get out. A goodwill walking stick will come with annoying scrapes etc that make removal tricky.
Someone set some golf clubs by the side of the road....I grabbed them and got a "high modulus graphite" shaft to play with. already cut off the head and the grip. It is 5/8" at the root and down to 1/4 at the tip and very stiff. About 1mm wall. Wounder about sneaking up on the properties by trying to measure the deflection. I wounder how stiff I want my tail skid. I have nose skid for braking and probably will land flat.
Young's Modulus, Poisson's Ratio, Density, Comment, 6.0000E+06, 3.5000E-01, 1.0000E-01 CF matrix ?????
A lot depends upon fiber orientation. Many of these tubes and shafts are either wound on the mandrel or by pulling braided tubes over the mandrel. By simply examining the shaft you might be able to ascertain the angles. Once you have angles, ID and OD at a couple places, you can figure out the elastic behaviour of the shafts you are looking at. You might have something useful, but understand that would be by accident... Which is why so many folks must design their composite parts to their strength and spring rates.
This is a pretty good website, with a braid calculator. http://www.braider.com/Products/Sharx-Braided-Biaxial-Sleevings.aspx. You would then have to figure out effective spring rates and strengths.
T300 (classic high modulus unidirectional graphite/epoxy from pre-preg tape): Ex=26 Mpsi, Poisson's Ratio = 0.28, density = 0.055 lb/in^3, epoxy matrix. If you knew the density of T300 fiber, you could estimate the resin content.
I think a used archery bow might work for you.
Thanks for then numbers...I was really off there.....The fibers look like UNI. My attraction to the fishing pole, golf club, archery bow, driveway marker protrusion is based on the true or mistaken belief that these items are heat-pressure cured and of a higher quality/strength than a room-temperature vacuum bagged item.
May well be made with something other than epoxy.
Not quite visualizing, would you be able to make a sketch or include a photo?
Should have included quote, this is in response to VB's testing method, post #14.
Here is a high priced version.
Pultruded rods are processed at decent temperatures and with higher Tg resins than we can usually run in a home shop. Pultruded glass shapes are usually polyester resin with reasonable Tg but low strength. You better know your source if you want to approach fiber strengths.
If you are trying to discern between polyester and epoxy smell quite different. Polyester smells strongly of styrene, while epoxy is quite different from styrene. Trouble with this technique is vinylester smells of styrene too.
If you want to approach fiber strengths in a composite part, you had better know it from the source.
I do not know if I would include a video that crappy on my website advertising high tech testing...
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