Looking good Flem-I think the fly is inspecting the neutral plane:)

That was Vic, now he's Vac the fly.
It's the real deal from Mexico. Lemmonwood grows in a limited area, down in the southern tropical region.
The membrane is a viscoelastic polymer. They call it VDF, vibration damping foil.

Quote from: Flem on December 22, 2021, 11:06:28 PM
I decided to add an uncoupling membrane between the two pairs. It acts as a shear plane to reduce the effect of the glue line.

What is the effect of the glue line?


Mark

The epoxy glue plane is going to to the most rigid part of a lamination. Epoxy is less elastic than fiberglass or Lemmonwood. Some might consider the effect insignificant, but thats a myopic focus on one aspect of the laminate.
I think its beneficial to look at all the small factors that combine to make a bow with the attributes you want to achieve. That and its fun to experiment

  Please post a link to this VDF stuff...  I want to research it...

I don't have a link. I can tell you the stuff I am using is similar to D-30 material, as far as vibration absorption. Lots of info for D-30 out there. Look for the stuff that is used for an uncoupling membrane.

https://www.sciencedirect.com/science/article/abs/pii/S0167273805002365

I not getting enough info from that abstract to know if thats in the same class of materials that I am referring too.

As far a one aspect of the physical properties go, this stuff is similar in its damping/absorbing ability.

https://www.d3o.com

 

I have d30 pads in my Moto Jacket-Its flexible until impact then it gets hard as a rock!

My MTB knee pads are also D-30. So is my phone case. The stuff is amazing. To be clear, the VDF is only similar to D-30. D-30 would not work well as an uncoupling membrane.

I like the mini oven & temperature . monitoring.  Do you think that when the inside temperature gets to the temp you want it been long enough in the oven.

Once the thermocouple inside the block gets up to temp, is when I start the clock. But I would imagine that it is probably done when it reaches the target temp. I usually preheat the materials, so it does not take long to get to temp.

Flem how do you know there wont be epoxy adhesion issues with the membrane youre using?

Good question! If you have been researching VDF and other viso-polymers, it becomes apparent their are many options for a multitude of uses. The one I am using is treated or "sized" for use with epoxy.

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This is exciting for me, its a new tool, or form for making fiberglass laminate.
Yes its just a slab of formica covered particleboard, but its special formica
Its surprising  how textured, even smooth looking formica can be. If you are going to make laminate your tool needs to be dead smooth. Glass is the best surface, but a 6'X6" slab of glass is heavy, needs a support base which adds more weight and makes it hard to move around or put in my hot box, plus nothing can be fastened to it.
So I am always on the look out for some smooth material. I happened to find a slab of this old counter at Habitat for Humanity resale store, its that old 60's or 70's stuff that was hard and very smooth. The stuff you did not want to scratch or face the wrath of Mom! I've got enough of it for three forms. These forms don't last forever. Its amazing what the epoxy will do to the surface, even though it technically does not bond to the surface, over the course of many uses, it slowly eats away at it.
Should be ready to go this week. Just have to finish drilling and then 5 coats of hard release wax.
Its already pretty glossy just from cleaning and buffing.
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Cool stuff, Flem. I like watching your mad scientist side at work. Have you ever tried using UHMW polyethylene plates as a work surface for lams? It should be smooth enough and the low surface energy means almost nothing sticks to it.

For instance:  https://www.busybeetools.com/products/slick-plate-36in-x-4in-x-1-8in.html


Mark

Mark, I have used UHMWPE. The stuff is awesome and you are right nothing sticks to it, but apparently it is very difficult to machine, because so far I have not seen a dead smooth plate and its impossible to smooth with even the sharpest of tools. I had a 2" wide piece I was using for a while and I was actually able to get it decently flat and smooth with a shaving sharp, low angle smoothing plane. But even that started to deteriorate after some usage. I also did a full wax job on it each time, even though it's UHMW!

I machined lot's of parts with it, it doesn't like a file but machined well

Max, is it possible to machine the stuff flat and smooth like glass?