Laminating tests

[bigal]

Just wondering if anyone has done any epoxy to fibre ratio tests.

I just started to test this with west systems and will soon try QCM and Aero Epoxy.

My press is heated at 200 deg F
I put wax paper on my aluminum bottom mold.
Two layers of fibre
More wax paper
Core material
More was paper
2 layers of fibre

For my first test I pressed at 60psi and ended up pressing out to mutch epoxy. Also more epoxy pressed out under the core than on top of the core. I wonder if it is because the heat source is under the core.

For my second test I added 1g of 404 west systems filler to one squirt of epoxy and hardener.
- under core had 30 percent epoxy, 70 percent fibre
- top layer had 34 percent epoxy, 66 percent fibre

I`m hoping that others have done tests like this. I would imagine that qcm epoxy must perform well without adding any filler. I havn`t heard of anyone having any problems! but has anyone actually tested this? I was thinking about also doing this test in the tip and tail section of the mold.

[bigal]

I was wondering what people us on aliminum to stop the ski frome sticking to it. Wax? Release Film? Plastic?

[Alex13]

Most people use a general purpose wax or automotive wax on the aluminium skins from what I've read.

[Jekul]

I use a high-temp wax specifically for epoxies. Got it through my local composites dealer. Works great and it's not too expensive..

[falls]

http://www.dalchem.com.au/index.php?Ite ... &task=view
I'm going to use this stuff.
Their rep said I should also use an aerosol spray of release on the wax before each pair. I have heard that hairspray can be used for this job too.
Others use honey wax from specialty products co.
http://www.specialtyproductsco.com/Honey%20Wax.htm

your tests are interesting jekul. I am going to use west system and am trying to work out how much epoxy to wet out the skis with without making a big squeezed out mess.

[krp8128]

3 coats of mold release wax* and then layer of wax paper. The wax paper works better if you're not using heat, today I tried parchment paper. For wax I use http://www.aircraftspruce.com/catalog/c ... relwax.php


bigal,

What are you trying to test by performing these layaups? Are you weighing the glass and epoxy to calculate a final ratio? Squeeze out really isn't going to tell you much, pretty much only that you used too much epoxy in the first place. Also, adding filler can drastically change the properties of the epoxy.

[skidesmond]

I was wondering what people us on aliminum to stop the ski frome sticking to it. Wax? Release Film? Plastic?

I've used wax paper and a wax called Butchers Wax (has carnauba in it http://www.bwccompany.com/ ), made for wood floors/furniture. The Butcher Wax is super cheap. I paid $5.49 US for a 1lb can many years ago. Both work fine. Wax paper works as long as you can keep it in place.

I'm using hard board that has a white coating on 1 side instead of aluminum. The wax works on that. I'm upgrading to aluminum over the summer.

[bigal]

3 coats of mold release wax* and then layer of wax paper. The wax paper works better if you're not using heat, today I tried parchment paper. For wax I use http://www.aircraftspruce.com/catalog/c ... relwax.php


bigal,

What are you trying to test by performing these layaups? Are you weighing the glass and epoxy to calculate a final ratio? Squeeze out really isn't going to tell you much, pretty much only that you used too much epoxy in the first place. Also, adding filler can drastically change the properties of the epoxy.

When I had spoken to the technical people at west systems epoxy I had aske d them how I would know at what presure to press my ski`s. they had told me that my goal should be to have a
39 percent epoxy to fibre ratio.

my first test with west systems there where many dry spots.
I wasn`t even close to the 39 percent.

it was the tech guy from west systems that told my I should try adding filler.

the last test I did was this afternoon. for one squirt of epoxy/hardener I put 1.5 grams of filler.

I ended up with 31 percent for the 2 layers underneath the core and 35 percent for the 2 layers above the core.

the point of this is to make sure I don`t us up materials for nothing. So i figure it is a good idea to test small samples before trying a real ski. I`m excited to build the real thing hopefully I will get this right soon.

Has anyone tested small samples like this before. and if not how do you know that the ratio of epoxy to fibre is perfect. I figure that most people don`t even know that they have dry spots because once you have your top sheet on you can`t see the laminates underneath.

[doughboyshredder]

Has anyone tested small samples like this before. and if not how do you know that the ratio of epoxy to fibre is perfect. I figure that most people don`t even know that they have dry spots because once you have your top sheet on you can`t see the laminates underneath.

I have literally laid up thousands of boards, so for me it's experience. But, before we built a run with clear tops and bases, I probably had a few dry spots. The key imo is to work fast enough that you can use a very viscous epoxy and really work it in to the fibers. You should be able to determine whether a layer is wet out properly before you move to the next layer. Some builders wet out the glass on a separate table and let it sit for a minute before bringing to the layup table, where it is flipped and the other side is wet out if necessary.

[MontuckyMadman]

what west are you using aside from the 404 filler?

The stuff you buy in the marine store is not suited for compression molding, to my knowledge.

I found much of the laminate to be 'dry' essentially with the west I used, in comparison to other resin/epoxy out there.

I have not layed up thousands of boards.

We found much of the resin to press out I guess? I don't know where the hell it went actually.

[doughboyshredder]

We found much of the resin to press out I guess? I don't know where the hell it went actually.

When the epoxy kicks it gets extremely viscous for a short period of time. During this time any excess and anything that hasn't been worked in to the fibers will press out. A lot of people seem to think the press will press the epoxy in to their glass, and that's not really the case.

[bigal]

I guess I was hoping there is a way to make west systems work because it is really accessible and easy to work with. Although it seems to be working mutch better with filler. I think I will just give up on west systems. I live in Canada so I am reluctant to order from qcm, but I will eventually. I will try the Aero epoxy that I found from Canada Composites.

I have been using 105 resin and 205 fast hardener. I have some slow hardener but I have been using up the fast for the tests.

[bigal]

And I will take extra care when working the epoxy into the fibre.

[krp8128]

If you're having problems with West Systems, you will have problems with any epoxy you use. It's not a materials problem, it is a technique problem.

I've used West on several pairs of skis. is it the best performing for skis? No, but it is pretty foolproof with the pumps and readily available.

When the epoxy kicks it gets extremely viscous for a short period of time. During this time any excess and anything that hasn't been worked in to the fibers will press out. A lot of people seem to think the press will press the epoxy in to their glass, and that's not really the case.

doughboy has it right, and i suspect that this is the issue that MM and bigal are experiencing. West 105/205 wets out 22oz triax great as is, filler will make it thicker and take longer to properly wet out glass, as well as screwing with the mechanical properties in undesirable ways for this application.

When you lay down a layer of glass, it needs to go almost completely translucent before you move on, air bubbles and dry spots will be white. Once it is wet out you can squeegee or otherwise press out any excess epoxy that you can, and this will get you as close to an ideal fiber/matrix ratio as you can in a hand layup.

Fillers, dry spots and pressing out all the epoxy just means you need to work on your skills, not switch materials.

[DutchDesigns]

I tried west system at the beginning and had dry spots and problems with flexing causing delams.. switched to System Three silvertip laminating resin and its actually cheaper and is easy to use 2:1 ratio and works like a charm. And I got it from a place in Calgary AB