What are you looking for in a ski building epoxy?

[Bloefeld]

I have made a lot off things out of composites. For the most part these are industrial products, with some aerospace stuff too.

I have used a lot of different epoxy, vinyl-ester, and polyurethane resins in these products. I have used all sorts of reactive and non-reactive additives in formulating resins. I have used many different additives to change the bulk properties of resins for use as both composite matrix resins and adhesives.

I am trying to get a handle on what it is that expert ski builders like those here want to achieve when they pick an epoxy system. I would also like to get some information on the products you now use and where you get them.

Cheers,

Bloefeld

[MontuckyMadman]

Whats wrong with your 8410 shit?
just to make sure, no one is using a vinyl ester resin to commercially make snow skis.
These formulations we use claim they are formulated for compression molding application.
I think you need to do some more reading here.

[Bloefeld]

Whats wrong with your 8410 shit?
just to make sure, no one is using a vinyl ester resin to commercially make snow skis.
These formulations we use claim they are formulated for compression molding application.
I think you need to do some more reading here.

It's 8084.

The statement about compression molding resin likely refers to nothing more than viscosity which everyone who uses them here seem to alter by heating them so they can get what they believe to be wet-out. The idea of higher viscosity is to use compression to wet-out the fiber and leave enough resin in place to maintain correct resin/fiber ratio's. That is good news from my perspective, as what you are saying is that the resins you use are vanilla bis a epoxies. Easy to formulate.

I would not be so certain that no commercial skis are made with vinyl-ester resins, but I will take your word for it. For home builders, I think they are a great option and much easier to get great results from.

FYI a friend of mine designed a very complicated antennae array for the space shuttle. He used a modified formulation of Durakane 8084. Good enough for space use, probably not too bad for all mountain skis.

One of us uses truck load per week quantities of both epoxies and vinyl-ester resins, one of us doesn't.

I am new to the idea of building my own skis. I am not new to composites. I have asked posters like you, who seem to have knowledge on the topic for opinions. There is little need for you to instruct me to read more, I have read a boat load of conflicting and just incorrect information on this site. Thus my request for more information about what posters here think would make a good system for use in skis.

Thanks for your post.

Cheers,

Bloefeld

[skidesmond]

Epoxy is such a big topic. I decided that I would use what a lot of others use, so I wouldn't spend years testing what works well and how well it works. I use QCM EMV 0049 resin and ECA-032 hardener. QCM is now part of Forrest Paints. It's documented here on the site.

Pros:
1. Crystal clear color. Great for when I use fabric as a top sheet and I use it as a skim coat for the top sheet for added protection.
2. Can be used at room temp. This is a big plus for me.
3. No odor.

Cons:
1. Long cure time. After pressing for 10-12 hrs it still needs to cure 4-5 days or more before I can begin the finishing process and flexing the ski. I know this can be remedied with a heating pad, just not there yet. I guess I could built a warming box and stick the skis in there for a day or so.
2. Environmental/health concerns. I know there are other epoxies that pose less health risks such as Entropy's. I need to try their epoxy.
3. Cost. Shipping cost for QCM 1 gal resin, 1qt hardener is $46 because of the hazard fee.
4. Need an east coast (or North East) distributor. Perhaps it would be cheaper.

Ideally I'd like a product that's 1 part (2 part is ok) with a 30min working time (I'm slow at layup ), easy to use, requires no heat, cures in a matter of hours and bonds to all ski materials (plastic, metal, rubber, wood, cloth, fiber glass, carbon fiber.....), low toxicity, that's why I tried Gorilla glue. Now a clear Gorilla glue might be just the thing!

[twizzstyle]

Epoxy is such a big topic. I decided that I would use what a lot of others use, so I wouldn't spend years testing what works well and how well it works. I use QCM EMV 0049 resin and ECA-032 hardener. QCM is now part of Forrester Paints. It's documented here on the site.

This. The QCM (now Forrest) epoxies are proven, popular, and affordable. Why re-invent the wheel? It is used by home-builders, and it is used in the industry by professionals. We, as home-builders, tend to accept the processes used by the "big guys" because we trust that the proper testing and research has been done by them for many years.

I've also used Entropy (currently using it for two more pairs). Works just about the same as the QCM (Forrest) stuff I've used in the past.

For me - I just need my skis to not fall apart, that's really the only requirement. My skis aren't going to space.

And Steve! Get some heat for pete's sake! It's a 30 minute cure with heat!

[Brazen]

Yeah, the epoxy works...it's quick, easy, reliable and cheap and although I'm always on the lookout for better there's a limit as to how much better it could be. My usual issues are with the materials being used and that's where we could use some insights and research, IMO there's just something inherently wrong with using materials that don't even bond in a layup without having to treat them with fire...


FIRE!!!!

[skidesmond]

I know Twizz, heat my last big hurdle. I have a friend who is an electrical engineer and I sent him Happymonkeys site with his PID box setup. Then there's the DIY heat blankets posts I've been following. So perhaps a summer project is in the works.

I agree w/, "I just need my skis to not fall apart". The bond needs to be strong. I'm not looking to use a product that is total over kill. I like to keep my builds on the simple side and prefer to make the wood core the focal point and use the other materials to support the function of the core.

[Bloefeld]

Epoxy is such a big topic. I decided that I would use what a lot of others use, so I wouldn't spend years testing what works well and how well it works. I use QCM EMV 0049 resin and ECA-032 hardener. QCM is now part of Forrest Paints. It's documented here on the site.

Pros:
1. Crystal clear color. Great for when I use fabric as a top sheet and I use it as a skim coat for the top sheet for added protection.
2. Can be used at room temp. This is a big plus for me.
3. No odor.

Cons:
1. Long cure time. After pressing for 10-12 hrs it still needs to cure 4-5 days or more before I can begin the finishing process and flexing the ski. I know this can be remedied with a heating pad, just not there yet. I guess I could built a warming box and stick the skis in there for a day or so.
2. Environmental/health concerns. I know there are other epoxies that pose less health risks such as Entropy's. I need to try their epoxy.
3. Cost. Shipping cost for QCM 1 gal resin, 1qt hardener is $46 because of the hazard fee.
4. Need an east coast (or North East) distributor. Perhaps it would be cheaper.

Ideally I'd like a product that's 1 part (2 part is ok) with a 30min working time (I'm slow at layup ), easy to use, requires no heat, cures in a matter of hours and bonds to all ski materials (plastic, metal, rubber, wood, cloth, fiber glass, carbon fiber.....), low toxicity, that's why I tried Gorilla glue. Now a clear Gorilla glue might be just the thing!

Gorilla glue is useless in this application. I started a threat on using polyurethane composite resins and after talking with a world expert on the topic who works at Huntsman, for us home builders we are simply better to forget about it.

It appears to me that Forrest is no longer making QCM and I certainly could not find any information on it from their site. They make coatings now.

Skis need a glassy but tough resin system, or at least that is what I think. The Super Sap from Entropy merely replaces one type of petroleum derived epoxied ring with another made of pine oil. Their Technical Data Sheet and MSDS didn't give me much information. However it sure looks like an interesting product.

That said, I have read of many posters heating the resin to dilute it to make it easier to handle. This is an error. Compression molded resins are made thixotropic so that when applied cold they sit on top of the fibre to some degree. The compression wets out the glass, not turning the resin into soup.

These types of resins are best compressed at no more than 35 to 40 psi and heat is almost essential to get them to kick and not leak out everywhere. Used correctly and with the correct amount of resin applied for each layer (based on the Arial weight of the fiber the weight of the resin should be about 38%) these resins should work well in compression molding.

The full properties of the resin matrix will not come without a post cure heat to the glass transition temperature of the system or at least 80% of that number. Your skis would work even better if you build a hot-box and better yet if you heated your mold.

Thanks a ton for your insight. I am hoping to come up with a superior formulation that I can make cheaper than what everyone is paying and pass the saving I get by buying in big quantities onto the home build group.

Cheers,

Bloefeld

[twizzstyle]

If you can come up with something similar/cheaper, you'll likely have a lot of interest from folks on here.

Lots of people are getting their epoxy from Forrest - QCM sold their epoxy division to Forrest a while back. If Forrest is no longer doing the epoxies, that would be news to me (and bad news!), but it would surprise me.

What you've said about leaving the epoxy thick in the layup is intriguing. I may have to do some test pieces now to see the differences. I personally don't heat up my epoxy much before layup, but I do like to warm it just slightly, just to make mixing it easier.

[Bloefeld]

If you can come up with something similar/cheaper, you'll likely have a lot of interest from folks on here.

Lots of people are getting their epoxy from Forrest - QCM sold their epoxy division to Forrest a while back. If Forrest is no longer doing the epoxies, that would be news to me (and bad news!), but it would surprise me.

What you've said about leaving the epoxy thick in the layup is intriguing. I may have to do some test pieces now to see the differences. I personally don't heat up my epoxy much before layup, but I do like to warm it just slightly, just to make mixing it easier.

I am certain that if you take your time and mix completely; mix until you have it completely mixed, and then mix for at least another two minutes. You will find what I am claiming will be true. Remember to use the right weight of epoxy as it relates to the weight of the glass.

One thing that most folks won't be able to do, but if you have a vacuum pump is easy is to de-gas the epoxy prior to application. I use sort of a glorified pressure cooker with the blow-out valve plugged off. Then I put my mixed epoxy into a plastic container and pull a 1 torr vacuum on it for about 2 to 5 minutes. No bubbles = no voids.

Cheers,

Bloefeld

[twizzstyle]

Yep, I do that a lot when working on other projects. Just not skis since it's never been a problem.

[skidesmond]

Epoxy is such a big topic. I decided that I would use what a lot of others use, so I wouldn't spend years testing what works well and how well it works. I use QCM EMV 0049 resin and ECA-032 hardener. QCM is now part of Forrest Paints. It's documented here on the site.

Pros:
1. Crystal clear color. Great for when I use fabric as a top sheet and I use it as a skim coat for the top sheet for added protection.
2. Can be used at room temp. This is a big plus for me.
3. No odor.

Cons:
1. Long cure time. After pressing for 10-12 hrs it still needs to cure 4-5 days or more before I can begin the finishing process and flexing the ski. I know this can be remedied with a heating pad, just not there yet. I guess I could built a warming box and stick the skis in there for a day or so.
2. Environmental/health concerns. I know there are other epoxies that pose less health risks such as Entropy's. I need to try their epoxy.
3. Cost. Shipping cost for QCM 1 gal resin, 1qt hardener is $46 because of the hazard fee.
4. Need an east coast (or North East) distributor. Perhaps it would be cheaper.

Ideally I'd like a product that's 1 part (2 part is ok) with a 30min working time (I'm slow at layup ), easy to use, requires no heat, cures in a matter of hours and bonds to all ski materials (plastic, metal, rubber, wood, cloth, fiber glass, carbon fiber.....), low toxicity, that's why I tried Gorilla glue. Now a clear Gorilla glue might be just the thing!

.....

Thanks a ton for your insight. I am hoping to come up with a superior formulation that I can make cheaper than what everyone is paying and pass the saving I get by buying in big quantities onto the home build group.

Cheers,

Bloefeld

That would be awesome. Keep us posted.

[Bloefeld]

Yep, I do that a lot when working on other projects. Just not skis since it's never been a problem.

Hi Twizz,

In my experience epoxy and vinyl-ester voids are always a problem. Take a look at a old pair with a microscope and you can see the stress fractures between voids all over the place. Major cause of premature failure in lots of stuff.

Cheers,

Bloefeld

[sammer]

It appears to me that Forrest is no longer making QCM and I certainly could not find any information on it from their site. They make coatings now.


Thanks a ton for your insight. I am hoping to come up with a superior formulation that I can make cheaper than what everyone is paying and pass the saving I get by buying in big quantities onto the home build group.

Cheers,

Bloefeld

This is where the "read more" comes in.
Forrest recently acquired QCMs epoxy division.
The reason you can't find anything online is it's still too new.

I've tried a couple QCM formulas and find them too thick with out warming them up.
I've had great success with West systems epoxies as they are less viscous and wet out way quicker ( but twice the price of QCM)
I work in my basement where the temp is a constant 12c
Vacuum does not produce enough pressure to push epoxy into the fabric.
QCM will pretty much just puddle on top. I've tried this.
You have to get your glass wetted out completely or you end up with dry glass. Granted I can only heat to around 140f.

Most of the bubbles I get in my layup come from trying to push the epoxy into the fabric.
I gave up using a squeegee or spreader and now use my hand as it doesn't cause the cavitation.

I would love a 300-500 cps epoxy. Something that flows like water into the fiber. Wet out would be so much quicker and more complete.

Not to offend,
I do believe you are an epoxy expert, I also believe you know a shit ton about composites.
But build a ski in your home, in a reasonable amount of time and investment, go ski on it for a couple days, then come back and tell us what works best.
Can't wait to see the product.


sam

[twizzstyle]

^^^^^^^^^^^