:: View topic - What are you looking for in a ski building epoxy?

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

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

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!

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!

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!!!!

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.

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

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

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

.....

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.

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

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

^^^^^^^^^^^

Sammer does use a vacuum to make his skis if I remember right from reading his journal. I think what he is saying is that he trying the method you are suggesting and he ended up with dry spots in the fibers.

PS. Is your first name Ernst per chance?

alright, i guess the more info you get the better.

i'm currently using the super sap cpm system by entropy. prior to that i was using the sr8500 / sz8525 combo by sicomin.

both for pretty much the same reasons. i want an epoxy that cures fast with heat since i think there's too much that can go wrong when pressing for 24h+. as for the properties i just picked epoxy systems that the industry successfully uses in ski production.

part of my shop is heated, so thats where i do my layup. never had problems with the glass not wetting out. to be honest i wouldn't trust the resin/fiber ratio to be perfect if i just spread out the epoxy and not let it wet out the glass completely. imo it's kinda hard to tell if it's really spread evenly.

working times need to be at least 20min for me.

hahaha, Dr. Evil!

I looked at the Super Sap line and found it interesting. On most of what you wrote I am in agreement, and yes I am Earnest, its important you know.

OK let me give you the gospel on compression molding. When you see Nordica make skis they run it through roller bath. This bath does not compress anything and only a notional amount of the epoxy wets the glass. It is the thixotropic properties of the resin, heat and compression that combine to get the right resin/fiber ratio. Wetting it out by thinning your epoxy with heat, then putting it in your press will give you a resin poor laminate. You may not actually see this, but I know the performance of your skis is compromised.

There is a great deal of science that is easily available for you to see what I am speaking about.

I am here to learn from you experts. I have not built ski one yet but before I do I am going to learn as much as I can from you.

In the process I have no problem sharing my expertise. I do not profess to know everything. So take or leave what I have to say. I will always reply to what ever is addressed to me, no matter how insulting.

Cheers,

Bloefeld

I've been a long time proponent of vacuum.

Don't have the room to build a pneumatic press in my basement, nor would I be able to get it thru the trapdoor.

I've built a vacuum press table and have had pretty good results with it.

But...

Vacuum and the heat available to me will not

Sam,

This is a tad frustrating for me. You have taken information specifically made about compression molding and gotten pissed off because it won't work for vacuum.

Vacuum resins are thinner. You can buy lots of great resins for vacuum infusion or doing wet lay-up. The D.E.R. 8084 I recommend will make you a bomb-proof ski. You can tune the resin to just about any reasonable viscosity and build your skis the way you do.

I have no idea what kind of equipment anyone has. Do you use a vacuum pump capable of a 1 atmosphere vacuum, or do you use a venturi pump that can give you half that?

Are you heating during cure? Can you do a post cure heat? Do you use proper bagging materials or do you use a hunk of poly painters drop cloth? Do you weigh your resin and glass to achieve optimal glass/fiber ratio's.

Do you give a rats ass?

If you are happy with your skis? Then ignore my posts. If you want to try to improve what you are doing, then ask me questions. You can take or leave my advice, or you can read from other outside sources and call other experts to get their input. Your choice.

I think this thread is dead. So I will only respond to messages from now on.

Cheers,

Bloefeld

It was not my intention to kill your thread.

And if I've insulted you I'm sorry.

As i said I'm using the materials that are easily available to me

Yes I have a vacuum pump and can get to 28inhg, about all that is available at this altitude.

I'm using a polyurethane vacuum bagging material, I use a breather around my mold but not over the top as it leaves an imprint.

No I don't use a caul as I like to see the air trapped under the p-tex top sheet. It makes it easier to roll it out.

Please take the time to read my (and everyone elses) logs.

You will see what we do and more specifically why we do it.

sam

i'm not heating my epoxy prior to pressing. my shop usually has an ambient temp of around 20 degree C. still the glass wets out just fine.

the glass i use comes with recommendations for the optimum amount of epoxy. i just use that +10%.

Sorry tony but much of what you are saying is just not correct.

Compression molding should not be used to force the resin into the material matrix. Trust me you need to read more here, a lot of experts similar to yourself have chimed in with tidbits of industry knowledge, you just haven't seen yet.

That's just dead wrong.

Warming the mixture to a workable room temp of 70-80F is totally appropriate and does not dilute the mixture in any way.

These epoxies are actually specified to be coatings by industry personal.

I'm not sure that space beams in 0 G have any where near the same type of repeated loads of skis or are in any way similar to what we are building here on earth.

A tapered core with multi dimensional shape and a light weight composite matrix is allot different than anything you have built regardless of you expertise, it would seem.

I suggest you read every post on this board and make a catalog of questions, comments and concerns and get back with those. Similar to what I have done over the last several years.

You should go to a ski factory, as I have done several times, watch layup videos online, there are about 200, and just get out and build and do some testing before you start telling people what to do and use to make skis that you have no practical experience in building yourself.

Better yet get some 8084 to one of us to test, we already have all the equipment, before you tout it as the best solution. Sounds like we can only buy it by the truck load, so no one around here can even try it.

BTW Nordica, that is a prepreg that is slightly coated with epoxy prior to layup, not raw glass.

Your intentions may be noble, however your posts are increasingly abrasive and obnoxious.

And another thing, if vacuum pressing or vacuum infusion was superior, than builders like igneous and prior and wagner would employ it without doubt as they are not concerned with turnaround time and mass production.

Head produced skis for 20 years with a vacuum process but it has been abandoned in the ski industry, mostly.

You casually choose to ignore the fact that most aircraft components are finish cured in an autoclave at extremely high pressure after the initial cure so simply standard atmospheric vacuum is not suuficiant for even the most advanced composites.

Most of these smaller ski and snowboard companies make a high end custom product and if they could increase the quality and produce a better product that would sell for more money they would do it without hesitation and they ALL use a pneumatic press upwards of 75 psi at the laminate.

Holy crap MM, that's the most polite flaming I've ever seen!

Not to mention, probably the longest post you've ever typed

sam

Since this thread is dead... I'll book end it with, Luke Nelson tears it up!

And I like Entropy Resin.

Done! [imagine a mike drop]

The underlying theme to this thread is that you must have read the whole forum and successfully built a number of skis before you can comment.

This is hilarious:

"Compression molding should not be used to force the resin into the material matrix"

You've had this conversation:

"if vacuum pressing or vacuum infusion was superior, than builders like igneous and prior and wagner would employ it without doubt as they are not concerned with turnaround time and mass production"

Again, hilarious:

"Head produced skis for 20 years with a vacuum process but it has been abandoned in the ski industry, mostly"

If the production values of the commercial companies were so high, this group of hacker wouldn't exist.

Most of these smaller ski and snowboard companies make a high end custom product ... pmsl.

Reality check:

This forum is not full of experts ... these guys hit the exit once they have learnt all they need from the forum. Broadly speaking we do what we can with the time, money and materials we have available. Trial and error makes up at least half of the forum. There are very few posts that state "guys, I've been reading this article ... what do you think". It is a shame that when we are offered expertise, we don't know how to use it, just because there a smell of coffee in the air.

For those who are at the start of the process, it is well worth reading through Tony's contributions, at least refer back to them once you have read more about the subject. These are some basic points worth further consideration:

Unsophisticated polyurethane composite are best avoided. There are a number of articles on the web explaining the issues. I'm still rebuilding my computer and have lost a few links, so you will need to find it yourself.

"Skis need a glassy but tough resin system" - check. If you want values in terms of flexural strength, look at the Huntsman catalogue. Arm yourself with facts before speaking to other epoxy suppliers.

"Diluting a resin makes 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".

This does leave you with a question of how to ensure the epoxy has penetrated the core sufficiently - more pressure isn't the answer, but I'm sure Tony will share this with you if you ask nicely.

"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".

This should help you narrow down the options, when considering the range of heat cure epoxies available.

One last thing general point, who the fck is this guy ^

if you are now the expert how bout you share more details?

Nothing I said is incorrect, it could be interpreted that way, however.

I would appreciate a more direct address in a response if you wish to debate these details.

I'm sure toney is an adhesives expert but much of what he was saying was based on little actual field experience in actually building a board.

If you have ever seen these companies products you would agree with me.

What i meant by 'compression should not be used to force it in' is in your layup if you leave dry spots you cannot expect the compression to take care of it for you. Please prove me wrong.

Clearly I'm no expert, I fail my own definition as detailed above.

I do think it is a little bit obvious that not applying epoxy to an areas will leave dry spots. If this the sort of issue you are struggling with, I would read through Tony's posts again. Contacting him directly is probably off the cards, which is a shame because I now have a qualitatively different laminate reflected in a much tighter fibre to resin ratio.

care to elaborate on the qualitative differences and how you achieve these different ratios?

The approach is called hot melt processing, the quantitative differences ... I sleep better.

I really appreciate the intentional obtuseness or cryptic responses.

I continue to assume you are not a native English speaker.

Personally I believe you weaken any epoxy leaving it under heat past the time it's set...if this is what you're talking about. It gets brittle.

I have read every post in this thread. I know nothing... let me start with that so nobody thinks I am an expert...lol...

Every one of you has talked about the Forrest products and heating the mold... or at least that's the short of it...

What about the West Systems "cold" epoxy set-up?

Is this just crap or can I make a good ski with it?

I am just starting out and want to know... from all you experts here... well, at least from the people who have made a ski before with both heated and not heated epoxies.

Thanks!

this has been discussed many times on here:

http://lmgtfy.com/?q=west+epoxy+site%3Askibuilders.com%2FphpBB2%2F

Yes you can use West System epoxy. I have used it at room temp as well as QCM/Forrest epoxy at room temp. It just takes longer to cure. Heat makes it cure faster... and stronger I believe.

The West system took a long long time to cure. It stayed rubbery for a couple days but finally hardened. Not sure if this is a typical characteristic of West or if it was measured/mixed improperly. I was helping out a fellow builder who used West because it was easily available. It's the only experience I've had with West so far.

To make it easy on your self, use what others have used. I did a search in the forum tonight on resinreaserch (another manufacturer of epoxy) and that lead me to at least 1/2 dozen other epoxy products.

West works fine, don't let anybody tell you different.

It's just stupid expensive for what it is.

The nice thing about west systems is you can literally find it anywhere.

I've got a couple pairs of skis built with west that have +100 days on them

I know a few people have had good success with resin research.

http://www.resinresearch.net/id6.html

Prices include shipping to cont. US.

I will probably give this one a try next after the QCM ( now forrest ) is gone.

My buddy JV is using it and it looks crystal clear.

I'll be looking at 2070/3100s. Should do well in a room temp cure and thin enough to wet out easily.

**(I have yet to try it so don't point fingers if it doesn't work for you)**

All epoxy will benefit from some heat, I have an old electric blanket ( like on the bed at grandmas ) works OK to help with initial and post cure heat.

sam

I can affirm this exact combination of Resin Research products. Works perfectly for ski building in my heated press. Holds up very well on the mountain, so far I don't notice any difference in the durability compaired with QCM epoxy.

-S