What are you looking for in a ski building epoxy?

[Bloefeld]

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

Hi, Thanks again for the information.

Maybe I should phone Forest. Among the last posts on the topic of QCM was they people at Forest said they would not be continuing with QCM and that was that. Their site reflects that and thus my not unreasonable assumption that they were selling off the last of their stock and it would not be or was not commonly available.

With all due respect, your opposition to vacuum is unfounded. Almost all wind blades are made by vacuum infusion. I mean hundreds of millions of tons of glass and resin used each year and every day to make blades up to 60 meters long.

I have made thousands of balsa cored panels 14 feet by 7.5 feet by 4.5 inches thick in the past 5 years with vacuum infusion.

Vacuum, even when pulled on pre-wetted cloth is the easiest way to get great resin/fiber ratios; crucial in making strong and durable parts.

You should read my previous post a bit more closely about using epoxies designed for compression molding. With your ability to heat to 140 degrees, just spreading the epoxy on the top of the glass and not worrying over much about trying to squeeze it in is exactly what you should be doing. Then put the whole thing under 40 to 45 lbs (in your temperature case) and the epoxy will wet-out the resin completely. Again I recommend a good post cure heat if you can build a hot box. At 140 the epoxy is not coming close to its Tg (Glass transition temperature) and is not fully curing. I would at least leave them in the hot press for a week or so.

I have done some compression molding, not enough to be an expert, but we were using 90,000 centipoise epoxy and it still wet out the fabric. We used a lot of pressure and heat too, but our goal was to make the part in less than 5 minutes and to tolerances in the 0.005 range. We failed.


Have you tried rollers to spread your epoxy and get rid of the bubbles.

http://www.fibreglast.com/category/Supplies_Tools

Fiberglast has loads of good stuff too.

I understand where you are coming from. My goal is to build a better ski than I can buy. I have some ideas about fiber direction and types that will be unusual.

I believe that I should probably build a heated press and a hot-box to get as close as I can to perfect cures.

I no longer have my Skunk Works, so I will have to rebuild a lot of my jigs and test fixtures to get me going. I will have to park my old Honda on the street and take over my garage to do this, or go nuts and rent some space.

When I have read as much as I can from this site, and torture good fellows such as you for information ;-) I will then build some skis. So I see this happening next fall with testing in December. Then I will keep doing iterations until I get it right.

Let the pressure and heat do the work for you on your wet-out. Weigh the epoxy and resin to make sure you get less than 40% resin weight. Then make up a pair the way you normally do, but don't pound in the resin, just spread it evenly. Heat them as much as you can or for as long as you can. Cross-linking will continue for a really long time. Do this and I am sure you will get a better feeling ski and at no cost.

When I get my epoxy thing sorted out I will sent you a couple of gallons to try and see what you think.

Thanks for all of your help, you have made me think a lot about the entire ski building issue and have given me some great advice. I appreciate it a lot.

Cheers,

Bloefeld

[WhitePine]

With all due respect, your opposition to vacuum is unfounded. Almost all wind blades are made by vacuum infusion.

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?

[chrismp]

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.

[chrismp]

PS. Is your first name Ernst per chance?

hahaha, Dr. Evil!

[Bloefeld]

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.

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

[sammer]

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 effectively wet out a fabric.
Vacuum will not pull edges into your mold if they are not already pre-bent perfectly. Close doesn't cut it, you will still get bridging.
In a shop/factory where you have access to all the gear and gizmos (aerospace composite world) you can probably make a bomber ski that would stand up on Neptune. Of that there is little doubt.
Now go and get the stuff that's available to the rest of the world and put that ski together. Give it to someone like my buddy Luke Nelson and see if it lasts more than a couple days.


Tougher yet build 2 skis, make them a pair, but build them a month apart.

I don't mean any disrespect, you have a ton of knowledge, it's just when someone comes into a community and starts saying this or that is the wrong way to do things without ever trying them kinda gets my hackles up.

Rant over (move along people nothing to see here)

sam

[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 effectively wet out a fabric.
Vacuum will not pull edges into your mold if they are not already pre-bent perfectly. Close doesn't cut it, you will still get bridging.
In a shop/factory where you have access to all the gear and gizmos (aerospace composite world) you can probably make a bomber ski that would stand up on Neptune. Of that there is little doubt.
Now go and get the stuff that's available to the rest of the world and put that ski together. Give it to someone like my buddy Luke Nelson and see if it lasts more than a couple days.


Tougher yet build 2 skis, make them a pair, but build them a month apart.

I don't mean any disrespect, you have a ton of knowledge, it's just when someone comes into a community and starts saying this or that is the wrong way to do things without ever trying them kinda gets my hackles up.

Rant over (move along people nothing to see here)

sam

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

[sammer]

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

[chrismp]

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%.

[MontuckyMadman]

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.

[sammer]

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

[holmtech]

Give it to someone like my buddy Luke Nelson and see if it lasts more than a couple days.

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]

[Richuk]

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 ^

[MontuckyMadman]

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.

[Richuk]

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.