Hot Box

Buz · Post by **Buz** » Mon Jan 16, 2012 5:01 pm

http://www.entropyresins.com/

MontuckyMadman · Post by **MontuckyMadman** » Mon Jan 16, 2012 5:14 pm

Not sure all of what you have said as I don't work in the industry but are you recommending a vinyl ester resin for use with skis?
Not good, as far as I understand and all of the data here will back that up, even though you seem to think much of it is wrong.

Bloefeld · Post by **Bloefeld** » Mon Jan 16, 2012 5:24 pm

Buz wrote:Hey Bloefeld, sounds like you know your epoxies, curious what you think of Entropy's 'eco-friendly' resins?
Thanks

Eco Friendly in this case means they derive some of the resin's components from recycled sources. The same can be more or less said for Soy based resin systems.

The properties look OK, the product to me looks crazy expensive, but I am used to buying by the truck load so what do I know.

This is a hybrid Bisphenol A and F resin system. I suspect the Pine Oil is used as a non-reactive dilutent to help bring the viscosity down.

They give no data on cure shrinkage so it is hard to tell what the real VOC content is of the system.

In my opinion any damage caused by petroleum derived resin systems is vastly out weighed by the benefits achieved. Everything would be a lot heavier without these systems.

In the quantities you will use building skis the impact is nil.

So I suggest finding the right resin system and ignoring these other factors. The fact is, we have no idea what it takes in energy and CO2 terms what it takes to get these wood oils out of the junk they get them from.

There are loads of other systems that give better properties. I believe I may have to get my buddy at a resin supply place in Canada to start packaging these superior systems so that we can all buy them cheap enough.

So sounding eco friendly is almost always easier than being eco friendly. Its that damn Second Law of Thermodynamics getting in the way again.

Cheers,

Bloefeld

Bloefeld · Post by **Bloefeld** » Mon Jan 16, 2012 5:33 pm

MontuckyMadman wrote:Not sure all of what you have said as I don't work in the industry but are you recommending a vinyl ester resin for use with skis?
Not good, as far as I understand and all of the data here will back that up, even though you seem to think much of it is wrong.

I am not recommending a vanilla vinyl ester system. It is a hybrid system that has been in use for decades and is very well proved.

I may however be ignorant about what is really needed to make good skis. From the various epoxy formulations I have seen and researched none of them has the properties of 8084 and all of them are much more difficult to use.

In my opinion, and keep in mind that I have not yet made a pair of skis; a resin with high elongation, high physical properties, excellent molecular memory, and high toughness (visco-elastic) properties will create a very lively ski that will not fall apart.

You can look at hundreds of epoxy formulas and not find many that come close to 8084.

I have infused millions of square feet of sandwich panels using this formula and have had zero resin failures. That tells me that they work pretty good.

They adhere great and they wet-out glass incredibly well because they are compatible with the sizing on the glass. To my knowledge there is only one glass manufacturer (Fiberex in Leduc AB) that makes an epoxy specific sizing.

So I would be curious about more detail from you as to why this particular product would be bad.

Keep in mind that many commercial skis are made with polyester resins which are nothing like this Bis A hybrid.

Cheers,

Bloefeld

Richuk · Post by **Richuk** » Mon Jan 16, 2012 6:01 pm

The criteria you've set for your choice of epoxy sounds good to me - your guy in Canada is going to be busy!

What a lot of custom builders forget to 'market' is the fact they are using epoxy - but slating the commercials directly is a fairly unprofitable approach.

MontuckyMadman · Post by **MontuckyMadman** » Mon Jan 16, 2012 7:14 pm

What commercial ski companies are using polyester resins to make skis?

OAC · Post by **OAC** » Mon Jan 16, 2012 11:17 pm

Bloefeld wrote: Most high-performance composites are built with no more pressure than one atmosphere of vacuum. So something between 14 psig and 30 psig. If it is good enough for most parts on a Boeing 787 and the F34 fighter, it will make great skis.

jellyfish · Post by **jellyfish** » Wed Jan 18, 2012 2:05 pm

I,m kind of confused we are here building skis/(snowboards for me)mostly in oru house or shop and we are using what we think is great stuff turns out a satisfactory product with heat in a reliably way, in a press which is way more versitile than vacuum without an autoclave( build that in your basement way harder than a press ) typically you may see a 10 psig vacuum unless your using a 1200$ vauum system been there done that, a press is better I keep all my camber no guessing or trying the decide how much I'll loose, the boards last way beyond commercial stuff anyone can buy, the resins we can buy does not have an odor that makes us wanna b sick or get our family's pissed at us an some expert thinks he is smarter than everyone else yeah probably in a factory but not within our limitations so congratulations now go home make something in your basement and share it with us.

End of rant
Cheers
Jim

MontuckyMadman · Post by **MontuckyMadman** » Wed Jan 18, 2012 3:46 pm

MontuckyMadman wrote:What commercial ski companies are using polyester resins to make skis?

Please answer the question?

powderho · Post by **powderho** » Thu Jan 19, 2012 2:52 am

OAC wrote:
Bloefeld wrote: Most high-performance composites are built with no more pressure than one atmosphere of vacuum. So something between 14 psig and 30 psig. If it is good enough for most parts on a Boeing 787 and the F34 fighter, it will make great skis.

So I'm really not trying to stir the pot here, but sorry OAC, keep dreaming. You make some awesome looking skis and have a very ingenious vacuum table setup, but it just doesn't compare to a bladder press. We have around 8 tables like the one you built in our facility and they only get used for intermediate debulks. Final curing is always done in a normal vacuum bag and then of course put in the autoclave where they see 75-90 psi. We make around 300 parts for the F35 and they are all vacuum bagged and then sent to the autoclave. The only composite parts on this plane that don't go into the autoclave (that I'm aware of) are produced using resin transfer molding. In that case they see at least 150 psi.

OAC · Post by **OAC** » Thu Jan 19, 2012 5:19 am

Thanks powderho! It was more like receipt that I'm not way out of line.

I'm done dreaming, I ski...

MontuckyMadman · Post by **MontuckyMadman** » Thu Jan 19, 2012 9:13 am

Bloefeld wrote:
Keep in mind that many commercial skis are made with polyester resins which are nothing like this Bis A hybrid.

Cheers,

Bloefeld

WHO USES THIS TYPE OF RESIN IN SKIS?

Answer??

chrismp · Post by **chrismp** » Thu Jan 19, 2012 9:28 am

haha, montucky getting impatient!

i'm not an expert on aerospace parts and similar stuff, but i too thought that these things are pressed at higher pressures in autoclaves. i recently saw a documentary about boeing and they definitely used autoclaves (can't tell to what extent though).

gladegp · Post by **gladegp** » Thu Jan 19, 2012 1:43 pm

This is awsome! I hereby set up an award for $5 for the first one to build their own autoclave for skibuilding

Or you can buy this one, it's called Econoclave so I'm sure it's cheap or "affordable" as they say. It's even "turnkey", piece of cake...

http://www.aschome.com/Composite-Autoclaves.htm

MontuckyMadman · Post by **MontuckyMadman** » Thu Jan 19, 2012 5:29 pm

chrismp wrote:haha, montucky getting impatient!

.

Because this is a dogshit statement. No ski makers use a polyester epoxy.
as much as this guy thinks he knows, he doesnt.

Ski Builders Forum

Ski Builders Forum

Hot Box

Entropy

Re: Heat Cure

Re: Heat Cure

Autoclaves