Expert forum: QCM epoxies (Questions answered!)

[kelvin]

We are excited to bring a new feature to skibuilders. We are going to invite experts from the industry to answer your questions. Post your questions on this thread and in about a week, I will compile the questions, forward them to the expert, and will post their answers on Skibuilders.

If you have general questions, please post them on the main board and not on this thread. If you have answers to any of these questions, please copy the question and your answer onto the main board, since this thread will be archived after the cutoff date.

If you have any suggestion for future 'experts', please PM one of us. We are hoping to make this a regular feature. Thanks.

Our first expert is Roy from QCM epoxies. They make high performance epoxies for the ski and snowboard industry.

Here are some of my quesitons:
Why are heat cured epoxies generally stronger than room temp epoxies?
How do you deal with different thermal expansions in materials in a heated press?
Can you suggest a good room temp epoxy for skis and snowboards?
What is the best way of cleaning materials prior to bonding?

-kelvin

[BigG]

What is the best way to bond steel edges on base and fiber? Do you have to threat them to get better bonding?

[burny]

would it be useful to glue the core and everything else together with epoxy that contains (added) cotton flakes. the cotton flakes are often used as far as I know when building aircrafts to enhance the flexibility and ductility of epoxy and the materials that are glued together. the epoxy works as the matrix between the material, the cotton flakes enhance flexibility and ductility. So ... my guess is, it would be a stronger bond and a more durable ski. Am I wrong or could this be correct?

[G-man]

Much of what I've read seems to indicate that a heat cured epoxy resin results in a higher service temperature range than a room cured resin. I interpret from this that a ski that has been built in a heated press can handle higher temperatures from a waxing iron. True or False? Also, what happens to the epoxy bonds if the ski is heated too much with a waxing iron.

Thanks K's. Great idea. Can't wait for the session with the Durasurf guy. I still have a number of questions regarding flame treating... what kind of equipment do they use?.. what dyne levels do they shoot for?.. how long is their surface treatment good for?.. what air/gas mixture do they use?.. what is their opinion of just using a propane torch and 'passing it over' the UHMW to get an adequate and consistent surface treatment?

G-man

[powdercow]

When repairing skis a slow cure epoxy is almost always preferable to a quick set epoxy because it's more ductile. Does the speed with which heated epoxy cures limit it's ability to absorb flex? In other words is heat set really stronger or just a stronger initial bond.

[MartinH]

How does epoxy add to ABS vs. PA plastic, if there are any differences? Are there any preferred treatments of plastic before glued with epoxy to other materials like steel and wood?
Would you prefer epoxy of ordinary glue used for wood when gluing the core together before profiling?
What kind of rubber makes the best bond with epoxy?

[NEngineer]

Have they worked with Soy based resins?
How does the strength/flexibility of soy based resin compare to traditional resins?
Do they supply soy based resins?

[G-man]

NEngineer wrote:

Have they worked with Soy based resins?
How does the strength/flexibility of soy based resin compare to traditional resins?
Do they supply soy based resins?

Yes, what he said.

G-man

[G-man]

What solvents will work to loosen unwanted cured epoxy from ski press parts?

What other substances or environments will degrade epoxy over time, thereby weakening the lay-up?

G-man

[mattman]

The epoxy resin I use during the layup cannot adhere the ABS topsheet. I was recently told that this is because the layup resin is too rigid. Is this true? Why? Finally, what epoxy will work that is affordable by the gallon? Will this adhere better than simply making the surface of the ABS sheet an adhesive with MEK?

[Alex]

Three questions regarding UV radiation contained in Sunlight:

Regular epoxy resins suffer from UV light changing their colour. Is there also a degration in mechanical properties?

Are those special resins with UV protection able to resist the amount of light a ski gets for about (100days / 6h a day - assumption for a skis life) in high altitude or is there an additonal Topcoat needed?

Does the addition of colour paste improve the UV resistance?

[dcaldous]

Can a room temperature curing epoxy be mixed with a higher temperature epoxy on prepreg fibers and still work?
I have access to some prepreg with a fairly high cure temperature but no heated press.
I would be open to any suggestions on how I could make the prepreg work without applying heat if that is possible.

[kelvin]

Great questions, everyone. Keep them coming; I will close this thread on Friday evening, Jan 19 and compile them over the weekend.

-kelvin

[MartinH]

One final question;

Basically, what epoxy would you recommend for ski building; Heated and non heated press? As you understand it has to bond allot of different materials, as well as being rather flexible and resistant to mechanical abuse, as vibrations and hard “hits”.

[bigKam]

hi Everyone!

Roy Wheeldon's answers have arrived, and he has some interesting things to say. Please have a look:

http://www.skibuilders.com/articles/epoxy.shtml

Again, thanks for your participation. I'd like to also thank Kelvin for compiling the questions and contacting Roy at QCM. Sometime in the next week we'll open up the forum and this time the topic will be: Ask an expert about base, sidewall, and tip/tail spacer materials -- stay tuned and start thinking about those questions!