Wed, 25 Sep 2024 12:28:07 -0700WeeblyWed, 02 Jan 2019 19:02:31 GMThttp://snowshark.com/tech-talks/tech-talks-3-structrual-failures-warranty​There are very few things that can go wrong with a composite structure i.e. monoski once proper material and process specifications have been established and are strictly adhered to. Composite structures just don’t fail for “no reason” and it’s very easy to find out what has happened when one does fail. I went over some of the reasons that we use top quality composite materials from the best manufacturers in the world and in a word, it is “consistency” or shall we say “quality control”.
In our ten years of building monoskis almost all of the problems (for lack of a better word) that we had were related to de-lamination. Breakage is another issue altogether as nobody warranties a ski, monoski or snowboard against breakage as in a 275 pound skier dropping into deep powder and flexing the platform beyond it’s capabilities. By description, de lamination is an adhesive or cohesive failure, where the failure is either in the bonding or in the adhesive at the point of bonding.
The most common “de-lamination” is where the base material or top sheet peals away from the composite structure. In all cases, this is a result of inadequate preparation or incompatible materials. To be assured of that, we do peal tests when ever we change something.
Another type of “de-laminations” is the failure of the adhesive at the point of bonding the steel edges or, in our case the aluminum tail piece on a Snowshark. This is almost always the result of an impact at the point of failure and in the past twelve years has become almost a non-issue as we have had only two occurrences that were undoubtedly due to abuse of the ski. The first was from freight damage where the ski was literally crushed in transit and the second just occurred which in our opinion, based on photos taken, is without doubt the result of a significant blow or series to blows to the tail of the ski that resulted in fracturing of the surrounding material and driving the aluminum piece into the ski effectively “wedging” the composite to the point of failure. (See Tech Talk #2) We have had no edge bonding failures since we went to the one piece full wrap edge six or fifteen years ago.
We follow strict protocol when we have a product related claim of any kind. First of all, I expect an honest explanation of what happened and if there’s any doubt, pictures and then have the ski back for our inspection. It’s the normal and professional way to handle this type of issue.
Close inspection always tells the truth, the whole truth and nothing but the truth. We are experienced in composites and always learn from what we see for both good and bad but one thing that we always do is give an honest and accurate evaluation and answer. Work with us and we will work with you and that’s how we all learn and improve.]]>Wed, 02 Jan 2019 19:01:02 GMThttp://snowshark.com/tech-talks/tech-talks-2-adhesives-glues-etc​Let’s talk a little about adhesives and “bonding” of two or more parts to make a structure. Bonding is simply the “gluing” of materials together to make a usable product. In ‘composites’ that can be anything from using Portland cement to bond together sand and rock to make concrete or epoxy to bond together fiberglass and carbon, plus a bunch of other things to make a TT Hammer.
Concrete is a little boring so let’s look at monoski applications. First of all, we have to be sure that everything is compatible. Simple stated the epoxy must bond well to all parts without causing any undesirable chemical reaction. Obviously wood glue would bond to the wood core but peal off of the plastic, composite, metals and fibers. Now, the only way to be absolutely certain is to test each and everything by itself and then in conjunction with the other parts. We quite often find out that different preparation of the materials will give distinctly different results than we initially thought.
As an example, I did extensive testing of adhesives for bonding composite panels and aluminum structures in commercial aircraft interiors. We got some very interesting results when comparing strength with surface preparation. One would think, the rougher the surface the better the bond? Don’t believe for one minute that is a universal truth. In face it is far from it! With some metals, a rougher surface gave a significantly lower test result.
So when we build skis, we test, test and test before we “set it in stone”. In the very rare event that we have a failure of any kind in a ski, we can track it back and see if there is or was a variance from our specifications. If not, we are well assured that something outside of our control happened.
As example of this was two situations where the aluminum tail piece broke out of the ski. Remember in “Tech Talk #1” I mentioned how epoxy likes to bond to metals and my reference to “SPS” or Standard Process Specification? Well here’s where it comes into play. We’ve used the same epoxy formulation for over then years, have the same fiber for seven years, the same aluminum alloy for twelve years and the same SPS for ten years. With regard to preparation and bonding of that part into the ski and the same guy doing it since we started. Now, I ask the question. After several thousand successful process repetitions Is there likely to be  failure at that point when everything has stayed the same?
Let’s go further into bonding and the different types of adhesives and some of the myths that are flying around out there. I look at adhesives (epoxies) as either “laminating” low viscosity and use to make a composite part and “structural” typically high viscosity and used to bond two structures together or also in repair.
Now, let’s dispel a few myths:

1. “Fast setting epoxies are weaker than slow setting epoxies”. Not at all and define “slow” and “fast”. It’s all in the “chemistry”. There are 90 second cure epoxies that have double the strength of 20 minute set or 8 hour set epoxies.
2. “The higher priced ones are always better” Utter nonsense!! I know of 90 second cure epoxies that can be purchased off the shelf of your local hardware store for $1.99 that will blow away the “brand name” competition at $11.00 for the same amount.
3. “Thicker is stronger than thinner” No, not at all true. In testing, we use several tests of which one is called an “overlap sheer” test. Simply put, two tabs of metal are overlapped and bonded together. When the adhesive is cured, we simply pull them apart and measure the results. I’ve got some excellent structural adhesives that are very thick like jello and have test results in the 3,000 pounds per square inch that drops as the part gets colder. On the other hand, I’ve got a water thin adhesive that gets stronger as it gets colder and at freezing temperatures has a test result of an amazing 12,000 pounds per square inch.

It all comes down to the right material for the right job and follow the manufacturers instructions to the “T”. I know, it’s a “guy thing” but why not read the instructions first? You know, somebody got paid a whole lot of money to make all of the same mistakes that you are about to make and he’s just trying to save you a little aggravation.]]>Wed, 02 Jan 2019 18:56:15 GMThttp://snowshark.com/tech-talks/tech-talks-1-predictability-or-repeatability​In those two words are two of the great truths in composite structures of which skis are but a small portion of our business. Some of the many composite and other related products designed, engineered, manufactured or worked on by our people include:

1. Showers on Air Force One
2. Shower for Saudi Royal Family Boeing 747
3. Table lamps for the above
4. Passenger escape ramps for AMTRAK
5. Composite galleys/food service equipment for high speed passenger rail
6. Recycled glass/epoxy counter tops
7. Composite cast glass/epoxy shower pans

Glass products include:

1. Custom colored glass wall panels for showers
2. Shower doors

 
In the word “predictability” we know that if we change a material specification or a process specification the result(s) will be, to a certain degree, different and in most cases predictable. This is very important in fiber and resin technology.
The word “repeatability” simply means that is you use the same materials in the same manner and with the same process parameters, each and every item manufactured will turn out with the same characteristics. In manufacturing, the definition of insanity is doing the same thing over and over again and expecting the result to be different. So, what the hell does all this double talk have to do with a monoski?? The answer is, a lot.
We design, refine and engineer skis as a result of constructive criticism and suggestions from our customers and other outside sources. When we make a change or do a new design, by experience, we have a pretty good idea what the strengths and weaknesses of the ski will be and this goes through all of the performance aspects of the product.
As examples:

1. Shorter ski with greater side cut will result in a tighter turning ski.
2. Longer and stiffer skis are typically better at higher speeds closer to the fall line.
3. Carbon fiber will give a lighter and stronger but stiffer ski.
4. Epoxy gives an excellent bond to many surfaces including steel and aluminum.

And we could go on and on but it’s these type of things that eliminate a tremendous amount of trial and error when we develop products.
When we take a ski into production, we already know what is physical and performance characteristics will be and this is where repeatability becomes critical. In other words, I know that in “sane” manufacturing if I repeat the same process over and over with the same material, the results will be the same every time. So we write two specifications. “SMS” or Standard Material Specifications” and “SPS” or “Standard Process Specifications”. Now we have a product that is guaranteed to be the same at serial #1 as at #10,000 and if we have a problem, we can track it back and see what really happened and in the world of composites, that is usually very easy to do. 

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