Interesting Paper on Gel Coat Cracking

[TuxedoPk]

Whitepaper (http://www.cfa-hq.org/resources/documents/gelcoatcracking.doc)

[Fish boy]

Good info Tux, defintely worth the read.

[MOP]

Good find Tux! The newer products are actually getting flexable and still give a great shine. Whats really good about that paper you found is it will give the guys a better idea of the difference between stress and possible stuctural caused cracking. Good to know when buying or attempting repairs.

[oldLenny]

Nice piece. Now I have a name for the deck on the sixteen...Isotropic Thermal Fatigue...most likely attributed to being uncovered in the TEXAS sun for many years. I mean, they have below freezing temperatures and days over 110. That sun IS HOT.

[MOP]

Valspar has about the best gel coat made, extremely flexable yet holds a vey high luster. It is used by alot of the quality builders. I'll scan the page I have that shows it fully cured and then bent around a 1/2" pipe.

[Kirk]

Great Post..Thanks for the read!!

Good one for Library,

KJ

[TuxedoPk]

Rather than gelcoat, I'm considering trying powder coating on of the X-18s.

While this has traditionally been used on metals because of the heat, after lots of reading I'm feeling comfortable that Ultra Violet Powder Coating will be a great alterntive to paint or gel. I'm guessing that within a few years gelcoat will be a thing of the past on new boats.

[MOP]

Being Satiated and a wee bit on the well you know side! Tux don't inhale! Ok I bite give us some info on cool powder coating!

[oldLenny]

Tux, interesting. We have been powder coating wood now for about 3-4 years. (not me personally, but big Companies) The stuff is bullet-proof. In my case it is bound to an MDF substrate, (stratified medium density fiberboard and then routed on CNC for profiles and then powder coated.) These are cabinet doors. Very DURABLE product and beats PVC doors anyday. Better than acid catalyst enamel as well.

Neat thread.

I bet it would stand up but what about elastomers? We don't bend our wood product after the fact. Boats move "slightly". hmmmm....

...and then there is the cross linking polymer reaction...Will an ISOPHTHALIC or VINYLESTER product find a good home with its' polyester make-up and BIND to this AND be flexible...???

..oh, and the "esters" in the polyesters, what would the component be?...In a conventional lay-up Vinylester has about HALF the esters avalable at the gel-coat as Isophthalic resins. These are the "molecular vehicles" in which "blisters and de-lam" run on. How will it fair in this scenario?

Tux, what "heat" are you referring to...???curing...??? powder coat is low temp stuff. A low temp, low current + - thing. If the ovens were not we would have a finished routed door, at the national acceptable average of 7% moisture content and "cook it" at which point we would have a hockey stick from what was once a flat panel.

The peak exotherm on a general lay-up in a mold of a fiberglass hull is 370 degrees...hence why there is "tooling" gelcoat for molds...

I also wonder how you would "charge a mold" with a difference of potential for this product when we use glass as the ONLY choice for a bucket truck to work with 500KVA on hydro poles. It is a natural insulator...hence why grounding is so tough in a boat or a Corvette and they reek of electrical problems...

Am I missing something?...feed me INFO!!! :D

[TuxedoPk]

Lenny-

There are constantly new types of elastomers coming to market; ones suitible already exist. For example take a look at what some of Dow's new Elastomers (http://www.dupont-dow.com/News/english/press.asp?pressRelease=05232003-NewEngage)

"Boats move "slightly". Will an ISOPHTHALIC or VINYLESTER product find a good home with its' polyester make-up and BIND to this AND be flexible" Short answer- the right ones yes. For a CDMA type answer:) Effects of Water, Salt Solution on the Properties of Composite Matrix Resins (http://fire.nist.gov/bfrlpubs/build01/art096.html)

"The peak exotherm on a general lay-up in a mold of a fiberglass hull is 370 degrees...hence why there is "tooling" gelcoat for molds" And they once thought boats had to be built from wood :) The processes used today from building molds-production can be greatly advanced by utilizing existing technologies.

"charge a mold" - I don't remember saying anything about charging a mold :)

[TuxedoPk]

It all comes down to the movie The Graduate- Plastics! If you're not satisified with what Dow, Basf, and the others are doing, you could always create your own :

Click on the feature tour at least! (http://polymer.bu.edu/vmdl/)

[MOP]

Gaawd I love it when you guys talk like that, me thinks things have come more than a long way. I have not asked this question in many a year, does anyone remember the base for early Epoxies? If not it was Cow Urine! I went through USAF Airframe Repair schools for fiber glass, aluminum and phenolic laminating, fuel cell, cable/tubing back in 1957. I was in SAC we got the best training. Gee I wonder if they still use a router to cut damaged honey comb out or shot it with a Laser. That stuff was relatively new then, our stuff at that time was really advanced. I had the opportunity to work on a British Canberra down at Eglin AFB (which later became the U-2) compared to our stuff it was all tin at the time and that was their hot model. I had the opportunity to have a few with a modern airframe guy a few years back, he said the U-2 was now a lot lighter and a ton stronger due to the new materials. Eglin was one of the neater places I was stationed because just about everything came there for testing in the climactic hanger. God I can't believe I typed this with a Booomer hang over. Some stuff is real new the Booze is the same!

[oldLenny]

Interesting read on a Sunday morn. Thanks Tux... :D I suggested charging the mold. I was assuming an open mold production scenario.

[TuxedoPk]

MOP-"Gaawd I love it when you guys talk like that"

Somehow I would have appreciated this statement more coming from Tuna wink