Fiberglass strength calculation

choppergabor

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I have been searching the net and I can't seem to find a procedure to calculate fiberglass strength. Is there a formula out there that gives a ballpark figure on the type of glass and its strength according to the thickness of it? Any info would be appreciated. I am trying to learn more about composites but the info is pretty limited out there or maybe I am not really good at finding them.
Thanks.
 

PalmPilot

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Gabor, I found this place after you helped me better understand layup & vacuum bagging... Hope it helps, trying to return the favor... :D

1st is home page:http://www.polymercompositesinc.com/

2nd is e-bay store:http://cgi.ebay.com/EPOXY-RESIN-FREE-VIDEO-HOW-TO-HELP-PAGE-GENERAL-GUIDE-/310129928798?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item48352f2a5e I like this one, tons of info on resins, fiberglass and carbon fiber.

This company is local to me, so if you need me to pickup & ship to you, no problem... If there rates are to much?

lym :)
Mike
 

choppergabor

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Thank you Mike a bunch. I am using their products :) and very satisfied with both the prices and the quality of the stuff they sell. I am not going to touch the carbon it's way too expensive to mess up :) And it's quite dangerous if you have to sand it and you hit the fiber. It's nasty stuff. I am due for mesothelioma anyways because of the long term asbestos exposure while I was working in the foundry so I am trying to buy some time here. But fiberglass is pretty harmless if properly outfitted for it. It makes me itch! LOL. I am such wuss. Anyways. Thank you for the links Mike :)
 

choppergabor

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Most excellent information. Greatly appreciated your help Dino. I am going to print it out right now. I love hard copies :) Thank you again for your help. You are the man Dino!
 

choppergabor

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LOL Kai as proud as I am for speaking a few languages I am at lost when it goes into the technical German. I can probably understand it better than speak it anymore. I only spent 2 years in Austria and whatever stuck on me 20 some years ago has worn off gradually. :( It's a shame but the saying is true about "if you don't use it you lose it" ..... I am sure a few beers would get me talking better though :)
 

Dean_Dolph

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Gabor, you, and others, may want to keep the following contact info handy in case you have other questions as you work with composites.

The guy's name is Gary Hunter. He retired as the Shell answer man for composites and is a EAA tech counselor. He does EAA forums on the use of composites. He serves as the crew chief for Bruce Bohannon's Exxon Tiger just as he did for Bruce's Shell sponsored Pushy Galore. He is quite knowledgeable and loves to talk to hobbyist.

You can contact Gary at Gary Hunter Composites email [email protected] Phone - 281-277-7767

Tell him I sent ya! On second thought maybe you better not!:D
 

Arnie Madsen

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I am glad you brought this subject up Gabor. I know quite a bit about fiberglass , done lots of it and every time I think I know everything I am humbled by new information.

Rotoplane (Ed Rosenberger) mentioned a few weeks ago about keeping the fiber strands straight and level for maximum strength (no dips and bends in the material when possible) .

Instinctively I have usually done that but when Ed pointed out the reasons why it should be done that way I valued the information. I love to be educated beyond what I think I know already.

I am just an observer on this topic but the two things I understand clearly is that the thinnest , hand laid glass with much fabric and minimum resins is the goal to aim for. The goal is thin and light and strong.

A cool autumn day in the garage in Montana will require many hours for it to cure and if it is too cold it will never cure properly.

The same mixture in Florida at 101* will kick off and start to cure before Gabor gets to apply it. When they refer to temperature control this gives us an idea of that subject (temperature controlled molds and shops)
In other words ..... are the conditions and temperatures the same every time we homebuilders do our own fiberglass work ?? . Just one of the many things to consider.

One final pointer. If you do indeed get a very well cured , thin and light and strong aviation component ...... make sure you do not sand away all the structural fiberglass and composite threads trying to get it smooth for painting .

I always color tint my structural resins and structural fabrics with a stand out color so if I am sanding too deep I will have instant notification. In the industry we call it a guide coat.

I love perfect flawless smoothly painted surfaces. These things are important when we showcase our homebuilt creations. But if we have sanded away the original structural integrity of the component we could have problems. Anticipate these problems in the garage. Not at a high altitude.

From memory every chemical reaction increases by 20% with every 10 degrees of temperature. Curing fiberglass and composite resins is a chemical reaction.

I am more than willing to be corrected on any of these topics. I still consider myself a student. I love fiberglass work and have done lots of it. But when lives depend on it I prefer to be well informed.

I am a person who loves structurally strong fiberglass aviation components that when painted look perfect. Several times I have come close .

Many thanks for this informative topic. I am all ears.

Arnie.
 

StanFoster

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Arnie- I know you would be one of the authorities on this fiberglass topic, yet you are so humble about it. I respect that knowing you are a wealth of knowledge on this topic. Thanks. Stan
 

choppergabor

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Thank you Dean that is a very important contact right there :) I do appreciate it a lot. Arnie I really would love to know more of the know hows of the composite world as I am heavily relying on them for my build. The brand name BeeGeeSee (BGC or big guys choice) will have it's first born offspring the Behemoth come to live pretty soon. The landing gear is made of fiberglass too.( 4.7 lbs per side!) Lightweight, durable, aerodynamic, and looks awesome! Anyways as we are blessed with the ability of using space age materials I found it to be my mission to modernize as thoughtfully as my limited brain activity allows me to the well established and safe builds. I ain't inventing anything here. Just trying out different options. I too heavily rely on Ed (RotoPlane) and God knows he has some working neurons still actively spinning around in his gray matter :) Every little info is a big help and especially from guys like you two who have hands on experience. I'd love to hear more about techniques and the dos & don'ts alon side with the suggestions for the beginners like myself.
Fortunately or unfortunately it has never detoured me that I didn't know anything about a certain subject from actually giving it a try. Everyone started out that way. So with a help of others I think I am making headways here :) Thank you all for the contributions and please keep them coming. I really do enjoy them. And I just know there are a lot of silent lurkers who learn a lot from it too!
Thank you gentleman.
 
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PalmPilot

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I will sign up for this course too... :yo:

Mike
 

Rotor Rooter

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Arnie,

Thanks for your mentioning some of your experiences. Do you have any thoughts on the use of uni-directional tape?

Dave
 

RotoPlane

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I'm sure that Arnie has more experience working with fiberglass than I and as a result also knows more than I do….one learns a lot by working with this stuff. Gabi is another modest one….he is the one who comes up with these off the wall ideas for his gyro, and somehow he makes them work….I only interject stuff when he asks. Guys unafraid to try something different like these two, and others here, are what make this forum great.
 
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