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resins? - 3/25/2002 8:15:03 PM   
tomgtv6


 

Posts: 64
Joined: 3/20/2002
Status: offline 		I have these epoxie resins

epocast 50
epocast 1656
shell chem. 828
aldolite 5052
epocast 9816 hardener only

have any of you used them in layups?
if you have likes or dislikes of certain types i would be intrested

tom
       Post #: 1

resins? - 3/25/2002 9:35:09 PM   
winship


 

Posts: 151
Joined: 3/18/2002
From: Plainfield, IN, USA
Status: offline 		Hi Tom:

The Shelll Epon 828 resin is very versitile. Many hardeners can be added to the resin for different properties. Also Modifiers can be added to lower viscosity. Shell also carries a variety of hardeners. 1-800-tec-epon I believe is their toll free number in Texas.

As with all industrial/commercial resins of this type you will need to follow their hardener/resin ratios to the "T" Also be carefull of the toxic nature of these resins and their addiditives and hardeners. Read the MSDS (Material Safety Data Sheet) A good gram scale of the tripple beam variety is essential when mixing these resins in small quantities for hobby use. Once you use a good resin such as these you will never want to go back to the hobby shop variety again.

I believe that the Epocast products are Ciba Geigy, Am I correct?

I have some literature on these resins out in the shop I believe! And I believe that I have experemented with these resins years ago.

Let me know what application you are going to use them on and I will help with further questions.

Winship

(in reply to tomgtv6)
       Post #: 2

resins - 3/25/2002 9:59:25 PM   
tomgtv6


 

Posts: 64
Joined: 3/20/2002
Status: offline 		yes the epocast stuff is made by ciba. I get this stuff from work when it goes out of shelf life. they guys at work tend to use the same old stuff, and not into trying new products. I have acsess to the msds but harder to get the engineering data, because they use what they like and dont question anything.

thanks tom

(in reply to tomgtv6)
       Post #: 3

resins - 3/25/2002 10:09:54 PM   
tomgtv6


 

Posts: 64
Joined: 3/20/2002
Status: offline 		oh yes

i forgot to say i would like to make a complete composite airplane model. in the range of72" wingspan. need to figure out types of cloth, internal structure, number of plys; all the engeneering stuff. dont want it to weigh 15lb or not be strong enough. the only fiberglass fuse. stuff i have had was old quarter midget pylon racers.

thanks tom

(in reply to tomgtv6)
       Post #: 4

resins? - 3/26/2002 8:08:51 AM   
winship


 

Posts: 151
Joined: 3/18/2002
From: Plainfield, IN, USA
Status: offline 		Tom;

There is a good web site by Mike James concerning the procedures that are necessary for fabricating tools and molds for a composite airplane.

You might want to try making a few small parts such as wheel pants before attempting a large project such as a 7' airplane.

http://www.nextcraft.com/rcbuildingtips/rcdesignandbuilding.html

The Epocast resins are for tooling that is cast or poured while the Shell Epon 828 resin is used primarily for laminating. The 828 resin can be used to laminate glass cloth for making tools also.

I have experemented with different resins and hardeners and had some success but you run the risk of reinventing the wheel so to speak. There are many resin formulators out there that allready have most of the problems figured out for you. West Systems makes a Pro Set resin that is good. Aerospace Composite Products and CST Composite Structures Technology and Fiber Glast in Dayton Ohio carry the proper resins for many applications. This is not to say you shouldn't experement with different resins but you might find it easier to purchase from one of these sources rather than chasing down products that you will have to get through an industrial supplier.

Dan

(in reply to tomgtv6)
       Post #: 5

resins? - 3/26/2002 8:16:35 AM   
winship


 

Posts: 151
Joined: 3/18/2002
From: Plainfield, IN, USA
Status: offline 		Epocast 1656-A/B Light Tan, 350°F (177°C) Syntactic
Non-sagging syntactic paste with a long 50-90 minute work life. Maintains superior mechanical properties after a room-temperature cure. Formulated for filling and reinforcing honeycomb composite structures using automated mixing/dispensing systems. Qualified to GM 4006, Type 1, Class B

(in reply to tomgtv6)
       Post #: 6

resins? - 3/26/2002 8:21:00 AM   
winship


 

Posts: 151
Joined: 3/18/2002
From: Plainfield, IN, USA
Status: offline 		Tom;

Here is a source for Shell Epon and a variety of modifiers and curring agents.

http://www.miller-stephenson.com/shell.htm

(in reply to tomgtv6)
       Post #: 7

RESINS; polyester vs epoxy??? - 3/26/2002 9:09:11 AM   
mrharrier


 

Posts: 8
Joined: 2/5/2002
From: CA
Status: offline 		My HARRIER molds(& plug) started life as polyester resin parts and then later as I became more confident with the resin(it is a chemical compound) then I tried different types of wet lay-ups & resins. Usually for a given quantity(pint, quart, 1/2gal, etc) the polyesters are cheaper than the epoxies, but the epoxies are stronger and will take at least a 24hr cure for maximum strength. for experimental purposes I would go with a small quantity such as a pint or so just to get a 'feel' for the resin and its cure rates. Remember this, RESIN IS VERY TOXIC, WEAR AN O. B. A. MASK WHEN LAMINATING WITH EITHER SYSTEM (or at least a water-saturated dust mask at least while laminating) Also, lay up your parts in the shade, let them cure in the sunlight, otherwise you will be working against yourself. This is just a little bit of info I had to learn on my own, that I thought might help you. Go to the 'New Products & Announcements Section', there you will find out how you can see my GULFSTREAM & HARRIER models that I designed & built, have fun & be safe!!!

(in reply to tomgtv6)
       Post #: 8

Composites - 3/26/2002 1:37:01 PM   
Mike James



Posts: 2464
Joined: 1/19/2002
From: Anchorage, AK, USA
Status: offline 		Dan, thanks for mentioning my web site (NextCraft™) above.

One note, though. If you go to that page directly, you miss the rest of my site, because it uses frames. To visit my site with full navigation, just go to http://www.nextcraft.com

I use West Systems epoxy and other products now, and have gotten excellent, relibable results with it. I also had very good results with the epoxy, cloth, and other items I got from Fibreglast (http://www.fibreglast.com) when I lived back east. (My first molded "sport jet" is still on their "Modelers" page.)

I am looking for a new "tooling resin" that can be used as a tough surface coat for pre-mold plugs, if anyone has suggestions.


_____________________________

Mike James
RC Design and Building - www.nextcraft.com

(in reply to tomgtv6)
       Post #: 9

resins? - 3/26/2002 8:53:53 PM   
tomgtv6


 

Posts: 64
Joined: 3/20/2002
Status: offline 		thank you every one!

winship, i think your right about using materials of known usage in such a large project. you said the epocast stuff is for cast tooling; does that mean for molding parts out of the resin? and thanks for the information.

mrharrier, yes safety is of great intrest to me. i see people at work, people who if did this on their own would be careful but because of the work enviroment are flipant about it. i dont want to loose my tolerance with working with this stuff. yes it will be a large learning curve. got to check out your planes next.

mikejames0, good web page! i will have to study on it. i like your 777 landings. reminds me of douglas' dc9 landing on a carrier i think in the 70's to prove it could be done to the navy, and Boeing's 707 test pilot rolling the plane at an air show.

thanks tom

(in reply to tomgtv6)
       Post #: 10

resins? - 3/27/2002 6:45:16 PM   
winship


 

Posts: 151
Joined: 3/18/2002
From: Plainfield, IN, USA
Status: offline 		Hi Tom;

I have made tools from casting resin due to the time savings involved. Instead of making a tool from a plug or mock up by layering glass or carbon cloth over the plug you simply pour the casting resin over the part to create a mold. The plug needs to have a box surrounding it to keep the casting resin contained. The proper draft angle is important here to keep the plug from locking itself into the pour. This method is usually used on small parts. Wings and fuselages will require the glass or carbon lay up method for making tools.

I am not sure if the epocast numbers you have mentioned above are for this purpose or not.

You mentrioned that the shelf life of the resins you obtained were outdated. Many times a resin will crystalize after the shelf life expires. You can reverse this by warming the resin up to about 125 deg F. I have a styrofoam box that has a heat lamp in it that is run off of a variac to control the temperature. The curing agent is usually the first thing to go and I know of no way reversing it.

winship

(in reply to tomgtv6)
       Post #: 11

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