Author Topic: Epoxy, best brand? (Read 6800 times)

John Lindberg · « **on:** July 24, 2011, 07:45:46 AM »

There is a very intresting post concerning Matt Colan's problems with stress cracks, which brought up the question (to me, at least) what is the best brand of epoxy for joints like motor mounts, wing mounting joints, etc.?

Robert Schroeder · « **Reply #1 on:** July 24, 2011, 11:10:26 AM »

I've been using Bob Smith epoxy for years with no problems. I bought some West system slow epoxy which is supposed to be more flexible but haven't had a chance to use it yet so can't say. The BobSmith I use is 30 minute epoxy.

Bob

Howard Rush · « **Reply #2 on:** July 24, 2011, 02:02:05 PM »

I use HYSOL EA-9430, http://www.aircraftspruce.com/catalog/wppages/hysol.php . It's good for pretty high temperatures. I fix pipes with it. For really fuel proof stuff that you can make fuel tanks out of, I use EPON resin 862 & EPIKURE 3234 curing agent.

Will Hinton · « **Reply #3 on:** July 24, 2011, 06:20:09 PM »

For building I won't use anything but Bob Smith's adhesives, including his CA. For carbon landing gears and tuned pipes I use Resin Services out of Michigan. They can get you the right stuff for both jobs. They do require an oven post cure at proper temps and times, but they can also guide you on that. They are really helpful folks, and their specialty epoxies are in the $30 t0 $35 a quart range. A quart goes a really looooooooooooong way! Google them if you are interested.
Will

Ross Smith · « **Reply #4 on:** July 24, 2011, 10:02:26 PM »

HI, From my experience the best epoxy brand is WEST SYSTEM use the 105 (standard) type with Z 205 or 206 hardener. For gluing mix with glue powder (aerosils) or for wing fillets mix with micro-lite filler powder (tan colour) easy to sand. Main points to know 1. Always mix by weight; most accurate (but you have a 20% error margin ) 2. Working and cure temp must be at least 15 deg C otherwise introduce a heat source ie; a fan heater, or a light-bulb in a hot box; or post-cure in the trunk of a black car !!!! 3. You can make mixed epoxy run like thin cyano by heating it with a hot-air gun ; set -up the job so gravity does the work.
4. Epoxy is lethal so wear gloves, glue things up at the end of a work session then close the door and run !!! don't hang around while the stuff is going off. West system has excellent technical support manuals etc. They also manufacture some real flash epoxies if you want to win the America's Cup but they are too crystalline for model plane use (prone to cracking) . The 105 is all good.
Get Sticky , Cheers Roscoe

PJ Rowland · « **Reply #5 on:** July 25, 2011, 12:39:40 AM »

Howard : So you use that for Wing Joints?

Chuck Feldman · « **Reply #6 on:** July 25, 2011, 06:33:48 AM »

They say West is the best? Most every store brand epoxy comes from the same place or factory in the Midwest. I got some bad stuff from Ace hardware then I got some from Lowe's. It was bad to. So I contacted them about it and that is now I found out that it all comes from the same place. I have never gotten bad stuff from the model supply places or a hobby shop. I do remember as do all of you that Hobbypoxy was great. Seems like to many things have gone the way of K&B epoxy, Aero Gloss and a few other of the things we liked in the day.

Chuck

John Eyer · « **Reply #7 on:** July 25, 2011, 11:03:39 AM »

Mike Greb · « **Reply #8 on:** July 25, 2011, 07:30:09 PM »

When I try to mix Bob Smith 30 min epoxy in half ounce cup or larger pot, it starts to harden much faster that 30 min. The bob marks epoxy that I really like to use for assembly is the 20 min finish cure. I don't have to worry about it going off fast, and even though it remains a bit pliable, it seems to do the job. All of my slow rats used the 20 min finish cure to glue the fuselage to the wing.

Mark_Gerber · « **Reply #9 on:** July 25, 2011, 07:48:36 PM »

I used to use Devcon 60 min epoxy, but it seems to be no longer available. I now us Devcon 30 min epoxy and have never had a problem.

Mark Gerber

John Lindberg · « **Reply #10 on:** July 26, 2011, 03:49:10 PM »

I have had the same problem with the slower drying epoxy, it dries faster (alot) than the time listed on the tube or container.

Kelly Wilson · « **Reply #11 on:** July 26, 2011, 04:17:54 PM »

Anopther good brand of epoxy is System Three Epoxy. Their T-88 construction epoxy is good stuff. They also offer the T-88 in a gel formula too. On their wersite they offer a trial kit for $20 that gives a lot of samples, free stuff and very good info. They are also a source of waterbased epoxy paint.

http://www.systemthree.com/

Peter Nevai · « **Reply #12 on:** July 26, 2011, 05:52:53 PM »

Quote from: Kelly Wilson on July 26, 2011, 04:17:54 PM

Anopther good brand of epoxy is System Three Epoxy. Their T-88 construction epoxy is good stuff. They also offer the T-88 in a gel formula too. On their wersite they offer a trial kit for $20 that gives a lot of samples, free stuff and very good info. They are also a source of waterbased epoxy paint.

http://www.systemthree.com/

This stuff seems like a winner. The G2 epoxy looks promising as well. Nice find

Steve Helmick · « **Reply #13 on:** July 26, 2011, 07:23:30 PM »

Quote from: Kelly Wilson on July 26, 2011, 04:17:54 PM

Anopther good brand of epoxy is System Three Epoxy. Their T-88 construction epoxy is good stuff. They also offer the T-88 in a gel formula too. On their wersite they offer a trial kit for $20 that gives a lot of samples, free stuff and very good info. They are also a source of waterbased epoxy paint.

http://www.systemthree.com/

Danny Dirt (AKA Dirty Dan) uses and recommends System 3 epoxy, but I'm not sure which formulation. I'll see if I can get him to comment, but he's not online all that much. I asked him where he got it, and he said at the System 3 store in Auburn, WA. I used to work close to there, but gave it up for fishin' and flyin'.

Steve

Robert Schroeder · « **Reply #14 on:** August 04, 2011, 04:41:35 PM »

Chuck, you can't buy West epoxy in a store other than possibly a large boat store. Mine comes from CST when I see them at Toledo.

Bob

david beazley · « **Reply #15 on:** August 04, 2011, 05:16:42 PM »

For structural or laminating and glassing I use West system as mentioned above, (105/205/206). For a quickee I use 5-15 minute what ever i can find (Tower, Bob Smith, Loctite, etc.
One tip to extend pot life is mix in a shallow container like a pie plate or paper or styrofoam plate. By increasing the surface area of the mix there is not as much exothermic heat build up and pot life is extended.

Howard Rush · « **Reply #16 on:** August 04, 2011, 06:56:49 PM »

Quote from: david beazley on August 04, 2011, 05:16:42 PM

Analog man trapped in a digital world

You, too?

Randy Cuberly · « **Reply #17 on:** August 04, 2011, 10:22:50 PM »

Quote from: Steve Helmick on July 26, 2011, 07:23:30 PM

Danny Dirt (AKA Dirty Dan) uses and recommends System 3 epoxy, but I'm not sure which formulation. I'll see if I can get him to comment, but he's not online all that much. I asked him where he got it, and he said at the System 3 store in Auburn, WA. I used to work close to there, but gave it up for fishin' and flyin'. Steve

I've also been using the system three stuff for several years and had very good luck with it. It has excellent shelf life here in the heat in my shop in Tucson and the same can't be said about a lot of the others.

Randy Cuberly · « **Reply #18 on:** August 04, 2011, 10:25:56 PM »

Quote from: Howard Rush on August 04, 2011, 06:56:49 PM

You, too?

Howard,
Just ignore the digital stuff...life is a lot simpler and better that way! One of the benefits of being retired.

Luiz Ribeiro · « **Reply #19 on:** August 05, 2011, 06:54:06 AM »

I have used many of those brands, and I prefer Devcon or Bob Smith. I never used West epoxies, maybe I can’t find them in Brazil. I will look for one to try.

Luiz

David Hoover · « **Reply #20 on:** August 05, 2011, 08:22:15 AM »

Some of the West products are available through Lee Valley Tools, at least they are in Canada.

Andrew Tinsley · « **Reply #21 on:** August 05, 2011, 11:50:43 AM »

Some Australian modelers have not got a good word to say about West. They claim that it softens at high ambient temeperatures and goes hard again when it cools. Living in the UK, I have never had the chance to match Aussie temperatures, anyone seen this behaviour in the hot parts of the US?

Regards,

Andrew.

Gary Weaver · « **Reply #22 on:** August 05, 2011, 02:05:00 PM »

The problem is not the epoxy brand. Most places these days sell 5 minute, 15 minute, 30 minute epoxy. Hardwood motor mounts is too hard for epoxy to soak into before it becomes hard so the epoxy is stuck to the surface and peals off under stress. If you could get some 24 hour epoxy it will stick to hardwood much better because it has a whole 24 hours to soak into the wood before it becomes hard. Epoxy will stick much better to ruff cut wood than wood with a smooth finish. I drill several 100 tiny 1/16" holes in my motor mounts on the glue side the tiny holes are only about 1/16" deep this gives the epoxy a place to hang on tight.

There are different typed of epoxy too but none available at the local stores. I don't remember all the classifications but there is Rigid, semi Rigid, another one like medium rigid but it has its own name, there is one softer than medium rigid and one softer than that. Rigid epoxy is brittle it will crack and break. The medium stuff is less brittle and does not crack easy. The softer ones are excellent for vibration and extreme shock. You need to read the book, ADHESIVE TECHNOLOGY.

I glued scope mounts to my Winchester 300 magnum rifle with Rigid epoxy the scope mounts fell of on the 3rd shot. I glued it on several more times it kept falling off about 2nd to 4th shot each time. I ruffed up the metal and glued the scope mounts on it fell off again on the 6th shot. After reading ADHESIVE TECHNOLOGY I ordered some soft set epoxy the scope has been on my rifle for 21 years and I have probably shot 3000 bullets in the gun. I like target shooting I reload 100 bullets then shoot 8" diameter targets at 1/4 mile.

David Murrell · « **Reply #23 on:** August 08, 2011, 05:26:06 AM »

Andrew, the "some Aussie modellers" are in the minority, mixed and cured properly WEST systems are fine at any ambient temperature that the body can stand. I have lived in the tropics and restored a wooden boat there using WEST without any problems, in fact the boat is now 81 years old and still in very good condition 30 years after the restoration.
There are a lot of top modellers and fliers that use WEST successfully, but like anything it has it's uses, and there is a limit to these.

Cheers

David M

Author Topic: Epoxy, best brand? (Read 6800 times)

Mark_Gerber