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Author Topic: Epoxy Brands  (Read 6873 times)

Offline Dick Pacini

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Epoxy Brands
« on: March 24, 2014, 09:56:20 PM »
Are there major differences in hardware store epoxy and hobby shop epoxy?
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Online Will Hinton

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Re: Epoxy Brands
« Reply #1 on: March 25, 2014, 08:10:04 AM »
My main shop is always quite cool so when I epoxy hardwood I always hit it briefly with my heat gun.  I make it warm enough to just start getting uncomfortable to the touch and then slap it together.
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Offline FLOYD CARTER

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Re: Epoxy Brands
« Reply #2 on: March 25, 2014, 11:01:19 AM »
I put both bottles of epoxy in the microwave for 10 seconds.  This makes pouring ans mixing much easier.

Floyd
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Offline Mark Knoepfle

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Re: Epoxy Brands
« Reply #3 on: March 25, 2014, 12:43:15 PM »
You've been using the same bottles since 1970?! No wonder it didn't work.  S?P LL~

To hear it in Tucson I'd think more and more engineers and ops folks are going your way Ty then coming here from there.

Mark

Online Will Hinton

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Re: Epoxy Brands
« Reply #4 on: March 26, 2014, 09:22:17 AM »
The bad wording thing must be catching, Ty.  I should have specified that I heat the hardwood!  Just a few passes with the heat gun will do.
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Online Brett Buck

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Re: Epoxy Brands
« Reply #5 on: March 26, 2014, 09:51:02 AM »
Are there major differences in hardware store epoxy and hobby shop epoxy?

   It depends on what kind and brand. Almost all of the epoxy used in modeling is consumer grade, with large amounts of filler in the hardener to get it to 1:1 or 2:1 mix. Industrial epoxy is frequently 16:1, 100:1, etc.

      Almost all the epoxy and catalyzed rubber-type potting compound used at my work is pre-mixed. They mix it at the factory, then freeze it. When you want to use it, you thaw it out and apply. That removes the need to carefully measure and mix anything at the user end, and permits much better QA and tracking.

     Brett

Offline Steve Fitton

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Re: Epoxy Brands
« Reply #6 on: March 27, 2014, 05:36:44 AM »
   It depends on what kind and brand. Almost all of the epoxy used in modeling is consumer grade, with large amounts of filler in the hardener to get it to 1:1 or 2:1 mix. Industrial epoxy is frequently 16:1, 100:1, etc.

      Almost all the epoxy and catalyzed rubber-type potting compound used at my work is pre-mixed. They mix it at the factory, then freeze it. When you want to use it, you thaw it out and apply. That removes the need to carefully measure and mix anything at the user end, and permits much better QA and tracking.

     Brett


Do you still use bottles of Eastman 910 at work? My Dad still has some amber glass bottles of 910 in his shop that were liberated from RCA Astro many years ago.  Last time I checked the stuff still worked...
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Online Brett Buck

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Re: Epoxy Brands
« Reply #7 on: March 27, 2014, 09:38:28 AM »
Do you still use bottles of Eastman 910 at work? My Dad still has some amber glass bottles of 910 in his shop that were liberated from RCA Astro many years ago.  Last time I checked the stuff still worked...

    No Eastman 910 or any other CA as far as I know. RTV/urethane and epoxy, yes. Most of it is either potting, conformal coating, thermal and electrically-conductive pastes, or epoxy as a binder for graphite.

     Brett

Offline RknRusty

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Re: Epoxy Brands
« Reply #8 on: March 29, 2014, 09:42:56 PM »
I've always used off the shelf epoxy; 5, 30 and 60  minute, Loctite if I can get it. Otherwise, Great Planes. It's getting hard to find 60 minute in stores anymore. But over the past year I've had more batches turn out soft and have had to start adding a tad more hardener to the mix. I don't recall this always being the case. I squirt small amounts side by side on graph paper which makes it easier for me to gauge the amounts. For larger amounts I always use measuring cups. The short time epoxy is worse about needing extra hardener, and even then it won't always snap when I bend a day old test puddle. A test puddle of JB Weld, on the other hand is sometimes stronger than I am when using exactly equal amounts.
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Online Lauri Malila

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Re: Epoxy Brands
« Reply #9 on: March 30, 2014, 03:23:01 AM »
Hi.

Over here in center of Europe, clearly the best "hardware store" epoxy glue is UHU Endfest 300. I don't know if UHU products are available in US.
We use it in the most demanding aeromodelling task; assembly of F1A (free flight) wings. Basically all other hobby grade epoxies are hopelessly too weak for the job. We glue mostly carbon to carbon or aluminium to carbon.
For contol line use with mostly wood-wood -joints it's not so critical. I'd recommend just to choose a slower epoxy (1/2h) or more and use some heat whenever possible.
Another problem with most hobby epoxies is the heat resistance, usually they start to soften & weaken at about 60 degrees C. The UHU epoxy resists up to allmost 200C.
And, by manipulating the resin:hardener ratio it's possible to manipulate the mechanical properties of Endfest 300:
 -If you need some elasticity in glue joint, add some extra hardener.
 -For maximum hardness and maximum heat resistance, you use less hardener in the mix.

Lauri

Offline Curare

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Re: Epoxy Brands
« Reply #10 on: March 30, 2014, 03:29:35 AM »
Lauri, I heard some F3A guys gluing in their skirt bearings with endfest, is the 300 high temperature, or are they using another endfest?

While we're on the subject of epoxies, I was always told that long drying epoxies create a greater bond as it soaks into the fibres of a wood joint. Not only that but the extra working time is a bonus.

You guys have now got me thinking I may have been a given a 'bum steer'.
Greg Kowalski
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Online Lauri Malila

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Re: Epoxy Brands
« Reply #11 on: March 30, 2014, 03:37:25 AM »
I don't know about F3A but yes, Endfest 300 resists about 200 degrees C. I use it to assemble my mufflers too, no problems.
Yep, heat helps to impregnate wood better, but it also improves the strenght of glue itself.
And by the way, epoxy doesn't really dry, it hardens:)

L

Online Brett Buck

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Re: Epoxy Brands
« Reply #12 on: March 30, 2014, 04:09:02 PM »
Lauri, I heard some F3A guys gluing in their skirt bearings with endfest, is the 300 high temperature, or are they using another endfest?

While we're on the subject of epoxies, I was always told that long drying epoxies create a greater bond as it soaks into the fibres of a wood joint. Not only that but the extra working time is a bonus.

You guys have now got me thinking I may have been a given a 'bum steer'.

    For gluing modeling materials like balsa/plywood/foam, any of them are plenty strong enough if used properly.

    I have a wide variety of various epoxy types that I have used over the years, and aside from picking them based on working time, any of them seems to be OK. I currently prefer the West System laminating epoxy for the very long working time, and lack of tendency to self-heat and reduce the pot life. It seems tougher than most of the slow-set finishing types.

    I like the PIC Coating epoxy (4:1 with little or no filler) for finishing but if you leave it in the cup it can go off in 15 minutes, instead of allowing it to spread out. It's much harder and more brittle than the West Systems type. I know that stuff is good because the hardener is destroying and bleeding through the plastic bottle it comes in.

      Brett

Offline Curare

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Re: Epoxy Brands
« Reply #13 on: March 30, 2014, 05:19:56 PM »
Yeah, I've had issues with exotherm using some of the SP systems epoxies. While using Ampreg 22 for the first time I had it bubble and boil while in the cup, I couldn't get it out of the house quick enough!!!

Greg Kowalski
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Offline Dennis Moritz

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Re: Epoxy Brands
« Reply #14 on: April 01, 2014, 07:59:05 PM »
What about polyester resin, perhaps to attach fiberglass, or as fill coat under epoxy paint or other paint. I used this method at one time. Very hard and strong. Years back (30 plus years as a matter of fact) we purchased an inexpensive sofa, made of press board and ply. Slats supporting the seat cushions were held in place by planks glued to the press board. Good for about a year. Then crash. I tried different glues, including epoxy to re-glue. Crash and crash again. At that time I used polyester resin as a fill coat on profiles, color painted with Hobby Poxy. One coat resin, scraped off as much as possible, one coat Hobby Poxy. I mixed the resin in paper cups. The left over resin setup up in the bottom of the cup. Tough stuff. Out of curiosity I took a hammer to the left over resin. Couldn't make a dent. I slugged it hard as I could. As a last resort to fix the sofa I mixed up the resin to glue the supporting planks. It worked. Laying on that piece of junk to this day. (Looks pretty good, the veneer has not stripped, an oriental rug on top-- improvised posh.) Anyone use polyester resin these days?

Offline Steve Helmick

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Re: Epoxy Brands
« Reply #15 on: April 01, 2014, 08:16:49 PM »
I wouldn't use Polyester resin again for any reason. Epoxy is less brittle (in general, they vary, depending on what their intended use is) and shelf life is at least 10x as long, maybe 100x. The two things Polyester has going for it is price and UV resistance. Howard may think of another, but I doubt if he'd use it, either. Oh, it burns nicely...

I also used polyester resin on solid wood speed models and racers, covered with epoxy boat paint. Monochromatic paint schemes...  H^^ Steve
« Last Edit: July 10, 2014, 04:00:27 PM by Steve Helmick »
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Online Brett Buck

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Re: Epoxy Brands
« Reply #16 on: April 20, 2014, 11:18:08 AM »
I wouldn't use Polyester resin again for any reason. Epoxy is less brittle (in general, they vary, depending on what their intended use is) and shelf life is at least 10x as long, maybe 100x.

   I had been using the finishing/laminating type for foam wing skins, but it gets pretty brittle. The West Systems type (I would tell you which one, but Uncle Jimby just gave me samples from the gallon can be bought) is just about as thin but doesn't heat itself very much, and is far more tenacious, and has a very good working time. Sheeting a foam wing with the finishing type is a race, mix it, pour it out into a flat container to reduce the self-heating effect, and slap it on there fast before it begins to set. Left in a cup, it gets noticeably thicker in maybe 15 minutes, spread out maybe 45 minutes.  No problem with the West systems type, it gets only vaguely warm and a cup of it will remain almost unchanged for an hour or more and could probably be worked at 2 hours. It takes a lot of the uncertainty out of the process, you never have to worry about how well it was covered and whether the penetration is correct.

    Brett

   

Offline FLOYD CARTER

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Re: Epoxy Brands
« Reply #17 on: April 20, 2014, 04:22:35 PM »
I think epoxy products first appeared about 1957 or so.  As a college student with a summer job, they (Sylvania E.D.L., Mountain View) used Shell "Epon".  Instructions said to place the mix in a bell jar and pump out the air to eliminate any bubbles.  Then it was good to go.  That was fun watching them glue stuff together!
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Offline Don Hutchinson AMA5402

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Re: Epoxy Brands
« Reply #18 on: April 20, 2014, 09:28:46 PM »
We had Shell 828 at Honeywell Aero systems in 1953. When they first got some into the lab they tested it by mixing up a coffee can full of it. Guess what they found out! We also mixed it and evacuated the air bubbles out of it before applying it.

Online Dave Harmon

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Re: Epoxy Brands
« Reply #19 on: July 09, 2014, 10:59:56 PM »
I don't use any 'hobby' type epoxy anymore unless it is a small amount of 5 minute.
I started using Loctite Hysol 9462 available at McMaster-Carr.
This is the same stuff sold by Bob Violett (BVM) as 'Aeropoxy'.
This stuff is definitely bullet proof and is great for critical structures.....it won't pop off....great for profile fuselage/wing joints.
I keep it in the refrigerator...the CA in the freezer
The Bob Smith stuff pops off like a dry booger......arrrgh

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steven yampolsky

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Re: Epoxy Brands
« Reply #20 on: July 10, 2014, 07:33:17 AM »
Are there major differences in hardware store epoxy and hobby shop epoxy?

There are two major epoxy producers in the US. They mix products for many brands but it will be essentially the same product.

The really noticeable difference is between 50:50 mix ratio epoxies and regular 2:3 or 1:5 ones. You see, resin is the actual product that creates bonds and makes things strong. The hardener is an accelerator and has no strength value. To make things easy for people to measure, the mixing company add neutral agent to the hardener to increase its volume. In other words, in a 50:50 mix, half of epoxy is resin, 1/4 is hardener and 1/4 is filler with no usable value. As a result, the bond made with a 50:50 mix is much, MUCH weaker than the one made with undiluted epoxy.


Offline Phil Krankowski

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Re: Epoxy Brands
« Reply #21 on: July 10, 2014, 03:10:15 PM »
   I had been using the finishing/laminating type for foam wing skins, but it gets pretty brittle. The West Systems type (I would tell you which one, but Uncle Jimby just gave me samples from the gallon can be bought) is just about as thin but doesn't heat itself very much, and is far more tenacious, and has a very good working time. Sheeting a foam wing with the finishing type is a race, mix it, pour it out into a flat container to reduce the self-heating effect, and slap it on there fast before it begins to set. Left in a cup, it gets noticeably thicker in maybe 15 minutes, spread out maybe 45 minutes.  No problem with the West systems type, it gets only vaguely warm and a cup of it will remain almost unchanged for an hour or more and could probably be worked at 2 hours. It takes a lot of the uncertainty out of the process, you never have to worry about how well it was covered and whether the penetration is correct.

    Brett

   

http://www.westsystem.com/ss/hardener-selection-guide/

I like west system too.  I have some left from building a canoe, although it is several years old now it seems to work fine still.

Phil

Offline Daniel_Munro

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Re: Epoxy Brands
« Reply #22 on: July 23, 2014, 08:19:27 AM »
I've been using some cheap stuff made in Malaysia branded Vtech. It's $5 for a 26ml syringe. Works a treat. However in the cold winter here I have to warm it up by popping it in warm water for a few minutes first.
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Offline BillLee

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Re: Epoxy Brands
« Reply #23 on: July 23, 2014, 12:33:21 PM »
We had Shell 828 at Honeywell Aero systems in 1953. When they first got some into the lab they tested it by mixing up a coffee can full of it. Guess what they found out! We also mixed it and evacuated the air bubbles out of it before applying it.

I bet they found a coffee can full of swiss cheese cured epoxy after the fire and smoke from the exotherm cleared away!

I use Shell Epon 815 to make props. 815 is simply 828 with a diluent to make it thinner. If you mix as little as 50 grams in a small cup, it will exotherm badly. Spread out: no problem, but a COFFEE CAN! Yikes!
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Offline Andrew Tinsley

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Re: Epoxy Brands
« Reply #24 on: August 29, 2014, 08:06:08 AM »
I have had some weird results with West system epoxies. Using it for boat building and repair has given good results. The same material from the same containers has then produced an epoxy which never appears to harden fully. If the plane is out in strong sunlight, then it feels a touch sticky after the plane heats up.
  I then used the same stuff on some stitch and glue dinghy construction and it behaved itself. I was very careful in getting the correct ratios of hardener to resin. Maybe some of the underlying paint had a bad effect on the epoxy layer. First time I had problems with the West system.

Andrew.
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Offline Randy Powell

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Re: Epoxy Brands
« Reply #25 on: August 29, 2014, 11:55:44 AM »
I've been using West Systems 105 for quite awhile. No issues other than to be sure that after application it's warm enough for the stuff to harden completely.
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Offline Mike Lauerman

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Re: Epoxy Brands
« Reply #26 on: September 05, 2014, 02:17:18 PM »
Not too technical here, but also a user since '58 I would like to know:

Is it pronounced  'E poxe' or 'e-POX-e' ?  ...been buggin' me for years... my flying bud pronounced it the latter way, but he was from a place he called "Joisey".

Offline RknRusty

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Re: Epoxy Brands
« Reply #27 on: September 06, 2014, 12:33:47 AM »
Not too technical here, but also a user since '58 I would like to know:

Is it pronounced  'E poxe' or 'e-POX-e' ?  ...been buggin' me for years... my flying bud pronounced it the latter way, but he was from a place he called "Joisey".
Well, that's a great question Mike. Now people in my area call it e-POX-e. Don't know what they might call it in the Carri-BE-an though. Or the carRIB-ean. And maybe somewhere there is some new relabeled stuff on the market for E-planes that they call E-pox-e. Lol.
Zat help?
Rusty
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Offline phil c

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Re: Epoxy Brands
« Reply #28 on: October 11, 2014, 06:17:42 PM »
Not too technical here, but also a user since '58 I would like to know:

Is it pronounced  'E poxe' or 'e-POX-e' ?  ...been buggin' me for years... my flying bud pronounced it the latter way, but he was from a place he called "Joisey".
It's been ee-POX-ee since chem 101  too long ago.
phil Cartier

Offline RknRusty

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Re: Epoxy Brands
« Reply #29 on: October 11, 2014, 08:49:08 PM »
      Almost all the epoxy and catalyzed rubber-type potting compound used at my work is pre-mixed. They mix it at the factory, then freeze it. When you want to use it, you thaw it out and apply. That removes the need to carefully measure and mix anything at the user end, and permits much better QA and tracking.

     Brett

Brett, do you think it would work well to mix a batch of hardware store 50:50 and dispense 10ml in a bunch of mixing cups and store in my shop freezer for convenient small jobs?
Rusty
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while you're doing it!

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