Good Epoxy brands

[dixontj93060]

On a standard build I use (i.e., not high performance/temp):

• Laminating: US Composites 635 and medium hardener
• Structural: System Three T-88
• Finish fillets: Bob Smith Mid-Cure
• Tacking and misc: System Three Quick Cure

 

[Feckless Counsel]

TRF,

Please find a chart of relative viscosities attached.

 

[DRAGON64]

I have used Mr. Fiberglass brand epoxy for years, and I still have some left... but he has since passed away, and I believe he was selling re-branded US Composites. Once I run out, I will probably go with US Composites.

Bob Smith and like epoxies are good for getting your feet wet in using epoxies, but soon you will find that you need more flexibilty (useage) with the higher quality adhesives. Especially if you get into laminating composites.

 

[FibreGlast]

Fibreglast System 2000 is my preferred brand, but I've also used lots of West and AeroPoxy.

I prefer AeroPoxy and Fibreglast for their ability to better handle elevated temperatures.

Adrian is spot on about investing in a small scale for mixing small batches. If your family eats yogurt, save the containers -- great for mixing in, rather than buying cups!

-Kevin

Thanks for the mention Kevin!! We appreciate it. We are very proud of our System 2000 Epoxy Resin!!!! Sorry for bumping an older thread mods! Just wanted to say thanks!

 

[degreaser]

Here's my vote for US Composites. I use the 3:1 Thin for laminating.

Ditto. I use a kitchen scale and dispense by weight rather than volume. It's close enough.

 

[bill_s]

Adding an alcohol to epoxy to thin it, even in small quantities, costs a lot of strength in final cured properties. Not a good idea. If you need thinner epoxy, use a thinner epoxy. Or in some cases, brief application of heat, if the epoxy is slow cure as is the case for laminating resins.

Acetone is actually the correct thinner for epoxy, but talk about nasty. It also kills the water vapor seal properties.

I have some old borrowed West at the moment .. pumps are jammed up solid but still leak all over the place when removed

 

[gdjsky01]

Man I just got some of the structural epoxy from GLR. Holy #$#%$ that stuff is thick. I am not sure how I'll dispense it. With System III I just use condiment squeeze bottles from smart and final (yeah they leak a little, I just clean em up now and then). But this stuff is thick goop.

Maybe I'll take a look at Fibreglast.

 

[CarVac]

Man I just got some of the structural epoxy from GLR. Holy #$#%$ that stuff is thick. I am not sure how I'll dispense it. With System III I just use condiment squeeze bottles from smart and final (yeah they leak a little, I just clean em up now and then). But this stuff is thick goop.

Maybe I'll take a look at Fibreglast.

Squeeze bottles are the way to go for ES6209. It's probably better to use something smaller than condiment bottles, though, or you will be waiting a long time for it to get to the nozzle. I think we use these: https://www.mcmaster.com/#4176T3 or maybe the 8 ounce ones.

 

[gdjsky01]

Thanks for the TIP! :handshake:
Coming out to play next Saturday?

 

[CarVac]

Thanks for the TIP! :handshake:
Coming out to play next Saturday?

Yup, and potentially with a new rocket for a new certification level...

 

[terryg]

Another way to dispense it is to use large syringes (60ml). This allows you to dispense and measure in one step. Disposable chopsticks work great to mix it. If you mix too much, then you can place the excess in the freezer to use in a day or two. Due to its thickness it tends to stay where you put it, which makes it easier to work with in my opinion.

 

[CarVac]

Another way to dispense it is to use large syringes. This allows you to dispense and measure in one step. Disposable chopsticks work great to mix it. If you mix too much then you can place the excess in the freezer to use in a day or two. Due to its thickness it tends to stay where you put it, which makes it easier to work with in my opinion.

Using big syringes would sure cut down on the wait versus squeezebottles, but it's an otherwise less-convenient form factor (storage-wise). What size syringes do you use?

 

[terryg]

I use 60 ml syringes which I fill to the 60ml mark from the cans. Since they are marked it is easy to measure 5 or 10 ml for mixing in a disposable cup. After use, invert the syringes and use plastic wrap and rubber bands to seal them up till the next use and place them upright (nozzle up) in a box for storage.

 

[gdjsky01]

I just ordered a few size small squeeze bottles. I measure by weight exclusively. Like CarVac says, waiting for large bottles would drive me insane. Smaller should work. Or at least I will try. McMaster-Carr is local. Ships Monday, here on Tuesday.

 

[cwbullet]

Weight really is the way to go. Reducing waste reduces cost.

 

[CarVac]

I just ordered a few size small squeeze bottles. I measure by weight exclusively. Like CarVac says, waiting for large bottles would drive me insane. Smaller should work. Or at least I will try. McMaster-Carr is local. Ships Monday, here on Tuesday.

I actually don't measure by weight, but I've been trained since age 3 to estimate volumes super-accurately (my mother is supernaturally good at figuring out the right Rubbermaid container for a given amount of food), so I just mix by eye. For 1:1 epoxy that's good enough.

Also, it means I almost never mix too much, since I'm thinking volumes as opposed to masses.

 

[G_T]

The tolerance on some of the better epoxy systems is approximately 2%, by weight. Being off by more than that starts to hurt the final properties.

If one cares about the final properties, then weigh the epoxy.

Gerald

 

[CarVac]

The tolerance on some of the better epoxy systems is approximately 2%, by weight. Being off by more than that starts to hurt the final properties.

If one cares about the final properties, then weigh the epoxy.

Gerald

2% by weight for which part? Do you mean 2% as in mixing a 100:15 epoxy at 100:13 (15 - 2), or as in 100:14.7 (15*0.98)?

I have a hard time believing that any epoxy will be so dramatically sensitive to a 2% stoichiometry change like the latter, but the "2%" change in the former situation is a 13.3% stoichiometry change.

What epoxy in particular are you referring to? I'd like to see what manufacturer numbers are on this subject.

 

[cwbullet]

I really like the small bottles from Bob Smith. If I am at home, I use US Composites or West. I have used just about all of them except Hysol. Anyone have any experience with it? I have though about using the Gun dispenser.

 

[CarVac]

I really like the small bottles from Bob Smith. If I am at home, I use US Composites or West. I have used just about all of them except Hysol. Anyone have any experience with it? I have though about using the Gun dispenser.

There are a lot of Hysol's.

 

[G_T]

2% by weight for which part? Do you mean 2% as in mixing a 100:15 epoxy at 100:13 (15 - 2), or as in 100:14.7 (15*0.98)?

I have a hard time believing that any epoxy will be so dramatically sensitive to a 2% stoichiometry change like the latter, but the "2%" change in the former situation is a 13.3% stoichiometry change.

What epoxy in particular are you referring to? I'd like to see what manufacturer numbers are on this subject.

I just grabbed the first one I looked for. Feel free to research others.

https://www.aircraft-spruce.com/catalog/pdf/mgs285tech.pdf - See page 1.1-13, the table giving mixing ratio. The recommended error for hardener is 2 parts in 140 to 150, or less than 2% total mass.

Do you by chance do any EX work? What would happen to the properties if you missed the curatives by 2%? It is easy to be dulled into a sense that the ratios don't matter much with epoxy, when most people's first exposure to epoxy is the consumer 5 minute and similar mixes. But if you want properties which match what the manufacturer intended, then like with most non-catalytic chemistry, it is best to have the correct ratios to start with!

Gerald

 

[CarVac]

I just grabbed the first one I looked for. Feel free to research others.

https://www.aircraft-spruce.com/catalog/pdf/mgs285tech.pdf - See page 1.1-13, the table giving mixing ratio. The recommended error for hardener is 2 parts in 140 to 150, or less than 2% total mass.

Do you by chance do any EX work? What would happen to the properties if you missed the curatives by 2%? It is easy to be dulled into a sense that the ratios don't matter much with epoxy, when most people's first exposure to epoxy is the consumer 5 minute and similar mixes. But if you want properties which match what the manufacturer intended, then like with most non-catalytic chemistry, it is best to have the correct ratios to start with!

Gerald

I would call that spec off by 5%, stoichiometry-wise; 40/2 = 0.05. But that aside:

I do not do EX work, but my question was what does happen to the properties if you're off by that 5%? The manufacturer gives the requirements, but I actually wanted to know what sort of degradation to expect from a 5% stoichiometry error.

 

[dlb]

Another vote for us composites.
I use both thick and thin formulas.

 

[G_T]

Research is your friend. Then you don't have to take my word for anything!

Gerald