Issues with Rocketpoxy/Questions (Oh no! Not another glue thread!!)

[Banzai88]

OK, decided to treat myself to a fresh batch of Rocketpoxy for Christmas since it's my go to glue and I've had great results (been through 1 1/2 sets of 2 pint batches so far with ZERO issues). Ordered/received, no issues at all(although it was NOT from my preferred vendor as he was OOS at the time and was extra expensive!). Expiration date is late 2023, sealed containers.

Whenever I get a new batch of any kind of glue, I always do a deep mix of the components to ensure that no shelf settling has occurred with the individual components, then mix a test batch and see how it sets up in a solid mass(simulating fillets) and a thin smear(simulating centering ring and surface mount joints) to check it's properties and make sure my mixing is good to go. Just mixed up some of my NEW lot of RP the other day and the mixing cup (solid mass) came out fine, but the 'smear' test (thin film) that I did on a piece of scrap fiberglass set up hard but has a 'sticky' feeling to it.

Second test mix, mixed even longer and more aggressively (probably 20 minutes or more, scraping the sides of the mixing cup constantly), came out the same way (glob ok, thin film sticky). Both test batches were mixed and set in a house that's 72 ambient temp, high 40s % humidity, and were evaluated after 12 and 24 hours set time.

Went back to my 'old' stock, probably 3 years old or older (dang, this stuff STINKS when it's been sitting for a while), mixed the 2 components up to eliminate any storage separation issues, and the test batch solid mass and thin film turned out perfect, no stickiness at all.

2 pint set was over $85/shipped.....not happy if I need to throw it away and will probably lodge a complaint/return with the vendor!

*What, if anything, am I doing wrong (other than you jokers who are gonna say "Using RP is your problem! ")
*Did I get a bad batch?
*Anyone else have any recent RP issues?

*(Soooooo gonna regret this, but it has to be done ) If I decide to switch, what is your preferred glue for fiberglass?

 

[roc_boy]

Hmmm. I use and love my RP. First thought that comes to mind, If both applications are from the same mixing batch, the bulkier application sets normally but the thinner one doesn't? Sounds like it might need more heat (for some reason, maybe more than you'd expect or is normal?). I'd probably try adding some heat to the thinner one (maybe from a close incandescent light bulb would be enough?) for a period of time and just see if that completes the cure.

 

[Titan II]

Aeropoxy ES6209 and Loctite/Hysol 9462

 

[kswing]

System Three T-88. It takes a long time to cure, but, overall it is strong and easy to work with.

I've also used the Aeropoxy ES6209 mentioned above. It also worked well, but, it was very, very thick and more expensive than the T-88.

 

[Banzai88]

Loctite/Hysol 9462

Preferred vendor?

 

[Banzai88]

Hmmm. I use and love my RP. First thought that comes to mind, If both applications are from the same mixing batch, the bulkier application sets normally but the thinner one doesn't? Sounds like it might need more heat (for some reason, maybe more than you'd expect or is normal?). I'd probably try adding some heat to the thinner one (maybe from a close incandescent light bulb would be enough?) for a period of time and just see if that completes the cure.

It's strange, but the joint is fine, cures tough and hard......but the surface feels sticky. Even repeated wipes with IPA doesn't seem to change it any.

 

[Titan II]

Preferred vendor?

My supply was from a wholesaler as I sold it in my hobby shops. Just Google it as there are several sources. You also need the gun and nozzles. I use it more in my jets than rockets, where I more frequently use the 6209.

 

[kswing]

It's strange, but the joint is fine, cures tough and hard......but the surface feels sticky. Even repeated wipes with IPA doesn't seem to change it any.

I wouldn't give up on it yet. It might continue setting and lose the sticky feel in a few days. Also, are you sure you mixed equal amounts of resin and hardener? Un-even amounts can have a big impact on how it cures.

 

[Banzai88]

I wouldn't give up on it yet. It might continue setting and lose the sticky feel in a few days. Also, are you sure you mixed equal amounts of resin and hardener? Un-even amounts can have a big impact on how it cures.

I use my reloading scale and mix exactly 50 grains of each component.

I'll give it another 24 hours and see what it looks like

 

[waltr]

Does it sand ok?
If not cured it would be gummy when sanding.

 

[Titan II]

It's strange, but the joint is fine, cures tough and hard......but the surface feels sticky. Even repeated wipes with IPA doesn't seem to change it any.

If still sticky after a day or two, try acetone.

 

[Banzai88]

Does it sand ok?
If not cured it would be gummy when sanding.

Sands just fine, no gumminess in the sanding or on the sandpaper. Hmmmm......

 

[SwingWing]

Amine blush? Was it humid?

 

[bobbyg23]

My new container does that also. It goes away after an extra day or 2. What is the expiration date on yours?

 

[Banzai88]

Amine blush? Was it humid?

No, not appreciably, and the (much, much)older batch cured just fine under the same conditions.

 

[Banzai88]

My new container does that also. It goes away after an extra day or 2. What is the expiration date on yours?

Resin = Batch Z1315 Exp 10/30/2023

Hardener = Batch Z1271 Exp 10/30/2023

 

[David Schwantz]

Where do you live Tom? I had a shipment, not RP, sit outside on the step until wife got home. It froze and would not fully cure. Tried heat guns, tried mixing with solvents. And I get my Hysol 9462 from Dreamworks RC. They are in FL.

 

[David Schwantz]

this is 9462, just rebranded under BVM. I have had both and are the same.

https://dreamworksrc.com/product/aeropoxy-glue-cartridge/
And Hysol is now under Loctite brand.

 

[cwbullet]

Not another glue thread.

I have used Rocketpoxy way past the expiration date by years and it still works.

 

[cls]

Yeah, as above, longer time curing, under an incandescent bulb, or even a heat lamp. A couple days ought to do it.

Second idea, double check the instructions. It maybe uses a slightly different ratio than you think.

For example, I tried a batch of TAP Plastics vinyl ester. Stayed sticky for weeks!! Took it back to the store, the ah mgr gave me a pamphlet, which had the correct mix in 8 point type at the bottom of the last page. By volume, not by weight. Oh yeah, my fault entirely. Rescued the work by wiping hardener all over, then a day under a couple 100w bulbs. Turned out fine.

 

[KenECoyote]

I have used Rocketpoxy way past the expiration date by years and it still works.

I'm currently using Rocketpoxy that I believe was made in 2014 or 2015 (Batch #151014)

 

[KenECoyote]

Rescued the work by wiping hardener all over...

IMHO that's a very smart thing to try.

 

[cwbullet]

I'm currently using Rocketpoxy that I believe was made in 2014 or 2015 (Batch #151014)

View attachment 558524

The other thing I like is the ability to color the adhesive to either match of not match the tubing.

 

[mtnmanak]

Tom - Try another smear test, but, this time heat up the resin and hardener a bit before you mix them. If the components did freeze during shipping, there could be crystals in the resin that could make it more difficult to mix and, since RP is a paste epoxy, it can be difficult to see the crystals. I would put each of the jars in a water bath at around 100 degrees for about 15 min and mix the components before they cool. Just note that your pot life will be lower if you heat the components.

 

[Tractionengines]

JUST TO ADD SOME "POSSIBLE BACKGROUND"...
ANYTHING that has to due with resins has been VERY disrupted by the pandemic and supply chain issues. We use custom manufactured epoxy at work. We have had to pay a $3000-5000 surcharge (yes 3-5k EXTRA) to make a 5 gal batch of harder. We also have had to work with the manufacturer to "reformulate" it twice, due to component supply issues. This is a BIG deal for industry.

I would be willing to bet at the basic chemistry level there are some changes in a LOT of epoxies. If the original purchasing company and manufacturer feel it is equivalent, they likely don't tell down stream customers of the changes. (THEY ARE ALL PROPRIETARY, AND NOT DISCLOSED ANYHOW.)

We have seen some residue on the surface of freshly cured items. It's likely humidity in the air reacting with some components. Give it 3-5 days to finish curing and wipe with alcohol or acetone. The other option is a moderate temperature "post cure" for a few hours after the initial 24 hour room temp cure. This will drive off the moisture, and finish the cure. The surface will likely not get that coating again, even in high humidity environments.

[ Edit : To make it perfectly clear; I have NOTHING to due with any of the specific epoxies, or manufacturers, in this thread. It is ALL SPECULATION, based on some industry exposure. ]

 

[Banzai88]

Where do you live Tom? I had a shipment, not RP, sit outside on the step until wife got home. It froze and would not fully cure. Tried heat guns, tried mixing with solvents. And I get my Hysol 9462 from Dreamworks RC. They are in FL.

I live in Virginia Beach. Glue was shipped the last week of November, and it wasn't cold here at all, but it came from Colorado.....so no telling.

I have used Rocketpoxy way past the expiration date by years and it still works.

The remainder of my 5 year old batch works perfectly, and doesn't have a expiration date on it!

Yeah, as above, longer time curing, under an incandescent bulb, or even a heat lamp. A couple days ought to do it.

Second idea, double check the instructions. It maybe uses a slightly different ratio than you think.

For example, I tried a batch of TAP Plastics vinyl ester. Stayed sticky for weeks!! Took it back to the store, the ah mgr gave me a pamphlet, which had the correct mix in 8 point type at the bottom of the last page. By volume, not by weight. Oh yeah, my fault entirely. Rescued the work by wiping hardener all over, then a day under a couple 100w bulbs. Turned out fine.

I tried putting the first batches under hte heat lamp in our composite shop at work, 2 days no change. Mix instruction on the bottle says 50/50 by weight or volume. I mix by weight, never had an issue with 2 previous lots of RP. I might try a little variation in some test batches to see what happens.

Tom - Try another smear test, but, this time heat up the resin and hardener a bit before you mix them. If the components did freeze during shipping, there could be crystals in the resin that could make it more difficult to mix and, since RP is a paste epoxy, it can be difficult to see the crystals. I would put each of the jars in a water bath at around 100 degrees for about 15 min and mix the components before they cool. Just note that your pot life will be lower if you heat the components.

I heated the resin and hardener in a 100F water bath until the internal temp was 100F (sacrificed a pair of cheap thermometers for the good of all mankind!) , then used some $.29 spoons from the thrift store to thoroughly mix the heated components. Another test mix batch comes out as previous batches, ever-so-slightly sticky even up to 5 days later, but sands just fine.

I will also note that after posting my batch numbers, 4 other folks have PM'd me that they have the same batch and the same issues, but that they've successfully built rockets that are doing fine. So, maybe a funky batch?

 

[David Schwantz]

Is the stickyness gone after sanding?

 

[Banzai88]

Is the stickyness gone after sanding?

Yes. Even just a few passes with 320 and it's gone. Does not make 'dough balls' nor does it gum up the sandpaper.

 

[KenECoyote]

Related (and I hope the OP doesn't mind me asking), but has anyone had some solidifying or "crusting" of their Rocketpoxy resin?

Mine had some after being unused for a bunch of years when I was on extended break from rocketry (bought around 2015 with batch number 151014).

It still worked great, but recently I knocked some of the solids in and now it can show up as lumps in my mix, so I was wondering if anyone has tried microwaving the resin to re-liquefy it (I've done this with regular epoxy several times).

 

[Banzai88]

Related (and I hope the OP doesn't mind me asking), but has anyone had some solidifying or "crusting" of their Rocketpoxy resin?
View attachment 558968
Mine had some after being unused for a bunch of years when I was on extended break from rocketry (bought around 2015 with batch number 151014).

It still worked great, but recently I knocked some of the solids in and now it can show up as lumps in my mix, so I was wondering if anyone has tried microwaving the resin to re-liquefy it (I've done this with regular epoxy several times).

My old batch has done this a time or two. Heating it in a water bath and stirring it up made most of it go away. I buy super stout table spoons from the local thrift store.