System 3 Epoxy vs. We$t $ystem

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

PT3

Active Member
Joined
Dec 4, 2017
Messages
43
Reaction score
6
My level 1 rocket is a fairly small phenolic tube build in which I used rocketpoxy and had good results. I’ve prepared it to fly on a J230 for my level 2, but the weather didn’t cooperate. In the meantime I built a Darkstar 2.6 dual deploy using a combination of System 3 medium cure and JB Weld High heat (for the external fin filets and mmt). The darkstar (54 mm) will serve as a back up for my level 2 cert if my 38 mm phenolic can’t withstand the J.

Since it’s winter in the Midwest, my question is whether there is good reason for me to scrap the system 3 epoxy for the pricier West System for the level 3 build that I will be starting once I’ve successfully completed my level 2. I’m not trying to jump the gun, but I couldn’t resist madcow’s Black Friday sale and purchased a 4 inch fg Dominator. West seems all the rage, but is it really that much better than properly mixed system 3 for a build that is not simmed to go much past Mach 1?

And no, I’m not jumping the gun. There just isn’t much to do in Oklahoma in January. Just sayin

NAR 107330
Level 1 H143 9/17 Loc Nuke Pro Max “Orange Peel”
Piedmont Amateur Rocketry Club


Sent from my iPhone using Rocketry Forum
 
I used US Composites 635 for most all my rockets including my L3 project. The exception was that prior to getting the info for an epoxy comparison thread I used System 3 T-88 for the fin root to mmt. With what I know now there is not a huge amount of difference in our common epoxies ( not counting BSI epoxies). And IMO Aeropoxy (laminating), West, and US Composites 635 are interchangeable for most common applications. Proline, Rocketpoxy, Aeropoxy's adhesive (not laminating), US Composites 150 adhesive ( with appropriate fillers) are all pretty much interchangeable as well. It really becomes a cost based choice, for me $65 per 1.5 gallon kit of US Comp 635 laminating it a good deal.

Epoxy Comparison Thread https://www.rocketryforum.com/showt...hnical-Data-Sheets&highlight=epoxy+comparison
 
Last edited:
I used System 3 on a hand layup rocket and loved it for how well it wet out cloth and moved air bubbles to the surface (and popped them, leaving a nice finish). Silvertip for the layup and EZ Fillet for the fillets. I've used West before long ago and didn't see any real differences. Last I checked, West had a 4:1 resin:hardener ratio, which isn't as convenient as a 2:1. I'd heartily recommend S3 again. If you use Silvertip for the fillets, you can fill the epoxy with wood flour or milled fibers to get a thick structural filler. Around M1 doesn't require anything exotic.
 
Raka makes a better epoxy than West Systems, and it is less expensive. It also uses a pump system for measurement.

An old school triple beam scale is hard to beat for mixing epoxy. With some epoxies, I would not mix without a scale. The thing I do not like about pumps for epoxy is keeping track of how many pump strokes, I have lost count a few times over the years when mixing larger batches, and, if one of the little ball valves inside sticks, and it blows air for part of the pump stroke, I no longer trust the mix with small batches. I far prefer mixing small batches of epoxy with a scale. Rocketpoxy too. One bad (mixed) batch of epoxy can ruin your whole day.
 
My level 1 rocket is a fairly small phenolic tube build in which I used rocketpoxy and had good results. I’ve prepared it to fly on a J230 for my level 2, but the weather didn’t cooperate. In the meantime I built a Darkstar 2.6 dual deploy using a combination of System 3 medium cure and JB Weld High heat (for the external fin filets and mmt). The darkstar (54 mm) will serve as a back up for my level 2 cert if my 38 mm phenolic can’t withstand the J.

Since it’s winter in the Midwest, my question is whether there is good reason for me to scrap the system 3 epoxy for the pricier West System for the level 3 build that I will be starting once I’ve successfully completed my level 2. I’m not trying to jump the gun, but I couldn’t resist madcow’s Black Friday sale and purchased a 4 inch fg Dominator. West seems all the rage, but is it really that much better than properly mixed system 3 for a build that is not simmed to go much past Mach 1?

And no, I’m not jumping the gun. There just isn’t much to do in Oklahoma in January. Just sayin

NAR 107330
Level 1 H143 9/17 Loc Nuke Pro Max “Orange Peel”
Piedmont Amateur Rocketry Club


Sent from my iPhone using Rocketry Forum

System 3 is more than good enough. I’ve never seen a Level 3 cert flight fail due to bad epoxy. I have seen flights fail due to poor technique, poor preparation, poor planning, and fin flutter. None of those could be blamed on epoxy. Work on those things and your epoxy will do just fine.


Steve Shannon
 
System 3 is more than good enough. I’ve never seen a Level 3 cert flight fail due to bad epoxy. I have seen flights fail due to poor technique, poor preparation, poor planning, and fin flutter. None of those could be blamed on epoxy. Work on those things and your epoxy will do just fine.


Steve Shannon

Thanks I appreciate all the responses.


Sent from my iPhone using Rocketry Forum
 
Centuries ago when I was in school my surface chem prof pointed out that 90+ % of glue joint failures were the result of inadequate preparation, water being the most common culprit. If the surfaces are prepared correctly, almost any epoxy will do nicely. Like rharshberger, I use U.S. Composites laminating epoxy for everything, thickening it with el-cheapo talcum powder (talc, not cornstarch) or wood flour as needed for glue-up. I bought a gallon of epoxy resin, a pint of fast hardener (4:1 mix) and a quart of slow hardener (2:1 mix). For intermediate cure use both in the proper proportion.

I agree with the use of scales for the most part, but you need to use the mass ratio rather than the volume ratio, which means knowing the density of resin and curative.

If you are mixing less than a half-cup of epoxy, IMHO nothing beats these 60 mL syringes for dispensing resin and curative. Good for anywhere from 3-4 mL up. The cap prevents leakage even over the long term, and the plunger uses an o-ring so there's no swelling problem to speak of. Anyone interested in obtaining some of these please pm me.

Best,
Terry
Epoxy dispensers02.jpg
 
Somenting that has not been mentioned, is amine blush, which is a film or chemical reaction that happens to the surface of epoxy that has cured. It must be sanded through/ off before any further epoxy work can be done which involves bonding to previously applied epoxy. Not super difficult, but it will cause problems if it is not paid attention to. West is the worst of these epoxies in terms of Amine blush.


Any problems with the mixing will most likely be noticed by the epoxy not curing well, despite good working temperatures.

Some epoxies are very particular about mix ratios, and small variances will be noticed. Others are not as picky. For consistent results with the epoxies mentioned, which are all sensitive to mix, careful mixing is important.

The first three epoxies mentioned can easily be 'reversed' with a heat gun, meaning that if one wishes to undo a joint, a heat gun can be used (the low setting on mine) taking care to heat the entire mass, and not just the surface. When it reaches 140-150 ish, the joint can be pulled apart. Wood glue, like titebond, is the same.
 
Somenting that has not been mentioned, is amine blush, which is a film or chemical reaction that happens to the surface of epoxy that has cured. It must be sanded through/ off before any further epoxy work can be done which involves bonding to previously applied epoxy. Not super difficult, but it will cause problems if it is not paid attention to. West is the worst of these epoxies in terms of Amine blush

During my 40+ years of using West epoxies, I have encountered blush once. Late in day...50F and 85% humidity. I just washed it off.
Blush is caused by using epoxy in low temp./high humidity environments. [below 60-65F]

It can be remedied by washing with soapy water.

Granted if epoxy reaches full cure, you must sand for future epoxy bond.

Most any epoxy, improperly used, runs the risk of amine blush.
 
I've been using System Three since I started in HPR over 15 years ago. Every rocket I've built (other then a 54mm CF Mongoose) has used S3 with a variety of fillers or other adjuncts. With the right additives it makes a very good adhesive and is excellent for fiberglass layups (it's original purpose) as is. My 30LB level 3 rocket (the one in my avatar) was built entirely with S3 and it has flown on a 6 grain 4" motor. I bought a gallon of resin and a pint of each of the hardeners so I could pick the cure time I needed for a project. Plus you can mix the hardeners to form an intermediate cure rate. For Texas the slow hardener helps when I'm working out in the garage and it's really hot.

Keep in mind that the slow hardener should be used at 75 or above, the medium at 55, and the fast can be used as cold as 35 degrees.

Other than inexpensive 5 minute epoxy really any modern epoxy should work well. But keep in mind that laminating epoxies generally need an additive to make them a decent adhesive.

Good luck,


Tony
 
When we built our upscale Dragonfly we used Aeropoxy. We had a lot of issues with amine blush at first (Oregon winters are all about high humidity and low temperatures). We started using a heat gun to smooth out the joints/fillets. This had the added benefit of eliminating our blush problems. I would gently heat the epoxy a few times during the cure and this seemed to guarantee an amine-free, glassy finish.


Sent from my iPhone using Rocketry Forum
 
John Coker also did a test of different epoxies. Not 100 percent relevant in that your epoxy wasn't included in the test, but it shows how West stacked up against other epoxies.

https://www.jcrocket.com/adhesives.shtml

I think Rich nailed it when he said that for most purposes the epoxy used won't be the determining factor in the success or failure of a flight. Structurally they all hold well unless you're north of Mach 2 for a sustained time.
 
System Three specs:

Tensile Strength, psi 7,500
Flexural Strength, psi 12,500
Compressive Strength, psi at yield 12,000


West System 105 w/206 Hardener

Tensile Strength, psi 7,300
Flexural Strength, psi 11,800
Compressive Strength, psi. 11,500

Data for S3 from their website and the West Systems from Rich's link above.

Back to the OP's point, I'm not sure why he thinks WS is better than S3.


Tony
 
Well since we are in the middle of another episode of Epoxy Wars, a side comment to derail is appropriate. Standard System Three and West System are laminating epoxies. Only Boatgeek mentioned this, likely due to his background with boats. Laminating epoxies are not designed for structural applications (without a significant amount and variety of fillers). In laminating applications you are using a fiberglass or carbon fiber matrix (i.e., a lot of filler). Without the right and appropriate amount of filler the typical outcome is cracking/brittleness under flexural stress. As a backup to the comments above, just check out any aircraft store like Aircraft Spruce. There they clearly designate "aircraft structural glues/adhesives." West System isn't carried and I'm not sure about their structural adhesives, but Aeropoxy ES-6209 and System Three T-88 are designated structural and are designed to survive significant joint stress.

From the Ether...
 
Last edited:
I have always used either milled fibers, or micro balloons to the West/ Raka, depending on the application, for uses other than wetting cloth. Fillers are critical
, yes.


T-88 is a great structural epoxy that is decent in bonding a wider range of materials including some phenolic. It is not much/ any better with heat than West/ Raka/ System 3 standard epoxies. It is fairly viscous, and very particular about mix ration. I use probably 8-10 gallons a year of T-88. It is a mainstay for me for bonding synthetic resin materials to wood, and also for bonding resinous woods to each other. I have done extensive testing to failure with this T-88 and many other epoxies and adhesives. T-88 is an epoxy that I would not even think about mixing without a scale, though having made mistakes on a batch or 2, it does seem to cure eventually, the resulting strength questionable.
 
System Three specs:

Tensile Strength, psi7,500
Flexural Strength, psi12,500
Compressive Strength, psiat yield 12,000


West System 105 w/206 Hardener

Tensile Strength, psi 7,300
Flexural Strength, psi 11,800
Compressive Strength, psi. 11,500

Data for S3 from their website and the West Systems from Rich's link above.

Back to the OP's point, I'm not sure why he thinks WS is better than S3.


Tony

Because I’m new to HPR and most of the build posts I’ve run across list West. I’m a lawyer, not a physicist, so as I start planning a level 3 build I wanted to ensure that I wasn’t making an avoidable mistake. If the consensus answer was that the pricier West was necessary to build a safe and well constructed rocket, I wouldn’t mind spending the extra money. But the feed back I’m getting, which is greatly appreciated btw, is that using System 3 is not a barrier to building a safe and sturdy rocket that is sufficient to ride an m class motor.




Sent from my iPhone using Rocketry Forum
 
I have always used either milled fibers, or micro balloons to the West/ Raka, depending on the application, for uses other than wetting cloth. Fillers are critical
, yes.


T-88 is a great structural epoxy that is decent in bonding a wider range of materials including some phenolic. It is not much/ any better with heat than West/ Raka/ System 3 standard epoxies. It is fairly viscous, and very particular about mix ration. I use probably 8-10 gallons a year of T-88. It is a mainstay for me for bonding synthetic resin materials to wood, and also for bonding resinous woods to each other. I have done extensive testing to failure with this T-88 and many other epoxies and adhesives. T-88 is an epoxy that I would not even think about mixing without a scale, though having made mistakes on a batch or 2, it does seem to cure eventually, the resulting strength questionable.
You don't need to weigh T-88 (1:0.83). It is 1:1 volume--so easy.

From the Ether...
 
I have always used either milled fibers, or micro balloons to the West/ Raka, depending on the application, for uses other than wetting cloth. Fillers are critical
, yes.


T-88 is a great structural epoxy that is decent in bonding a wider range of materials including some phenolic. It is not much/ any better with heat than West/ Raka/ System 3 standard epoxies. It is fairly viscous, and very particular about mix ration. I use probably 8-10 gallons a year of T-88. It is a mainstay for me for bonding synthetic resin materials to wood, and also for bonding resinous woods to each other. I have done extensive testing to failure with this T-88 and many other epoxies and adhesives. T-88 is an epoxy that I would not even think about mixing without a scale, though having made mistakes on a batch or 2, it does seem to cure eventually, the resulting strength questionable.


For small projects T-88 comes in a uTah tube that fits in a standard caulk gun, leave off the auto mix nozzle, dispense into the contaner of your choice in what quantity you need, mix and use. Re-cap the tube and save the rest. A uTah tube dispensescat the proper mix ratio, without having to buy a special dispesing gun, or measuring a viscous epoxy..
 
I use T-88 professionally, like I said, probably 8-10 gallons a year. Have mixed thousands of batches of it. Before I started using a scale with it, frequently I could detect differences in the cure. Mix it with a scale and you will notice a difference. Unless you have a seriously accurate method of mixing by volume, like a pipette. For me, I cannot mix anywhere near as accurately by eye as with a scale, and the 2 parts with different (thick) viscosities make using small containers, or any containers, a PITA. A scale is so simple, why would you not? Maybe with the small 2 chamber containers, yes. For me, a scale. I cannot afford a mistake.




You don't need to weigh T-88 (1:0.83). It is 1:1 volume--so easy.

From the Ether...
 
I used T-88 and Raka on many rockets. IIRC my L3 rocket we built with T-88 and had (RIP) 45 flight on it. T-88 is pretty thick. I made a couple of smaller 54mm rockets with thinned down T-88. They all flew to mach 1.9 several times.

Here is a link to a rocket I made with RAKA
[video=youtube;Oi624glWhmw]https://www.youtube.com/watch?v=Oi624glWhmw[/video]

I wanted to prove you could do extreme flights with boat epoxy (thinned) and hand laid fiberglass

I think this is the build thread..https://www.rocketryforum.com/showthread.php?19534-My-next-project


Tony
 
Last edited:
BTW... where are you using T-88 in rocketry? Just curious.
Everywhere except toward aft end of MMT/booster where I move to JB Weld. My laminating epoxy of choice is US Composites 635/Medium.

From the Ether...
 
Last edited:
Cool! Thanks tfish and Dixon.

Tony, I had seen that video, and some others. I am about to roll my first tube.
 
Everywhere except toward aft end of MMT/booster where I move to JB Weld. My laminating epoxy of choice is US Composites 635/Medium.

From the Ether...
I shouldn't say everywhere. Really it is everywhere internally. On external fillets I typically use RocketPoxy or ProLine 4500 depending on the application since they set up faster.

From the Ether...
 
On Epoxies... I needed an epoxy for aluminum to aluminum. After numerous hours of searching, and then testing the candidates, Cyberbond 'Cybercryl 805' was the winner. Metal was just on the list of what it is made for. It has a short working time, but is very strong. I may have recently checked it's heat resistance, as something tells me that it is just average good there. It is great for sticking aluminum to things. Cyberbond has a ton of specialized epoxies.
 
Well since we are in the middle of another episode of Epoxy Wars, a side comment to derail is appropriate. Standard System Three and West System are laminating epoxies. Only Boatgeek mentioned this,..<snipped>...
Hmmm, not to be pedantic, but if you read my post #10 above, you'll see I clearly state " With the right additives it makes a very good adhesive and is excellent for fiberglass layups (it's original purpose) as is." I use S3 as both an adhesive (with the recommended S3 additives) and for laminating fins and tubes. Without adjuncts no lamenating epoxy makes a good adhesive.


Tony
 
Back
Top