Epoxy Amendments

[Mad Rocketeer]

Ah! I could do that too. I have a good kitchen scale which measures grams and has a tare feature, so factoring out the weight of the cups is trivial. The West Systems instructions show how to do it by weight or volume (not that it would be hard to figure out if they didn't).

Hmmm. I have heard great things about Aeropoxy. How does it compare in price? In availability of good amendments? I guess the same additives that work in West Systems would do just as well in the Aeorpoxy.

Has anyone out there used the Aeropoxy high temperature stuff?

 

[Stymye]

I got the system 3 kit. yesterday... the earlier comparison is not correct you get 25 oz(not 15oz) of mixed epoxy..for $20
the different formulations come in a premixed state , there are no additives to blend in ..you just combine the 2 components that give the result you are after.

for example you have the standard- resin /hardener mix

or for fillets you have two components- Fillet resin/Fillet hardener

you get 2 containers of metelweld resin/hardener if you want the jb weld type mix

you also get a gel version of resin/hardener

and finally a quickfair resin/hardener
all the formulations would be right at home as far as rockets go

I also have the West system but for the price this trial kit blows it out of the water... the west system is good to have for glassing ..but if you just do glueing and fillets ..it's hard to beat

 

[Stymye]

With the system 3,since some of the components are premixed they are like a cream and would not work well in a pump

I measure by weight(as most epoxy systems suggest) so I didn't get the pumps for my West system, for my typical purposes the pumps dispence far more than I usually use unless I'm glassing.. so I put the resin/ hardener into squirt bottles for dispensing onto a scale.but thats only my preference.

I just thought I might pass along my impression of the trial kit
for those who want to try an epoxy system without a $40 start up cost (and that does not include any additives)... .. the sticks and cups an squeege are just extras,it also includes a sheet of fiberglass,, looks like enough to do a midpower set of fins.. or a number of fin joints. It also comes with 2 books, a catalog with coupons for more epoxy and "The epoxy book" like jcrocket says ..a great beginner kit !

 

[Mad Rocketeer]

I'm really going to have to get this sampler soon. Sounds good.

I've got the Bob Smith 50:50 mix 30-minute epoxy and 20-minute finishing epoxy in the small squeeze bottles as well as a bottle of microballoons. I had hoped to use the 30-min and balloons to do my LOC Gaduator fillets, but now I'm leery of them coming out as a gooey never-setting mess. I really want this Graduator to come out nice. It's my first larger-than-D rocket, so I don't want to goof it up. Maybe I should just use the 30-min for the fin joints that don't touch the MMT and JB Weld for those that do, making sure to do internal fillets, and just use 30-min for small, strong fillets, using Fill-N-Finish to bring the fillets out to a smooth finish and aerodynamic size/shape. F-N-F might form surface cracks though, and I'd like to use this baby for a L1 attempt.

 

[DumasBro2]

Does the Graduator’s fin extend all the way to the motor tube? Bob Smith 30 epoxy would be fine for all construction of this rocket. External fillets would be unnecessary for strength if the fins were glued to the MMT and the inside of the BT. However if you want external fillets Bob Smith 30 min. would work for that as well. Use some tape to dam the ends of the fin/BT joint and the epoxy will seek it’s own level; just make sure the rocket is laying level. The ends will need to be touched up where the tape dams were and a Dremel with a sanding drum works well for this.

steve

 

[jetra2]

My technique would be about perfect for your uses. It tells you exactly how to do everything, with pictures and such to help you along. You can't screw up that way!

Jason

 

[Stymye]

I have to agree with Steve ... you can just use some 30 min epoxy for everything, internal and external.and have a very strong rocket.and get nice fillets by following Jasons technique

If you want to play around with the different mixes and additives,
by all means get the sampler kit.. once you have your technique
figured out , you can buy just what you need in the quantity you need.

If I were to suggest the most usefull additive for L1 and below rockets, it would be microballoons for sanding and blending

when you get into really high stress applications you might add fibers to the mix. and you probably want to be doing some glassing at that point also. lots of options.

any good quality epoxy will do the job.

 

[Mad Rocketeer]

Steve (DumasBro2): Yes, the Graduator's fins go all the way to the MMT. I understand earlier versions didn't go all the way, but the design was upgraded due to customer feedback.

Steve & Andy (DumasBro2 & stymye): Thanks. Just using the Bob Smith 30-minute for all the joints would be a lot simpler, as long as the heat isn't an issue.

Jason (jetra2): I actually printed out your technique a while back, pictures and all, and let it get covered up with other things. Out of sight - out of mind. Thanks.

I don't have a Dremmel . . . Yet.


Steve (Mad Rocketeer)

 

[DumasBro2]

Steve,
Heat shouldn't be an issue. Also, power tools are your friend. and a Dremmel should be high on the list.

steve

 

[Mad Rocketeer]

Believe me. A Dremmel is at the top of my list. Second is either a small drill press or a small lathe.

Thanks for the advice on heat. Does that go for H motors in this bird too? (I motors? That's probably pushing it, huh?)