Quantcast

90 second epoxy??

The Rocketry Forum

Help Support The Rocketry Forum:

Vance in AK

Well-Known Member
Joined
Jan 6, 2003
Messages
188
Reaction score
0
I tried this stuff for the first time this evening. Used it to put the fins on my Estes Polaris. I think I'm in love. I mixed up a seperate very small batch for each set of two fins(one forward & one main fin). Worked great. Had plenty of time to get both fins set, & it was tacky enough that they held in place well. Probably 15 minutes total & all 6 fins were in place without me pushing any of them out of alignment. Now I'll use yellow glue for the fillets.
I know probably everone but me has used this 90 second stuff, anybody have any negative aspects I haven't seen yet?
 

rbeckey

Well-Known Member
Joined
Jul 19, 2012
Messages
1,517
Reaction score
1
Try some epoxy gel for the fillets. It sets in 4 or 5 minutes and is easy to smooth with a gloved finger dipped in alcohol. Also wipe off unwanted excess with a paper towel dipped in alcohol. Unlike other epoxies, it doesn't get brittle when set. It stays slightly flexible. Makes it hard to sand.
I had a 2.6 inch V2 shock cord fail and it fall from apogee on it's side. The fins were made from 1/8 inch lite ply with gel epoxy fillets and there was no damage or cracked fillets.
 

OccamMD

Well-Known Member
Joined
Jan 20, 2004
Messages
243
Reaction score
0
Is epoxy gel a mixed component? What type of gloves, Latex? This is just the question I had this morning, how to make good fillets. Does the epoxy gel have good strength?

Thanks so much,
Ray
 

rbeckey

Well-Known Member
Joined
Jul 19, 2012
Messages
1,517
Reaction score
1
Epoxy gel comes in a double syringe and is mixed after it is dispensed. I use latex gloves when handling any epoxy. A serious alergic conditon can develop after repeated exposure unless protective measures are taken.
As far as strength, opinion varies. I have had no problems with any model or midpower rocket I have used, and after learning a few techniques and getting a little practice, I am more than satisfied with my results.
Within two posts of this one there is a fifty/fifty chance that other member(s) will chime in with the opinion that anyone who uses anything other than white glue (or maybe yellow glue if they are feeling really radical that day) needs his oil checked and is plain wrong and is wasting his money. The word "heretic" isn't used, but it is implied. Try both and form your own opinion. Both methods have their advantages, and I have used both on different projects. I don't like the wait invloved with layer after layer of white/yellow glues. Other people apparently don't mind/enjoy that aspect of it. Whatever floats your boat.
 

OccamMD

Well-Known Member
Joined
Jan 20, 2004
Messages
243
Reaction score
0
Thanks on the advice about the allergy, I haven't used any protection to date, b ut will now. The LOC kit I just built insists you use epoxy due to the motor types being used.
 

Vance in AK

Well-Known Member
Joined
Jan 6, 2003
Messages
188
Reaction score
0
Doxiedog, it was "Super Glue" brand, & came from Home Depot. It was with all the other glues in the paint dept. Also picked up their 5 min. epoxy to try on motor mounts & the like if the need arises.
I'm pretty much a yellow glue kind of guy as I only play with stuff up to E or maybe single use F power, although I'm not quite as radical as the guys Kermie was talking about or I never would have tried the epoxy. To be honest with you the only reason I tried it is that the heater in my garage is having a hard time keeping up right now, & the last time I used yellow glue in marginal temps I had problems. But, I think I might stick with this stuff. Probably still be the yellow stuff for fillets though, as I can do those in the house with no fumes.
I haven't seen the epoxy gell yet but might give it a try if I find it.
Man I got a lot to learn!
 

flying_silverad

Well-Known Member
Joined
Jul 23, 2002
Messages
3,141
Reaction score
1
Originally posted by rbeckey
Epoxy gel comes in a double syringe and is mixed after it is dispensed. I use latex gloves when handling any epoxy. A serious alergic conditon can develop after repeated exposure unless protective measures are taken.
This can't be said enough. EVERYONE will at some point and time, after repeated exposure, become alergic to epoxy. The sooner you start wearing gloves the better. When I was a kid, I used to go to model airplane events and the man that took me was REAL alergic! I watched his hands turn almost beet read after a meet. It was not pretty!
 

powderburner

Well-Known Member
Joined
Jan 18, 2009
Messages
7,356
Reaction score
4
Originally posted by rbeckey
Within two posts of this one there is a fifty/fifty chance that other member(s) will chime in with the opinion that anyone who uses anything other than white glue (or maybe yellow glue if they are feeling really radical that day) needs his oil checked and is plain wrong and is wasting his money.
If I, in any past postings, ever implied that I thought epoxy users were frivolous, had sub-standard intelligence, or were somehow sub-human, I apologize profusely and completely. Heck, I use the stuff too.

Epoxy is GREAT for many purposes. And if you are set up with a bucket-o-westsystems glue, why not use it? Thin epoxy is excellent stuff for soaking into balsa, and the insides of BT. Thick epoxy and gell-poxy is excellent stuff for fillets, and it never leaves holes along the fillet as it 'dries' like white glue does.

Having said all that, I would humbly point out that white glue is perfectly good for 90+ percent of low-power rocket assembly needs. And as I have pointed out many times, if you buy it during the back-to-skuul sales, it is dirt cheap. I just don't want any newbies reading about epoxy and thinking they can't be a man unless they too use epoxy for everything.

These adhesives all have their places, and they are worth having on hand so you are ready when you need 'em.
 

Vance in AK

Well-Known Member
Joined
Jan 6, 2003
Messages
188
Reaction score
0
Yeah, what powderburner said except I use yellow instead of white because everyone knows it's better;) Just Kidding!!!!:D I'm betting powderburner has a WHOLE LOT more builds under his belt than I do. Most here do.
Actually I do use yellow because it seems to get tacky quicker, but I'm sure white works just as well. I do have to admit those 90 second epoxy fins came out stout & quick though.
 

rbeckey

Well-Known Member
Joined
Jul 19, 2012
Messages
1,517
Reaction score
1
I guess my point is for a newbie just to keep an open mind, and be willing to try different things. As I said, I use many different adhesives in many different ways. My rockets look presentable and hang together as good as any and better than some. When I am building with my kids, I try to stick to yellow glue. (Wow. That was a terrible pun.) I let them use other types of adhesives only in a very limited way. I prefer CA, epoxy and polyurethane for my own use, but still occasionally use yellow glue.
On rare occasion in this forum I have had information and opinions presented to me in ways that would seem intimidating to a less experienced builder. The point is that it is silly to insist that there is only ONE way to stick parts together in a more or less permanent fashion. I do not labor under the delusion that my way is the only way or even the necessarily the absolute best way. It does, however, work for me, and quite well, I might add. To discount any technique or point of view right out of the gate would usually be a mistake. Some people will try all and settle with one exclusively, others will use what suits them at the moment.

Powder: I did not put this here for you specifically.
 

Vance in AK

Well-Known Member
Joined
Jan 6, 2003
Messages
188
Reaction score
0
Bob, I agree with you completely & was just kidding around, so if anything I said came out otherwise I'm sorry.
Along the lines of what you are talking about, I've heard people speak of the shrinkage yellow glue causes as it dries. On my Super Big Bertha, I used yellow glue on the centering rings & I can feel a contracted ring in the body tube where each centering ring is located. It is contracted not swelled. I have to assume this is from the yellow glue shrinking. If so, could this have been avoided with the use of epoxy?
 

rbeckey

Well-Known Member
Joined
Jul 19, 2012
Messages
1,517
Reaction score
1
Try polyurethane glue. I would assemble the MMT with whatever, usually epoxy, but yellow glue is good for that as shrinkage isn't an issue. Dampen a paper towel and wipe it on the inside of the tube and on the assembled and set MMT parts. smear the poly in the tube just before the forward resting position of the MMT and slide it in part way, then smear a little more just before where the rear of the MMT will rest. Slide it the rest of the way in to the final position and lay on its side. The mount will move around if it is disturbed, so let it sit quiet for several hours. This stuff is tough and waterproof and the materials will fail long before it does. It does have minor foaming, which can be cut or sanded away when curing is complete if it is obtrusive. Usually it is not.
Of course, fifteen minute epoxy would be good also, and more than strong enough for most rockets.
One thing about white and yellow glues is that they can theoretically soften in high humidity or if they get directly wet (i.e. rain). This is not a problem with poly and epoxy. There is a yellow glue that is outdoor rated and I that is what I use when I use that kind of adhesive.
 

powderburner

Well-Known Member
Joined
Jan 18, 2009
Messages
7,356
Reaction score
4
Originally posted by rbeckey
On rare occasion in this forum I have had information and opinions presented to me in ways that would seem intimidating to a less experienced builder. The point is that it is silly to insist that there is only ONE way to stick parts together in a more or less permanent fashion. I do not labor under the delusion that my way is the only way or even the necessarily the absolute best way. It does, however, work for me, and quite well, I might add. To discount any technique or point of view right out of the gate would usually be a mistake. Some people will try all and settle with one exclusively, others will use what suits them at the moment.
Powder: I did not put this here for you specifically.
Wow, rbeckey, did you really think I got mad or something? I'll have to tone down my sarcasm in the future.

Some of you guys have hit 'dead center' some of the weaknesses of water-based glues. Yes they can indeed cause local shrinkage as they dry, especially if you put them on in a heavy layer. So I don't. In fact, I usually water down my glue for just about every application, and use only a thin layer at a time.

I have never had these glues re-absorb enough water, even in a humid environment, to come anywhere close to getting loose again. I think you would have to literally submerge the assembly for a few days before the glue would get soft enough to be dangerous, and by then your cardboard BT and balsa NC will be ruined anyway. It may be theoretically possible, but I don't ever worry about it.

I don't like to use water-based glues to fill or cover balsa grain, because it takes too long to dry, it gets too messy for me, and because if you go through all that pain-and-agony, the coated balsa part does not take spray paint very well. I have had finishes craze and peel when put directly on white glue. You have to use a primer coat, and that means you have to lightly sand the exposed glue so the primer can get a grip.

One of the quirks of using water-based glues is that when you try to apply a thick fillet (like along fin roots) you will almost always get uneven drying, and probably some holes where the glue shrinks as it dries. If you put on a thick fillet, it usually dries with a raised ridge along the edges of where you place the glue (the edges dry first, and harden in place). Again, I only put on a light layer, and only do this a few times per fillet. If I want big, fat, swoopy fillets, I don't use white glue.

White glues (and for that matter, yellow glues, and epoxies, and all the rest) are heck to sand. You gotta be pretty careful to get it only where you want it, and to wipe up/off the rest, and to get it smooth before it starts drying. If you think you are going to fix it after it dries, you are mistaken. You will end up sanding away everything AROUND the dried glue before the glue itself begins to give way to your sandpaper.

One of the outstanding places I have found to use water-based glues is to water them down and lightly paint the insides of BT before assembly. This helps reinforce the BT slightly, but I do this mostly for other reasons: After the cardboard has absorbed the glue and dried, it is much more resistant to peeling at the edges, it is more resistant to charring from hot ejection gasses, and it assembles better. By this I mean, when you have to add a motor mount, you assemble the mount with centering rings and can easily 'dry' fit the mount into place (no hurry, there's no wet glue in the middle of things to worry about). Afterward, when you add a light bead of glue around the outer edges of the CR, it quickly grabs to the insides of the BT and makes a solid attachment. (Kind of like 'pre-glueing' the balsa fin roots) But you have to be careful to get the BT well dried out, or else you can have the NC start sticking in the front end (not good).

White glue is good for a lot of things------and it's not good for a lot of things.
 

doxiedog315

Well-Known Member
Joined
Dec 4, 2003
Messages
121
Reaction score
0
Thanks vance,and you guys are giving me a good course on glues. I'm about like vance,low to small mid power.I sure know about slow drying glue,i'm staying in a trailer,on the river(ten feet out the back) in the fog! 30* this morning with freezing rain! Ah sunny California:)
 

powderburner

Well-Known Member
Joined
Jan 18, 2009
Messages
7,356
Reaction score
4
Well, at least you have good fishing close by for most of the year, right?
 

BlueNinja

Well-Known Member
Joined
Jan 18, 2009
Messages
2,690
Reaction score
1
I'll have to say I prefer water based glues over anyting else because of my bad day with CA, and epoxy is a little too tacky when mixed.
 

limd21

Well-Known Member
Joined
Jan 3, 2004
Messages
207
Reaction score
0
Just used some of this 90-second stuff for some fillets. What a great thing! Mix, apply, and under a minute later, an alcohol dipped finger (gloved) shaped it to a perfectly smooth, beautiful fillet. The whole rocket was done in under 10 minutes.
 
Top