Adhesive

Was at the local ACE hardware store recently and noticed that Elmers has an EXTERIOR yellow glue. I surmise this variation remains waterproof once cured (unlike the interior). Has anybody used this product and how would you evaluate it?

Thanks

Now ya done it! Here we go on the adhesive discussion again!

You're about to get more info than you ever wanted to know from a dozen sources. Let me sum up. A bunch of people will start yelling "EPOXY"!! Others will yell "CA!!" (super glue). Then Sandman will jump in and tell ya that everything you need to know about adhesives begins and ends with Elmer's white glue.

Here's my take:

LPR: You're fine using white or yellow glue. CA is okay to tack things, but you still want to use white or yellow glue (interior or exterior are fine)

Aerotech: Some will tell you to use epoxy on these. I prefer to stick with the CA that they recommend in the instructions.

Other MPR: Depending on the size, white/yellow glue may be okay, but you will want to consider epoxy for F and G powered rockets.

HPR: Definitely epoxy. For most projects, the 5 minute hardware store stuff is fine (if you can work that fast--I have dumb thumbs and almost always use at least 15 min epoxy).

Either way, the exterior yellow glue will work fine, but, unless you plan on recovering from a lake on a regular basis, it's not necessary (even if you do recover from a lake, you're probably going to have more trouble with your cardboard body tubes than with your interior yellow glue).

On the advise of my attorney, I decline to answer any question about this topic.

I figured the post would stir up the fire ants.

Yes, my next question was going to be about epoxy. I see the hardware store varieties make the proporting idiot proof with the dual syringes. But what is the consistancey once mixed? Is it more like yellow glue or thin CA before setting? As I understand it, a finger dipped in alcohol (isopropyl) works well for fillets.

Thanks guys and gals.

I don't recommend buying epoxy in the syringe. I used to use it all the time, but after about three or four uses, if you're not VERY careful, one of the tubes will likely plug up just a little bit thus making it difficult to get equal amounts of epoxy, which is important! I recommend going to a hobby shop and buying the stuff that comes in two 4oz bottles and while you're at it, buy some mixing cups, which will be little clear plastic cups that you can measure the right amount of epoxy every time. What I have noticed is that the epoxy itself is denser than the hardener, so if you put the epoxy (usually the clear one) in the cup first, then the hardener, and hold it up, you can tell what you need to add to make it even. The cups that I have a set of lines on the side...2.5, 5, 7.5, etc, that you can use, so when you get to 2.5, stop, then add the other part until you get to 5, and you're mixture will be almost exactly perfect. I personally prefer, after the two are even, to add one or two more drops of hardener, just in case.

If you've gots lots of money, splurge and buy a set of West Systems epoxy or similar. I'll let someone that knows more about that stuff to talk about it... CARL!!

Usually, the 12-20 minute epoxy is what you'll want to use for most applications, and when you have mixed it, the 12 minute stuff is thicker than yellow glue, but not by much. As the time goes up, the epoxy gets thinner, which is why most people recommend buying 30 minute epoxy for HPR, because it is thin enough and has a long enough setting time that the epoxy will soak into the part for a STRONG bond. Also, for doing fillets, I use 12 minute epoxy, since it is thick enough that it won't run and you block it with a tape dam in the front and back. Does anyone has a pic showing a tape dam?

OH, BTW, I use toothpicks for mixing the epoxy in the small cup, and I don't really follow any set pattern, but usually what I'll do ispick the cup up, turn it a little so it's at a angle, and most of the epoxy is at one side of the cup, and fold the epoxy into itself. I'll do this for about a minute, then I'll return the cup to level and go around the cup in a circle and get all the stuff off the bottom, then put the cup an angle again a fold it over itself some more.

That's basically all I know about epoxy and most of its uses. This was just for standard epoxy. There is Finishing Epoxy, with is thinner and takes a LONG time to set, which allows it to soak into fiberglass real well. DO NOT USE FINISHING EPOXY FOR GENERAL CONSTRUCTION!!!!!!!!!!!! It is too flexible and not strong enough for that use!

Jason

Yeah what Kermie said about Adhesives and glues.

I agree with jetra2, don't buy epoxy in syringe tubes. buy in the 2 bottle kits.

we use yellow glue for most stuff, it really is the right thing for these cardboard & wood rockets. cheap, non toxic, easy clean up, paintable, etc.

CA is great stuff too. when it works it works really well. when it doesn't work it just makes a mess.


don't be afraid of epoxy though. buy a few packs of 5 minute and 15 minute and do some experimenting and see what you like better. it's not that hard to mix, most brands are pretty forgiving. with a little practice you will be filleting with the best!!


get a box of latex gloves from the pharmacy - epoxy allergy is serious and there's no use courting it.

and, while you can clean up with acetone, save your money and your lungs and liver, and use white vinegar instead!

I use WEST epoxy because that's what I am used to. I know how the hardeners work in our local weather conditions.

sometimes I use CA to tack a piece together, then come at it with the epoxy.

Originally posted by jetra2
I don't recommend buying epoxy in the syringe. I used to use it all the time, but after about three or four uses, if you're not VERY careful, one of the tubes will likely plug up just a little bit thus making it difficult to get equal amounts of epoxy, which is important!

Click to expand...

Yeah, that's definitely a potential problem, but I really have not had much difficulty keeping the tips of those things clean. And I find it pretty darn handy to dispense the two parts together and just mix with a toothpick on a piece of paper or notecard, works great for small jobs. It's just so handy! (did I say that already?)
If you do run into a clogged tip, you can clean it out easily by letting the dispenser sit tips-up (so the liquid drains away from the tips) and reaming out the offending orifice with a round toothpick.

When I am through using gap filling CA, and before I put the cap back on, I rap the bottom on the table. This drives the glue in the spout back into the bottle. Then, I squeeze the bottle to make sure the tip is clear. Put the cap on and there is no problem with the cap glueing itself on the bottle. Gosh, this sounds like a hint from Heloise. But, it works.

I use the syringe epoxy a LOT. What I do, that seems to work, and keep it from clogging, is after dispensing, pull it back up a tad, carefully wipe any excess off of the outside, and store upside down. I've had great results with this stuff. I do still use hobby store stuff from time to time. Mostly when I attach shock cord anchors. Exterior wood glue is probably pretty good, although, as pointed out, would be just as good as interior.

I still think the very best stuff overall is cheapo white "school" glue. Sticks to just about everything I use for low- or mid-power, it is water soluble (so you can adjust the glue for different uses), dries tough and not brittle. Only bad thing I can think of to say is it doesn't sand worth a darn. Stock up during the back-to-school sales and this stuff can be found for 5 or 6 three-ounce bottles for a buck.

As far as LPR/ModRocs are concerned; definatly Yellow Glue is the way forward. Its not that easy to get it, in the UK, but my local hobby shop does Deluxe Material's Aliphatic Resin, and this stuff is wicked! Theres nothing wrong with white glue; but yellow is just that little bit better, overall.

As for epoxy - always keep some handy, its very useful in certain situations. I don't bother with any of the expensive stuff, the £1.29 stuff from my local cheap shop does the trick. For small amounts, don't waste your money on mixing cups, do what I do.

Post 500! - 1/2 way to that celebrated 'KiloPost'

I have to say I've never had a problem with the syringe type plugging. I do the same as some others mentioned, & just pull the syringe back while holding the tip up before I put it away. Fo mixing cups, I just use the protective plastic tops off of single serving yogurt containers.
They are going to get thrown away antway, might as well give them one more good use first.
That said, I use yellow interior glue for most stuff including filets, 5-15 min. epoxy on some stuff, CA to tack fins, and am going to try Apogee's epoxy clay for the filets on my current projecy, a Super Bib Bertha.
Vance in AK.

I have been eyeballing the epoxy putty too. Does this stuff sand well?

Some does and some doesn't. I have used Loctite brand as well as SuperFil from Sahdow. The Loctite is hard to use and sand. The SuperFil is fantastic. If you search the forums, there was another thread where others shared their experiences.

For white/wood glue, I use a glue called Weldbond. It looks, smells, has the consistency of, and tastes like white school glue. But it has the strength of wood glue. It tacks up pretty quick, for attaching fins, ect. It's available in my area at True Value hardware stores.

When I built my first mid power kit a few years ago, a LOC Graduator (older version, fins through the wall, not to the mmt), I used Weldbond on it. I went back over the outer fillets with epoxy. If it weren't for the Weldbond, the fins would have come off many times. The Epoxy has cracked on practically every flight, but the Weldbond is holding strong. Even on the shock cord mount.

I agree with all that has been said... white/yellow glue on smaller projects (through E you should be fine, maybe low-thrust Fs)... when you get to things like F50s and G+ motors, I recommend epoxy (I should try building an all-cardboard and wood rocket with wood glue and see if it holds up to a J285... would be interesting). As far as the epoxy syringes go, I always have issues with them clogging or getting air bubbles so they don't measure equally or... etc. I've just found the 5-minute squeeze bottle stuff to be the easiest. For fillets, you can't go wrong with West System or Aeropoxy. I personally prefer Aeropoxy, it's cheaper than West and has a higher Tg temperature. You can also use Aeropoxy with a curing oven, keeping it between 150-180 degrees will cure it in 1.5 hours. For fillets, I use Aeropoxy with milled Kevlar added, and a little fumed silica if the consistency is too thin. Add a little masking tape along the fin roots at equal distances from the root intersection on the fin and the BT for nice, neat lines. Then slop stuff in the gap until it's full. Drag a tongue depressor or a plastic spoon (nice cause they catch all the excess overflow) over the fillet to smooth it out, rip off the tape, and you're done. With thick enough epoxy, you can do all your fillets at the same time. Pop it in the curing oven and it'll be done in 1.5 hours, and you'll have a superior bond to the BT. Ask rocwizard, when I crashed my minimum diameter M rocket, the fins were still solidly attached even though the motor casing heat had managed to bubble the paint on the fin can.

So yeah, epoxy is great for HPR birds!

Question
Is it worth it to use 5 min epoxy when you can get 15 or 30 min for the same price ?.From what I gather ,yellow glue is stronger than 5 min epoxy,because it has much more time to absorb into the paper/wood?

I have a tip on the CYA clogging problem

never actually touch the CYA bottle nozzle to the object you are glueing.. what happens is it will eventually contaminate the excess glue on the very tip of the bottle and causes it to harden and hence,, dry and clog..


I discovered this in the NAR member book (I think)...and it's true

daveyfire, I like your tip on making fillets!! I am going to try that tomorrow.


I disagree with daveyfire about the threshold for epoxy.

we used yellow glue on the Mighty Crayon V rocket (Ralphco Crayon) and it's flown a dozen times on 29mm motors with no trouble, nothing is loose. mostly it has flown on G40s but also a couple H97 flights (my level 1 - yeah!) and some F40s. it's retired for emotional reasons but looking at it right now I see no reason it couldn't fly another dozen.

we used yellow glue on all our other rockets, even those that take E, F, & G motors.

Originally posted by astrowolf67
. . . tastes like white school glue . . .

Click to expand...

Do you use much salt and pepper, or do you use other seasonings? Do you serve that with some greens?
(Sorry, couldn't resist)