Glue

Glue

Postby illusionist on Mon Aug 29, 2011 10:55 am

Holds everything together.
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Re: Glue

Postby eta150 on Thu Sep 01, 2011 10:01 am

illusionist wrote:Holds everything together.

Especially your fingers :mrgreen:
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Re: Glue

Postby illusionist on Thu Sep 01, 2011 10:16 am

Oh yeah, i've had a lot of experience with that ;)
Every year, when SO season starts, my fingers are always covered with glue...Always.
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Re: Glue

Postby Lily Essence on Wed Sep 28, 2011 10:36 pm

One of the funniest moments of my sci oly life...

One of our members goes up to our coach with a finger touching his nose and says "Mr. L, I have a problem..." XD

But I digress, CA really hurts my hands after a while. And when you accidentally glue yourself it feels like liquid fire for a moment...
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Re: Glue

Postby jander14indoor on Thu Sep 29, 2011 2:43 pm

Sounds like time for my annual lecture on glue.

If you are having problems with glue on your fingers, especially super glue, YOU ARE USING TOO MUCH!

If you must use from a bottle, make sure you use one of those with a VERY thin tip that lets out very small drops.

Better still, use a precision micro super glue applicator. Two pins stuck through a stick that come together to a point. Make a small puddle on some wax paper that's brightly marked somehow to show its your super glue spot. Pick up small parts of a drop with your applicator to apply to joints.

There is no place on a helicopter, bridge, tower, whatever that needs a whole drop at a time. Heck, I can build a helicopter with one large drop of glue total. Weigh a drop sometime, you can't afford much more than that in your whole weight budget!

And check http://www.soinc.org/sites/default/file ... weight.pdf its a paper cobbled from other SCIOLY posts I made on smart glue use for SO (and a lot of other uses). More detail there on a precision micro super glue applicator.

Jeff Anderson
Livonia, MI

PS, I have to admit, glue does generate some funny stories. You can be sure most of my recommendations were either learned or reinforced from my OWN mistakes.
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Re: Glue

Postby Lily Essence on Sat Oct 01, 2011 3:54 pm

jander14indoor wrote:Sounds like time for my annual lecture on glue.

If you are having problems with glue on your fingers, especially super glue, YOU ARE USING TOO MUCH!

If you must use from a bottle, make sure you use one of those with a VERY thin tip that lets out very small drops.

Better still, use a precision micro super glue applicator. Two pins stuck through a stick that come together to a point. Make a small puddle on some wax paper that's brightly marked somehow to show its your super glue spot. Pick up small parts of a drop with your applicator to apply to joints.

There is no place on a helicopter, bridge, tower, whatever that needs a whole drop at a time. Heck, I can build a helicopter with one large drop of glue total. Weigh a drop sometime, you can't afford much more than that in your whole weight budget!

And check http://www.soinc.org/sites/default/file ... weight.pdf its a paper cobbled from other SCIOLY posts I made on smart glue use for SO (and a lot of other uses). More detail there on a precision micro super glue applicator.

Jeff Anderson
Livonia, MI

PS, I have to admit, glue does generate some funny stories. You can be sure most of my recommendations were either learned or reinforced from my OWN mistakes.


Wow, thanks for that treasureload of links and information! And when I glue myself, it happens much like you described in your paper "in some convenient spot on the wax paper where you WON'T accidentally stick your hand (or anything else) and glue yourself to the building board".

When working with glues in general, you say to join side grain to side grain and to keep joints tight. What's the best way to form tight joints before gluing? And I noticed that alot of the joints in my new helis are endgrain to side grain. Is this going to make a difference? I have four joints that are really loose, and they need to be strong and held at an angle, but when I tried gluing them together (it's end grain to side grain), it... well didn't really work. There's a lot of weight pulling at the joints even when the helicopter is resting. What can I do to make it stronger in my next helicopter? (The helicopter I'm describing was like a rough test run of an idea I had for the "chinook" style challenge. I haven't flown it yet because that joint is wobbly. It's currently being held in place with duct tape.)

Thanks a bunch~!
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Re: Glue

Postby jander14indoor on Sun Oct 02, 2011 8:29 am

There's a limit on what you can due to strengthen end grain joints, but in these devices it can be hard to avoid. There are some things you can do.

End grain is bad because it tends to wick more glue away from the joint as the hollow structure of wood is meant to move sap. One thing you can do to help that is to seal the end grain before gluing. Dip the end grain piece just into the glue puddle and then quickly wipe off everything you can with a paper towel or rag. Let dry. Some glue will wick into the pores and seal them, sucking less glue away from the joint when you are ready to join pieces.

Tight joints come from careful cutting with SHARP tools. Sometimes I sand my joints, use fixtures, whatever. Practice. When fitting two pieces, if I don't have a convenient way to jig something, I'll lay the piece to be cut in place and cut along the joint by eye. Willingness to throw away pieces that just don't fit right.

A moment about knives. Dull knives do bad work and are unsafe. Be willing to discard and replace any knife that's not sharp. Its a foolish economy, one trip to urgent care will buy many THOUSANDS of replacement blades. Been there, done that, in front of a class of high school students no less!

A second moment about cutting. Many people don't understand how to cut. Balsa is soft, it will cut if you just push the knife through it or chop it. But it won't cut well. Look closely at the cross section of your cut wood some time. It will have a large indent, and then a torn appearance on the face of the cut if you push it through. Instead, slice or saw at the wood with your sharp knife sliding it along the edge. You'll get much cleaner, flatter cut faces that way and with MUCH less effort. Especially across the grain.

Hope that helps,

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Re: Glue

Postby illusionist on Wed Feb 22, 2012 8:45 pm

For applying the covering to the rotors, is there a significant difference in terms of weight or strength between 3M Super 77 or 3M General Purpose 45 spray adhesives? I remeber reading an article for Wright Stuff that recommended the Super 77, which is quite a bit more expensive.
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Re: Glue

Postby jander14indoor on Wed Feb 22, 2012 11:52 pm

Use whatever is convenient. The idea is to use as little as possible with whatever glue so the covering just holds in flight. Less glue is less weight.

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Re: Glue

Postby eta150 on Thu Feb 23, 2012 4:05 pm

I've only used super 77 and 75 (I think?) in the past, and the nice thing about them is that the cans will last awhile, and the stay tacky for a long time, giving you a lot of wiggle room when covering. You just have to be careful to store and use it, or else the nozzle can get clogged and make the spray almost impossible to use. Also, it's nasty stuff, so you might want to use a mask when using the spray.
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Re: Glue

Postby illusionist on Thu Feb 23, 2012 4:26 pm

I used to use the Super 77 last year and for Wright Stuff, and it does hold a while for readjustment. The 45 isn't too bad either, and I haven't noticed any significant difference in terms of weight or lack of tackiness
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Re: Glue

Postby himlynx on Thu Aug 23, 2012 2:02 pm

jander14indoor wrote:Sounds like time for my annual lecture on glue.

If you are having problems with glue on your fingers, especially super glue, YOU ARE USING TOO MUCH!

If you must use from a bottle, make sure you use one of those with a VERY thin tip that lets out very small drops.

Better still, use a precision micro super glue applicator. Two pins stuck through a stick that come together to a point. Make a small puddle on some wax paper that's brightly marked somehow to show its your super glue spot. Pick up small parts of a drop with your applicator to apply to joints.

There is no place on a helicopter, bridge, tower, whatever that needs a whole drop at a time. Heck, I can build a helicopter with one large drop of glue total. Weigh a drop sometime, you can't afford much more than that in your whole weight budget!

And check http://www.soinc.org/sites/default/file ... weight.pdf its a paper cobbled from other SCIOLY posts I made on smart glue use for SO (and a lot of other uses). More detail there on a precision micro super glue applicator.

Jeff Anderson
Livonia, MI

PS, I have to admit, glue does generate some funny stories. You can be sure most of my recommendations were either learned or reinforced from my OWN mistakes.



Thanks Jeff. That's very useful.

I find that CA dissolves Styrofoam. What is a good glue for Styrofoam ?
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Re: Glue

Postby jander14indoor on Thu Aug 23, 2012 4:54 pm

himlynx wrote:I find that CA dissolves Styrofoam. What is a good glue for Styrofoam ?


Styrofoam safe CA, of course. Seriously, there is such stuff. Also known as odorless CA for those of us who've developed sensitivity to CA. Might be overkill for some projects, but it is fast.

Oh, and what kind of CA are you using? If its dissolving foam that tends to be a sign of a lot of impurities.

A cheaper, but slower alternative is PVA or 'white' and 'yellow' glues like Elmer's or Titebond and Titebond II.

SOME kinds of spray glues can be used with foam. Trick seems to be not to use too much too fast so the solvents can boil off before they attack the foam.

Kind of depends what you are trying to do and how you are using the foam.

I typically use foamboard for jigs.
- If I'm in a hurry I use odorless CA with no problem.
- If I have time, I use Titebond or similar.
- Tacky craft glues from Scotch or Alene's are also PVA glues, a little more expensive, between Elmer's and Titebond in speed.
- If I really want it to hold up, I'll reinforce the joints with a strip of paper across the openings.

The only time I've seen spray glues useful is for attaching paper to the foam surface to reinforce it, or to glue blocks together where a hard glue line might be a problem. That's a pretty specialized circumstance though.

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Re: Glue

Postby retired1 on Thu Aug 23, 2012 7:32 pm

I tried 3M's high strength 90. Too thick! save your money. I like 77. Consider this as spray paint. When you are done, invert the can and spray for 2 seconds. (OUTSIDE)

I really like Titebond III for balsa "butt joints".
It slow to set but extremely strong, so do not use any more than is necessary. I say use half as much as you think you need and normally that will be too much.

For CA glue, I have the builders put a tiny drop of glue on the duller side of aluminum foil. Then coat just the area of the stick that needs to be joined by a light touch and possibly a swirl. Old CA is not any good, so start with tiny drops and throw it away after say 3 minutes. For most, it works out much better than even micro dispensers and costs a lot less.

Being a retired chemist, I did not like blue or purple glue, so mixed them in a nearly empty bottle until I got the consistency that I liked. TLAR method--That Looks About Right.

It must work OK because the MS teams and HS teams blew away the competition at state in towers.

Gorilla glue and I do not get along well.
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Re: Glue

Postby himlynx on Fri Aug 24, 2012 1:02 pm

jander14indoor wrote:
himlynx wrote:I find that CA dissolves Styrofoam. What is a good glue for Styrofoam ?


Styrofoam safe CA, of course. Seriously, there is such stuff. Also known as odorless CA for those of us who've developed sensitivity to CA. Might be overkill for some projects, but it is fast.

Oh, and what kind of CA are you using? If its dissolving foam that tends to be a sign of a lot of impurities.

A cheaper, but slower alternative is PVA or 'white' and 'yellow' glues like Elmer's or Titebond and Titebond II.

SOME kinds of spray glues can be used with foam. Trick seems to be not to use too much too fast so the solvents can boil off before they attack the foam.

Kind of depends what you are trying to do and how you are using the foam.

I typically use foamboard for jigs.
- If I'm in a hurry I use odorless CA with no problem.
- If I have time, I use Titebond or similar.
- Tacky craft glues from Scotch or Alene's are also PVA glues, a little more expensive, between Elmer's and Titebond in speed.
- If I really want it to hold up, I'll reinforce the joints with a strip of paper across the openings.

The only time I've seen spray glues useful is for attaching paper to the foam surface to reinforce it, or to glue blocks together where a hard glue line might be a problem. That's a pretty specialized circumstance though.

Jeff Anderson
Livonia, MI


Thanks, Jeff. Last year I coached only Bottle Rockets among the building events. We used adhesive tape. Just a wee bit of CA was used for sandwiching the fins. Yes, we quickly learnt to use wee amounts of glue. Once a styrofoam nose cone broke when the rocket landed in a parking lot. A wee bit of PVA put the nose cone together again.

The PVA was the ordinary Elmer's craft glue from Walmart. CA was also from the craft section of Walmart.

The 2011 nationals for bottle rockets was held during rain. It played havoc with some of the bottle rockets. PVA dissolves in water and I'm wary of that for outdoor events.

This year, my 2nd grandson also comes into the fray. They intend taking Boomilever, Elastic Launched Glider and Bottle Rockets (NC only). The first two are far more weight critical than Bottle Rockets. Half a gram could make a lot of difference. This year we will have to move up from Walmart to a hobby shop, especially since balsa is involved.
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