Glue

[illusionist]

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

[himlynx]

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 ?

[jander14indoor]

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

[retired1]

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.

[himlynx]

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.

[himlynx]

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.

Thanks Retired1. I'm also retired and Sc Oly brings me to 2nd childhood. I worked with balsa more than half a century ago and the world has changed.

[jander14indoor]

PVA has its place, but if for outdoor or wet, you need the weather resistant formulations from hardware stores/big box home centers like titebond II or III.

Note, I'm an indoor flyer where the whole plane might weight less than half a gram and .001 grams can be important, so I don't normally use CA for flying things, it is too heavy. BUT, the SO rules have been written to NOT be that critical (though you'll find they are critical to 0.1 gm or less) and the reduced building time is so valuable until the students are hooked that it is not a significant penalty if you are careful.

Jeff Anderson
Livonia, MI

[retired1]

Last year I started the students out with a thin coat of diluted Ambroid and then a coat of slightly diluted. Put on with a brush. It did not add much weight. It was superbly strong. Time was killing us, so we switched to the mixed CA glue.
It takes a while for new model builders to figure out how much glue is enough and then how much is too much. The first is a weak or failed joint and the second is added weight. For boomilever, I think that 0.2g is going to make a significant difference in positions. Same with glider. Great gliders only weigh 2g.

[himlynx]

PVA has its place, but if for outdoor or wet, you need the weather resistant formulations from hardware stores/big box home centers like titebond II or III.

Note, I'm an indoor flyer where the whole plane might weight less than half a gram and .001 grams can be important, so I don't normally use CA for flying things, it is too heavy. BUT, the SO rules have been written to NOT be that critical (though you'll find they are critical to 0.1 gm or less) and the reduced building time is so valuable until the students are hooked that it is not a significant penalty if you are careful.

Jeff Anderson
Livonia, MI

Wow ! A whole airplane weighing less than half a gram ! What is the wingspan ? What is the material you use ? Balsa ? Carbon fiber ? Do you use a magnifying glass while building ? Any videos on Youtube ?

[himlynx]

Last year I started the students out with a thin coat of diluted Ambroid and then a coat of slightly diluted. Put on with a brush. It did not add much weight. It was superbly strong. Time was killing us, so we switched to the mixed CA glue.
It takes a while for new model builders to figure out how much glue is enough and then how much is too much. The first is a weak or failed joint and the second is added weight. For boomilever, I think that 0.2g is going to make a significant difference in positions. Same with glider. Great gliders only weigh 2g.

With an efficiency of 1000, 0.2 gms makes a difference of 200 gms. Yes, we always have to aim for gold, even if we are finally happy with doing our best.

A 12 inch wingspan glider capable of withstanding the launch force and yet weighing only 2 g is going to be a tough call. Thanks for letting us know what to aim for.