Spar braces build tip

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Hat Trick
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Spar braces build tip

Post by Hat Trick »

I've been building a new batch of wings and tried a new method that I liked. Maybe others are doing this already but maybe you'll find this helpful. I've tried lots of methods to try to keep fiberglass spars in place and make the wing tougher. I've drilled holes between the spar slots so glue can fill the hole and bond the spars together but this was messy when building the wings because as you put in the f[^]irst spar glue ran out the other side and went all over. I've tied the rods together with thread or zip ties but this seemed to lead to the foam between the rods getting crushed and this failure was a lot tougher to fix than a popped spar. I even tried little lexan stands between the rods to stop the foam crushing but then the rods broke over the stands. Anyway what I did this time is to install one rod and then use a small screwdriver to punch a hole through the foam up to the installed spar. This was easy to do and made no added mess! I'm not sure it makes a huge difference but it might prevent some failures and takes little time and no $!

One other tidbit is that there have been numerous reports of dogs or cats ingesting polyurethane glues. Evidently it tastes good! Not recommended though as when the glue hits the acidic and wet stomach it foams tremendously! I saw a pictured of a huge glob removed from a dogs stomach that made a perfect cast of his entire stomach and upper intestines! Keep the glue away from your pets!
Fred420
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Post by Fred420 »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">One other tidbit is that there have been numerous reports of dogs or cats ingesting polyurethane glues. Evidently it tastes good! Not recommended though as when the glue hits the acidic and wet stomach it foams tremendously! I saw a pictured of a huge glob removed from a dogs stomach that made a perfect cast of his entire stomach and upper intestines! Keep the glue away from your pets!<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
I swear that is the same glue Roy stuffed Trigger with!!
mark s
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Post by mark s »

I just tried this Gorilla Glue tip and works real well!

New twist on using Gorilla Glue

PU/Gorilla Glue will setup in less than hour the way I was taught to use it. I premix GG and water in a small Dixie cup. you don’t need an exact ratio, it will only accept so much water and the rest you can just pour off the top. You also don’t need that much glue, a little will foam a lot. Stir it up well with a tooth pick, popsicle stick, etc and it will start foaming in minutes. Then spread the foaming mixture onto what ever it is you want glued and mate the parts together. I use painters tape to hold the parts together until the foaming stops. Just wipe off any squeeze out as it sets up. Normally within a half hour its setup enough to remove the tape and get rid of what squeeze out. After its setup you can cut or sand off any excess. The key is water. Without water, it will take a long time to cure. They say in the instructions to dampen one side before mating together. squeeze out. You really need a lot less glue than you think. I love the glue and use it on many things from EPP to wood. Its really great for filling in larger cracks from damage since it foams. Its fairly lightweight and very strong bonding.

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boiler
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Post by boiler »

I keep a spray bottle filled with water next to my PU glue. I spritz the spar grove and lay a very small bead of glue down. I then run the spar through a we paper towel and insert it. It cures in about an hour and any foam that has bypassed my tape is easily trimmed off with either a hack saw blade or the Great Planes motorized plane. I prefer the hack saw blade. Oh, by the way Mike, thanks for the tip about the dogs. I let my wife's three dogs sleep with her but they are not allowed in my workshop, that is reserved for combat pilots.
Captain America
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Post by Captain America »

Could probably do the same thing with a small drill bit in hand to make sure you get a clean hole to the opposite spar and a good contact patch. the screw driver seems like it would not leave a nice spot on the opposing spar. How often are you doing this, 6"?
Hat Trick
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Post by Hat Trick »

I did it every 2 or 3 inches. I rotated the screwdriver once it was in contact with the rod to get a good opening. You'll poke a few holes through until you get the hang of it! The screwdriver I used had a head just a little wider than the slot. Orient the blade parallel to the slot until about half way through the wing. Rotate 90 degrees so you are most likely to hit the rod on the other side. Then twist a rotation or 2.
Captain America
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Post by Captain America »

Ill give it a try, ive got a pile of wings to get started on tonight...
drewjet
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Post by drewjet »

Just bringing this back up. Any new ideas to try. I had 4 spar failures at my last contest.

Mike has the Y cut for spars shown to be any help? Could it be done somehow without a CNC?
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lightning
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Post by lightning »

Speaking of Gorilla glue, has anyone else run into the situation where it does not completely harden, stays rubbery and is very hard to sand back?
Elmers PU on the other hand sets up totally hard and is easily cut & sanded.
BTW, have you noticed the 16oz bottles of Elmers have disappeared, (at least from Home Depot) to be replaced with redesigned 8oz bottles at almost the same price?
Here http://theconsumerlink.com/product_deta ... vStart=0&.is the Elmers site where 8oz is $11.99!!
I have several of the original 16oz bottles - does anyone know if the stuff goes off? Seal is not broken. Should I freeze them if I don't plan to use 'em up in the next few months?

(Edited for typos)
Alex Treneff
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Post by Alex Treneff »

And walmart has raised their price on the 4oz. bottle to $5.00. This was a while back, but it used to be around $4.00.
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o1moregil
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Post by o1moregil »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by lightning</i>
<br />Speaking of Gorilla glue, has anyone else run into the situation where it does not completely harden, stays rubbery and is very hard to sand back?


<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

it has happend to me a cupple times, ill take for ever too cure, but it was because i wasn't misting it with water, now i alway mist and haven't had that problem
OzMo
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Post by OzMo »

I needed a light filler on a 1/2A plane so i did the water trick and added some micro ballons.
VERY light and strong. sanded quite easily as well.
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