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Removing hot glue and dealing

#1
I've been working on building an FT Seaduck. Everything's been good so far. I wasn't able to get my hands on a Power Pack C so I just bought the individual components I needed, however I forgot to get servo extensions. The local hobby store had more than a few of these at a semi-reasonable price so I picked up a pair.

I calibrated my servos. Elevator servo installed without much trouble. So, I went on the aileron servos. The right aileron servo had no problem so I moved onto the left. Glued and fit in all good. Just for kicks I went ahead and re-tested the servo connections with the servo centering tool. The right servo worked great, but the left wouldn't move unless i shook the connection from the center :(

Elevator and aileron servos were all taped by their connections to the extension cable but, I guess the connection on the left side just wasn't tight enough. The big problem though is that the servo is glued to the wing and it's impossible to get to the extensions connector without surgery on the wing or taking out the servo.

I used isopropyl alcohol on the wing. Sadly just going at it with a q-tip was only enough to get the top layer of glue off the servo, I had douse it to get the slot on the win and wiggle the servo free. Once it was free I simply reseated the connection between the servo and the extension cable and everything was testing just fine. So I'll re-connect more firming with tape next time.

I've had a similar ordeal with a servo that wouldn't stay in place on a sport wing for a Tiny Trainer. I fear that the wing may not be able to hold the servo in.

Has anyone gone through this before? I was thinking about just re-enforcing the entire area with tape but I'm wondering if there's something else I should do the strengthen the wing now that I've potentially weakened it with alcohol.

https://1drv.ms/i/s!AsCZkLJ8Wp9HqAhcRQCe6WlHaJv8
 
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Hai-Lee

Old and Bold RC PILOT
Mentor
#2
I build a number of prototypes for research and other purposes and reuse parts over and over from model to model. I developed a method of making the recovery of servos from a plane not a matter of having to destroy the model as I have persons to whom I gift the models when I am finished with them.

I make servo cutouts slightly smaller then the servo and force the servo into the cutout. When seated and tested I either add a line of Hotmelt around the surface of the servo edge or cover with a patch of cloth backed tape. When removing the servo I just cut the cloth tape or peal the line of Hotmelt and then pull the servo out.

My servos do not come unplugged because I either use hotmelt on the connection to lock the connection or use the old cloth tape yet again.

Where the servo to harness connection is to be buried within the wing in use I use an extension lead and ensure that there is a connection outside of the wing which can be unplugged to allow the servo and extension harness to be extracted together.

As for strengthening the wing a coating of tape can work wonders as can sealing and painting. If the spar has been weakened a slit in the wing underside in which a CF strip is glued flush with the surface Just ensure each wing is treated equally or the plane balance and performance might be effected.

Hope that helps!

have fun!
 

varg

Build cheap, crash cheap
#3
A less destructive method for removing hot glued in parts is to heat the glued areas with a hair dryer. I've used it to remove servos and even to remove a glued in tail assembly. You can heat the plastic body of the servo up with it and it will eventually slide out pretty easily, it doesn't seem to cause the foamboard to delaminate either like alcohol will. Tape should be fine to reinforce the area you've put alcohol on, it doesn't weaken the foam, just causes the paper to come off. Alcohol can be used to remove paper easily from a particularly stubborn sheet of foamboard if you ever run into that.
 
#4
One more tip to add that's helped me do cleaner rework, is a hot knife method.

I extend the blade of a snap-knife a few inches and then hold it in front of a hot air gun for several seconds. This gives me a thin, flexible blade that, for several seconds, will be hot enough to slice glue bonds, yet won't transfer enough heat to the foam to do any damage. I then heat the blade for a few seconds and wipe the glue that stuck to the blade off on a rag. By a few repeats of heating, and slicing, and wiping, blade you can clean glue out of a joint and separate parts completely without damage to the foam.

You can also clean off globules or cleanly smooth or scrape away heavy glue smears.
 

Brett_N

Active member
#5
Easiest method is with some cheap-ol' rubbing alcohol and a Q-tip. I have tons of plastic syringes around for different types of glue and keep a couple of those filled with isopropyl also.

Either way, just get some alcohol on the bond line between the foam and the servo, let it sit a minute, and it comes right apart.

Or - the eco friendly option is to just put the plane outside in the sun here in Phoenix in the middle of August! Then it just melts apart.

EDIT - just saw you tried this to no avail - I only use the high proof alcohol....93% or better if I can find it. I think the lower % stuff doesn't work as well (and I also use the high-proof to light the grill...keep a jar of cotton balls soaking in it all the time.)