Glueing servos into foam

[PappaBear]

A lot of servos are glued into place in foam planes. Its quick, easy and simple to do. However it can be a real pain to remove them should they fail for what ever reason.

You may find this little tip a help.

Before you install the new servo, install a short length of heat shrink tube over the case of the servo and shrink it into place. Now when you glue the servo into the wing or where ever, you are actually gluing to the heat shrink and not the servo case. The next time you need to remove the servo, simply cut through the heat shrink and the servo will just come straight out.

Now it will be easier to clean the area where the servo has to fit and also the servo won't be covered in glue.

I hope this helps

Martin.  

[Konrad]

RE: Glueing servos into foam

Any hints as to how to remove the factory installed servos (without destroying the servo or servo pocket)? Also what does the OEM use to glue in these servos?

As you have hinted it is not an end user or customer focused type of installation, it may speed up production but is sure slows down and frustrates the end users (your customers). I see that Freewing is starting to include servo pockets with screws to hold the servo in place (not just the servo cover).

All the best,
Konrad

[Alpha]

RE: Glueing servos into foam

Most manufacturers use a type of rubber cement to mount the servos. You're right, Konrad, from the factory's point of view, quick and secure installation are the primary concerns. Manufacturers like Freewing and some of FMS' newer planes often use screws and plastic plates. This makes swapping servos more convenient, at the cost of increased parts, complexity, weight, installation time, and cost.

For servos which are glued in, I used a butter knife to wiggle under the lip of the servo, then place a wide sheet of thin ply under the butter knife to prevent the knife from digging into the top surface of the foam. Then I gently pry the butter knife upwards, using the ply sheet as a fulcrum, until the servo pops out. Most servos pop out with a few seconds of effort.

From my glider days, when reinstalling a servo, I'll wrap it in blue painter's tape and then either hotglue or epoxy the servo into place. Removing the glued tape is easier if ever the servo needs to be removed yet again.

[PappaBear]

RE: Glueing servos into foam

I do like the tip about the thin ply under the knife to give something to lever against. Thats a great idea and I'll remember it. As long as I've been doing this, I've never thought of that. Such a simple idea thats works.

Martin.

[Konrad]

RE: Glueing servos into foam

Most manufacturers use a type of rubber cement to mount the servos. You're right, Konrad, from the factory's point of view, quick and secure installation are the primary concerns. Manufacturers like Freewing and some of FMS' newer planes often use screws and plastic plates. This makes swapping servos more convenient, at the cost of increased parts, complexity, weight, installation time, and cost.

For servos which are glued in, I used a butter knife to wiggle under the lip of the servo, then place a wide sheet of thin ply under the butter knife to prevent the knife from digging into the top surface of the foam. Then I gently pry the butter knife upwards, using the ply sheet as a fulcrum, until the servo pops out. Most servos pop out with a few seconds of effort.

From my glider days, when reinstalling a servo, I'll wrap it in blue painter's tape and then either hotglue or epoxy the servo into place. Removing the glued tape is easier if ever the servo needs to be removed yet again.

From a durability and a liability perspective I'd like to know what is the glue used at the factory, be it a chemical type, trade name or brand. I ask as I want to be able to say that I repaired the product to a standard that is as well or better than the OEM original condition. I know that the weak contact cement (Rubber cement) is not what is used. I also know that most CA glues are brittle and are prone to fracture as a result of the foam flexing. I also know that epoxy tends to debond from EPO. 

All the best,
Konrad

[StormyDog1962]

RE: Glueing servos into foam

Any silicone based sealant will work as good as or better than glues manufactured overseas. I would highly recommend using Foam-Tac for gluing in the servo.
http://www.motionrc.com/beacon-foam-tac-glue-2oz/ This is an excellent adhesive manufactured by Beacon Adhesives right here in the U.S. This company is the only manufacturer allowed to sell Mil Spec Epoxies to the U.S. Military so they have very high standards. Most Epoxies and glues used in the RC world are manufactured overseas despite some marketing techniques that would make you think otherwise. I would never use CA (again) especially Thin as it is very capillary and can seep into the servo and glue the gear train, trust me I know. Like I said Foam-Tac or Silicone Caulk are probably the best as the servo can still be removed with a bit of effort.

[Konrad]

RE: Glueing servos into foam

Any silicone based sealant will work as good as or better than glues manufactured overseas. I would highly recommend using Foam-Tac for gluing in the servo.
http://www.motionrc.com/beacon-foam-tac-glue-2oz/ This is an excellent adhesive manufactured by Beacon Adhesives right here in the U.S. This company is the only manufacturer allowed to sell Mil Spec Epoxies to the U.S. Military so they have very high standards. Most Epoxies and glues used in the RC world are manufactured overseas despite some marketing techniques that would make you think otherwise. I would never use CA (again) especially Thin as it is very capillary and can seep into the servo and glue the gear train, trust me I know. Like I said Foam-Tac or Silicone Caulk are probably the best as the servo can still be removed with a bit of effort.

Thanks I'll look into it.

Rather than "ANY" silicone based sealant, I assume you are recommending any non-etchant RTV (AKA electrical grade). After all we don't want the corrode any electrical copper traces on the servo PCB or the copper wire in the servo leads. 
 
Beacon as being the "Only manufacture allowed to sell Mil Spec Epoxies to the US military" sound a bit too broad. There are a lot epoxy types and formulations, I suspect there is a modifier missing in that statement. 

[ss0028]

RE: Glueing servos into foam

Any hints as to how to remove the factory installed servos (without destroying the servo or servo pocket)? Also what does the OEM use to glue in these servos?

As you have hinted it is not an end user or customer focused type of installation, it may speed up production but is sure slows down and frustrates the end users (your customers). I see that Freewing is starting to include servo pockets with screws to hold the servo in place (not just the servo cover).

All the best,
Konrad

From what I have discovered when removing servos is that you don't see glue. My guess is that when they mold the planes they have the servos in the mold so when the foam dries the servo is in it.

All the best

[fhhuber]

RE: Glueing servos into foam

Depends on the maker... Dynam, when you pull an aileron servo from their WWII 1200-1500 mm series its gobbed in with glue.

for removal you have to grab it with pliers and twist.... start twisting a littla and go back and forth... twist more and more and pull.

There are a lot of approaches possible for mounting your servos in a foam plane.

If appearance isn't an issue you can poke holes through the wing and strap them in with a zip tie.

Dynam's contact cement that comes in their kits works really well for mounting servos in EPO models. Apply the glue, stick the servo in place to spread it, lift it out for 30 sec to a minute. then stick it in and it will stay.
There is an EPO glue sold at my local hobby shop which is labeled with the shop name... not sure where he gets it, but its essentially the same as the Dynam EPO glue.

You can epoxy them in or use thick CA (thin will seep in where you do not want it)

3M gray foam/double-stick tape (auto trim mounting tape, also sold with other labels) unfortunately peels right off of the EPO. Don't do it. I love the stuff for sticking servos to balsa or styro...

And I'm sure others have even more favorite ideas.

[Konrad]

RE: Glueing servos into foam

From what I have discovered when removing servos is that you don't see glue. My guess is that when they mold the planes they have the servos in the mold so when the foam dries the servo is in it.

All the best

I hope this isn't true!
Most servo cases and plastic gears would distort or actually melt in the molding process of foam. Then there is the stress on the many electrical silicon parts due to the heat.

All the best,
Konrad

[ss0028]

RE: Glueing servos into foam

From what I have discovered when removing servos is that you don't see glue. My guess is that when they mold the planes they have the servos in the mold so when the foam dries the servo is in it.

All the best

I hope this isn't true!
Most servo cases and plastic gears would distort or actually melt in the molding process of foam. Then there is the stress on the many electrical silicon parts due to the heat.

All the best,
Konrad

Every freewing plane I have had to remove second from doesn't look like there is any glue on the foam. I would prefer contact cement to hold them in since it would be a heck of a lot easier to remove. But in China quick, cheap, and fast is all they care about.

[Konrad]

RE: Glueing servos into foam

From what I have discovered when removing servos is that you don't see glue. My guess is that when they mold the planes they have the servos in the mold so when the foam dries the servo is in it.

All the best

I hope this isn't true!
Most servo cases and plastic gears would distort or actually melt in the molding process of foam. Then there is the stress on the many electrical silicon parts due to the heat.

All the best,
Konrad

Every freewing plane I have had to remove second from doesn't look like there is any glue on the foam. I would prefer contact cement to hold them in since it would be a heck of a lot easier to remove. But in China quick, cheap, and fast is all they care about.

I agree that many of the Freewing models are shy on glue. My earlier Me 262, SU-35 had lightly (less glue) glued in servos. The servos were tight in the pockets.  My later F-5 and Mirage all had more glue bonding the servos in the pocket. I like what I'm seeing in that more and more of the offerings are coming with plastic servo bows where the servos are held in with screws. Do use some canopy glue like adhesive to keep the screws from backing out. 

All the best,
Konrad

[ss0028]

RE: Glueing servos into foam

From what I have discovered when removing servos is that you don't see glue. My guess is that when they mold the planes they have the servos in the mold so when the foam dries the servo is in it.

All the best

I hope this isn't true!
Most servo cases and plastic gears would distort or actually melt in the molding process of foam. Then there is the stress on the many electrical silicon parts due to the heat.

All the best,
Konrad

Every freewing plane I have had to remove second from doesn't look like there is any glue on the foam. I would prefer contact cement to hold them in since it would be a heck of a lot easier to remove. But in China quick, cheap, and fast is all they care about.

I agree that many of the Freewing models are shy on glue. My earlier Me 262, SU-35 had lightly (less glue) glued in servos. The servos were tight in the pockets.  My later F-5 and Mirage all had more glue bonding the servos in the pocket. I like what I'm seeing in that more and more of the offerings are coming with plastic servo bows where the servos are held in with screws. Do use some canopy glue like adhesive to keep the screws from backing out. 

All the best,
Konrad

The best thing freewing has done it the screw covers where they don't use glue. I prefer those plane over the ones with glued servos.

Thanks
Sam

[Konrad]

RE: Glueing servos into foam

I may be in error. I see that my SU-35 has screwed on servo cover plates. I'm not about to try to remove a servo to see if it is glued in the servo box.

All the best,
Konrad

[WintrSol]

RE: Glueing servos into foam

The best thing freewing has done it the screw covers where they don't use glue. I prefer those plane over the ones with glued servos.

Thanks
Sam

My Pandora did not have glue to hold the aileron servos, and has those covers. The downside is, the servos can move around in the little box; I use round toothpick ends to  take up the slack, pushed in point first.

[doctormike]

RE: Glueing servos into foam

I glue my servos, receivers and ESC's in with E-6000 contact cement. Foamies and balsa-ply ARF's. Hours of flying time without a single failure. What's nice about E-6000 is that it holds things in place, but, things can be removed, if wanted, with a little prying and little or no damage. Doc

[martmichals]

RE: Glueing servos into foam

I find that using hot glue is a good option, as it peels off fairly easily from the servo case once taken out of the aircraft in which it was glued into. It may ruin the foam around it to a small degree, but it is easy to peel off of the servo once out.

[mr.frankenjet]

RE: Glueing servos into foam

I was a di hard epoxy guy but with epo foam being so flexible the contact cement supplied seems to work the best for most things. Not only as strong as the foam (which is all you need) but steady pulling pressure and or a little twisting gets things apart with little damage. For major more permanent stuff I like the gorilla glue especially if you need to fill gaps as it foams up, don't use too much and wipe away any unwanted expansion before it dries. The small clear tubes hold up the best as it's moisture cure, store tip down.

[KitBuilder]

I wrap mine in painters tape with and hot glue in low to the foam. Placing a piece of dental floss in first - non waxed - allows one to pull it along and slide the tape out cleanly from underneath once the servo is removed.

[PappaBear]

Hi Kit builder,

That is a really great idea putting the dental floss in first, it would make it so much easier to remove should you ever need to.

Martin