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MMD

Hot glue gun advice

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MMD

Thinking of getting one for mainly for servo/wing attachments and  perhaps other modelling jobs/fixes.

Will this do the trick?

https://www.argos.co.uk/product/7004937 

Thanks 

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pete beadle

Hi Slap

I was working with Henkel Chemicals/Supergloy  when the first hot melt guns came on the market in the UK.......there, that shows my age, doesn't it?

We, Henkel, got a LOT of complaints early on, from people who didn't understand the basics of which adhesives were best for what jobs, and complained of failures of the bond, and other perceived faults because they hadn't read the "instructions for use":no:

The hot melt gun was originally designed for "tacking" ie temporary fixes, and the flexibility of the hot melt adhesive was described as a fault rather than an advantage because users, initially didn't realise this. For example, hot melt adhesive wasn't designed for its gap-filling properties, although many of the original users complimented it on doing just that!:) Also, hot melt adhesive is not, in itself, particularly strong..... 

Many modelers remember Stabilit Express, another flagship Henkel product, and didn't realise that this was a polyester-based product, and therefore great for repairing the polyester fuselages available at the time.......when epoxy fuselages became the norm, Stabilit rapidly lost favour

So, how does this reply apply to what you were asking? Hot melt is NOT the best product for mounting servos - it flexes in use which affects the precision of your servo linkages and it doesn't have a particularly strong bond, especially on dusty surfaces. If I had to suggest what I thought was the best product for servo mounting, particularly if you weren't using a servo tray, I'd say don't use a hot melt gun, wrap the servo(s) in masking tape or electrical tape, and stick them into the servo well with five-minute epoxy. If it was sticking things like on/off switches to fuselage sides it's great, the proverbial sh*t to a blanket.....(sorry!).......but, temporarily fixing something in place, and using a different adhesive to  to replace it, when fixing something firmly over a long period - magic!

So, read and check the instructions, especially the instructions for use, and what it is actually recommended for bonding, and you won't go far wrong, good luck:thumbsup:

Sticky Pete

BARCS1702

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cirrusRC

I learnt the hard way not to wrap servos in masking tape.   It goes brittle and crinkly.     Best approach I have found is to use heat shrink plastic wrap  on the servos and then  glue in with some IC-2000.#

certainly wouldn't use hot glue sticks.

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Woodstock

I love hot glue, and use it a lot. 

I usually mount servos with hot glue, BUT I then epoxy a strap across the "top" of the servos to tie into the lower skins of the wings.  The strap will be whatever suits, aluminium, steel, ply.  Looks ugly, so does not make for pristine photos taken 20 mm from the servos (al la) certain Continental forums, but is in my mind  100% more secure than mounting servos to the top skins only (with frames etc. as many like to do). Changing of servos has to be a workshop job, but easy enough to grind or cut the straps away with a Dremel.

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Redbird

Lidl are selling a good looking hot glue gun in a case at the moment for £7.99. It has a short period cordless facility too but mains not battery.

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oipigface

Since we are talking about servo installation, here are a couple of photos of a frame that has taken me about a day to program into my CNC router. It’s for my Personal Best Pitbull, which is having all its electronic bits and pieces replaced. I’ve considered upgrading to HV, but this got complicated and in the end I decided to install new  Futaba S3150’s, but only after I had ripped out the original  frames. The design is basically the Baudis original, reinterpreted because I couldn’t source any 5mm ply. This is made of 6mm ply, which has to be routed out so that the 10mm thick servo sits flush to the bottom. The bearing frame (which is a Baudis original) also sits flush to the bottom. I’m pleased with the way that it turned out. It’s the most complicated piece I’ve made with the router, and the remaining three will take less than 10 minutes each to produce. Along the way, I also programmed a frame for the MKS HBL6625.

Servos are removed by undoing the screws that eventually will fit in the holes you can see. Probably could be done on the field if necessary.

54147FB3-8484-4C09-A356-B65F367F7BCC.thumb.jpeg.80ea2df9d35faa4aa9420a85ecf01674.jpeg

44E44D00-FC67-4C8F-8EB7-36A6397AB538.thumb.jpeg.0861b7995da3778b7242a16aab8a2d4a.jpeg

 

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MMD

Thank you all for the advice and suggestions.  Much food for thought. 

I like the tape/heatshrink idea!

12 hours ago, oipigface said:

Since we are talking about servo installation, here are a couple of photos of a frame that has taken me about a day to program into my CNC router. It’s for my Personal Best Pitbull, which is having all its electronic bits and pieces replaced. I’ve considered upgrading to HV, but this got complicated and in the end I decided to install new  Futaba S3150’s, but only after I had ripped out the original  frames. The design is basically the Baudis original, reinterpreted because I couldn’t source any 5mm ply. This is made of 6mm ply, which has to be routed out so that the 10mm thick servo sits flush to the bottom. The bearing frame (which is a Baudis original) also sits flush to the bottom. I’m pleased with the way that it turned out. It’s the most complicated piece I’ve made with the router, and the remaining three will take less than 10 minutes each to produce. Along the way, I also programmed a frame for the MKS HBL6625.

Servos are removed by undoing the screws that eventually will fit in the holes you can see. Probably could be done on the field if necessary.

54147FB3-8484-4C09-A356-B65F367F7BCC.thumb.jpeg.80ea2df9d35faa4aa9420a85ecf01674.jpeg

44E44D00-FC67-4C8F-8EB7-36A6397AB538.thumb.jpeg.0861b7995da3778b7242a16aab8a2d4a.jpeg

 

Great stuff doing all that with a router OPF! Well done.  Will you use rubber grommets between the servo/tray screw fixings for shock/impacts or do you think it is unnecessary? These servo trays would lend them selves well to a laser printer.  

https://www.t9hobbysport.com/rc-gear/servo-frames-and-bearings

 

Tbh, glueing servos into a wing of a flying machine seems like a quick fix when compared to a dedicated servo tray.  But in saying that, perhaps like Pete said, the right glue for the right job and perhaps it is best that servo has a chance to break away on a heavy impact/crash rather than destroy a more secured/fixed setup?  Thinking out aloud. 

 

Cheers

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pete beadle

Hi Slap

I think the most important thing to remember as regards servo fixing is the trade-off between providing a slop-free linkage and having ready access for removal and replacement of the servos involved All too often I see servo installations that are both literally sloppy and without any means of removal that doesn't involve damage to the servo case or to the structure to which the servo is attached

It seems to me that "modern" servo instals are, in the main, a recipe for disaster when the model  is flown by a relative beginner......I once saw a model that had been landed heavily, that had managed to shake loose ALL of its wing servos, simply because there was nowhere for the energy produced on landing to go except through the linkages and ultimately through the servo's attachment system, that basically saved the servos from damage, but, in doing so, stopped any chance of flying again that day!

For me, servo frames are  the best trade-off when/as they provide both a solid mounting as well as the facility for easy removal:thumbsup:.....trouble is, all too often, this facility isn't recognised in advance, and repair/replacement becomes a very big job that a bit of forethought would, hopefully,  have prevented :yes:

Regards

Pete

BARCS1702 

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oipigface

Well, yes, I can’t think of any good reason why a printed version shouldn’t be possible. I’ve never used grommets in gliders. I believe that their main purpose is to absorb vibration from a motor.

Pete’s point about landing stresses is a good one, but it’s one of those trade-offs that can probably never be fully resolved. The F3F model for which this frame is intended needs to have really slop-free surfaces to perform at its best, and this means that a gear will be stripped from time to time. 

I agree that  it may be worth using a glue that is able to handle normal flight loads, but gives way in a heavy landing, but what glue that is, I don’t know. 

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Woodstock

I still think servo trays fail the primary test of a secure fastening to the wing structure, in that they are affixed to one skin only.  That makes the latent Engineer in me go all OCD 😖 ...

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oipigface

I have been known to fit straps, but this does make them more difficult to get out. It’s another of those trade-offs!

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isoaritfirst

A simple way to secure the servo to the opposite skin is to use either a piece of balsa or blue foam. 

Glue to the servo then fix the servo cover securely in place with this packing piece filling the gap 

UHU por give a firm but removable fix for this piece and the servo cover. 

Straps work equally well if there is room to fit them, but in many f3 models it can be difficult. The Shinto uses a strap constructed of carbon on a balsa backing. The carbon gives it strength and the balsa allows its thickness to be changed to make it a good fit  

gear breakages can be prevented by good linkage design, although this is more difficult these days with models having lds fitted under the skins . But it’s still should be considered. 

I replaced the original lDS in my first Shinto to increase the advantage the servo had. Despite only small differences in horn lengths it made a significant difference. 

 

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Woodstock
14 hours ago, oipigface said:

I have been known to fit straps, but this does make them more difficult to get out. It’s another of those trade-offs!

It does eliminate "at the field" replacements, but back in the workshop they are very easy to remove  with a dremel.

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Darren_O
On 22/05/2019 at 10:07, Redbird said:

Lidl are selling a good looking hot glue gun in a case at the moment for £7.99. It has a short period cordless facility too but mains not battery.

Can confirm these are a great buy

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MMD
6 hours ago, Darren_O said:

Can confirm these are a great buy

Cheers Darren. I can't find them at Lidl online at mo. 

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Darren_O

I've got a couple if you want one?

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MMD

Yes please Darren.

Thank you.

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MMD

Let me know how much and how best to pay you if you please Darren.

Cheers

Marc 

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Darren_O

Email me vocnorthern@gmail.com I'll get it sorted.

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MMD

Email sent, thanks Darren! :)

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