AnneRanch
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Using hot glue to mount 3B ?

Wed Nov 28, 2018 10:42 pm

The title says it all.
I am building a test gear "breadboard style".
Since I design as I go (!) I find it unnecessary challenging (!) to keep drilling "daughter boards" mounting holes and messing with tiny screws.
The 3B board has NO components requiring air circulation on the BOTTOM of the board - so can I use hot glue to mount it ? Or just any silicone - cold - caulking? Just small dabs will work.

I do not like supper glue - it lack "cushioning" , and requires flat non porous surface.

Any comments?

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Imperf3kt
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Re: Using hot glue to mount 3B ?

Wed Nov 28, 2018 11:07 pm

Hot glue is fine, however I do suggest you allow it some ventilation as the RAM chip is on the underside and can get very, very hot. As hot as the SOC (measured with inaccurate finger test only - I literally burnt my finger one day)
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davidcoton
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Re: Using hot glue to mount 3B ?

Thu Nov 29, 2018 12:15 am

AnneRanch wrote:
Wed Nov 28, 2018 10:42 pm
The 3B board has NO components requiring air circulation on the BOTTOM of the board -
See @Imperf3kt's reply -- the RAM chip needs air circulation.
AnneRanch wrote:
Wed Nov 28, 2018 10:42 pm
silicone - cold - caulking?
Be aware that silicone compounds release Acetic Acid (the acid in vinegar) as they cure. This could damage the Pi's printed circuit board.
At the end of the day, M2.5 bolts work and are easily undone when I make a mistake :o :shock: :? :roll:
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tweak42
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Re: Using hot glue to mount 3B ?

Thu Nov 29, 2018 1:46 am

AnneRanch wrote:
Wed Nov 28, 2018 10:42 pm
The title says it all.
I am building a test gear "breadboard style".
Since I design as I go (!) I find it unnecessary challenging (!) to keep drilling "daughter boards" mounting holes and messing with tiny screws.
The 3B board has NO components requiring air circulation on the BOTTOM of the board - so can I use hot glue to mount it ? Or just any silicone - cold - caulking? Just small dabs will work.

I do not like supper glue - it lack "cushioning" , and requires flat non porous surface.

Any comments?
Aside from the ram cooling, a handy tip I learned from Youtube is to use poster putty such as Blu Tack to temporary anchor a Pi to a wood board. I do this when doing solder work on small electronic boards. Lining up gpio headers to solder on a Pi Zero is a cinch.

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HermannSW
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Re: Using hot glue to mount 3B ?

Thu Nov 29, 2018 7:25 am

AnneRanch wrote:
Wed Nov 28, 2018 10:42 pm
I do not like supper glue - it lack "cushioning" , and requires flat non porous surface.
I never glued a Pi somewhere, but in general I superglue nearly everything.

I had to be careful in supergluing (Lego or other) wheels directly on motor shaft.
Once I lost a motor due to superglue getting inside.
But in general superglue is super firm and allowed circular robot speeds of >18m/s without issues.

A flat surface is not needed, I was able to superglue big round motor on flat plastic surface.
The trick is to superglue with small amount initially, where the motor and flat surface have contact.
Later add more superglue to both sides, filling the area between flat surface and motor.
That way superglue takes exactly the round shape needed on motor side.
Hot glue is no option for this since motors get hot on high speed.

For the same reason I would not trust hot glue wrt PI, PIs get quiet hot and hot glue will peel away.

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achrn
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Re: Using hot glue to mount 3B ?

Thu Nov 29, 2018 10:14 am

HermannSW wrote:
Thu Nov 29, 2018 7:25 am
A flat surface is not needed, I was able to superglue big round motor on flat plastic surface.
The trick is to superglue with small amount initially, where the motor and flat surface have contact.
Later add more superglue to both sides, filling the area between flat surface and motor.
That way superglue takes exactly the round shape needed on motor side.
If you want to fill big gaps with superglue and don't have gel it's better to use bicarbonate of soda as a packer. Hold your pieces in place (perhaps with dabs of superglue) pack bicarbonate of soda into the gap and then drip low visocsity superglue on the bicarb. Bicarb acts as kicker for cyano glue, so it solidifies basically instantly (and depending on your materials, possibly fast enough to get hot, so watch out for that). It's not as strong as a properly configured cyano joint (I wouldn't rely on it in a configuration that needs a high tensile performance), but it's a handy trick when you want a solid plug with a bit of bond.

However, back to the OP, I use hot-melt to glue down circuit boards, including an opccasional Pi. I find that it's not generally as reliable as a proper bolted install though.

MarkTF
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Re: Using hot glue to mount 3B ?

Thu Nov 29, 2018 6:44 pm

Would Velcro Tape work? That would make it far easier to remove the Pi if necessary.

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Imperf3kt
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Re: Using hot glue to mount 3B ?

Thu Nov 29, 2018 8:20 pm

Velcro would not work as the glue that holds the Velcro tape to the Pi will melt at a much lower temperature than hot glue will.

The temperatures produced at the edges of a Pi will NOT melt hot glue, likely won't even soften it.
Even sticking it directly next to or on the SOC won't melt it as hot glue doesn't melt until around 120 degrees C with some glues not melting until over 200 degrees
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