How to solder a chrystal that does not sit flat(image included)

Thread Starter

Mark Smith 1

Joined Feb 19, 2016
2
I have a PCB board where I place a chrystal onto it by putting the legs through the holes then bending the chrystal so it lies flat. Problem is sometimes the chrystal does not lie flat. Instead it is sticking up a little bit and there is a gap underneath it. I need to solder the chrystal to the PCB board over a gap so the solder reaches the Gold colored plate. I obviously cannot solder and push down the chrystal at the same time. So how do I do it? Here is an image of what I am trying to do > solder.png
 

KL7AJ

Joined Nov 4, 2008
2,225
I have a PCB board where I place a chrystal onto it by putting the legs through the holes then bending the chrystal so it lies flat. Problem is sometimes the chrystal does not lie flat. Instead it is sticking up a little bit and there is a gap underneath it. I need to solder the chrystal to the PCB board over a gap so the solder reaches the Gold colored plate. I obviously cannot solder and push down the chrystal at the same time. So how do I do it? Here is an image of what I am trying to do > View attachment 101112
I would bend the leads into an S shape, close to the body of the crystal. Form them so that there's a bit of downward pressure of the crystal against the PCB when you poke the leads through the holes. The tiny extra lead length shouldn't affect the operation. I'd also solder the body first, before the leads.
 

hp1729

Joined Nov 23, 2015
2,304
I have a PCB board where I place a chrystal onto it by putting the legs through the holes then bending the chrystal so it lies flat. Problem is sometimes the chrystal does not lie flat. Instead it is sticking up a little bit and there is a gap underneath it. I need to solder the chrystal to the PCB board over a gap so the solder reaches the Gold colored plate. I obviously cannot solder and push down the chrystal at the same time. So how do I do it? Here is an image of what I am trying to do > View attachment 101112
Bend a wire around the body and solder it down.
 

SLK001

Joined Nov 29, 2011
1,543
How about simply gluing the crystal down? Or use double sided tape? Applying that much heat to the crystal body does long term damage to the crystal. And if you HAVE to solder it down, you can push it down and solder it at the same time. Just don't remove what is pushing down the crystal until the solder solidifies.
 

ian field

Joined Oct 27, 2012
6,539
How about simply gluing the crystal down? Or use double sided tape? Applying that much heat to the crystal body does long term damage to the crystal. And if you HAVE to solder it down, you can push it down and solder it at the same time. Just don't remove what is pushing down the crystal until the solder solidifies.
The gum on tape could deteriorate and produce a leakage path.

Usually its sufficient to just hold the component down and re-melt the solder joints - just repeat until the part is fully flush.

You can now get Z-axis conductive double sided tape that can be use for such things as attaching flexiprint to all glass LCD modules.

That would work for earthing a crystal can - but I stand by the warning about gum contamination - maybe die cut generous clearance holes for the leads so the gum can't contaminate them.
 

SLK001

Joined Nov 29, 2011
1,543
The gum on tape could deteriorate and produce a leakage path.

Usually its sufficient to just hold the component down and re-melt the solder joints - just repeat until the part is fully flush.

You can now get Z-axis conductive double sided tape that can be use for such things as attaching flexiprint to all glass LCD modules.

That would work for earthing a crystal can - but I stand by the warning about gum contamination - maybe die cut generous clearance holes for the leads so the gum can't contaminate them.
Would depend on the case. I'm assuming an HC-49 type case, but we'll have to wait for a picture to really know.
 

SLK001

Joined Nov 29, 2011
1,543
Too much stress on the leads I would think.
Again, this would depend on the package. Here's what I think the package looks like:

HC_49_ULF_t.jpg
Plenty of lead for stress relieving. Also, this package is fairly easy to solder to - if you have to solder it.
 

jpanhalt

Joined Jan 18, 2008
8,505
Can you reach it with a cloths pin or rubber-band hobby clamp (reach about 2")? That is what I use when I need to hold something down.

John
 

hp1729

Joined Nov 23, 2015
2,304
Again, this would depend on the package. Here's what I think the package looks like:

View attachment 101159
Plenty of lead for stress relieving. Also, this package is fairly easy to solder to - if you have to solder it.
Yep, plenty of lead length to bend it better. The original picture just indicates a single bend, not a stress free "U" (up first then down) that would allow for holding it down while soldering.
 

spinnaker

Joined Oct 29, 2009
7,837
The OP has only one post. Has not bothered to post back with a followup. It is pointless to continue this thread till the OP gives feedback otherwise all other posts are speculation.
 
Last edited:

GopherT

Joined Nov 23, 2012
8,012
The OP has only one post. Has not bothered to post back with a followup. It is pointless to continue this thread will the OP gives feedback otherwise all other posts are speculation.
Good point, I will wait to post the crystal planing and leveling device I designed for him until he returns.
 

Thread Starter

Mark Smith 1

Joined Feb 19, 2016
2
The chrystal cannot have any solder on top of it. Only the side can have solder(the side next to the Gold colored plate). The solder from the Gold plate to the side of the chrystal has to be a joined in a concave shape.
 

SLK001

Joined Nov 29, 2011
1,543
The chrystal cannot have any solder on top of it. Only the side can have solder(the side next to the Gold colored plate). The solder from the Gold plate to the side of the chrystal has to be a joined in a concave shape.
I'm sorry, maybe I'm not getting it. What is a chrystal?

And where is your photo of this new device?
 
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