Shimming sensor magnet on window...

[kaosweb]

So we are all moved into the new house; so far things are going well with the DIY install I did during our build.
 
One issue is I forgot to plan for some wider gaps on a few windows.  Sensors are already buried under trim.  I am using Tane pills on all the windows.
 
I ordered some new sensors from Tane for wide gap; of course I cannot do anything with the buried sensor but the magnets on the new sensors work when positioned in the "right place."
 
The issue is the "right place" requires me to shim down magnet about 1/4 inch.  Any recommended techniques for the shim work, keeping in mind this will be on a window that will open.
 
More details... the Windows crank out, the magnet will be on the windows - there space between the window and window trim I will be sticking the magnet.
 
 
 
 
----------
|           |
Window       |           |
|           |
----------
 Magnet                         ---         
Window Trim         ======
 
Magnet stuck to bottom of window - needs to almost touch trim (shim to fill gap above magnet)
 
Thanks...

 

[BraveSirRobbin]

I wonder if getting a stronger magnet would work in this situation in lieu of shimming...

 

[kaosweb]

I wonder if getting a stronger magnet would work in this situation in lieu of shimming...

 
Any recommendations for a magnet?  Place to buy?
 
Any way to compare current magnet strength to a new magnet purchase?
 
Here is what I currently have - http://www.tanealarm.com/products/surface_mount_contacts/sm_20_wg.asp

 

[RAL]

Ideally, you'd like something that will not expand or contract with temperature, and also won't rot.  A thin piece of PVC would be my choice.  You can buy PVC "lumber" in many standard sizes, although I haven't seen it in 1/4".  If you have a table saw or radial arm saw available, it would be a simple matter to cut a larger board down to size.   It sands nicely and can be painted to match the color of your window frames.   Some plexiglass would be an alternate choice.  Lacking either of these, I'd use a small piece of plywood with some paint to protect it from the elements.

 

[kaosweb]

Might give this a try...
 
http://www.amazon.com/Cast-Acrylic-Sheet-Thick-Thickness/dp/B004N1JLI4

 

[signal15]

http://www.gaussboys.com
 
They've got just about any magnet you want, including stuff that is downright dangerous.  I accidentally dropped a couple of their magnets a few years ago, and the cat screamed and ran off.  When I looked, the magnet was stuck to the kitchen table leg with a huge tuft of fur under it.  

 

[BraveSirRobbin]

%5Burl="http://www.kjmagnetics.com/Default.asp"]http://www.kjmagnetics.com/Default.asp[/URL]
 
Same danger warning as Signal15 above.
 
Used some two inch diameter magnets with a mounting stud incorporated into it for mounting large twin Yagi Antennas (for a cell network) on the side of a butler building (could not do any penetrations or tower).
 
Wound up using eight of them on a sheet of aluminum.  Had to use a pry bar to remove the plate once installed!
 
On the plus side, the assembly could withstand 60 plus MPH winds (right at the side of the Yagis).

 

[kaosweb]

Thanks... checking out both sites...
 
Now the $20,000 question is what size magnet should get...
 
The gap is 7/8 from bottom of window to sill - I needed to almost place the Tane magnet on the sill for the contact to close.  Any suggestions...
 
Perhaps a stupid question, but should I be concerned on the shape for the contact to close - the polarity of the magnet and all.  I ask because I have some of the Buckey Balls and tried to get the to close the contact and could not.

 

[kaosweb]

I guess now would be a good time to have a 3D printer...  I could fabricate my own enclosure - letting me buy a smaller magnet - or heck pull the magnets out of the sensors I just got and put them in new enclosures.

 

[kaosweb]

Just some feedback on what I ended up doing... I ended up using other magnets, ones from my garage door sensors that were still laying around to be wired - assuming stronger magent.
 
Then I used sugru - http://sugru.com/ to attached them to windows and was able to shim down a little with a nice install.

 

[Desert_AIP]

I went low tech.
I shimmed my sliders' magnets with a small strip of 1/4" plywood.