Mechanical protection for target question

[3v0]

I burned a few days making small target boards that plug into a solderless breadboard. There is a not so great photo attached. To remove them from the BB you need to pry/lift on the underside as you would a large chip.

The plan is to coat the PCBs top and bottom with Krylon's clear conformal coating but that will not be enough. It needs to be protect from the prying.

• Coat the bottom with epoxy
• Etch and drill a protective board the slides over the pins
• Hot melt glue a protective layer to the underside

The problem with epoxy is that I can never get at the bottom of the board again. Maybe not so bad but messy.

Adding a 2nd board is a lot of work. Maybe if I can find some plastic to use instead of PCB I can get by with just drilling and cutting.

I liked the hot melt glue idea up to the point I pictured one of the kids leaving their project case in the hot car.

If you have an idea I am open to suggestions.

3v0

 

[futz]

I burned a few days making small target boards that plug into a solderless breadboard. There is a not so great photo attached. To remove them from the BB you need to pry/lift on the underside as you would a large chip.

The plan is to coat the PCBs top and bottom with Krylon's clear conformal coating but that will not be enough. It needs to be protect from the prying.

Why not just don't coat with anything, and instead make some small wood or plastic wedges wide enough to just fit between pin rows. That will spread the load so the board won't be damaged. Put one under each end and just gently wiggle/pry it out. If the breadboard is piled full of stuff, you might have to make some in a 90 degree configuration, like a little "cat's paw nail puller" type thing.

Or just a little piece of wood/plastic (like the above wedge, but small/flat) still full width between the pins. Slide it in as a load spreader and pry on the underside of it. Once you do that you might as well just glue the things on the underside permanently though.

At a model store (RC airplanes) you can buy 1/16" and 1/8" and possibly 3/32" plywood. Nice and strong. Just epoxy it on.

Just some wacky ideas.

 

[user_88]

idea .... high voltage silicone

... found these items .... silicone products for electrical applications:
Product Finder

The company seems eager to provide samples ....

I do not have any particular experience with these products .....

 

[bassnut]

Yes, apply a strip of regular silicone sealant (any hardware store/supermarket) along the underside of the PCB at both ends. This would protect the PCB enough from prying with a flat device/screwdriver, (just dont twist it to bite with a sharp edge)

 

[Mike - K8LH]

Nice looking boards 3v0...

 

[BeeBop]

Adding a 2nd board is a lot of work. Maybe if I can find some plastic to use instead of PCB I can get by with just drilling and cutting.


If you have an idea I am open to suggestions.

3v0

They are nice little boards. Poly-styrene (like the inside of a refrigerator or a model car part) is very easy to work with and should be available, in flat sheets of varying thickness, in model stores or hobby shops.

 

[3v0]

Nice looking boards 3v0...

Thanks. I am still learning the SMD stuff.

 

[Oznog]

Yes, apply a strip of regular silicone sealant (any hardware store/supermarket) along the underside of the PCB at both ends. This would protect the PCB enough from prying with a flat device/screwdriver, (just dont twist it to bite with a sharp edge)

You use silicone caulk as sealant and it'll corrode every exposed bit of copper there. Probably not all the way through, but it's bad form.

Your solution should probably not be overly "flammable" either. Styrene is pretty flammable.

 

[bassnut]

You use silicone caulk as sealant and it'll corrode every exposed bit of copper there. Probably not all the way through, but it's bad form.

Your solution should probably not be overly "flammable" either. Styrene is pretty flammable.

There are corrosive (used on glass) and non-corrosive ("neutral" used on copper and tin) varieties , used it for years without trouble. Caulk is also different to silicone sealant.

 

[3v0]

I took another shot at the PCB. I used the header pins as vias. That got rid of all the solder joints that were in harms way. About the only way to harm it would be to flex the PCB and pop of the SMD parts.

Anyway the new board will be much faster to build. I still need to add protection to the ones I have already constructed.

Thanks
3v0