I am mounting some mini pots to a PCB and one of them will hang over the solder side of the board. Since the back of the pot is metal I need to insulate it. I was thinking of coating the back of the pot with epoxy? Any reason why I shouldn't? Is there a better way?
Also, is there a way to temporarily connect the pot to the board so that I can try the circuit out? The pot will cover some solder points on the board so if I had to fix anything I would need to unsolder the pot.
double sided foam tape was always my preference ...
Quote from: FloorIt on September 28, 2014, 09:29:28 PM
I am mounting some mini pots to a PCB and one of them will hang over the solder side of the board. Since the back of the pot is metal I need to insulate it. I was thinking of coating the back of the pot with epoxy? Any reason why I shouldn't? Is there a better way?
Also, is there a way to temporarily connect the pot to the board so that I can try the circuit out? The pot will cover some solder points on the board so if I had to fix anything I would need to unsolder the pot.
I think epoxy would work fine. It's actually a clever idea. There are tons of ways to insulate pot bodies from the board including things like thin foam and electrical tape. The most elegant way is to use one of the pot dust covers (http://www.smallbearelec.com/servlet/Detail?no=1195) that Smallbear sells. Unfortunately they are out of stock right now. :(
You can solder tack some leads to the board to test your circuit or you could use wires with alligator clips or test clips. Honestly, if you lightly solder in some wires, it's really easy to get them back out without lifting the pads or clogging the holes with solder. Do you have solder wick or a solder sucker?
Quote from: LaceSensor on September 28, 2014, 09:47:03 PM
double sided foam tape was always my preference ...
Yeah, I think this is the safer approach.
The thing about epoxy is that there is always the possibility that it will run somewhere you don't want. Now, if it's a higher viscosity epoxy then it'll more likely to be OK, but double-sided tape is so much more convenient.
I've taken to using sugru (see www.sugru.com) to insulate my pots - works a treat.
If I'm feeling lazy, I just put electrical tape over the back. Quick, works, removable, nonconductive. The only people people likely to care are forum nerds like us.
If I'm not, I find a pot that I know doesn't need it, and lever the plastic dustcover off the back (Tayda pots come with these), or dig into my stash of Smallbear pot covers.
Quote from: Leevibe on September 28, 2014, 09:50:41 PM
You can solder tack some leads to the board to test your circuit or you could use wires with alligator clips or test clips. Honestly, if you lightly solder in some wires, it's really easy to get them back out without lifting the pads or clogging the holes with solder. Do you have solder wick or a solder sucker?
Yes I have solder wick. I'll give that a try.
Quote from: pickdropper on September 28, 2014, 10:20:54 PM
Quote from: LaceSensor on September 28, 2014, 09:47:03 PM
double sided foam tape was always my preference ...
Yeah, I think this is the safer approach.
The thing about epoxy is that there is always the possibility that it will run somewhere you don't want. Now, if it's a higher viscosity epoxy then it'll more likely to be OK, but double-sided tape is so much more convenient.
I know alot of guys use foam tape. It just doesn't seem that durable to me. Seems like the sharp leads could poke through the foam.
Try rtv
Quote from: FloorIt on September 28, 2014, 11:35:00 PM
Quote from: pickdropper on September 28, 2014, 10:20:54 PM
Quote from: LaceSensor on September 28, 2014, 09:47:03 PM
double sided foam tape was always my preference ...
Yeah, I think this is the safer approach.
The thing about epoxy is that there is always the possibility that it will run somewhere you don't want. Now, if it's a higher viscosity epoxy then it'll more likely to be OK, but double-sided tape is so much more convenient.
I know alot of guys use foam tape. It just doesn't seem that durable to me. Seems like the sharp leads could poke through the foam.
It really depends on the foam tape. You can also leave the backing on, which is usually very stiff.
The best are the Small Bear pot covers Alan mentioned. Inexpensive, too.
When needed i cut a piece of recycled plastic packaging the size of the pcb and use that between the pots/whatever and the back of the pcb. I also mount pcb's on standoffs so the plastic is held in place by the screws holding the pcb.
And like others mentioned had fine result with 3M double sided auto trim tape.
I have a strong aversion for those plastic pot covers and cut them off and promptly trash them.
Can just see the plastic insulator in this one.
(http://i216.photobucket.com/albums/cc305/davent/IMG_5142_zpsc55acc53.jpg)
dave
I have used this for a similar situation: http://www.amazon.com/Gardner-Bender-LTB-400-4-Ounce-Electrical/dp/B000FPAN2K (http://www.amazon.com/Gardner-Bender-LTB-400-4-Ounce-Electrical/dp/B000FPAN2K)
I use this stuff to hold the PCB down to the pots when I don't use PCB mounts. I'm sure it will work the same the protect the PBC from the leads.
(http://www.bostik.es/_upload/ressources//productos/fotos/expositor_blu_tack-003.jpg)
I am not sure I'd use Blu-Tack for anything long term. Blu-Tack is tremendously useful stuff, but over time it can get very oily (you'll notice it stains a lot of surfaces if left there for a while).
Quote from: pickdropper on September 29, 2014, 02:17:14 PM
I am not sure I'd use Blu-Tack for anything long term. Blu-Tack is tremendously useful stuff, but over time it can get very oily (you'll notice it stains a lot of surfaces if left there for a while).
That I didn't know, thanks for the info. Might stop using it now.
I started using the prickly side of hook and loop Velcro strips. It looks great, and fulfills it's purpose.
Quote from: davent on September 29, 2014, 01:51:07 AM
When needed i cut a piece of recycled plastic packaging the size of the pcb and use that between the pots/whatever and the back of the pcb. I also mount pcb's on standoffs so the plastic is held in place by the screws holding the pcb.
And like others mentioned had fine result with 3M double sided auto trim tape.
I have a strong aversion for those plastic pot covers and cut them off and promptly trash them.
dave
Hey Dave send those plastic pot covers to me..no aversion here...(joke)
Insulating the bottom of the board with leftover plastic seems like a great idea.
Dan
Dan, I'm afraid my method of removal is expeditious and fatal, a sad and lonely death. I don't think Canada Post would be very kind to us either, but plastic... i got plastic... well some anyways...
dave