Adhesive for Large Electrolytics to PCB

TerryC · 14th March 2007, 10:11 PM

What's a good adhesive type/brand for securing large electrolytic capacitors to a printed circuit board.

dangus · 14th March 2007, 10:34 PM

RTV silicone or hot glue can work, and can be removed without extraordinary effort.

AndrewT · 14th March 2007, 10:39 PM

Hi,
RTV silicone makes an excellent adhesive.
I use the clear window sealer. It seems to withstand heat, oil and fuel better than the real engine types.

I_Forgot · 14th March 2007, 10:47 PM

I have always used contact cement, but make sure you are gluing driectly to the aluminum can and not a plastic piece held in place by the shrink-tubing that covers the rest of the cap. If that stuff cracks, your cap may fall and cause a big problem.

Adhesive isn't very good for things that get shaken or jarred a lot. It is best to bolt caps in place in that sort of app. I also bolt down HV caps because I just don't trust adhesives to do their job for 20 years.

You can put one long bolt through the PCB and then use a couple tie-wraps to hold the cap to the bolt. Use at least 2 tie-wraps in case one breaks.

I_F

Elvee · 15th March 2007, 08:34 AM

Hi,

Silicone (the neutral, non-acetic variety) is excellent: it is compliant, durable, has good adhesion and can be removed if needed. Hot glue is less reliable regarding the long term adhesion; contact glues based on neoprene tend to degrade with time, hardening and releasing corrosive sulfur compounds.
LV

Narcisse91 · 17th March 2007, 08:28 PM

One thing I've found with RTV (may only apply to certain types, may apply to all, I don't know) is that it seems to release a corrosive vapor as it cures. Make sure you don't apply it to a cap and then seal up your chassis. Let it cure on the bench, and when it is fully hardened, put it in the chassis.

Maybe someone knows exactly what causes this and can explain. I only know about it because I've seen it happen.

DigitalJunkie · 17th March 2007, 08:43 PM

acetic acid...vinegar.

Apparently as it cures it releases acetic acid..or maybe that's the chemical that makes it cure,I'm not too sure on the exact chemistry of it...But yea,it's stinky,and can cause corrosion issues from the acid.

AndrewT · 17th March 2007, 09:31 PM

Hi,
these silicones are two part adhesives.
The second part is the water in the atmosphere.
The by-product of the reaction is the acetic acid, given off as a vapour.
Yes, let it evaporate before sealing it up in an enclosure.

TerryC · 17th March 2007, 09:35 PM

I Googled +RTV +Silicone +adhesive +"electronics grade" and found this from Allied Electronics which should do the job.

http://www.alliedelec.com/Search/Pro...E17F&tab=specs

SY · 17th March 2007, 10:17 PM

So-called construction adhesive works well and I haven't had any corrosion problems. If you get some on your hands, it will be there for a while...

14th March 2007, 10:11 PM	#1
TerryC diyAudio Member Join Date: Jun 2005 Location: WA-USA	Adhesive for Large Electrolytics to PCB What's a good adhesive type/brand for securing large electrolytic capacitors to a printed circuit board.

17th March 2007, 10:17 PM	#10
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	So-called construction adhesive works well and I haven't had any corrosion problems. If you get some on your hands, it will be there for a while... __________________ If there's a sucker born every minute, where do the rest of them come from?

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14th March 2007, 10:34 PM	#2
dangus diyAudio Member Join Date: May 2004 Location: Vancouver Island	RTV silicone or hot glue can work, and can be removed without extraordinary effort.

14th March 2007, 10:39 PM	#3
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, RTV silicone makes an excellent adhesive. I use the clear window sealer. It seems to withstand heat, oil and fuel better than the real engine types.

14th March 2007, 10:47 PM	#4
I_Forgot diyAudio Member Join Date: Jan 2005 Location: Phoenix, Az.	I have always used contact cement, but make sure you are gluing driectly to the aluminum can and not a plastic piece held in place by the shrink-tubing that covers the rest of the cap. If that stuff cracks, your cap may fall and cause a big problem. Adhesive isn't very good for things that get shaken or jarred a lot. It is best to bolt caps in place in that sort of app. I also bolt down HV caps because I just don't trust adhesives to do their job for 20 years. You can put one long bolt through the PCB and then use a couple tie-wraps to hold the cap to the bolt. Use at least 2 tie-wraps in case one breaks. I_F

15th March 2007, 08:34 AM	#5
Elvee diyAudio Member Join Date: Sep 2006	Hi, Silicone (the neutral, non-acetic variety) is excellent: it is compliant, durable, has good adhesion and can be removed if needed. Hot glue is less reliable regarding the long term adhesion; contact glues based on neoprene tend to degrade with time, hardening and releasing corrosive sulfur compounds. LV

17th March 2007, 08:28 PM	#6
Narcisse91 diyAudio Member Join Date: Aug 2002 Location: NY	One thing I've found with RTV (may only apply to certain types, may apply to all, I don't know) is that it seems to release a corrosive vapor as it cures. Make sure you don't apply it to a cap and then seal up your chassis. Let it cure on the bench, and when it is fully hardened, put it in the chassis. Maybe someone knows exactly what causes this and can explain. I only know about it because I've seen it happen.

17th March 2007, 08:43 PM	#7
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	acetic acid...vinegar. Apparently as it cures it releases acetic acid..or maybe that's the chemical that makes it cure,I'm not too sure on the exact chemistry of it...But yea,it's stinky,and can cause corrosion issues from the acid.

17th March 2007, 09:31 PM	#8
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, these silicones are two part adhesives. The second part is the water in the atmosphere. The by-product of the reaction is the acetic acid, given off as a vapour. Yes, let it evaporate before sealing it up in an enclosure.

17th March 2007, 09:35 PM	#9
TerryC diyAudio Member Join Date: Jun 2005 Location: WA-USA	I Googled +RTV +Silicone +adhesive +"electronics grade" and found this from Allied Electronics which should do the job. http://www.alliedelec.com/Search/Pro...E17F&tab=specs