SMT glue, where to get it?

[buenos]

hi

I am looking for some SMT glue for securing large soldered SMT components to the PCB for mechanical stability.
In factories they use something called SMT adhesive.
Can someone suggest a type of SMT adhesive that I can buy in an online shop in small quantity in the US?
I am not interested in Loctite superglue or other generic types of glue, but specifically SMT glue.

 

[keith1200rs]

https://uk.farnell.com/electrolube/sma10sl/adhesive-syringe-10ml-smd/dp/106610 or something like it should be available near you. That is heat cure, some are UV cure.

Keith

 

[buenos]

thanks.
the link is unavailable. do you have another link to a different shop?

 

[keith1200rs]

Strange, it seems to work for me. The product is ELECTROLUBE - SMA10SL - ADHESIVE, SYRINGE,
10ML. As it is available from Farnell I would guess Newark might do it in the USA.

Keith

 

[betwixt]

Oddly, that link doesn't work for me either, and I'm in the UK.

I found it on Farnell's web site and this is the link I see: https://uk.farnell.com/electrolube/sma10sl/adhesive-syringe-10ml-smd/dp/106610 see if that works. I looks the same as Keith's, maybe the Edaboard link converter choked on it. If it does it again, this is the link without the h**p:// in front of it so it should appear as plain text:
uk.farnell.com/electrolube/sma10sl/adhesive-syringe-10ml-smd/dp/106610

Brian.

 

[jpanhalt]

I use medium to thick (i.e., old medium viscosity) cyanoacrylic adhesive, which is often known as "CA". In other words, the stuff I use to build model airplanes. Chemically, it is very similar to the so-called SMD adhesive.

For application, I put a small drop in a piece of old, bare PCB copper -- almost anything should work that does not set it off. Like all CA's, its polymerization is set of by bases (chemical bases). The drop on the PCB will stay liquid for quite awhile. I then take a small piece of music wire (about 1/32") and grind it to a dull point. Almost any wire will work, and even some acidic woods may work, like tooth picks made from spruce trees. Touch the wire to the drop on the PCB, then transfer a micro drop to the PCB and place your component. I estimate the microdrop at << 1uL. For larger components, the amount of CA probably doesn't matter. What I have describe works fine for SMD down to 805 sizes. I have not tried smaller.

The nice thing about CA is that its vaporization/depolymerization temp is less than soldering temp, so if you get a little too much, it just disappears during during soldering. In fact, it probably acts like a flux. If you place the component slightly wrong, you can heat it and adjust the position.

Edit: If it helps, Cleveland is/was a home office. I tried to buy small quantities of SMD glue and was not able to do that. Why do the words on the label make a difference?

Regards, John

 

[buenos]

thanks.
I searched for ELECTROLUBE - SMA10SL - ADHESIVE, SYRINGE on farnell/uk and found it, although Newark does not have it. google search did not find much either, this might be a local product of a small uk company.
Newark has this:
https://www.newark.com/loctite/3621/adhesive-epoxy-syringe-10ml/dp/31M3706?in_merch=Popular Products
based on the description: 3621™ is designed for the bonding of surface mounted devices to printed circuit boards prior to wave soldering. but its a littlebit expensive, but probably ok.

Normally we need glue ffor large and heavy components, like smt conenctors on the bottom side, or corner bonding of large bgas, and in my case fixing an so8 socket on the board, as it requires a lot of force to open it and I can rip it off the board while trying.

 

[betwixt]

Jpanhalt - be extremely careful, Cyanoacrylate adhesives "superglue" decomposes at soldering temperatures and releases cyanide compounds. If you are going to use it, be careful to keep the area well ventilated. Speaking from experience, you do not want to inhale the fumes or get them in your eyes, it really hurts!!

Brian.

 

[jpanhalt]

Jpanhalt - be extremely careful, Cyanoacrylate adhesives "superglue" decomposes at soldering temperatures and releases cyanide compounds. If you are going to use it, be careful to keep the area well ventilated. Speaking from experience, you do not want to inhale the fumes or get them in your eyes, it really hurts!!

Brian.

Thank you for the warning. Superglue is a cyanide compound. To put your warning in perspective, the drop I refer to is no more than 0.1 uL, which if converted to cyanide would equal 0.02 mL (0.9X10^-6 mole)of gas at STP. That amount is hardly toxic in any common room. Moreover, CA monomer is the first product produced in heating the polymer. While safety is important, one's concern about it should not lead to paralysis. We are exposed to far greater amounts of HCN, H2S, CO, and other toxins and cyanide compounds daily.

John

 

[buenos]

We tried super glue but that is not suitable to glue big components to the board. By the time it dries, everything in the area is covered by glue or with that white residue. It is especially bad for sockets as the deposit makes the contact surfaces insulating. That Is why I want to use SMT glue, that does not run or deposit on everything.

 

[jpanhalt]

It takes almost no catalyst on the component to make the CA set very quickly. Hobby stores sell a liquid quick-set catalyst. You can wipe it on. The stuff I use has a slight vanilla-like smell. An organic base could probably even be allowed to dry on the component and still work. When working with acidic woods, such as spruce, a very slight dusting with baking soda, which an be wiped off before applying the CA, works.

On re-reading your original post, however, I am not sure CA is the answer. As you note, there are some plastics that are degraded by it. I was thinking of typical epoxy-encapsulated components, resistors, and capacitors.

Sorry to drag this question a little OT.

John