Where to get neutral cure silicone?

Keefy · January 2022

I enjoy building and repairing amps and other electronic doodads, and there are times when a dollop of gunk can be very useful to hold things in place, e.g. large capacitors. I have generally used hot glue for this purpose, but it may not be the best solution in places where it's going to get hot!

I have been looking for the following:
- Neutral cure silicone (does not release acetic acid);
- Clear rather than white;
- In a tube with a cap, not the cartridge that you put in a caulking gun.

Google has been little help so far. Do you use this stuff , and if so, what brand and where from?

TIA

TheMadMick · January 2022

Try Stixall. It's not quite what you're looking for but it might do the job. Toolstation is my preferred supplier but you can get it elsewhere e.g. Amazon.

Keefy · January 2022

TheMadMick said:

Try Stixall. It's not quite what you're looking for but it might do the job. Toolstation is my preferred supplier but you can get it elsewhere e.g. Amazon.

Hmmm... Seems more like a clear version of No More Nails, and the data sheet is pretty terrifying!

BillDL · January 2022

I have an old mains powered glue gun that I acquired when I used to be a sales rep for a wholesaler of florist sundries. Florists use them for sticking all manner of things together. I use it for the purpose you are seeking a solution for. You can probably get different types of glue stick, but the ones used in my gun are quite flexible and a very slightly milky colour, as is the dollop of glue when it cools and hardens. The sticks are oval and about 7 inches long. You push one into the back and plug in the gun until it heats up and then just pull a trigger that pushes the stick through a heating element and the glue comes out a fine nozzle. It hardens with the same kind of flexibility as the glue stick and, although it holds capacitors and such like in place well, it can still be pried off if needed. It doesn't take much heat to soften the glue stick into a gloopy araldite type of viscosity so there's no risk of overheating components. The only drawback is that when you pull the nozzle away you can get some fine spiderwebs of glue trailing behind, but they are easy enough to gather in.

Search any hardware store like Screwfix, B&Q, Toolstation, or even hobby shops for "hot melt glue gun" and read the reviews to see what kind of jobs buyers found the different models suitable for.

If you are definitely still looking for suitable silicone in small squeezy tubes, what you are looking for is high modulus neutral cure. The stuff you buy for sticking glass to glass for fish tanks is clear, high modulus, and comes in squeezy tubes, but most of it is the acetoxy cure (i.e. vinegar stench). Normal low modulus bathroom sealing silicone is usually low modulus, is very spongy unless you apply it thickly, and peels off far too easily. High modulus stuff dries more like window frame mastic.

It's hard to know from items on Amazon whether they are the neutral cure or acetoxy cure, but you can get multipurpose clear silicone in tubes:

https://www.amazon.co.uk/Silicone-Sealant-Clear-Waterproof-70g/dp/B0036GEK9W (This one IS acetoxy cure)

https://www.amazon.co.uk/GORILLA-1144301-Gorilla-Versatile-Mould-Resistant/dp/B079D359V2/ ("Causes serious eye irritation" - must be acetoxy shit as well).

Keefy · January 2022

Thanks @BillDL we do have a hot glue gun which I have used, but I think the melting point is around 100C. My concern is that in valve amps, particularly those where the valves hang below the chassis, it may become warm enough to soften the glue (even if it doesn’t completely melt).

You’re right about the online descriptions too, I’m having a hard time working out what is neutral cure and what is not.

I have been looking at the stock in DIY shops - at some point I’m bound to hit lucky!

BillDL · January 2022

Very true about the heat from valve amps. Maybe just using small blobs won't make too much of an acrid smell unlike the smell that hangs for a while after sealing in a bath or shower. If you do it only on nights when you are having fish and chips maybe you wouldn't even notice.

Keefy · January 2022

BillDL said:

Very true about the heat from valve amps. Maybe just using small blobs won't make too much of an acrid smell unlike the smell that hangs for a while after sealing in a bath or shower. If you do it only on nights when you are having fish and chips maybe you wouldn't even notice.

Ha ha! I can live with the smell, it's the effect of acid on the components.

BillDL · April 2022

Just curious, did you ever find some suitable compound to use?

Keefy · April 2022

BillDL said:

Just curious, did you ever find some suitable compound to use?

Yes, a couple of days ago I found and ordered (on eBay) a tube of ‘Mannol’ neutral cure silicone intended for gasket repair. It’s grey rather than clear but that’s fine. Should arrive in a couple of days.

elstoof · April 2022

How about Sugru, it’s a mouldable silicone glue, a bit like blu tack

BillDL · April 2022

I was just thinking about this the other day when I saw the neighbour out replacing a gasket on his motorised lawnmower. He was using the old red Hermetite gasket sealant and it made me think about this question again.

PeteC · April 2022

I wonder if you could also try the Milliput mouldable epoxy putty - given that Mr Dumble used to goop his HRM circuit and others in black epoxy! I haven’t tried it but after buying some black to make fretboard dots i am thinking about using some to stabilise a couple of board mounted PS caps on an
old build i have.

You can mix and shape the stuff and work it into any shape you like. Sets in about 4 hours.

Its pretty cheap too

Keefy · April 2022

elstoof said:

How about Sugru, it’s a mouldable silicone glue, a bit like blu tack

PeteC said:

I wonder if you could also try the Milliput mouldable epoxy putty - given that Mr Dumble used to goop his HRM circuit and others in black epoxy! I haven’t tried it but after buying some black to make fretboard dots i am thinking about using some to stabilise a couple of board mounted PS caps on an
old build i have.

You can mix and shape the stuff and work it into any shape you like. Sets in about 4 hours.
Its pretty cheap too

Those sound quite similar. @PeteC let us know it works out with those caps.

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Where to get neutral cure silicone?

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