Intro: Cyanoacrylate (CA) Glue Storage and Dispensing Using Syringes
Sometimes all you need from 'instructions' is the concept behind the product or process. This one is very much just such an 'idea' -ible.
The concept is simply to use syringes to store and dispense your cyanoacrylate (super) glue.
There. If that makes perfect sense to you and it's all you need, then go in peace and start using the idea. If you want to know more, stick around and read below.
Why it's a good idea:
Cyanoacrylate (CA) or super glue cures or sets by chemically changing when it is exposed to and reacts with water. Usually this is the water vapour in the air, or in the items being glued (and it's why skin sticks so quickly). Now knowing this, you can proably see why a 'typical' glue container is a poor design for storing and dispensing CA. There's often a large volume of air (and water vapour that comes with it) in the container with the glue. Even when there's just a small apeture in a 'nozzle' style bottle, fresh air still moves in at minimum replacing the glue volume used. This can result in the liquid glue getting more viscous over time (may be an issue if you really need a certain viscosity), or indeed the whole 'pot' setting before you get to use it. Even if a partially affected pot is still usable, having some of the bonding already done before it is used may affect bond strength or other behaviours of the adhesive. The simple solution to getting more out of your pot of CA glue is minimizing exposure to the air during storage. I do this by transferring the glue to syringe(s).
Why it's a bad idea (temporary edit)
When i wrote this instructable all was fine. But i've found that some syringe plungers (the rubber seal) do not hold up to the glue. I'm working on a solution. Maybe coating the plunger in something, such as wrapping it in plastic wrap before using it?) There are syringes where the plunger is only plastic.
Why a syringe:
- The first advantage of excluding water vapour from the container needs no more said.
- There are obvious advantages to applying the glue using the syringe it is being stored in. The plunger system is designed for controlled dispensing.
- The use of a needle allows precise dispensing of small amounts. The applicator needle can be swapped between different sizes to suite different purposes (though these needles will be 'spent' once glue has set in them). All syringes have the same size nozzle so that 'any' needle can fit 'any' syringe, and you won't have compatibility issues in your 'adhesive delivery system'. And you can make fine nozzles to replace the metal needle if you like or need to.
- Syringes also come in a range of capacities, and so you'll find one appropriate to your needs. Syringes (single use, disposable ones - which are also conveniently the cheap kind) are in my experience made from plastics which are not affected by the CA or its solvents. (and vice versa - so no worry about affecting the glue).
- The glue does not 'stick' the plunger in place and stop you from using the syringe.
- You can also easily 'charge' your syringe, obviously by reverse of 'discharging' it.
- A larger pot can be bought and shared between friends etc. (possibly reducing cost even more than preventing 'loss' of prematurely setting glue).
- And there's no guessing or quibbling about quantity when it's in a gradated syringe. Hell, employers who are into micro-managing could even track the rate of glue use. It also lends itself to accurate ratios, say if you were mixing glues of different viscosities for a custom application.
Sealing the tip
Tthere's even a means for capping or sealing when not in use that's the cherry on the cake of this method of storing and applying CA glues: The needle can simply be stabbed into a (scrap) piece of rubber as an airtight 'cap' for the fine tip. This also makes the sharp needle tip safer. A piece of silicone caulking (such as that last morsel left in the conical nozzle) is perfect. This doesn't even ask you to screw on a cap. :)
You could probably just leave the needle tip worth of glue exposed when not in use. Only the very first bit of glue in the needle should set (and seal off the rest). Though this will likely mean cutting away a small portion of the needle in order to use it again, needles are normally long enough for this.
- As mentioned above, AFTER ABOUT A WEEK, THE PLUNGER RUBBER WILL BE AFFECTED BY THE CA GLUE. This hasn't happened to all plungers i've tried, but is at least very likely.
- Having anonymous clear liquids in un-labeled containers of any kind is dangerous. Label and store appropriately! If not for safety, then as a way to keep track of which is which for yourself.
- Syringes come with a small amount of a lubricant in the cylinder. You must remove this (don't forget the pluger head) before using the syringe for CA storage.
- The plungers on some poor quality syringes don't slide smoothly and easily, so that sudden spurts of CA might be a possibility. So exercise fine motor control.
- Be weary of applying great pressure to the plunger which might push the needle or other applicator off the front of the syringe and cause an 'ejaculation'.
- Not all CA viscosities will pass easily through all diameter (guage) needles. Select appropriately. This goes for 'sucking-up' the glue as well.
- There are (speciality) CA adhesives which cure when exposed to UltraViolet light. I assume that a conventional syringe will not block normal environmental UV light from setting this glue in the syringe.