Question regarding applying CA glue to plastic models

[Cap'n Snack]

Hi all;

 

So I'm new to CA glues, and found that my wee squeeze bottle from Tamiya dispenses a LOT more adhesive than I needed (now my Photo-etched 1/350 scale ladders have large blobs at the bottom of them!)

 

Does anyone have good advice on techniques to dispense JUST the right amount of glue? I tried squirting some onto a tinfoil cup ad dipping my glue applicator into it, but it didn't seem to 'get enough' on the applicator. 

 

Any tips or tricks are most welcome. Thanks in advance!

[robdurant]

I tend to put a little on a scrap of card and use a cocktail stick to pick up a little and move it to the joint. If it's thin ca glue, capillary action will draw the glue in between parts. The angle of the cocktail stick can change the size of the drop of glue on the end... then it's just experience and getting a feel for it. 

 

There are plenty on this forum who are far better at this than me though so there may be better advice forthcoming

Edited October 26, 2020 by robdurant
Clarifying

[wefalck]

Some people also grind half away half of the eye of a sewing needle, leaving a forked end, and hold the needle in a pin-vice or in a round length of wood. Some people also use wire-loops (steel wire preferred, as copper ions can inhibit the curing of CA). Any cured CA can be burned off with a cigarette lighter flame. Once the needle has been heated to a red-hot it can also be bent to shape to reach difficult places.

 

Personally, I don't like CA too much and use a fast drying varnish to attach small parts. One has to be aware, however, the bond often is less strong. One has to make trade-offs between ease of application (with a fine brush in the case of varnish), the possibility to correct positioning (by using solvent), and the strenght of the bond.

[shipman]

CA de-bonder (basically acetone, which is the main component of nail varnish remover) does the job of releasing  CA joints. I'm not a big fan of noxious substances, but common sense goes a long way.

Good ventilation and avoiding skin contact should do.

[wefalck]

Trouble is, that such 'debonders' break up the cross-linking of resins such as CA. When you use varnish, the solvent would just soften it, allowing you to reposition the part.

 

I have been working for so long with aceton in the lab (we used to rinse glass-ware after washing it to dry quickly), the a few drops here and there now don't shorten my life too much ...

[Nunnehi (Don)]

I like CA and use quite a bit on both wood and plastic and agree with the above comments with respect to using large sewing needles chucked in a pin vice to apply it, particularly the super thin version. I’ve also used an applicator called a glue-looper a bit and have been happy with it. CA will remain liquid for a couple of hours outside the bottle and I like the small, cheap paint mixing trays to hold it for dipping. A plastic pipette with a fine tip is also useful for both applying and for transferring from the bottle to the tray. You can get fine tip extensions for the bottles but I still like using the tray. How much to use is a matter of practice but it’s real easy to use more than necessary and make a mess. There’s been some discussion about its longevity but I’ve got models over 20 years old that are holding together just fine. 

 

Don

[Cap'n Snack]

Love the tips and advice. Thanks to all!

[Nunnehi (Don)]

Don’t want to leave the impression that CA is the be-all and end-all, it’s not. While it’s great in the plastic world, particularly for photo-etch detail stuff, and filling seams and gaps, these also have their place and may be the better tool for the job. Micro crystal clear is great for attaching clear plastic parts and filling portholes. I’ve never used wefalck’s varnish technique and would like to give it a try. 

 

Don

 

[ah100m]

Amazon has (or have if you're British!) the loopers:

 

https://www.amazon.com/s?k=glue+looper&ref=nb_sb_noss_1

 

They're all I use.  Small and medium for thin CA, large for thick.

[rkwz]

Not an expert but my cheap and nasty 

method is to unfold a paperclip and use the pointy end to apply a tiny amount of CA.

 

Later you can scrape off any excess hardened CA with a knife.

[Canute]

You can also burn it off your applicator.

[Cap'n Snack]

16 hours ago, Nunnehi (Don) said:

Don’t want to leave the impression that CA is the be-all and end-all, it’s not. While it’s great in the plastic world, particularly for photo-etch detail stuff, and filling seams and gaps, these also have their place and may be the better tool for the job. Micro crystal clear is great for attaching clear plastic parts and filling portholes. I’ve never used wefalck’s varnish technique and would like to give it a try. 

 

Don

 

Thanks for the tips and the picture!

[Cap'n Snack]

15 hours ago, ah100m said:

Amazon has (or have if you're British!) the loopers:

 

https://www.amazon.com/s?k=glue+looper&ref=nb_sb_noss_1

 

They're all I use.  Small and medium for thin CA, large for thick.

I'll head out to the local hobby store on the weekend and see if they have loopers!

[wefalck]

A wire loop will do the same job at virtually no cost. Biologists and chemists have used this technique for decades or even centuries to apply small quantities of liquid. The amount of liquid dispensed depends on the diameter of the loop and the thickness of the wire and so can be modulated to your needs.

[James H]

I use a toothpick (sharpened) and a disposable weighing boat. Just pop a spot into the boat and use the pick to apply. 

Sharpen the pick as necessary. 

 

No need for fancy tools.

 

[Rik Thistle]

Don,

 

"... CA will remain liquid for a couple of hours outside the bottle ..."

 

I have been wondering for a while about how long I could leave a blob of CA lying on a piece of paper and it remain useful before I dipped a thin applicator stick into the blob? From what I understand about CA (and it's not that much) doesn't CA set in the presence of water molecules ie in the wood, on the plastic, in the air?

 

Maybe a blob of CA forms a protective shell (reaction with the air's water molecules)  around the blob keeping the CA inside the blob active for a lengthy period?

 

Or even though the CA is still liquid after a couple of hours has it lost some of it's adhesive capability as water molecules merge with it?

 

Regards,

 

Richard

[wefalck]

It depends on the temperature and particularly on the ambient humidity. Water vapour will trigger the cross-linking reaction. Thus, breathing on it will speed it up.

[Rik Thistle]

Yes, I've used 'breathing on joints' for years (eg when I was a design engineer working on prototypes etc).

 

Thought - would applying a very slight layer of moisture to both sides of a joint when hull planking give a more assured result?

 

Regards,

 

Richard

[wefalck]

CA will bond planks humid from steaming immediately. After all, CA was originally developed for battlefield paramedics to close wounds rapidly without the need for stiching and is used for the same purpose in civilian context too - guess how I know

 

I was told about 'breathing on joints' by my father, who was a biochemist working inter alia on the application of acrylics in pharmaceuticals etc.

Edited October 28, 2020 by wefalck

[Cap'n Snack]

On 10/27/2020 at 11:23 AM, James H said:

I use a toothpick (sharpened) and a disposable weighing boat. Just pop a spot into the boat and use the pick to apply. 

Sharpen the pick as necessary. 

 

No need for fancy tools.

 

Admittedly, this is something I tried, along with my 'glue applicator' (which is a fancy plastic version of the toothpick, IMO)

I certainly felt like Godzilla trying to use knitting needles!