Stuck on Glue

[talan2000]

Hi All,

I'm a newbie diligently working not to glue my fingers to my new kits as you may have seen in my recent posts :) I've read a ton of stuff recently and I'm not sure WHEN I'm supposed to use which type of adhesive.

Specifically - I've left behind the testors tube of glue that leaves long strings in its wake and moved on to Tamiya extra thin. This seems to work great for attaching small pieces but less well at doing things like merging upper and lower wings together etc.

I read of people using Super Glue/ CA but I'm not at all clear as to when one should use one or the other. I've also seen in some videos that over long periods of time the superglue will fail.

Any help you could share on when to use Extra Thin vs Ca would be appreciated. Also - is there any practical difference between Tamiya "thin" vs Extra thin?

Thanks!

Todd

[Netz]

If your gluing plastic to plastic stay with the Liquid glue, the only time I find the need to use CA glue is when attaching a metal (photo etch or wire) to plastic.

If your having problems with parts not holding together as you mentioned your wings, check your prep work, your edges should be flush, not beveled as some may be, I mean you need to flatten the mating surface of you wings and fuselage, you can use a full sheet of emory paper taped to a flat surface (I use a marble tile) or use a large flat file.

Curt

Edited August 23, 2014 by Netz

[talan2000]

Ok, thanks for the tip. I seem to have read a number of times about people using CA on some parts and not on others (all plastic). I haven't used any photo etch yet, though I have some kits with it now, so I'll definitely be sure to use the CA on the etch and on the resin bits.

Todd

[Joel_W]

You don't mention how you tried to apply the Extra Thin to the upper and lower wing joint. Unlike tube glues where you laid down a consistent thin bead, then joined the two parts together, with Extra Thin it's done completely the opposite way. 1st you have to make sure that the parts mat correctly so that the glue can join the two surfaces. Then dry fit the two parts and start to apply the Extra Thin by touching the brush to the joint. The glue will run down the joint a inch or so and into the joint as well. Then press that area together so the glued can start to melt the plastic. Then do the same thing over and over working your way all around the joint line. I follow this up with running the glue brush along the full joint line. Then I tape the joint with pieces of masking tape, and let it dry. Neatness counts, as the glue will run under your fingers if you're not careful. Done properly, you end up with a very strong glue joint.

Joel

Edited August 25, 2014 by Joel_W

[dmk0210]

Any help you could share on when to use Extra Thin vs Ca would be appreciated.

Generally speaking a plastic solvent will give you the best bond. It welds the plastic pieces together. This should be your first choice whenever possible. CA is strong, but brittle.

Glue two sprues together with solvent, then glue two with CA. After two or three days cure time, try to break them apart. See which one has a stronger bond.

CA is best to use when you are trying to attach dissimilar materials such as metal or resin to plastic. Solvent will not work there. 5 Minute epoxy can be used as well, but is thick and requires mixing a batch right before use, so it's less convenient.

CA also cures very quickly. So this can be an advantage when small parts won't stay in position on their own long enough for a solvent to cure and hold them there.

The third consideration is a glue for clear parts. Something like Testors Clear Parts Cement or watch crystal cement are the safest options. CA can 'fog' the inside of the canopy.

Edited August 25, 2014 by dmk0210

[talan2000]

Thanks again for the additional feedback.

I think my technique for applying the Extra Thin needs some improvement.

Joel - thanks for listing clear steps. I think I've been trying to "paint" on too much of the glue at once and it is drying before the parts are mated together. That or drenching the closed seam/join line.

I guess I'll use the CA for trying to fill seams - I've been playing with that lately after doing a mediocre job with Squadron white putty...I resolve myself to learn, be patient and improve with each build but it can be frustrating journeying into the modeling wilderness alone -- thanks for being my sherpas!

Todd

[Joel_W]

Thanks again for the additional feedback.

I think my technique for applying the Extra Thin needs some improvement.

Joel - thanks for listing clear steps. I think I've been trying to "paint" on too much of the glue at once and it is drying before the parts are mated together. That or drenching the closed seam/join line.

I guess I'll use the CA for trying to fill seams - I've been playing with that lately after doing a mediocre job with Squadron white putty...I resolve myself to learn, be patient and improve with each build but it can be frustrating journeying into the modeling wilderness alone -- thanks for being my sherpas!

Todd

Todd,

CA for filling small seams or cracks works great. But just let it set up, then try to sand before it gets rock hard, as it' becomes quite difficult to sand and blend in.

I use basically 4 different methods to fill seams, cracks, etc.

1- Good old Squadron Green stuff. But these days I thin it with Extra thin to a toothpaste consistency. It's much easier to apply and work into the seam, and much easier to control where it goes. Try to use some tape on either side of the seam to keep it clean and protected from sanding.

2- For seams that need only minor filling or blending, I prefer Vallejo White Putty. I apply it, wait like 2 min, then with a damp Qtip lightly wipe the joint line clean and level. I I give it like 15 min, then a 2nd coat. Works great.

3-CA glues. Apply over the joint. let dry, the sand off the same day. Mask on either side of the joint line to protect details.

4-Tamiya's Gray Surface Primer hand brushed on. Let dry for a few hours then apply a 2nd coat. Lightly sand and polish the joint. Works great for very small blemishes that putty doesn't work in.

Joel

[Devilleader501]

I have just started using Tamiya Extra thin and I have to say where the hell was I in not heading advice. You will come up with the best ways to apply it on your own but I can tell you now I am sold on the product. The stuff bonds quick enough to not get you into a hell of a situation but dries slow enough you can put clamps and things of that nature on without having to break the weld that it makes. + 1 for everything said above. I put the glue around the inside of a seam if I can get to it but also outside. It to me creates a stronger bond but the clean up is not all that bad. I use a scriber to re scribe lines that have become a little lost from the glue and after letting the parts sit for 24 hours I can easily sand the portions that have too much glue.

I am getting into scratch building and this stuff is a must. For small parts or to hold big parts together with what I call tack welds I use super glue. But only to keep the parts where they need to be until I apply the extra thin. The Extra thin gives a bond much greater than super glue ever will because of the vulcanization of the two parts with extra thin that super glue cant do. Done right and I am still learning myself on how to apply will give a better bond faster and with less mess than any other glue you find.

[Joel_W]

Devilleader501,

Your modeling life just got a whole lot easier.

Joel

[talan2000]

Thanks Guys

Any thread with "vulcanization" lights my fires :)

I'll be printing out your tips Joel - I just used some "zapagap" CA glue to try to fill the horrible seam on my Monogram T-28. I used CA accelerator immediately after applying it and then sanded it off. I think perhaps that I should skip the accelerator although the wanna-be chemist in my was amazed at the instantaneous crystalization of the CA when sprayed...

I have Squadron white and Tamiya white putties. I just was disappointed with how fast the squadron stuff set up and was chalky. Thinning it with thinner seems a good idea. It just seems like I'm in a science lab with SOOO many variables and I keep making just basic mistakes leading to poor/mediocre outcomes on basic stuff -- like fuselage seams! But then, I don't know which aspect CAUSED the poor result! Was it improper application of putty, improper diluting of putty, too quick sanding of CA, CA accelerator etc.

I have amassed a ridiculous stash at this point and am now getting gunshy of actually building the darn things in between diaper changes for my 6 mo old and tantrum crushings for my 3 yr old :)

Thanks for your help as always

Todd

[Joel_W]

Todd,

I generally use an accelerator on CA glue. Since it's clear, it's hard to tell if if filled the seam or not. Run your finger nail over it. If you can't feel a gap, then you're home free. I don't use Squadron Green Stuff in very shallow seams as it just doesn't work well in that application. CA glue or a few coats of primer will do the trick. You have to develop a method of applications based on the seam, gap, etc. that works for you.

Joel