Baking Soda or Powder to mix with CA for Gaps?

[hirohawa]

DO you use the powder or the soda to mix with Crazy glue to fill the gaps?

This is used to make the glue thicker I also heard Talcum powder works.

Sorry if this is OT but I want to fill gaps in the toys not Models.

Thanks

Steve

[Eternal_D]

well, unless you're going to sand and repaint those gaps, probably wouldn't recommend doing that to your toys.

[Lynx7725]

You can do that, but I honestly think putty is a better idea overall.

Either way, you do need to repaint, at least over the filled parts.

[hirohawa]

It's for a custom that will be repainted.

What kind of putty, Bondo?

[VF-19]

Bondo is one, so is Tamiya. I use Tamiya putty, and it usually covers the gap in one application. I just wish it dried faster. You have to wait a few hours, and then some, when you apply thick coatings to a surface.

[Culverin]

the professionals use aluminum putty

and "green stuff"

to my knowledge, your supposed to use baby powder to make CA powder

[Wicked Ace]

DO you use the powder or the soda to mix with Crazy glue to fill the gaps?

This is used to make the glue thicker I also heard Talcum powder works.

Sorry if this is OT but I want to fill gaps in the toys not Models.

Thanks

Steve

What gaps are you filling?

[ewilen]

I've used baking soda with CA to fill gaps. It hardens quickly, which is good. But it gets harder than the surrounding plastic, which is problematic when you sand. So if you go this route, you should definitely use a sanding block (don't apply the paper directly on the surface by hand); it's also a good idea to mask the area to be sanded. I've also read that the CA/powder mix gets harder over time, so the earlier you sand after it sets, the less of a problem it will be. But I can't vouch for that last point.

I did NOT mix the CA with baking soda before applying, and to me that sounds rather dangerous. Instead, I put the powder in the gap to be filled, and then added the CA.

Edit: I just want to add that using baking powder sounds like a bad idea. The ingredients in baking powder are intended to react with each other when they're wetted. I don't know what they'd do in the presence of CA but I can't see how baking powder would be any better than baking soda and I can imagine that even if the mixture doesn't bubble up, it could still be a less stable material over time due to slow chemical reactions. Plus, baking powder costs a little more than baking soda.

Edited April 26, 2004 by ewilen

[Neova]

I thought all you guys use CA powder mix to re-sculpt parts since it is hard yet is easy to remold. Interesting as a gap filler.

If you need to sand those gaps on a toy, do not use epoxy or get a dremel. That stuff is extremely hard to hand sand after it has cured.

[ewilen]

I thought all you guys use CA powder mix to re-sculpt parts since it is hard yet is easy to remold. Interesting as a gap filler.

If someone has experience mixing CA and powder before applying, then by all means listen to them. It's just that I've never tried it.

[Lynx7725]

Personally I rather not mix. Putty (Squadron White/ Green, Bondo, Tamiya, etc. etc.) are easily available and in principle you should use the appropriate material for the appropriate job.

'Sides, putty allows you to contour to fit the shape, which is better than sanding like crazy.

[nedragdnuos]

If you can find it, I recommend using Glasarit Automotive putty, its ultra smooth almost like butter, sets in a few minutes... sandable within 20 or so minutes.... does not have air bubble problems like cheap nasty auto putty and sands away like talcum powder!!!!!!!

[ewilen]

For the record, the next time I do any modelling, I plan on giving one of the putties mentioned in this thread a try instead of using CA (or the crappy Testor's tube putty I started with). But I'll mention one last advantage of the CA/powder approach--it doesn't shrink at all.

[hirohawa]

Gonna do some work on a 1/48 custom.

Thanks for the answers!

[The6ftTallAZN]

Um... what exactly is CA powder? and what do ou need to mix it?

[ewilen]

Cyanoacrylate glue (Krazy Glue) applied to a gap which has had baking soda or talcum powder stuffed into it to provide a matrix for the glue.

Edited April 26, 2004 by ewilen

[Gundamhead]

I use baby powder and mix it with CA. (CA is crazy glue) You can get any 'thickness' you want this way, as in like water compared to silly putty.

The advantage is it does not shrink and produces a pefectly filled seam. If you sand it moments after it cures, it is relatively easy. It becomes rock hard the longer you wait.

[Gerwalker]

This was discussed way before in the how to model section. As Gundamhead said the hardening depends on the curing time: the baking soda + CA is softer than plastic a few seconds after mixed and it gets harder with time (seconds!!) i ussually wait 10seconds until it gets as hard as the plastic. It is very easy to cut and sand then. If you wait longer it gets very hard and it is not easy to sand.

I first put the CA in the gap or part I want to reshape (it is ver good for reshaping small parts since you can build it layer by layer until you get the proper thickness) and then cover it with powder. I've never tried the opposite (I will try) and I think that mix them before is a bad idea.

Baking soda is alcaline and common CA reacts with alcalis that's why it get hard fast.

The main advantage of this stuff is that it dries in seconds (I hate waiting for the Tamiya Putty to dry) and so it's it's main disadvantage: you must work fast.

I don't use it as my only putty. Just for the worst seams and for reshaping. Tamiya putty and more recently the wonderful Mr. Surfacer are my other choices.

[tetsujin]

Bah! Amateurs...

First off, yes, there are definite advatages to super glue+powder mixes over different kinds of putty and other fillers in certain circumstances. I usually mix with talcum powder (making Super Glue + Talcum: SGT). SGT is more resilient than super glue alone, harder than most putties, and bonds pretty much as well as super glue. It's carvable, sandable, and very versatile.

Of course, the first thing you need to know about SGT and similar mixtures is that the resulting mix varies greatly depending on what super glue you use. There's a lot of variety in the glues, there are thin, runny varieties, thick gel-ish stuff, fast curing, slow curing, etc. I usually use a thick gap-filling type, it gives me several minutes of work time before it cures. I used to use a thin, fast-curing variety and that, too, gave me several minutes of work time. Some super-glues have worked out very badly for me in these kinds of mixtures: either they cured too quickly (resulting in something like half-dried elmer's glue within about 15 seconds), or the mixture didn't stay suspended, resulting in a weak surface and a somewhat stronger core. It takes experimentation, but it's great stuff if you can get the hang of it. Beware the super glue fumes, though. They can hurt your eyes.

Different powders can yield different effects, too. Baking soda, corn starch, microballoons... I've not tried them, really.

Comparatively, Bondo has similar advantages in terms of fast curing time and carvability, but it doesn't bond as well to plastics. (It bonds better to metal or fiberglass) Modeling putties are easier to work with, but take longer to cure, and are softer when cured. Their main advantage is that they are solvent-based, so if the plastic is compatible with the solvent they'll bond rather well. SGT is especially great for holding detail. It takes an edge very well, for instance.