Model Forum / General / Models / June 2008

Yes, it cures very hard.  If you can build it up from the inside, that
is best.

Vern

Is it a huge gap? Where? Did he make sure the kit isn't warped?
If the gap is big enough, I'd fill it with scrap plastic first, then
the putty/filler of his choice.
I used to use wood putty in my younger days. Cleans up with water and
dries fast, but if the model is flexed a lot, it can crack. Correction
fluid is good for small seams as well.
But practice with a good putty is still the best choice if possible.

In article <fsrr441ctanuem16kksd77345uahbbk13r@4ax.com>,

it works. i prefer using talc and CA, though. no chemical reaction
(baking soda + CA gets hot)  and the talc + CA putty takes a little
longer to set (a few seconds) than the almost instantaneous baking soda
+ CA mix.

It's also a bit softer than the baking soda mix.

I'm making a 1/350 scale 76mm gun turret (similar to the MK-75). The
turret was vacuformed from very thin plastic and it just wouldn't stand
up to sanding. So I slathered some CA + Talc inside and let it set.

You can see the border between the white plastic and the darker CA+talc
in the gun slit in this picture:

http://149.142.139.138/web/Images/PGL/pgl080608E.JPG

I also flattened the top of the turret. You can see the mix showing
through in this picture:

http://149.142.139.138/web/Images/PGL/pgl080608D.JPG

Frank

The baking soda formula made sense back when superglue came only in
thin consistencies. Nowadays I use gap filling superglue, like Pacer's
Zap-a-Gap. It's the consistency of honey, and if you apply a little
accelerator to the area to be filled before adding the glue, it will
set in place instantly (if you apply a thick layer of glue, then add
the accelerator afterward, it may foam up, which is disastrous). The
key is, sand it as soon as it sets up, while it is still malleable.
The curing continues for a while, and after an hour or so, the glue
will be harder than the surrounding styrene, and will be difficult to
feather in. The good thing is that you can fill the problem area NOW,
and continue your build. This is also the only filler that can be
added to thin edges--you can even apply a bead to the edge of an
aircraft stabilizer, for instance, and sand it to the original contour
without the superglue chipping or coming off.
Gerald Owens

This is a very old technique. Some people love this techinque and
swear by it. I have never tried as I could never justify mixing a
water soluable chemical powder with CA glue.  Adding to that I've hear
horror stories where some glue joints started "oozing" when exposed to
moist (humid) weather.  Talc OTOH should be safe to use.  CA glues in
general are harder than styrene (whether filled or unfilled).  The
trick is to sand CA joint when it is not yet fully hardened (within
few hours of it setting).  If you wait a day or so then it is too
late.

IMO, this baking soda techinque should be put to rest.  As others have
mentioned in this thread there are many cleaner, safer and more
reliable alternatives available.

I much prefer using various thickness CA glues straight-up while also
using accelerators.  Keep your baking soda in the fridge...

Peteski