# Baking soda and Titebond II don't mix



## riderdan (Jan 2, 2014)

I was out in the garage working on one of my buildings this afternoon when a funny thing happened...

Because the CMS structures aren't 1:24 (more like 1:29) they're out of scale compared to other buildings on my layout. To remedy this, I build up the first floor with two layers of block--cast from Hirst Arts molds and glued to the bottoms of the buildings. This gives a satisfactory look (like the foundation is showing) and raises the first floor enough that I can install actual 1:24 doors. Overall, I'm happy with the buildings once they're "raised" enough so be similar in scale to Pola/Piko buildings.

Anyway, because I'm gluing cast blocks together and I need to keep them aligned as the glue dries, I generally use a drop of CA on the corners to hold them. I use a slower drying, gap-filling CA because the blocks are textured like rough-hewn granite. I accelerate with a dusting of baking soda, which makes the work go faster. Once all the blocks are bonded, I seal them with Titebond (the casting material is weather resistant only when sealed and painted)

Apparently there's something in the Titebond that reacts with baking soda, and I didn't get all the baking soda brushed off. When I finished gluing a section and looked back, the glue looked all puffy. Looking closer, I could see that it was where I painted on a layer of Titebond where the baking powder was. The glue started foaming up like vinegar.

The moral of the story: blow off all the baking soda before gluing.


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