Blue Foam safe Gorilla Super Glue

[Ara Dedekian]

        Gorilla cyano with the brush applicator seems to work on blue foam where the standard odorless 'foam safe' instant glues turn it into a liquid. Brush applicators are pretty handy in modeling and there are two brands with them, Gorilla and Krazy Glue. Gorilla brushed cyano is compatible with blue foam and Krazy Glue isn't. However, the Gorilla is not compatible with white foam and I haven't tried the non-applicator version.

        I say 'seems' to work because the Gorilla brand is either super gap filling or the bottles I bought had kicked off by sitting on the shelves for so long. I found this to be the case at both True Value and Walmart. The first bottle I got was almost solid and the replacement wasn't much better. The third was a little better but was viscous enough to work.The picture shows a blue foam pushrod guide on a backyard foamy that was successfully assembled with the Gorilla brush applicator glue.

      Does it have a compatibility with blue foam or was the glue nearing the end of its shelf life and lost its mo-jo to attack the foam.

       Ara

[Istvan Travnik]

I do not have any certain chemical infos on Gorilla branded glues.
One thing is sure: both the Blue (and Pink) and white foams are chemically polystyrene material. The colored ones are extruded (fully homogeneous) and the white one is expanded (i.e. from "grains" or "pellets" expanded (puffed) up to fill the plain, or shaped mold.
All solvents and thinners are harmful for polystyrene, and cyano, as well. Alcohols and water is exception.
Epoxies without thinner are not harmful. So I suggest for general use 5 min clear epoxy glue, for foams. Maybe 20 min ones for bigger, complicated surfaces.
There is some special kind of cyano, for polystyrene, but I do not know its brand. It is easily find on specialized pages, or shops.
There is some not-too-hard siliconrubber based glue (in Europe:Pattex Total), easy to cut after drying.
The vinegar-smelled water based white tablemaker glue is affordable, too, but bigger surfaces need several hours for dryig. (polystyrene foam is tooo hermetic for humidity...)
Istvan
Remark: recent years appeared a new kind of white foam in modelling: EPP (extruded polypropylene foam), it is absolute resistant of every glues, resins, paints and solvents/thinners. Sorrowfully it is far more expensiver than XPS, and the elementary structure is 5-10 times rougher than XPS...

[Will Hinton]

Bob Smith Industries make a foam safe ca

[Ara Dedekian]

       Istvan,

           Thanks for taking the time to explain the various types of foam.  I wonder if the chemistry of the Gorilla brushed on glue is different so as not to fuse the bristles together and as a side benefit, not react with the blue foam.

            Also, I've been looking for the type of soft silicone glue that you identified as Pattex Total. It can be seen in the photo holding the circuit board ('Brick' in RC speak) and motor mount in place. It's easy to cut, as you mentioned, and allows for swapping out the components without tearing the foam. I'll try a search using that name.

      Ara     

[Istvan Travnik]

Ara,
This circuit of questions & variants show the best explanation for that prowerb: "THERE IS NO BEST, OR ABSOLUTE UNIVERSAL GLUE!"
Let's take Pattex Total:
-you can cut by knife, or even plain it by planner (balsaplanner, filled with razorblade).
-it is not comfortable to rasp, or sand it, being rubber-like
-and impossible to cut it by heat-wire, since silicon bears several hundred Centigrades more, than polystyrene foams.

When you need some soft, and heat-cuttable glue, take melting gluepistol, and super low melting pointed ammunition for it.
It is common by us, to fix something correctly, but not for the "ethernity"...
Istvan