Flashcrete Stepping Stone Tutorial

[Lou Ann]

I have done a very limited number of these so I am still experimenting and will update this tutorial as I learn new things... anyone who wants me to add tips, please pm me and I will gladly do so...
 
Pick a work area where the mold can be left undisturbed for 1 - 3 hrs.

See package for water to mix ratio – I left the water at the amount indicated and added Weldbond adhesive in a 1:5 ratio (ex: my mold called for 10 oz of water so I added 2 oz of Weldbond)

the product I am using is call Jennifer's Mosaics Outside Cement -- it is advertised that it dries porcelain white on some websites; however, this is not accurate, it dries more of an antique or offwhite

1.   Verify “black line” shows around all the pieces – more is better than too little.  In glasseye I change the line thickness to 1/8” and I actually cut the pattern away from both sides of the line; smaller pieces I may leave some of the line on them to make them workable but then I cut more of the larger abutting pieces. On printed patterns that are too thin, I trace the line with a thick marker to make it wide enough for the mix to get between the pieces

2.   Cover the pattern with contact paper. This will help get the glass off the pattern once the contact paper is on it – I didn’t do it on one and the contact paper stuck to the pattern paper and I can see a slight difference in the area that was affected on the stone

3.   Make sure pieces are taped to the pattern. Helps keep them in place when you put the contact paper on

4.   Grease mold with petroleum jelly (Vaseline). Smear the bottom and sides pretty good but try to get rid of any ridges or clumps as they will be evident on the finished stone.

5.   Cover pattern with contact paper making sure tight against glass – if the glass goes to within a ½“ of the edge, cut off overlap; if the glass is just a design in the middle, you want the contact paper to go all the way to the edge of the mold.

6.   Turn the piece over and remove pattern and all tape. Smaller pieces tend to want to stay on the pattern so I try and lift just an edge off them and slide a popsicle stick in to hold the piece down while I remove the rest.

7.   Place in mold making sure placed in center – contact paper down. After I put the Vaseline in the mold, I center the glass on the bottom and make sure the contact paper is as smooth as possible then I use an exacto knife to cut off any contact paper that is going up onto the sides of the mold – I didn’t do this on my first stone and there were divits in the sides where the folded contact paper had been.

8.   Dissolve Weldbond in water.

9.   Mix water and flashcrete until completely smooth. Tends to want to stick to the bottom of the bowl in the middle.

10.   Pour into mold. Do this in a spot where the mold can be left undisturbed until set.

11.   Gently tap the sides of the mold to release air bubbles. My box says to do this for 1 -2 minutes.

12.   My box says it is dry within 1 hr. I check it in 1 hr and make sure the mix looks dry (it will go from slick, wet looking to a matte look; I had one take closer to 4 hrs before I felt comfortable and it was still soft on the bottom when I accidentally touched it while taking it out.

13.   Turn face down onto surface. Not sure what is the best to use here – I did cardboard with my first one and it didn’t really stick to it; the second 2 I used packing paper and they stuck bad so my last 2 I tried the shiny side of the paper that came off the contact paper.

14.   Gently peel off contact paper.

15.   Fix any air bubbles. I took a small amount of dry mix and water (really watery consistency) and I went   all over the top of the stone, wiping it off with a paper towel until the air bubbles were filled it; make sure not to leave any small granules on the stone because they will dry as rough spots

16.   Let sit for 28 days before sealing . I buy clear concrete sealer for concrete stepping stones and I plan to use the same with these; just brush it on. I generally do 3-4 coats on the top and sides and 2 coats on the bottom.  


Again glass selection is important; however, flashcrete has a very different effect than the gray of concrete; have not worked with colorants and flashcrete so I don’t know the effect they will have.

[Lou Ann]

Here is an example that shows how flashcrete can impact glass color

This bird was cut out of Spectrum 828-72 S seafoam green wispy...

[Lou Ann]

Flashcrete also seems to have less of an effect on color with glass that is relatively clear...

The UK stone was cut out of Spectrum 136 cobalt smooth cathdral and the UT was cut of Spectrum 171 clear orange cathedral