McKenzie rock mix

[Manny]

My rock mix wont stick to foam.....

I have been carving rocks with the blue Dow foam than trying to add the rock mix over the carved foam, but it slides right off.
I have roughed it up but when I try to add a thin layer of the rock mix it does not stick.

What am I doing wrong ?

Do I need to try and mache the rock first ? ( Will that stick ? )

I usually mold and cast my rocks but would like to make my own little scene. My carved rocks are no bigger than a baseball, and smaller.

Help..... Manny

[George Roof]

Manny, IT WON'T STICK TO FOAM.  You need to coat your foam with plaster of Paris first.   Now it WILL stick if you make it the consistency of gravy and stick after it as it starts to cure, but it's still best to put down a base coat of plaster first.

[Manny]

OK George.. Do I need to rough up the foam first ?

Are we talking like just a splash coat of plaster first ?
Mix the plaster thin like pancake batter ?
Then plunge the whole piece of carved foam ? or paint it on with brush ?

[George Roof]

All of the open cells need to be exposed.  That may mean taking off the "candy coat" to expose it.  I use the method Marcus Zimmerman uses in the "Super Seminar" video series (from WASCO).  It's watery to some extent at first but quickly starts to thicken.  That "in between" transition period is best as I press it against the foam with my gloved hands to insure it's in all the nooks and crannies of the foam.  It should be hard to the touch in 20 minutes or less and you can put the rock mix right on at that time.

[buckfeverallyear]

This works just as well and not near the trouble.
add about 1/2 cup Elmer's white glue to the mix. Mix just enough to apply before it sits up on you. it will sit up a little quicker because the glue drying. I add a table spoon of brown brick dye to color mine.  It will stick to the foam with out doing the plaster thing. Like george said the candy coat (slick shinney side) needs to be ruffed up or burnt i prefer burnt. and that doesnt mean charcoal it. just slightly run propane tourch over it.

[George Roof]

buck, I take it you haven't used the rock mix before.  The entire process is COMPLETE in 30 to 40 minutes.  That includes the painting.  And when you're looking for "rocks" , the dirt doesn't do you much good.  You take a foam chuck roughed up all over and coat it with plaster of Paris - cure time, no more than 20 minutes.  Then you mix up the rock mix like oatmeal.  Add tempera if you'd like, but I prefer the natural gray.  Pat it all over the rock - cure time, no more than 20 minutes.  Then with black, green and/or red water based paint thinned enough to spray through a bottle, mist the rock.  The waterbased paint soaks in someplaces, puddles in others and give the natural patina of moss or sandstone.  If you use the black heavily as your first coat, you get granite and then the green will add an algae tint to your rock face.

[buckfeverallyear]

buck, I take it you haven't used the rock mix before.  

George do you just like arguing or simply BLIND. what do you think the three pics are.  ROCK MIX ! no dirt on them just dye and some paint. Third pix  is rock mix that was applied vertical it stuck its still there and will all ways be there.  Gees George do just have to argue about everthing. Your starting to look like the old man screaming at the kids to get off your grass.  30 or 40 min . humm my way is 5 min. George the problem with you is not the disagreeing with everone its being a prick about  it. To even write you havent used rock mix before is exactly what i mean. Your way is not the only way.  None of what i said was called for. and neither was your opening line. so were even. With that said you should drop it but you wont you cant help your self you will have to repley.  

[R.J. Meyer II]

OUCH !!!!!!!!!!!!

[Jeff Hunter]

I don't see anywhere how George was arguing or being a jerk He was talking about the actual "McKenzie rock mix" that they sell and how to properly use it, not your own personal concoction where you yourself said wouldn't stick unless roughed up or burnt. I think you may have misinterpreted his answer...

[George Roof]

Thank you Featherhorn.  At least SOMEONE can read.

[Wildside]

At least SOMEONE can read.

In reading it, Buck said he adds Elmers to the "mix".  So it appears he does use the mix.

It may set up in the times you both say, but how long to "cure"?

[buckfeverallyear]

I think you may have misinterpreted his answer...

I may of did and if so then i am man enough to apologize. I took the statement  (i haven't used rock mix before ) as meaning i didn't know what i was talking about. when i clearly had pictures posted of rock mix posted.

[buckfeverallyear]

I did this to prove my point this morning 3rd pick is upside down still wet 4th hanging vertical wet 5th ti rockmix stuck to my window (glass)

[buckfeverallyear]

I was still pissed when i made this , this morning , thinking You meant i didn't know what i was talking about.  So it was directed at you George, So if i miss took what you meant by all means i Apologize. for my statements.
Glenn

[George Roof]

Well, since your BVDs are sufficiently tucked up your asscrack, The POINT is that the Elmer's Glue prolongs the CURE time.  If you use plaster of Paris ON FOAM (will not work on your rear window), it will CURE in less than 20 minutes.  Then if you use the rock mix, it, too, will CURE in less than 20 minutes.  Though the mix will retain moisture (LIKE ANY BRICK IN THE RAIN WILL) the "medium" is cured and you COULD give it to your customer with no worries.

Now I apologize if you thought I implied that you'd never "used" it.  What I was implying that if it were used as advertised, suitable results could be had FASTER than if you added Elmer's glue or by adding dextrine to the mix.  Those additions WOULD make the medium more "stickly" however, and if you want some rocks affixed to your picture window, I'm sure this is a much better way.