Replies

1. 
   FastEddie1 | Feb 08, 2005 04:10pm | #1

   An ash tray, like one that sits on a desk for cigarettes?  Concrete could be a problem because of the small size of the object vs the large size of the aggregate, and difficult to reinforce.

   You need to think a little larger, like possibly the size of a shoebox.  Need very small aggregate, like pea gravel. 

    

   I'm sorry, I thought you wanted it done the right way.

1. 
   Piffin | Feb 10, 2005 02:06am | #8

   not so, Ed, You can find aggregate almost as small as talcum.I would simply use fine sand and do this as a ferroconcrete project. There are ferrocement conoes that are only about 1/2" thick through much of the body. I recall some sort of a race up the AMazon done in conrete canoes.The wire is laid and shaped int ot he form and the contrete pounded in as dry aas possible to eliminate shrinkage cracks. The from is lined with pastic coating and plastic is used to contain all the moisture and temps kept up around 85° for a week. When I first heard of this, i couldn't believe it, so I took an old thermos bottle with the glass interior. The metal had already rusted out pretty much ( I know that sounds unbelievable enough as it is. how often does a thermos last that long without breaking the glass vacumn insert?) so I discarded that, and wrapped the glass bottle in wire, than applied the mud. It wasn't even a special mix. It was plain old mortar mix with a little extra portland that I was using for man-made stone facing. I smoothed the mud onto it by hand and then wrapped it all with some Saran wrap for the plastic cure. Then I placed it in a warm spot for three days before i touched it. I swear, you could take a hammer and make it ring off that surface without hurting it. I tried. It was ugly and heavy so I never used it as a thermos, but the experiment was interesting.I was intrigued with the properties of concrete for awhile. I once tried making some precst brick surfaced hearths and floor covers for wood stoves. I didn't have all the wherewithal to keep on with the trial runs and solving all the problems I ran into, but I believe in the produict. Had I kept on with things, we might now be buying Piffin panel instead of Hardie boards. I played with the idea of cement shingles too. Have you noticed that you can now buy lightweight concrete shingles and tiles? 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

2. 
   SamT | Feb 08, 2005 04:43pm | #2

   Formed, ie. cast, or hand molded, like clay?

   SamT

   
   

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   Edited 2/8/2005 8:44 am ET by SamT

3. 
   PhillGiles | Feb 08, 2005 06:17pm | #3

   Easiest is a pail, use two plastic flower-pots for a mold.

   .
   Phill Giles
   The Unionville Woodwright
   Unionville, Ontario
4. 
   DThompson | Feb 09, 2005 05:26pm | #4

   What you can use is cement mixed with sand and water but don't make an ash tray, that is ugly, make a replica of those nice quaint red mail boxes you find on your streets.

5. 
   Mongo | Feb 09, 2005 06:59pm | #5

   If it has to be concrete and you need aggregate, then just use chipstone or the smallest stone you can find.

   If it just needs to be made out of cement, then omit the aggregate and use portland/sand, what was already mentioned...essentially, mortar. But no lime.

   Add pigment for color. The same stuff they sell in art stores.

   The aggregate will add a bit of a mottled look and a bit of depth to the look of the ashtray. Mortar will be more uniform in color, sort of bland. If you use aggregate, you can grind the surface for a terrazo look.

   You can toss in a bit of fiber as well. A very little bit.<g> Unreinforced concrete is quite weak in tension, so design accordingly.

1. 
   BillHartmann | Feb 09, 2005 11:46pm | #7

   Or peat moss.Depending on exactly what she is wanting she could do hypertufa.http://www.taunton.com/finegardening/pages/g00117.asp

6. 
   andybuildz | Feb 09, 2005 09:42pm | #6

   you might wanna try using Structolite mixed with plaster....its lighter and easier to work with....
   Be well bloke
   a...

   The secret of Zen in two words is, "Not always so"!

   When we meet, we say, Namaste'..it means..

     I honor the place in you where the entire universe resides,

   I honor the place in you of love, of light, of truth, of peace.

   I honor the place within you where if you are in that place in you

   and I am in that place in me, there is only one of us.

    

    

   
    

    

7. 
   MojoMan | Feb 10, 2005 03:32am | #9

   If I wanted to make an ashtray (Is smoking still legal in the UK?), I'd form a mold with sand in a pot (Think upside-down), cover it with plastic and pour in sand/cement mortar. The suggestion to add color or interesting stone additives is good. Make the mix rich in cement and it should be plenty strong enough to sit on a table and hold fags.

   Al Mollitor, Sharon MA