Posts: 272
Threads: 0
Joined: Jan 2007
Location: Warrenton, MO
I have a hollow project that, when finished, will be a little top heavy. Plus I don't think it feels right when you lift it. The bottom has a cavity 10 inch diameter by 3 inch deep. I thought I could fill this with some kind of plaster to get the desired effect, but I'm not familiar with casting products, procedures or techniques.
Help! Can I use casting plaster or plaster of Paris? Which would work best? Would something else be more suitable? Thanks for any help.
Was living the good retired life on the Lake. Now just living retired.
Posts: 2,001
Threads: 1
Joined: Aug 2016
(06-22-2024, 11:29 AM)Eurekan Wrote: I have a hollow project that, when finished, will be a little top heavy. Plus I don't think it feels right when you lift it. The bottom has a cavity 10 inch diameter by 3 inch deep. I thought I could fill this with some kind of plaster to get the desired effect, but I'm not familiar with casting products, procedures or techniques.
Help! Can I use casting plaster or plaster of Paris? Which would work best? Would something else be more suitable? Thanks for any help.
Will moisture from the plaster of Paris cause a issue ? Would dry sand work ? Blocks of wood ? Hard to say without more info. Also how much weight has to fit in the hollow section ? Roly
Posts: 272
Threads: 0
Joined: Jan 2007
Location: Warrenton, MO
(06-22-2024, 12:39 PM)Roly Wrote: Will moisture from the plaster of Paris cause a issue ? Would dry sand work ? Blocks of wood ? Hard to say without more info. Also how much weight has to fit in the hollow section ? Roly
Good question. First no weight requirement goal. Just too light as is. The piece looks substantial but the weight would feel cheap. Like picking up a bronze statue to find its made of foam.
I would spray outdoor poly into the cavity first to reduce moisture issues but unless the plaster swells (does it?) I don't foresee an issue. Wood is too light. Sand in a bag would shift. Good idea though.
Was living the good retired life on the Lake. Now just living retired.
Posts: 10,720
Threads: 1
Joined: Jan 2006
Location: Orlando, Florida
Water will not dissolve plaster of paris. In fact, water is what causes it to cure. If the entire volume of the cavity is filled with plaster of paris, you'll get a little less than 20 lbs of weight in the base. Not knowing what you have on the top, I can't tell you if that's sufficient to keep things upright. If you believe that's sufficient, then I would recommend lining the cavity with wax paper before casting the liquid into the cavity. That way, you're not exposing the wood to moisture during the cure.
Still Learning,
Allan Hill
Posts: 12,898
Threads: 0
Joined: Jan 2010
Location: Lewiston, NY
I have filled cavities with dry sand. Easy to use, easy to remove if you leave a lid. Other options are gravel or lead wheel weights.
John
Posts: 691
Threads: 0
Joined: Apr 2003
Plaster not a good idea in wood. Use BB's
Posts: 69
Threads: 0
Joined: May 2023
06-22-2024, 11:59 PM
(This post was last modified: 06-22-2024, 11:59 PM by TABlank.)
I made hollow column speaker stands with a removable base for a grandson. He filled sandwich bags with sand, taped the bags shut, and stuffed them in the columns. Stand up the column and the bags all settled in the bottom of the column. No problems to date.
If you need more weight, there is a "heavy" sand shooters use to fill their benchrest bags. Lead bird shot might work too.
TB
Posts: 21,943
Threads: 0
Joined: Oct 2003
Structural concrete is heavy and cures in 15 minutes.
Gary
Please don’t quote the trolls.
Liberty, Freedom and Individual Responsibility
Say what you'll do and do what you say.
Posts: 216
Threads: 0
Joined: Jan 2018
I think Plaster of Lyon might work better....
Posts: 4,445
Threads: 0
Joined: Jan 2005
Lead wool comes in a 5 lb. box. Home Depot and others carry it. I used to make chessmen and filled a cavity with lead wool.
then glued apiece of felt to the bottom.
mike
