Mary,
Consider not removing the riveted parts, but instead using damp sand to cover them. Then covering the entire inside with a thin sheet of plastic, such as a dry cleaner bag.
My weber lid only had the handle at the top, which would be at the bottom of the form if doing the construction on the inside of the lid. The handle itself (on the outside of the lid)could be placed in the ground allowing the form/lid to sit more level.
No suggestion is doing the building on the outside of the lid.
Happy casting,
dena

Hi Mary
An Angle Grinder is the tool you need to grind these off.
It is an inexpensive tool (as low as $15) and very handy for also grinding, polishing, brushing tufa and concrete. Make sure you use eye protection.

I used a drill and drilled from the inside where the rivet was. In 15 minutes, I was able to pop off all the rivets. I then put a the sticky plastic wrap in the grill and used a quick setting concrete to form a bowl. I am planning to put hypertufa (with bonding liquid mixed in) on the outside to give it texture. I have half a sphere with 24 inch diameter.

I forgot to paste the image. That is a 2 liter soda bottle. Still not finished this....... need to get to work!!
{{gwi:73377}}

BB, thats going to make an awesome tufa bowl! I cant wait to see the finished product. What if you did the form twice and put it together? It would make a giant sphere, wouldnt it?

Jo

Jo, I was going to make a sphere with it originally. I thought if I was to do that, I should have put steel diamond mesh sticking out of the end, so that I could join it to the second one. I may do that in the future with another one. But the quick setting concrete made a great start! and could form this in an afternoon.
Mary, hope this helps you.

Neat mold! I don't think I have ever seen this kind of grill lid before. Are they the right age to appear in garage sales ?
Laura

Actually, I think this was the base of a charcoal grill, and I found it at the dump!!!! Oh, what we tufa people won't stoop to!!!!

Hi i have been making hypertufa pots with weber grill,Just use a hammer and a chisel to pop the handles and legs off. I put about five layers of wet newspaper on the outside of the grill. and then about one half inch of tufa mix and then chicken wire ,Then about another inch of tufa mix . in 24 hours pop it out of the mold

That wet newspaper idea sounds great. Never thought of it myself....hmmm. Have any pictures of your stuff? I like to see!!

I am trying to get a picture posted and I am doing something wrong .I will keep trying

Here is a picture of my Tufa Bowl.

Here is a link that might be useful: {{gwi:73376}}

Hi rcp1959,
I want to see your bowl but I'm not able to open the photo. Would you try to resend it please?
Thank you and thank you to everyone who has responded. I'm glad I found this forum. I'm learning this probably isn't as easy as making leaf casts or stepping stones.

Photo works now. Thanks. This is a wonderful shape for a bowl. Did you do anything special to the outside texture after you unmolded it?
Laura

Hi No I didn't do anything to it after I unmolded it. I have made two other sizes also will post a picture sometime

Hi rcp, Great bowl. Thanks for posting the photo. I look forward to seeing your other two bowls. Are they made using a grill form too?