Hi Gai

Thanks for the clarifying for me the points in my previous post.
I exploded the group of Dome Pieces and now I am able to access each piece individually without entering a group. I indirectly learned about the Explode Function.

@unknownuser said:

(or don't care about the other instance if it is not too much in your way)

I don't really care about the other instance as it doesn't come in the way though I will start making use of that function of hiding similar.

Now comes a small problem
I've managed to intersect the entrance and clean whatever is not required.
Now I am at a stage where I need to close of the face of the entrance but every time I draw a line from 1 end point to the other, it doesn't close the face. Please assist me.

Thanks
Regards
D0me

Dome X 5 - Opening-Cleaned.skp

Hi Gai

I’ve gone quite far but a few questions and minor problems arose and are discussed below.

While following the tutorial, I came across a post where you said my dome is upside down. How do I check if I’ve made this mistake again or not?

After continuing further, I came across this image where you mentioned some extra line segments and to delete them but I can’t seem to find them on my current model. Are the segments there somewhere and I am just missing it?

After creating my slicing plane, I positioned my rotate tool on the slicing plane till I got the inference (Intersection in Group (Rotate Tool Is Green)) and then I dragged the tool up until I got an inference saying “On Blue”. I then grabbed the corner of my slicing plane and moved it to the nearest midpoint. It did snap to the Midpoint but the inference I got was End Point though I could physically see my slicing plane on the midpoint. Is this anything to worry about?

You mentioned here that you temporarily Grouped Everything, do I did the same by selecting everything and right click > make group.
Now I am at this image . This is what I’ve done so far. I double click my dome which still has everything grouped except the newly created arch entrance (At this stage, I’d like to ask whether all the pieces of my dome should still be grouped as you mentioned here that it is a temp grouping). Once I enter the editing context of the group, I triple clicked the left dome piece to get inside of the geometry. I then right clicked and selected intersect with model. After doing this, I used Ctrl+H to hide the rest of my model but now my dome doesn’t look like yours found in this image .
I have a backup before intersecting the model and I may have a backup before the temporary grouping if we need to go back a few steps.

Thanks
Regards
D0me

Dome X 5 - Opening Arch Intersected.skp

Hi Gaieus

Once again, I am at a jam. Well not really a jam as I managed to find a tedious solution but Im curious to know why this happened.

When I double click on a group and try selecting my 2 semi circles so I can set my path for the follow me tool to follow and create the dome, I find that small bits and pieces of the semi circle are selected rather than how I am able to select the entire semi-circle on your model with one click.

Any idea why it would do that?

Thanks
Regards
D0me

Dome X 3 - Additional Arcs.skp

Hi Gaieus

Thanks, didn't even realize that there was some left over circles on the model.

Now I can proceed.
Will keep you updated on my progress and surely drop by with any issue I experience.

Take Care
Regards
D0me

Hi Gaieus

I've been trying to do that since yesterday but instead of clicking once on the semi-circle, I ended up double clicking, which is probably the reason I was unable to group it.

I have managed to group the arcs with the 2 semi-circles but I did notice a slight difference between your model and mine.

I have attached images explaining the difference.

The first image is my model and the 2nd image is yours.

Should I be concerned about what I noticed.

Thanks
Regards
D0me

Dome X 3 - Additional Arcs.skp

Hi Gaieus

I've started redoing this exercise but didn't get too far.

I came up to this point and then couldn't get further.

I noticed in the link mentioned above, you said that the ideal solution was somewhere between yours and mine. I downloaded the version you uploaded there and tried looking at it to see if I can find my way around. I noticed that both arcs in your version were made into individual groups using the same circle. My guess is that 2 circles were created with the same radius.

I also noticed that the ARC's in my sketch (attached)are not as smooth as the ones you created found in the link above (Edit: After posting, I rechecked my sketch and realized that i forgot to set my segments for the arcs to 24. After doing so, it looks much more smoother and rounder. I have attached the sketch with the new line segments on the arc. You will also notice that I have added additional arcs on this new sketch. My sketch will have a total of 5 domes piled onto each other as can be seen in the sketch.)

Thanks
Regards
D0me

Dome X 3.skp

Dome X 3 - Additional Arcs.skp

Hi Gaieus

Thanks for the response. I will go through the link you gave me and follow through to make the pattern I require for the floor

With regards to the Dome, I will follow through the tutorial from the beginning of this thread.

I will start by first creating the cylindrical 2" pole in the center of my first circle and then start drawing the domes around it. Will that be the correct way to start or should I first do the domes and then fit the pole in and then intersect?

With regards to the entrance, I will play around with putting it into a single segment and see how far I get. I will update my progress here and if its OK, request assistance when need be.

A quick question. Since this dome will now be divided into 4 pieces, what should the segment count be. I know that we originally made it 24.

Thanks
Regards
D0me

Hi Gaieus
I trust you are well.

Seems like a long time since posting here. Actually missing all the challenges I had in creating this dome but let’s see what the future of this project holds.

I’ve been doing a bit more thinking (Never really stopped) and I can safely say that these are the new dimensions of my oven. By following through this tutorial, I will be able to do this without much heartache but there are a few more additions and possible subtractions to the current design.

I will list them below if it is OK.

1. The cooking floor size will be 15 Inch radius
2. The dome size will be 12 Inch radius. The dome will sit on the floor and will be 13 Inches high. The dome will be 3 Inches thick and will be a neat fit to the edges of the floor. Below this dome will be another dome that is 1” thick and below this 1" thick dome will be another dome which is my Sand Dome and my main guideline for building the final dome. There is no real thickness to the Sand Dome as it will cover all of the area below it.
3. In the center of the dome will be a round pole with a radius of 2 Inches as suggested by Chris. The dome will sit against this pole creating a bevel at the top.
4. The dome will be divided into 4 equal pieces.

That’s all that I can think of that has changed from the previous design. I should be able to proceed with steps 2 and 4 comfortably.

Step 1 is a little complex for me as the floor will consist of bricks and these bricks come cut into a size of more or less 230mm(length) X 114mm(Breadth) X 76mm(height). I am still sourcing out these bricks but this I believe is the standard size unless I find someone who has a different size. Is it possible to sketch these bricks over the concrete slab from the center of the slab going in a Herringbone pattern and eventually ending up with a radius of 15 inches. Also will it be possible to tell me how many bricks I would require and how many bricks would have to be cut to specific sizes to achieve this pattern.

As for step 3, please can you assist me there as well.

I hope all this makes sense but if there’s any further explanation, please let me know.
We don’t have to start with this right away but I thought I’d pass the plans through you so any preliminary planning can be done and we can answer anything that needs to be questioned.

Look forward to hearing from you
Regards
D0me

@unknownuser said:

DOme, I am beginning to think you are really some kind of maniac.

Ouch!!! "Maniac", that makes me sound crazy. I would rephrase that to a more appropriate word like, "Determined".
I know what you getting at Chris. You feel that for a start, I should work with materials that are cheap and would result in less damage to my pocket and my project.

Never the less, I did do a considerable amount of research here and feel that I am truly ready to use refractory Cement. I admit that sometimes I use the wrong terminologies when referring to certain materials, but I do know the difference between the two and will try not to mix them up in future.

I really appreciate your concern and will keep the safety tips in mind like rapid hardening of refractory cement and exploding of concrete.

Thanks
Regards
D0me

@tig said:

I have redone it for you - since the shapes weren't 'manifold' I've fixed them...
The figures are in cubic meters - not an area.
You'll probably buy cement [concrete] by volume if it's bagged [you need to buy it in 'steps' anyway - so pick the next size up] - if it's to buy by weight then get an estimate of the equivalent volume from the supplier...
The '1%' accuracy is how accurately you let it calculate - the more accurate it is the longer it takes to do - 1% is the size of a walnut and you'll spill more than that pouring it into the molds
The green/yellow dome is ~0.067 cubic meters, the red one is ~0.159 cu.m and the white entrance 'arch' is ~0.11 cu.m...
[assuming you made it to scale = 1:1 and the parts intersect properly ???]
[attachment=1:3cp7me2g]<!-- ia1 -->Learning--Fixed--Latest.skp<!-- ia1 -->[/attachment:3cp7me2g][attachment=0:3cp7me2g]<!-- ia0 -->Learning--Fixed--Latest.png<!-- ia0 -->[/attachment:3cp7me2g]

Tig: thanks for working this out. Now I can attempt working out the volume myself and I can use your numbers as my guideline. Once I can accurately find my way around this neat plug-in, I can then confidently do this when I redo my dome in a different size.

With regards to the accuracy, I'm guessing the higher I make this, the more room I allow myself for wastage. This being my first ever such project, I will have to increase this number as I can anticipate wastage due to my inexperience.

As for the model being on a 1:1 scale, I think it is so, as all the dimensions I'm going to use on my real model will be exactly the same as the sketch. Gaieus can confirm this for us though.

Lastly, the arch. The volume of the arch is not the whole arch piece as you have it displayed but rather the protruding part of the arch that sits right at the mouth of the dome which I think is +-2" (Sorry, I'm replying from my mobile so don't remember what thickness this was). I'm sure this can be sorted out quite easily.

Thanks a mil for all the help.
Regards
D0me

Hi Pilou
Thanks for pointing out the Volume Calculator. Never new this existed but then again never new Sketchup existed and after finding it, I never new its power until my mentor, Gaieus tutored me.

TIG thanks for the calculations.
I am busy downloading the plug-in and hopefully find my way around installing it.

@unknownuser said:

Volume ['by Integration'] ~= 0.227 cu.m [@~1% accuracy]
that's the whole thing - both inner+outer [with entrance]...

Sorry if some of my questions seem silly but my knowledge on these calculations is really limited to say the least.

1. I will tell my supplier that the cement I require should be enough to cover an area of 0.227 Cu.m (Cubic Meter's, "Am I right"). Is there any other way I can explain to them the area that needs to be covered as sometimes its surprises that these guys sell products that they know nothing about so the more detail I give them, the better.

2. What does [@~1% accuracy] mean?

3. Lastly you mentioned this is the volume of both the inner and the outer incl the entrance. If we look at the file found here the inner dome is shaded in green and the outer dome is shaded in red. The inner dome is 3" and the outer is 4". Is it possible to get the surface are of each piece individually as the 2 domes (Green and Red) are separate material all together.

Thanks

Hi Guys

It seems like such a long time since last posting here.
Actually feels like something is missing from my daily routine.
I trust all are well.

I need some assistance.
I need to calculate the surface area and volume of my dome as it stands right now.
The reason for this is I need to know how much of cement I require to build this dome and the only way for me to know this is if I know the surface area of my dome. Also guys, don't forget to take into consideration the opening in my dome.

Do you'll by any chance have a formula for this and can you'll assist me with doing the dome size as it is in this thread as an example so when I redo this whole exercise, I can follow the example.

Thanks
Regards
D0me

@unknownuser said:

a vibrator isn't a joke.. it's a real tool used on many jobsites
http://www.amazon.com/b?ie=UTF8&node=552994

you don't have to buy one as most equipment rental places will rent them for cheap (~$20-30 per day)

it wouldn't really work for you unless you used a mold or were pouring something somewhat level.. if you vibrated a dome built as chris is suggesting then none of the concrete would stay in place.. gravity would basically be amplified and all the mud would end up on the ground.

an alternative for smaller projects is using a regular drill.. turn it on then rest is against the forms.. or, tap the forms with a hammer (though don't rely on that method to fill all voids)

I will keep the vibrator in mind. Whatever helps to do a better job is needed. Should I vibrate my cement after it is mixed? Also, what suggestions do you have for mixing the cement as I believe those commercial mixer can be expensive. Is there any cheaper economical method or make shift tool that one can use to mix the cement?

@chrisglasier said:

@d0me said:

...

As for experimenting, well that’s what I would be doing but keep in mind that this type of a project is costly. If my experimentation goes wrong, it will impact on me financially which I can’t afford to happen though I wish I had the funds to play around with a project like this. I would like to be prepared going forward. Once I have all the preliminary steps sorted, I guess the next steps will be pure experimentation that can’t go too wrong.

...

Also, what type of sand do you suggest I use to make the sand dome?
Lastly, how do I attach the dome to my floor of the stand which will be my concrete slab?

Why not keep the first one super simple and super cheap. Use clay and sand as I did. Use 50 mm of sand and firebrick as the base. (Concrete will blister (spald) under heat.) Draw circles on the brick base for the sand and the clay. Mark a small pipe with the height of the sand and finished top and stick vertically into the centre of the sand mould when it is sufficiently high. Make a curved screeder out of plywood. Hold the top of the screeder against the mark on the pipe and move with reference to the circle on the bricks and up and down if too short. This will work fine with sand but you will need to lightly press the clay to show the high and low points, then correct by hand or trowel. Of course making a spinner would be more accurate.

For the sand go to the beach or builders merchant and see what will stand firm when slightly damp.

Your dome will be fantastically heavy; it will stick to your base by gravitational stickion.

Bon chance!

Chris

Simple it shall be. To be honest, I was getting ahead of myself. I explored all different oven options and chose the one that is of a "World Class" stature so to say. I failed to realize that I am a total beginner at this and should first wet my feet by doing it simple and easy at first before sinking all the way in as how professionals do it.

I still choose to use refractory cement. I will make a sand dome using a spinner screeder. I will do everything directly on the surface where it will stay. I will need this to be mobile as I don't have space to permanently place this and will bring it out as I need it.

Thanks for all the advice guys.
I guess I would have found myself in quite difficult situation if I chose to go the route I initially decided upon.
BTW keep the tips coming. If anything pops up, let me know.

Regards
D0me

@gaieus said:

OK, I see.

Well, in any case, D0me should now be able to remodel the whole thing in whatever variation!

Gaieus, with regards to the extent you have taken this lesson to, I can’t disagree.
Remodeling the dome differently shouldn’t be a problem at all though I may nudge you here and there for some assistance.

@chrisglasier said:

Cracking on reasonably thick casting is most often from poor compaction. I doubt you have a vibrator handy but ...
Chris

A vibrator would come in handy, I see. Pity I don’t have some lying around the house. I probably would need to invest in one.
On a more serious note, what sort of light weight, inexpensive equipment would you suggest I use to vibrate the cement after it is mixed with water. I guess this will remove air bubbles and compact it further lessening the probability of cracks.

@unknownuser said:

As for the other questions I suggest you experiment. You can make most of what I suggest from offcuts or trash.

I guess the best viable option for me at this time is to cast the dome in 1 piece as you have suggested.
As for experimenting, well that’s what I would be doing but keep in mind that this type of a project is costly. If my experimentation goes wrong, it will impact on me financially which I can’t afford to happen though I wish I had the funds to play around with a project like this. I would like to be prepared going forward. Once I have all the preliminary steps sorted, I guess the next steps will be pure experimentation that can’t go too wrong.

I guess having a wooden spinner with various thickness options in 1 doesn’t seem doable but if you or anyone else has some idea, please enlighten me.
Also, what type of sand do you suggest I use to make the sand dome?
Lastly, how do I attach the dome to my floor of the stand which will be my concrete slab?

BTW nice pics. Is that your oven?

The rest of the steps in my 13 step process seems fairly in order.

Thanks
Regards
D0me

Hi Guys

Jeff, the reason i chose to do this in 6 parts is because someone told me that casting it in 1 piece may cause the dome to crack due to Expansion and Contraction due to the extreme heat the oven will produce. Also, the oven will probably be moved around and this could cause further damage to the dome but this may not be true. Maybe you can give me more insight?

Crushed Fingers!!! Ouch, don’t want that to happen else I would have to add medical bills to the budget .
I looked at the model you created and seems like a good way forward.. There are 2 concerns however.

1. As you mentioned, I would need equipment to lift the dome out from the mold and this could be costly.
2. How do I go about physically making the mold you drew? Will it be difficult and complicated?

Chris, thanks for the explanations. It makes more sense now.

Gaieus, the sections were only for the mouldings and I guess that would change now since Jeff and Chris explored new methods to do this.

I think the best route for me right now, cost effective and less complicated is that which Chris mentioned. If it's ok to go ahead and cast this oven in 1 piece (Jeff and Chris can help decide this), I would proceed with the following sequence of events.

1. Place the spigot centred onto my base board.
2. Stick a pole into the spigot. How thick should the pole be?
3. Fit onto the pole a wooden spinner. Is it possible to have 1 spinner but allow me to have it such that it will be a guide for different thicknesses as I go along plastering my dome?
4. Start building my Sand Dome around the pole until I reach the thickness of the starting point of my inner dome as I have pointed out in red on the picture attached.
5. Once I have reached the first layer of my inner dome using sand, I will remove whatever attachment or contraption you created to allow me different thicknesses on the spinner.
6. My spinner will now have a new thickness which will stop at the end of the inner dome as pointed out in green in the picture attached.
7. I will begin plastering my refractory cement onto the sand dome and this will end at my current spinner thickness which will be at the point shown in green on the image.
8. I will then once again remove whatever attachment or contraption we create to cater for new different thicknesses on my spinner.
9. My spinner will now be at a new thickness and different point or guideline for my dome as I have pointed out in purple.
10. I will repeat step 8 only this time using insulation as my material, and this will stop at the point or guideline of the spinner as pointed out in purple on the image.
11. At this stage, I will remove the pole and indirectly this would create the bunghole or not? Chris, you can guide me further with regards to the bung. Never the less, I will pour sand into the area where the pole was and then fill is with cement and insulation.
12. After completing, I can dig out the sand through the oven opening and then work on further cosmetics to the oven. I can say that once the dome is created, the hardest part is done.

I guess that would now complete the dome in one entire piece.
I was wondering whether I should cement the dome as I am plastering each layer to the surface of my stand (which will be a concrete slab) rather than cementing the entire piece after it is done as this will be harder requiring me to pickup the dome and then place cement and set the dome into that cement to hold it in place on my concrete slab..

Sounds easy in 13 steps but I know I'm in for some surprises along the way but I'm preparing myself for it.

You guys have brought me a long way that I don’t need to tell you to please change anything that may seem a miss.

Look forward to hearing from you'll

Regards
D0me

Hi Gai

I'm not technically orientated either but because I have been researching this oven a bit, i can grasp a little of what Chris is saying.

Hopefully Chris and the guys here can detail this a bit more in simpler terms so we can put pen to paper or should I say Mouse to SU.

Thanks
Regards
D0me

Hi Chris

Thanks for that. I think we have something going here.
Sounds like a plan to me.

My apologies for the questions to follow. To be honest, some of the terms are gibberish to me but I more or less understand it in context so I'll try and re-iterate what you just said in my own way and please correct me if I am wrong.

1. A Spigot - My understanding of this term after googling it, is a plug for the bung hole. I tried to find some pics of it but nothing really. Do you know of any? After reading further down the page, I notice u mentioned the spigot needs to be attached to the base board, so I'm little confused here.
2. Screeders - From what I've read Here, a screeder is someone who levels and removes air bubbles from wet concrete.
3. Collar - What sort of collar should I ask my hardware store for?

I got a good idea of what you have in mind, just need to get more detail on finer bits.

Gai: Is it possible for us to draw whatever Chris has mentioned, basically labeling each item so I can get a much better understanding of how this puzzle fits together.

By the way Chris, your idea is brilliant. It will save me money on creating a mold, as well as time and effort in learning how molds are created. As Jeff mentioned, you need to have experience with Complex Curved Construction. Maybe if this oven is a success and I do decide to go commercial, I can look at a mold at a later stage or just stick with this method, whichever works best.

Thanks

Thanks Gaieus

Hi Gaieus

Currently, Chris is assisting me with further design options on the dome.
He feels that there may be certain flaws in my design and we are currently working and rethinking the design as a whole. I would really like your input as well.

Thanks

Hi Chris
Sorry to keep you from your work

I understand where you coming from.
Just out of interest, why did you set the caption "DOmes for developing countries"?

Anyways, when you have some time, could you put your words into a picture. What I mean is if I see what you mean as an image or sketch, I could visualize this better and maybe will proceed further using this method.

Thanks so much for taking the time out to assist.
Sorry again for keeping you away from work.

Thanks
Regards
D0me