70 replies to this topic

[KarlosH]

Hallo. This is my amateur method without press. Mouild is made of gypsum. Glue : dextrine.
Hemispheres are enough hard.
http://img34.picoodl...mmm_5f297dc.jpg
http://img33.picoodl...mfm_2364486.jpg
http://img38.picoodl...ldm_7e36ca1.jpg
http://img33.picoodl...esm_ca92b05.jpg
http://img02.picoodl...mmm_652d95f.jpg

[Anders Greenman]

ahhhh finally some info on making hemis tooling they look a bit like giant walnuts how are you going to smoothe them suckers out?

Well, that's the problem. These are already dry and as they dry, they become ugly due to shrinking. It can be controlled with some practice though.
To smooth out the hemis in the mold before they dries and dry them as quick as possible are the general words here. If you can manage that (easy with simple tooling like a smooth ball), you'l have nice hemis

KarlosH: Forgot to comment your hemis, the very best homemade hemis I have ever seen! Looks just as good as commercial strawboard!

Edited by Anders Greenman, 11 August 2007 - 10:51 PM.

[pudi.dk]

Hallo. This is my amateur method without press. Mouild is made of gypsum. Glue : dextrine.
Hemispheres are enough hard.
http://img34.picoodl...mmm_5f297dc.jpg
http://img33.picoodl...mfm_2364486.jpg
http://img38.picoodl...ldm_7e36ca1.jpg
http://img33.picoodl...esm_ca92b05.jpg
http://img02.picoodl...mmm_652d95f.jpg

Only thing I can say: That's really nice!

[Pretty green flames]

Hallo. This is my amateur method without press. Mouild is made of gypsum. Glue : dextrine.
Hemispheres are enough hard.
http://img34.picoodl...mmm_5f297dc.jpg
http://img33.picoodl...mfm_2364486.jpg
http://img38.picoodl...ldm_7e36ca1.jpg
http://img33.picoodl...esm_ca92b05.jpg
http://img02.picoodl...mmm_652d95f.jpg

Oi, those are some very nice shells. Good job. Do you cut the paper to a special form or do you just press the uncut paper into the form?

Cheers

[pudi.dk]

By the look of it, I suppose he cuts out circles and cut them out like a "sun",
stack them and press them, like the professional method, am I right?

[KarlosH]

Hallo. This method is a really easy and very suitable for amateurs. You need only mould, stronger paper, dextrine or another glue and any former. Movement is similar like with pestle in grinding mortar. I pasted every layer apart.
On the picture are two types. First is complicated, but secon on the right is the best. I used white drawing paper, and give 5 layers of paper for 70mm hemisphere, 6 layers for 90mm. Dextrine is really suitable, but is too hygroskopic.

http://img35.picoodl...mim_a398376.jpg

http://img29.picoodl...ekm_35db834.jpg


http://img28.picoodl...lem_f60a7b3.jpg

http://img34.picoodl...nem_1aec696.jpg

http://img36.picoodl...mim_cb10b88.jpg

Good video, hydraulic press and hemispheres.
http://pyrotechnics....g/files/039.wmv

Bye. Sorry, my english...poor.

Edited by KarlosH, 11 August 2007 - 07:00 PM.

[Frozentech]

Hallo. This method is a really easy and very suitable for amateurs. You need only mould, stronger paper, dextrine or another glue and any former. Movement is similar like with pestle in grinding mortar. I pasted every layer apart.

Those are really fine looking hemi's for home-made ! Excellent job.

[dr thrust]

thanks everybody some great ideas! check out that video karlosh has added, great shells(sigh maybe one day) that press looks great iam building a press at the moment, so adding a few bits here and there wont be a prob

[Pretty green flames]

KarlosH, what kind of former was used to make the mould? Did you use a plastic aerial shell?

Cheers

[KarlosH]

Pretty Green flame:

I need optimal size of hemispheres, and I can´t buy acceptable ball in czek shops.
I made mould with easy method. You can try too. You must cut out wheel from aluminum plate, and add rotation axix. This wheel must be fixed in bigger bowl. You must operate with optimal consistence of gypsum. Slowly rotate of wheel forming fovea in the mould. When mould is hard, cutt off margins with knife. When is th mould perfect dry, lackuer this mould etc. with shellac. Mould is resistant and durable. This mould is perfec. Dont worry about size, hemisphers from this mould are sufficient.

http://img34.picoodl...mmm_5f297dc.jpg

http://img33.picoodl...mfm_2364486.jpg

http://img01.picoodl...dem_19f36f6.jpg

Fory drying is necessary this method: http://img01.picoodl...ekm_dadb281.jpg

Plastic hemispheres? Never! Paper is ecological and traditional.

Yes, my englis is poor, I know it, but .......aaaaaaaaaaaaaaaaaaaaaaaaaa >:-()

Edited by KarlosH, 12 August 2007 - 09:50 AM.

[Pretty green flames]

I understand, this is an ingenious idea, very nice.

Thanks

Edited by Pretty green flames, 12 August 2007 - 09:44 AM.

[dr thrust]

whats that "paste" there putting on the shell in the video at 5.05 mins?also how do they get the heart shaped rings shell bursts

[Mortartube]

I can honestly say that I think that the hemis made by KarlosH, are the most professional looking hemis I have ever seen made at home. Excellent work.

[Bonny]

I've started to make some hemis using the method here:http://www.pyroguide.com/index.php?title=Shell_hemisphere
It seems to be working OK, just need more practice cutting in half evenly and straight.
If I am going to use 1/4" timefuse on 3" paper shells, what is the best way to attach it? Should I glue the fuse right into the hemi, or maybe roll a small paper tube, glue that in place and then glue in the fuse?

[marble]

.

Edited by marble, 27 September 2007 - 06:03 AM.