http://www.youtube.com/watch?v=jQ-aW...eature=related
Watch the link, just scan your horn into the PC and print!
http://www.youtube.com/watch?v=jQ-aW...eature=related
Watch the link, just scan your horn into the PC and print!
If you can remain calm in a crises, you don't understand the situation!
I got to get me one of these!!!Originally Posted by jcrobso
http://www.youtube.com/watch?v=jQ-aW...eature=related
Watch the link, just scan your horn into the PC and print!
Man, technology is really amazing
That stuff is rather old now. You will not like it so much when you see the price
Allan.
How much do you think will cost?
Here are a 3D cutted horn but this time on plywood and have the same topology....and not cheap at all:
http://gtsound.web.infoseek.co.jp/en..._horn01_e.html
http://gtsound.web.infoseek.co.jp/en...roducts_e.html
A short BBC clip on how to reproduce... by machine.
http://news.bbc.co.uk/2/hi/programme...ne/9550469.stm
To create an entire horn? Depending on horn size it could be a few grand... and the material isn't going to be sonically as good as sonoglass or some other very dense resin.
Widget
Well a simple two halves plaster mold will do it for a couple of copy´sWell, I started this thread in order to keep another one clean
When I have an original horn that I want to replicate from resin. What are the different types of molds that can be done. Obviously, we are not talking injection molding here. I am familiar with rotomolding, but I don't think t will be cost effective to CNC an aluminum mold for such a project.
So, Rich, share your experience
One step higher will be a resin mold with a solid wall
My experience of plaster is of extreme shrinkage ,not to mention the fragility . I would not waste my time. If you tare the release it pulls away the surface of the plaster . The release I use is water based and spray applied . Washing the release off to to re-aply is fraught with danger . If you use a wax based release , patching would be impossible .... You would need to remove all the wax to ensure a good finish . All these variables considered , you would be better off making them individually in wood if you only want 2 pairs
another 2 cents worth .
You are rigth, I usually pour wax on them and forgot the release coat needed for the resinMy experience of plaster is of extreme shrinkage ,not to mention the fragility . I would not waste my time. If you tare the release it pulls away the surface of the plaster . The release I use is water based and spray applied . Washing the release off to to re-aply is fraught with danger . If you use a wax based release , patching would be impossible .... You would need to remove all the wax to ensure a good finish . All these variables considered , you would be better off making them individually in wood if you only want 2 pairs
another 2 cents worth .
I will try a acrilc spray coat on the plaster surface of the mold ( spray it to the point the plaster wont suck more ) followed with wet sanding..then the spray coat
You can deal with the shrinkage using medical plaster bands in thin layers, but require practice
the same with the spray and sanding..multiple coats on black and grey automotive paint and a lot
of wet sand to grain 1500 wil produce a perfect ( is very easy to notice defects just locking at
the mirror image ) surface for a mold.
For a "production mold" I will follow the same procedure on the original and then do a mold
in resine 50% and fine grain quartz 50...dont try to do a one piece molde.
Just got TAD 4002 drivers and hopefully will try to build some horns
There was a link to a company that produces JBL's horns. Anyone have that URL? I forgot to bookmark it!
here is the thread:
http://www.audioheritage.org/vbullet...-horn-supplier
Did one of you contact these guys?
I talked to them at the SF AES conference... what do you want to know?
Widget
Im a DT school teacher by trade, and forgive me but all these processes seam overkill for what you want.
Just vacuum/pressure form it.
Get a large sheet of vac form plastic (HIPS) in the thickest gauge you can get your hands on (3mm?)
heat it up till it goes floppy,
place it on a flat board (kept warm)
place your horn on the top, mouth down, with a 'bung' in the top that acts as an adapter for a vacuum cleaner,
suck all the air out,
leave for 1 min.
pull the mould off.
voila!
It will take you at least 2 attempts to get the temp right. As long as the horns throat continuously increases in size from the entrance to the exit your alright.
The only problem is that your finished product will be smaller than the original by the thickness of its wall (think russian dolls). What you would need to do to correct for this is to make a negative mould of the original first, then vac form over this instead, making a positive of the negative= original.
The finished product will be stiff'ish' but you will probably want it stiffer, so just wack some fiberglass on the outside while its resting on the male mould (keeps its shape propperly while the fiberglass dries)
Dear DT teacher ,
You wont get the detail with this method . You need sharp corners . To achieve this the plastic would need to be almost molten. Have a look at some horns . They do indeed flare both ways . BTW, please explain how you get polyester or epoxy to bond structurally to acrylic or perspex ?
Rich
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