Al Klappenberger Posted February 5, 2005 Author Share Posted February 5, 2005 Chris, The top and bottom are intended to be made of wood. How can a watter jet cut wood withut getting it soaked? Besides, the jet would have to be tilted and held a specific angle from vertical and then move in two directions to form the tractrix curve on both sides. It can't be cut flat. I was just handed the name and phone numbers of two outfits locally with CNC machines. I just need to know what kind of quantity I need! Al K. Quote Link to comment Share on other sites More sharing options...
BEC Posted February 5, 2005 Share Posted February 5, 2005 Al, Having a mold made to make the horn out of composite material is an excellent way to do it. However, for small, quantities, getting the mold built is usually the deal breaker. My quotes on molds for small plastic pieces have usually been in the $5000.00 range. For larger pieces expect $10,000 or more for the mold. Then perhaps a few bucks each for a production run of the parts using the mold. Small parts are just pennys each after buying the mold. Sure wish I could find a cheaper way to get some molds built. I need small quantities of lots of different parts. The economics never seem to work out for me on how to come out on these things after paying for the mold. Bob Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 5, 2005 Author Share Posted February 5, 2005 Bob, $5000! Outch, no way! I'm to small-time and operation for that kind of outlay. If anybody is serious about buying a set of these horns, let me know by email. I am NOT taking orders, I just want to know if I should persue this! I am going to assume that the price will be on the order of $600 to $700 for a drop-in set of two. That may be way off, but it should give me some idea of quantity at THAT particular price just to see if it's do-able at the price. Al K. Quote Link to comment Share on other sites More sharing options...
J.4knee Posted February 5, 2005 Share Posted February 5, 2005 OK Al I remove your "Tease" moniker. I believe your response to Bob should have been Ouch!, as in Ouch factorial. NO offense aimed at Bob on this but start up costs can be a mother to control in custom device manufacturing. I e-mailed you my interest in your project. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted February 5, 2005 Share Posted February 5, 2005 Making a male mold of the horn portion itself should present no real problem. I know people who have made a "plug" of a boat hull and built their own boats. You could build it yourself with standard marine resins and cloth using your prototype for a female pattern. For the horns themselves there is no need for cloth or mat since there is no structural load. A "chopper gun" could build one up in minutes and produce a finish like that of a fiberglass bath tub. Another advantage of the chopper gun is the ability to adjust the density of the plastic/fiber ratio to minimize resonance. A local boat builder might even make horns cheaply with the left over resin from a lay-up rather than throw it away. Rick Quote Link to comment Share on other sites More sharing options...
tigerwoodKhorns Posted February 5, 2005 Share Posted February 5, 2005 ---------------- On 2/5/2005 1:37:09 PM Al Klappenberger wrote: Chris, The top and bottom are intended to be made of wood. How can a watter jet cut wood withut getting it soaked? Besides, the jet would have to be tilted and held a specific angle from vertical and then move in two directions to form the tractrix curve on both sides. It can't be cut flat. I was just handed the name and phone numbers of two outfits locally with CNC machines. I just need to know what kind of quantity I need! Al K. ---------------- Al, If wood is cut on a waterjet, it will get soaked. But, if you cut templates out of aluminum for a router, then router cut the wood, it will not get wet. Without being able to supply a picture, try to picture this. You need to form a compound tractrix curve on the edge. You said that the prototype used a flat piece of wood that was hand filed to achieve the intended results. Picture this. Take the flat piece of wood that you hand filed to form the tractrix curve on each side and "cut" it into 3 thin slices. Each slice is somewhat smaller than the one above such that the edge approximates the intended finished edge. The "slices" are then stacked and the edge looks like "stairs" that approximate the curve. Remember for calculus in engineering school when this method was used to approximate a sine wave using several rectangles. Same theory. Anyway, the edge can then be filled in with fiberglass epoxy. After it dries, very little finishing work will be necessary to achieve the proper tractrix curve (compared to hand filing). I can make you some aluminum templates when I build my ALK's. As far as the transition from the driver to the horn. What about making a plaster model. Cover it with releasing compound and make the transition out of a fiberglass repair kit. (I have owned and restored 60's and early 70's Vettes) This stuff is really easy (but messy) to work with. There is another fiberglas material that is a thick resin that contains the fibers. You just goop it on and let it dry into a very hard finished product (strong enough for repairing big holes in body panels). If you form this into a block with the transition on the inside, you can put screws into the side to attach it to the horn via brackets. This stuff is really strong. The solutions above are both very "backyard mechanic" and "low buck" friendly compared to CNC machining in 3D (or 2D for that matter). Chris Quote Link to comment Share on other sites More sharing options...
tigerwoodKhorns Posted February 5, 2005 Share Posted February 5, 2005 ---------------- On 2/5/2005 3:19:49 PM 3dzapper wrote: Making a male mold of the horn portion itself should present no real problem. I know people who have made a "plug" of a boat hull and built their own boats. You could build it yourself with standard marine resins and cloth using your prototype for a female pattern. For the horns themselves there is no need for cloth or mat since there is no structural load. A "chopper gun" could build one up in minutes and produce a finish like that of a fiberglass bath tub. Another advantage of the chopper gun is the ability to adjust the density of the plastic/fiber ratio to minimize resonance. A local boat builder might even make horns cheaply with the left over resin from a lay-up rather than throw it away. Rick ---------------- Actually, Rick's idea is even easier than my idea above. The entire horn, including the transition can be made of fiberglass (if that is an acceptable material). Chris PS: My offer does still stand if you want to go that route. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 5, 2005 Share Posted February 5, 2005 If chris can make templates even for the baffle opening for the horns, this would allow you to use a router with a bearing, easing the amount of work that would go into building the front baffles for the K-horn and Belle. I will also agree that a chopper gun would also work, just not quite as nice a finish on the outside of the horn as a manual lay up. If you intend to go through with these horns, I would think that you should make them appeal to a wider audience, including those who utilize a horn exposed and sitting naked. With a small amount of hand finishing a manual lay up, and sanding with 40, then 80 grit, it could be textured and painted with a satin or flat finish. Alternately, you could offer a spruced up one for extra cost, and leave the rough finish ones for inside of the hf section of a belle or k-horn. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 5, 2005 Author Share Posted February 5, 2005 Chris, I like the fiberglass idea, but I think wood will be more interesting to stereo adicts than fiberglass. I will definitly keep that idea in mind! I suspect you still do not understand the double taper problem. You can't cut the top and bottom from a template like that. It could only be cut with a vertical cutter (like a band saw) if it was setting at an angle from horidontal. The angle would be half of the angle the top and bottom are fixed at. It is very hard to visualize, but the angle will be 90 deg at the throat and almost "half angle" at the mouth, but not quite becasue the top and bottom do not extend to the extreme edges of the mouth. They would taper to nothing. You have to stop somehwere before that. Al K. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 5, 2005 Author Share Posted February 5, 2005 Chris, This figure lifted from the Bruce Edgar article shows the problem. Notice that the cut will be 90 degrees at the throat and as you turn the top plate and approach the mouth the angle slowly becomes the angle of the wedge. Either the cuttor (saw) has to be at the angle of the wedge, or the top plate has to be. Al K. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted February 5, 2005 Share Posted February 5, 2005 Al, but of course, I am interested! Wood is probably the hardest material to use, though. Think about resin casting; it is the best alternative for dealing with compound angles. It will require 2 molds be made, female and male. Then the appropriate resin selected for the job, and ease of use. Once the molds are made, you are good to go. DM Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 5, 2005 Author Share Posted February 5, 2005 Guys, MAN! I think everybody is telling me it should be of fiberglass! This area where I live is pretty big into boating. There is a boat building company right here in town. I guess that's going to be "Plan B"! AL K. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 5, 2005 Share Posted February 5, 2005 Al, you can build it out of any material you like! I think it cost PWK around "40 kilobucks" for the mold to produce the K-400, but this is different. You could also use kevlar and epoxy, or carbon fiber and epoxy, but they are a lot more finicky resin systems. Good ol' polyester resin and mat will work quite fine. The male mold shold waxed and be gel coated before applying either chopped glass and resin from a gun, or manual lay up. If you want, the gel coat is available in several different colors. If using a manual lay up, it is advised that you use mat instead of woven cloth. First, the binders that hold the mat together dissolve in the resin, and will lay down much nicer than a woven cloth, and second, you will not get print through, as you would using woven cloth, without a layer of surfacing veil ( really thin mat ). Quote Link to comment Share on other sites More sharing options...
3dzapper Posted February 5, 2005 Share Posted February 5, 2005 With "glass" (FRP) you can build the whole horn from the flange to the tail just needing one of these on the tail to install a screw on type driver bolted to the flange. http://forums.klipsch.com/idealbb/files/Adapter.jpg A bolt on driver would need just the proper holes drilled and a suitable gasket. IOW the horns would be universal. Rick Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 5, 2005 Share Posted February 5, 2005 Great idea rick! That would ease the fabrication of the end of the horn. The only thing is that the flange that this adaper bolted to would have to be fabricated seperately and then attached with an epoxy adhesive, unless you can think of another way. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 5, 2005 Share Posted February 5, 2005 This is what the male portion of the mold might look like, if it were made longer than needed at the throat end, and then trimmed using a jig to the correct length. After trimming, you could attatch an flange, again with an epoxy adhesive, using a jig to ensure that it is square with the centerline of the horn. To this flange, you could then bolt the driver adapter that rick proposed. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 5, 2005 Author Share Posted February 5, 2005 At least we are singing the same tune on the adaptor! The one in the photo is one of the adpators I plan to use. I expect to have to make adaptors for the Altec and JBL drivers. Al K. Quote Link to comment Share on other sites More sharing options...
Jim E Posted February 5, 2005 Share Posted February 5, 2005 Hello Al, I guess the fiberglass matte and polyester resin approach makes the most sense. In viewing the fact that there is no way to predict how many of these you might build, a simple male mold would be the easiest and most practical. In high school we made several pick-up truck camper shells and row boats with single molds. The construction of the molds were nothing more than lumber and plaster with a seal coat. We applied wax mold release to the form, sprayed a gel coat and "glassed" the entire surface until we had good thickness. Once the fiberglass cured we removed the new shell from the mold and cut off any excess on the edges. A little bit of sanding and the part was ready for hinges and accesories (windows, seatboards etc.) Good luck Al, I'm really interested in your results on the finished prototype. Keep us updated if possible. Quote Link to comment Share on other sites More sharing options...
Klewless Posted February 5, 2005 Share Posted February 5, 2005 Al, When SpeakerLab was in business over in Seattle, I paid them several visits. We were discussing the Klipsch copy of the midrange horn and the issue of metal alloy vs fiberglass. I believe they were originally fiberglass. They changed because the yield for fiberglass was not very good. Apparently it is very difficult to get consistent quality with it. IMHO this is one of the better topics I have seen. You and Gil are right in there. Thanks to the both of you. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 5, 2005 Author Share Posted February 5, 2005 Klewless, Thanks for the kind words. It's always nice here that sort of thing! I like the idea of fiberglass but I don't know squat about what's involved in doing it that way. Wood has always been supposed to be the ultimate. It certianly won't have a ringing problem! I believe Bruce Edgar makes all his horns out of wood. Even the salid-bowel horns. I suspect he has a reason for doing it that way. If I can get the critical parts made on a CNC machine, I'll be able to make them myself, at least in the warm wether. It would have to be done in my garage! The big question is cost versus quantity. Al K. Quote Link to comment Share on other sites More sharing options...
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