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Frugal Horn construction videos

Discussion in 'd.i.y.' started by orangeart, Jul 9, 2018.

  1. orangeart

    orangeart KJF Audio Ltd.

    sam_cat and narabdela like this.
  2. chiily

    chiily PFM Special Builder

  3. orangeart

    orangeart KJF Audio Ltd.

    I know!

    My own builds all looked like that, my first kits required people to have clamps as well, I even hired or lent some clamps to early customers which obvioulsy isn't easy to fanny about doing. Then I moved onto partially self jigging but some clamps still needed. After that I spent a stupid amount of time fanying around with CAD and my CNC router and spindle moulder and finally I ended up at a point where truly repeatable and idiot proof perfect mitres without any woodworking knowledge were doable by anyone.

    It was nice at the northwest audio show recently, I did a pair of pencils just in ply, sanded nicely but no finish and a pair of Frugal Horns just hand painted methodically with really good paint and a decent brush to show what was easily accomplishable for those on a tight budget but still wanting a decent finish. Hardly anyone cottened onto them being kits which just goes to show that with almost no knowledge or skill and a small budget you can not only end up with a great sound but something that looks decent with some fun thrown in.
     
  4. h.g.

    h.g. pfm Member

    Making a speaker cabinet without clamps looks like an attractive thing to do but I had thought, perhaps mistakenly, that wood glues required a particular level of pressure to make a good bond. I presume the applied pressure from taping is fairly low? A good bond is normally stronger than the wood and so I can see that a reasonable bond is likely just as good in practise. But what does it take to be confident in getting a reasonable bond with low pressure? Can you comment from your experience (or tell me I have missed something) because it would be a useful to know given that it can be awkward sometimes to get pressure on a joint.
     
  5. Pete MB&D

    Pete MB&D Pete Maddex, the one and only!

    Glue doesn't fill gaps so clamping is necessary to reduce the gap not to make the glue go off, and in real wood woodwork you get no glue line with clamps.

    Pete
     
    orangeart likes this.
  6. orangeart

    orangeart KJF Audio Ltd.

    The tape produces a very strong clamping force as you are applying pressure along the whole joint. It is only possible to use tape however on mitred joints. If you can imagine the mitre closed up without glue or tape, the inside surfaces of the joint touch each other everywhere, now when you add the tape it acts as a hinge, assuming you have the points of the mitres together, folding will bring those surfaces into contact once more. Now add glue to that joint and fold it, there is now a lot of pressure needed to close that gap (as the glue is in the way) the glue will squeeze out of the way, leaving the joint filled with just enough glue and because of the tape holding the mitred points they can move anywhere so there is no visible glue line. This is the method used in most large scale production of mitred boxes and is how almost all box shaped speakers are produced by the big boys. In fact the tape holds things so tight that 45 degree mitres are normally cut at 44.75 degree other wise it's almost impossible to close the joint.

    These types of joining glues (PVA) are essentially thermo-plastics that cure, they don't require pressure like impact adhesives or the pressure sensitive adhesives used on stuff like sticky back plastics.
     
    h.g. likes this.
  7. h.g.

    h.g. pfm Member

    Thanks for the explanation. I can now see how high pressure is being applied by the tape/mitre approach and that it does not offer a solution for gluing awkward butt joints.
     
  8. Pete MB&D

    Pete MB&D Pete Maddex, the one and only!

    What’s awkward about a butt joint, they are usually at 90deg so a clamp will pull them tight.

    Pete
     
  9. orangeart

    orangeart KJF Audio Ltd.

    What Pete said.

    The reason I moved this way, and away from rabbets, is two fold, firstly it looks nicer especially if you don't want to paint/veneer but most importantly my customers were having to spend as much on clamps as the kit which defeats the object. Now I may think that all real men should have enough clamps in the garage for every eventuality but not everyone agreed!
     
  10. Pete MB&D

    Pete MB&D Pete Maddex, the one and only!

    You can never have to many clamps, or routers (8 at the moment)

    ;)

    Pete
     
  11. orangeart

    orangeart KJF Audio Ltd.

    I've only got 4 routers, mind you, the one in my CNC router is 3Kw and water cooled so that makes me feel pretty manly.
     
  12. Pete MB&D

    Pete MB&D Pete Maddex, the one and only!

    Still it's only 4...

    ;)

    I have 2 1/4" Hitachi's, one with a chamfer bit one with a round over :)

    Pete
     
  13. orangeart

    orangeart KJF Audio Ltd.

    My biggest is a 3¼ Hp Triton dual mode, it's really nice. I've got a smaller Hitachi (maybe the same as yours) in a router table.

    :)

    My CNC router uses solid carbide bits ;)
     
  14. Pete MB&D

    Pete MB&D Pete Maddex, the one and only!

    I use solid carbide slot drills in my routers, I have a 1/4" that just won't blunt.
    In fact I use lots of slot drills I had a 6mm and 10mm adapters so I can use them in my 1/2" routers (3)

    Pete
     
  15. chiily

    chiily PFM Special Builder

    Router envy...
     
  16. bugbear

    bugbear pfm Member

    I've got a couple of nigh-endless rubber strips - you just wrap them on, no "softening" blocks needed. More wraps = more pressure.

    I made them by spiral-cutting 1" strips out of lorry inner tubes (free from your local QuickFit).

    Effective and FREE!

    BugBear
     
    orangeart likes this.
  17. df_genius

    df_genius Solder slinger

    Great vids, Frugal Horn's (and the XL's) are a stupidly good speaker for the money and effort required to make a pair.
     
    orangeart likes this.
  18. orangeart

    orangeart KJF Audio Ltd.

    Why, thank you.
     
  19. chiily

    chiily PFM Special Builder

    I thought the tape and hinge idea really good, especially for perfectly mitred edges, something I could never achieve with a circular saw in my back garden. :) I went for biscuits in the butt joints for my speakers. These I found easy to get right, giving almost perfectly aligned and very strong joints.

    I'm still keep lusting after a pair of James Egro IX speakers from your site and now I've seen the video I'm even more keen. Would it be worth adding a free roll of that tape in with each speaker flat pack??
     
  20. orangeart

    orangeart KJF Audio Ltd.

    Well probably not free, it's expensive stuff! I've been trying to order a whole box but the manufacturers are a bit of a pain to deal with!

    TBH, frog tape or equivalent does a good enough job.

    The Ergo IXs are even easier as you've only got the 4 edges to line up and the front and back baffles are inset. I might do a video about them at some point but the interest in them seems to have disappeared at the moment. Shame they are a great speaker.
     

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