Help! Do I have to make new end caps?

Discussion in 'Archived Threads 2001-2004' started by Casey H, Aug 24, 2002.

  1. Casey H

    Casey H Stunt Coordinator

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    Hey all,
    I first have to warn you this message is going to be very hard to follow, but I am just frustrated (ramble), hope you understand.
    I had one of those experiences this morning when you feel everything you have done is in the toilet. OK, here is the scenario; I was gluing my endcaps together and wanted the inside caps to stay in line with the outside caps (not to shift while the glue was drying). So I drilled 2 - 1/8 inch holes to put 1/8 inch dowels in to hold them in place. Well let me first tell you that it didn't quite work as I had envisioned. It was a pain in the ass to get the 2 pieces together without the dowels breaking off, but I eventually succeeded. So everything was going OK until it was too late last night to change (glue drying) my process. I noticed that after I had inserted the dowel and broke the excess off when I put the weight on top of the stack the compression (now making the dowels a titch too long) caused my caps to set high on one side (think teeter). So now I have dried glue and the caps are not fully compressed on both sides. It means that one side of the caps is compressed with glue oozing out and the other side has a 1/16 inch gap with no glue oozing. One thing I did notice though is the middle where holes line up are as tight as they could be.
    So am I at redo stage? or can I use some polyurethane glue or something to fill in the slight gaps?
    Thank you very much for letting me ramble.
    Casey [​IMG] [​IMG]
     
  2. Casey H

    Casey H Stunt Coordinator

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    Anthony,

    I don't have 2 layers inside so mine would be layers 2 (inside) and 3 (outside). I do have a layer of 1/4 inch ply for the t-nuts. Like I said the gap ins't consistent over the whole cap, just on on side or another and only about 1/16 of an inch or so.

    Thanks, Casey
     
  3. Casey, if the gap will be within the tube, then I wouldn't worry about it.

    Here is what "I" would do. Use Bondo to fill the gap. (you can use poly, but I think bondo would be better at filling the gaps)....fill it well.

    Then when you put the cap into the tube, use poly glue (I like gorilla) to make the cap a perminent fixture to the tube=)
     
  4. Casey H

    Casey H Stunt Coordinator

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    Thanks for the help Anthony! :) I will report back with results.

    Casey
     
  5. Casey, you may want to do 1 additional thing. Since the glue did not give you the bond you want, it is hard to say how strong (still probably very strong) the bond is between the two disks. If you want, you may want to put a few screws in to hold them together. Just do it from the inside so you will not see anything on the outside. Predrill all holes and use a little glue in the hole. Make sure the screw will not go all the way through both disks [​IMG] Stupid mistakes suck!!! [​IMG]
     
  6. Casey H

    Casey H Stunt Coordinator

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    Anthony,
    Thanks for your suggestions! But! I have been bitten by the "it really isn't the way it should be" bug and have decided to redo! WHAT A PAIN IN THE ASS!
    I just don't want to have any problems with the end result though you know? How do you glue your caps an keep them from sliding around while the glue is drying?
    Thanks, Casey [​IMG]
     
  7. Clay Autery

    Clay Autery Stunt Coordinator

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    Casey,
    I've never built a sonosub, but I've laminated large pieces of MDF, plywood, maple, et al... The "best" way to laminate the discs depends mostly upon the tools and stuff you have available.
    Actually, the most precise way to do it (IMHO) would be to laminate two oversized pieces together first and then cut the disc out with a router making multiple passes (from either side if necessary). A plunge router and a circle jig would be of great help here, AND you MUST make sure your pivot hole is precicely perpendicular to the plane of the wood AND a through hole (if you are going to make passes on both sides).
    Otherwise, simply cut two identical discs the same way cutting from one side only and laminate them together...
    Regardless, the lamination process is similar...
    Ideally, you would have access to a panel press and an under-sized (thickness by about 3/64") partial arc jig (with a belt clamp attached to complete the circle). You'd (using a glue spreader preferably) spread the (slow-set) glue as evenly as possible on the mating faces. Put the discs together and set them vertically in the arc jig (which is located inside the panel press). Then tighten the belt clamp down to such the discs into the jig. Then, tighten down the panel press.... Release pressure on the panel press to see what's up... release and re-tighten the belt clamp (as the belt may tend to hold the discs apart a bit). Re-apply the panel press to setting pressure. Release the belt clamp and let dry.
    But you probably dont have these tools right...
    So... Cut the discs. Clamp together dry. Pre-drill for screws over the entire surface of the discs with no more than about 4" between screws.... Pre-drill through the top panel only to clear the screw threads... Then change bits to a smaller size (size based on fastener size) and drill 3/4 of the way through the bottom panel... tapered bit would be preferable... With discs STILL clamped together, drive all of the screws to almost completely in (about 1/16" up).
    Mark the outer edges in three places with reference marks for re-assembly of the discs. Take screws out...
    Pull discs apart and spread both mating surfaces with slow-set glue. Re-align and mate discs together. Start in the center (dip each screw in a bit of SLOW-SET glue if you plan to leave them in), and HAND start each screw to make sure you use the same threading you created earlier... After they are all started, then begin tightening the screws down from the center and work outward in a circular pattern to squeeze the excess glue out of the middle of the panel to the edges and to prevent lumps, bumps, and voids... Tighten all screws... Let dry... Voila, properly aligned and VERY solid end cap...
    BTW, plan your screw holes NOT to interfere with any other cuts you need to make or fasteners you need to install.... that is if you leave them in... If you pull them, remember that you need to fill all those holes with something that will completely displace all the air and set at least as hard as the MDF.... I would use a 2:1 thin epoxy with a syringe...
    BTW, this is the anal retentive, over-engineered way to do this....
    Easy way... same procedure... like six screws... slap em together, clamp with screws, and move on.... [​IMG]
     
  8. Patrick Sun

    Patrick Sun Moderator
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    When I was glueing up the MDF endcaps, I marked where I wanted the inner endcap to be glued to the outer endcap, applied the glue, and then just carefully clamped the endcaps together for half a day or so. No screwed, no fuss, no muss.

    You do have to "monitor" the clamped layers to make sure they don't shift in the early drying stages, but once the layers do dry under careful supervision, the clamps work just fine.
     
  9. Pete Mazz

    Pete Mazz Supporting Actor

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    For anyone that doesn't want to use screws or fasteners, and just weight to do the glueing up of multiple panels. Try this:

    On a larger flat scrap piece of material, lay the first layer(3/4" thick) of the stack down. Cut some small strips of 1" thick scrap about ~2" wide by ~4" long. Screw 3 of these around the perimeter of your first layer, butting them into the edge as you fasten them down with a screw. Now, if you lay the second layer on top of the first, it should perfectly align. If you have a hot glue gun, this goes a lot faster, and if you need to glue up a thicker stack, just glue the blocks down on edge to get a taller stop.

    BTW, if you're getting a lot of squeeze out of wood glue, you're using too much. A thin film is all that's needed to produce an excellent bond without adding a lot of excess moisture into the joint.

    Pete
     
  10. warrick

    warrick Stunt Coordinator

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    Here is another suggestion.

    Cut one disc to the correct size and glue it to another that is slightly larger (this one doesn't need to be cut with a circle cutter) and once the glue has dried you can use a flush cutting bit in a router to trim the larger disc to the correct size. If the discs move slightly during the curing of the glue it will have no effect one it has been trimmed. (Repeat for other end)
    This is not the method I used but I have the tools to do this and will do this if/when I construct another, I did have a slight amount of slip when I glued mine but epoxy and screws cover a multitude of little mistakes

    Warrick
     
  11. Casey H

    Casey H Stunt Coordinator

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    OK! Very nice suggestions all! Thank you for the help. I will let you know how the second go, goes! [​IMG]
    Casey
     
  12. Brian Steeves

    Brian Steeves Second Unit

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    The way I do it is...
    Cut the inner endcap first (with a router and circle jig) then glue it to the outer piece. The outer piece can be square or even a large irregular scrap just as long as it is larger than the intended size of the outer endcap. Then after the glue dries I drill through the original pivot hole of the inner endcap piece through the outer endcap making sure the drill is perpendicular to the wood (make sure you have a piece of scrap underneath so the through-hole is clean). Then turn it over and rout the outer endcap side like I would normally. This ensures a perfectly aligned outer endcap. [​IMG] This of course assumes that the hole will be filled and the endcap is going to be painted.
     

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