pmarlin Posted April 2, 2007 Report Share Posted April 2, 2007 What is the secret to keep the joint from sliding when clamping? Quote Link to comment Share on other sites More sharing options...
verhoevenc Posted April 2, 2007 Report Share Posted April 2, 2007 If you're 100% sure that the angles are exactly the same (IE: you planed them together by stacking them one on top of the other) then you can clamp them on a flat surface by laying down some foil, clamping hte headpiece in place, then sliding the neck piece into the joint, and clamping over it. I know that makes NO sense, so please go watch the "How it is made" video on Godin guitars on youtube, that shows PERFECTLY the clamping procedure for scarfs I just talked about. Chris Quote Link to comment Share on other sites More sharing options...
Jon Posted April 2, 2007 Report Share Posted April 2, 2007 I use a flat piece of wood beneath the neck and use waxpaper inbetween the clamping piece and neck so I don't accidently glue them together. I give the scarf joint about 15 minutes to dry before clamping so it doesn't slide around like crazy. Quote Link to comment Share on other sites More sharing options...
verhoevenc Posted April 2, 2007 Report Share Posted April 2, 2007 15 minutes to dry before clamping!? That sounds like a BAD idea to me. Titebond only takes 30 minutes to give it's "glueing". 15 is half of that, so it's gettin' pretty far into it's initial cure by then. Also, keep in mind, wood glues have high adhesion and low cohesion, meaning, they stick great to other stuff, like wood, but not so well to itself. That said, that's why you always hear about people wanting to get the tightest joint possible with wood glue to the point that there's no glue-line, and thus, less reliance on cohesion. If you wait 15 minutes, it'll be partially cured, thus giving you less ability to tighten up that joint perfectly cause the glue won't squeeze out as well and therefore it will cause a much weaker joint. So please do NOT let it cure for 15 minutes before clamping, there are much better ways to deal with the slipping than that. That said, if you were using epoxy that's a different case since epoxy is the opposite, extremely high cohesion, and thus you WOULD want a slight glue line. However, I would not recommend epoxy here cause for wood-to-wood joints wood glues are the best choice, and like I said, with epoxy you'd have a visible, unattractive line in the joint. And I'm sorry Jon, I think your building is excellent and you have some great stuff, so don't take this as a personal attack, I'm just trying to save some joints, but that is bad advise to let the glue set for 15 minutes before clamping. Now, like I said, watch the "How It's Made" video on youtube about electric guitars (deals with Godin). In fact, here is the link, and the part in question about gluing up the scarf occurs at the time 2:15 to 2:40, enjoy. Chris Quote Link to comment Share on other sites More sharing options...
Setch Posted April 2, 2007 Report Share Posted April 2, 2007 Here's my solution, which I find far, far simpler than any of the other options: http://www.setchellguitars.co.uk/ant/blog/?p=121 Quote Link to comment Share on other sites More sharing options...
Hector Posted April 2, 2007 Report Share Posted April 2, 2007 I do the hinge thing like setch does, and before clamping, I drill 2 holes, where the tuners will be, and place a broken drill bit (the same size I used to drill the holes) there so it won't slip. apply the pressure. as much as I can get, and then remove the bits. works like a charm! here you can see the holes. voila I use this tecnique all the time. even when gluing other things. Quote Link to comment Share on other sites More sharing options...
SwedishLuthier Posted April 2, 2007 Report Share Posted April 2, 2007 (edited) Got to hand it to you Setch. Your solutions are always simple but seems to work perfekt. I really like it. Next time I have to try it and add hectors trick. I have one multi lam neck right now that I was sooo shure the blanks were lined up perfect, but after removing the clamps they had slipped like 0.4 mm. Not much but VERY visible on a 3-piece maple neck with 0.6 mm black Graphite lams between them. Edited April 2, 2007 by SwedishLuthier Quote Link to comment Share on other sites More sharing options...
Mattia Posted April 2, 2007 Report Share Posted April 2, 2007 I always used the 'cumpiano method' before (ie, flat board, clamp neck shaft down, clamp a stop for the headpiece, apply glue, then clamp), some also done with pins/brads in the waste areas, but the last two (done in the last week, actually) were done using the Setch Method, and I gotta say, it's excellent. Two or three strips of masking tape is all that's needed (I use the heavy stuff from StewMac, but good quality regular should work fine). Also an excellent solution for headstock veneers (add another strip or two at the top and/or sides after applying glue to help slippage in those directions. Seriously, it's idiotically simple, and quite idiotically fool-proof. As for joining lammed necks (done it before successfully, mind), I think it's waaay more pain and trouble than it's worth to stress too much about slippage; if your lams are even a fraction off square, sand the back of the headstock and it's all visible again. I prefer to put the joint in the headstock and add a backstrap at that point. One of the two necks I've made is a 2-piece, and the joints do line up perfectly (and since it's got no accent veneers, and it's mahogany, it's a bit of a 'squint and search' to find it anyway), but I'm still adding a backstrap Peter: how do you find the graphite lams are on tools? Does it significantly add to your neck strength overall, you feel? And where do you get your lams? I've pondered it before, but every time I chicken and stick with CF rods (of which I recently ordered an extra 30, so...), partly because of the machining (dust is nasty stuff), partly because of the finishing (I oil or french polish my necks). Quote Link to comment Share on other sites More sharing options...
Prostheta Posted April 2, 2007 Report Share Posted April 2, 2007 I cheated by tapping in a couple of tacks into the area which would be routed out for the truss rod channel :-D Centres it nicely! Quote Link to comment Share on other sites More sharing options...
SwedishLuthier Posted April 2, 2007 Report Share Posted April 2, 2007 (edited) Well, I question my way of building every time I have to line up the neck lams... Mattia: Graphite lams on cutting tools: a nightmare. I have developed a method that is not as bad. I joint the wood down to the same thickness as the width of the graphite. That way I can get them almost dead flat from the beginning. I then use a long aluminium “sanding stick” to even things out. Then I split the head part (yeah, I have got hold on some really long graphite) and thin the head part out with a Wagner Safe-T. In this use (the cutting is “sideways” through the wood and graphite) the wear isn’t that bad. I prepare the scarf joint area with a jig and my router. The wear on the router bit isn’t that bat either. I then thickness the neck blank down on my belt sander (nasty job) to include the taper and leaving the neck pocket part untouched. I then join the parts and shape the neck with spockeshaves, surforms and sandpaper. I generally don’t have to cut that much at all into the graphite with this method, except for the thicknessing of the head and the jointing. Regarding the strength/stiffness of the neck with rods vs lams I made an experiment a couple of years ago. You can se the results here: http://projectguitar.ibforums.com/index.ph...st&p=216422 That thread was indeed a little silly from time to time, but you have a “scientific” answer to your question there. Haven’t tried oil finish on that up until now. Shaped a neck this weekend, but I haven't got around to put oil on it yet Edited April 2, 2007 by SwedishLuthier Quote Link to comment Share on other sites More sharing options...
guitar2005 Posted April 2, 2007 Report Share Posted April 2, 2007 Here's my solution, which I find far, far simpler than any of the other options: http://www.setchellguitars.co.uk/ant/blog/?p=121 I vouch for this method. Simple and effective, this is the way I've done ALL my scarfs (4 in total). Quote Link to comment Share on other sites More sharing options...
pmarlin Posted April 2, 2007 Author Report Share Posted April 2, 2007 Thanks guys, very good info here. I knew I had seen something before but couldnt remember what it was. Quote Link to comment Share on other sites More sharing options...
!!METAL MATT!! Posted April 2, 2007 Report Share Posted April 2, 2007 This Is A Jig I made up so I could fix a few hard things I found about building necks Ok first with the problem your haveing, I first cut Scarf and than sand them Flat for glueing I than take what will be the headstock and I sand down close to the thickness of a headstock (i do mine to 5/8"s) once every thing is ready for Glue up I then line it all up as if I was about to clamp it down, now I drill to holes off to the side of the neck thru both pices of wood where I know there going to be cut off and removed and will not cause any Problems I than make the pilot holes I just driled out in the headstock a bit biger so that I have some movement and nothing will get bound up, Ive done a few where Ive not drilled to larger holes and Its caused problems in the Glue up the screws kept things from being flat and level ANY WAY after drilling your holes a bit larger only on the headstock part of the Scarf joint make sure that you now drill counter sink holes for thr heads of the screws, that will come in to play latter with this jig as I use the jig to pass the neck thru my thickness sander to get a perfect level gule area for the fretboard !!METAL MATT!! Quote Link to comment Share on other sites More sharing options...
westhemann Posted April 2, 2007 Report Share Posted April 2, 2007 just want to support verhoevenc for a sec...i completely agree that waiting 15 minutes before clamping will result in visible glue lines... Quote Link to comment Share on other sites More sharing options...
Mattia Posted April 2, 2007 Report Share Posted April 2, 2007 Basic rule with ALL screws: if you want a tight joint, you DO NOT want the screw to thread through the first piece of wood, only the second. There's a reason why bolt-on neck screws aren't threaded in the body portion... Quote Link to comment Share on other sites More sharing options...
Jon Posted April 2, 2007 Report Share Posted April 2, 2007 So I'm guessing you guys have your headstocks clamped pretty quick then? It sometimes takes me 15 minutes to get my neck completely clamped from start to finish, no glue lines ever (Typically 5-9 laminates in my necks). Now if I were letting it set more than 30 minutes, I would be destroying a great deal of the bond as well as the most important set time. I have glued 5 headstocks with the first one pretty badly failed (not using the 15 minute method) and the other 4 giving it about 10-15 minutes to set before clamping. No glue lines visibile on any of them. Come on guys, why would I do something stupid that would result in glue lines? Not to mention I tested this on scrap many times until I nailed perfect results. I will definitely adopt a more efficient method, but I've got great strong results. Quote Link to comment Share on other sites More sharing options...
Mattia Posted April 2, 2007 Report Share Posted April 2, 2007 Titebond's open time is in the 5 to 10 minute range, I think (see the bottle); clamping should be fast, though! Applying glue and applying 4 clamps to a scarf joint takes me all of - tops - 1 minute to do. Maybe another 30 seconds cleaning up some squeezout between the clamps, adjusting them a little, that sort of thing. Even a full neck blank lam (although I don't really do multi-lam necks much, or at all) only takes 2 or three minutes. Now, mostly I use cam clamps, which you can apply in a very short period of time, sometimes supplemented by F-clamps which I go back and tighten afterwards to make sure it all holds together properly. Quote Link to comment Share on other sites More sharing options...
verhoevenc Posted April 2, 2007 Report Share Posted April 2, 2007 Thanks for the backup Wes, although, I'd be less worried about a glue line and more worried about the loss in joint strength. Whether or not you're seeing a glue line that still could mean there's more space than you want with titebond... I mean, if they're holding up, that's cool, good on ya, but I wouldn't suggest doing it anymore. Chris Quote Link to comment Share on other sites More sharing options...
Jon Posted April 2, 2007 Report Share Posted April 2, 2007 Now, mostly I use cam clamps, which you can apply in a very short period of time I don't. Sounds like it's time for me to go clamp shopping. Wouldn't two parallel jaw clamps work well for clamping a scarf joint? Quote Link to comment Share on other sites More sharing options...
Mattia Posted April 2, 2007 Report Share Posted April 2, 2007 Any clamp will do fine, really; I like cams because they're light (made of maple with a bit of steel bar), apply more than enough pressure, but never really so much you could call it too much pressure, can be adjusted quickly, applied with one hand (with a bit of practice and depending on the size). I get Klemmsias, have about 14 right now, pick up one or two every time I order/buy somewhere that carries them. Before that, I only used metal clamps. Other MAJOR advantage to cams: zero need for clamping cauls, unless you're doing it to distribute pressure. No risk of marring your work/damaging it as you have with some metal clamps. Quote Link to comment Share on other sites More sharing options...
westhemann Posted April 2, 2007 Report Share Posted April 2, 2007 there are many different ways to achieve results...if the two bar clamps work for you,keep on with it...i use a combination of bar clamps and spool clamps on everything...and i usually prevent joint slipping in different ways.finishing nails in unused areas,wax paper-backed straightedges,stuff like that.nothing set in stone. the only thing i would not do is wait too long before clamping...max 5 minutes,usually less,before i get the clamps all set...and i do the squeeze out gradually...1/2 turn here,1/4 turn there,until all clamps are snug. main thing is,on a wide joint such as a neck lam,waiting until the glue sets a hair can result in the middle section of glue getting trapped in there...i want as thin a joint as i can get..and for me(and most others i would guess)that means having the main squeeze out occur while the glue is at it's runniest Quote Link to comment Share on other sites More sharing options...
Jon Posted April 2, 2007 Report Share Posted April 2, 2007 finishing nails in unused areas I think overall, this seems like the best way to replicate quality. How do you guys go about screwing / nailing the scarf joint together properly without it sliding any? Quote Link to comment Share on other sites More sharing options...
Mattia Posted April 2, 2007 Report Share Posted April 2, 2007 finishing nails in unused areas I think overall, this seems like the best way to replicate quality. How do you guys go about screwing / nailing the scarf joint together properly without it sliding any? Tap brads into one half (the harder half, if there is one), cut them off so a little protrudes, align the pieces dry, clamp, and you have little index pins in place. Apply glue to the side without brads, line up, hold in place, clamp, done. I still think the masking tape makes this (Even with brads) a LOT easier. Aligns things perfectly during the dry run, even during the wet. Quote Link to comment Share on other sites More sharing options...
westhemann Posted April 2, 2007 Report Share Posted April 2, 2007 if i were to do a scarf joint(i don't),i would put a very small finishing nail in one piece(in the cutoff part),cut the leftover part of the nail down to about 1/16" to 1/8"(soall that is left is a small pin),fit it against the other piece dry and apply just enough pressure to indent the wood a bit,take it back apart,and drill a tiny hole for the pin to slide into,retest the fit,and then glue up... basically a fancy,tiny dowel system i just do alot of neck lams... Quote Link to comment Share on other sites More sharing options...
westhemann Posted April 2, 2007 Report Share Posted April 2, 2007 hehe...mattia posted whilst i was typing.only difference is the drill holes,which i think would help make sure the joint clamps tight,especially in harder woods Quote Link to comment Share on other sites More sharing options...
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