thekt88killedjfk Posted April 25, 2021 Report Posted April 25, 2021 I use a dewalt planer to plane the individual laminations flat, yet it seems the laminations thinner than 1/2" are not jointing wholly with their sister boards. What can cause this? My tools are new. Please see pics here: https://imgur.com/a/eg4OXqa Quote
curtisa Posted April 25, 2021 Report Posted April 25, 2021 Mating surfaces (one or both) on the left hand laminate could be slightly convex. Could be some foreign material contaminating the joint before clamping, stopping the two pieces from meeting flush. Maybe some wood shavings, dried glue from the bottle, dirt etc? Insufficient clamps or uneven clamping force distribution. Quote
thekt88killedjfk Posted April 26, 2021 Author Report Posted April 26, 2021 On 4/24/2021 at 9:58 PM, curtisa said: Mating surfaces (one or both) on the left hand laminate could be slightly convex. Could be some foreign material contaminating the joint before clamping, stopping the two pieces from meeting flush. Maybe some wood shavings, dried glue from the bottle, dirt etc? Insufficient clamps or uneven clamping force distribution. Looks like I needed to plane multiple passes after jointing slightly bowed boards. More even glue coverage probably helped. I did another neck and it has came out well. Will post pics tonight. Quote
thekt88killedjfk Posted April 26, 2021 Author Report Posted April 26, 2021 https://imgur.com/a/RiYTbgb 1 Quote
thekt88killedjfk Posted May 13, 2021 Author Report Posted May 13, 2021 Did another few necks, trying to get good/consistant/eliminate variables. Last two necks have the same gap as the first pic. I wonder if I'm using too much glue? I lay down 5 * 2mm beads of glue over each piece of 2.5" wide wood, then spread it with a spackle tool/joint knife. Quote
Bizman62 Posted May 14, 2021 Report Posted May 14, 2021 There's a million ways to spread glue, most of which are correct. Fingers, brush, credit cards, joint knives... You mention it. If you're uncertain, a toothed joint knife of sorts is your friend. Builders use glue spatulas all the time as the glues used for flooring can be pretty stiff and the amounts are huge. The right amount is measured by the size of the teeth. For guitar building the tooth size of the spatula should be something like that on a hobby saw, about 15 tpi. You can easily make one yourself of an old credit card. The right amount of glue is when you get a thin bead of squeeze out all along the seam. No squeeze out means there's no glue there. Lots of squeeze out means lots of extra work to wipe the excess off plus wasted money since you can't usually put the glue back into the bottle. Also remember that wood glue isn't a filler. Perfectly matching surfaces with an invisible film of glue in between is what we're after. Some pressure is needed to keep the pieces together while the glue dries. In theory it's possible to squeeze all of the glue out of the joint so don't overdo it. Clamping is not the right cure for curved boards unless you can squeeze the gap tight with your fingers when dry fitting. Quote
thekt88killedjfk Posted May 14, 2021 Author Report Posted May 14, 2021 (edited) 16 hours ago, Bizman62 said: There's a million ways to spread glue, most of which are correct. Fingers, brush, credit cards, joint knives... You mention it. If you're uncertain, a toothed joint knife of sorts is your friend. Builders use glue spatulas all the time as the glues used for flooring can be pretty stiff and the amounts are huge. The right amount is measured by the size of the teeth. For guitar building the tooth size of the spatula should be something like that on a hobby saw, about 15 tpi. You can easily make one yourself of an old credit card. The right amount of glue is when you get a thin bead of squeeze out all along the seam. No squeeze out means there's no glue there. Lots of squeeze out means lots of extra work to wipe the excess off plus wasted money since you can't usually put the glue back into the bottle. Also remember that wood glue isn't a filler. Perfectly matching surfaces with an invisible film of glue in between is what we're after. Some pressure is needed to keep the pieces together while the glue dries. In theory it's possible to squeeze all of the glue out of the joint so don't overdo it. Clamping is not the right cure for curved boards unless you can squeeze the gap tight with your fingers when dry fitting. Thanks man. I'm never sure just how complimentary they should be. I just processed wood for a neck yesterday. I jointed each piece while checking in between passes by drawing a squigly line on the face I was jointing. I have not done this before but I think this is going to help a lot more than relying solely on my 4' level to test for straightness. After I got one face of each board jointed this way, I planed them in my planer using the same squigly line method. Then I finally planed them to the desired thickness. All in all, it seems the boards sit very tight with no cupping or warping. I buy s3s poplar so I expect to have to process it quite a bit. I numbered the boards so I knew the orientation in which I checked fitment. This time I used a contact cement adhesive roller to apply the glue across all boards simultaneously accept one. It looks very consistent. Hopefully all this effort will result in a better neck. Additionally I used my bad neck blanks to make multiple neck jigs, so now I got clamps on top and bottom. I got about 32 clamps on there, but that's because the 4" clamps I use will only do about 300lbs of force. I really hope this works lol. I started with a 12'x12"x7/8" board that was warped quite a bit. Edited May 14, 2021 by thekt88killedjfk Quote
thekt88killedjfk Posted May 15, 2021 Author Report Posted May 15, 2021 (edited) Okay okay okay looks like I did not use enough glue on the previous necks but this one came out great. For whatever reason, I struggle with getting the right amount of glue but it looks like I really should be applying a 3/32" to 1/8" bead for every half inch width. I've seen some youtube videos advocating for as little glue as possible, but they were probably assuming people were putting down larger beads. I built a 12 ton neck press out of 4x4 steel square tube and bottle jacks and even that wasn't enough to squeeze all the glue out. 12 tons at ~200 square inches still is on the low side of the recommended pressure by glue companies, so I'll probably add more bottle jacks lol. Unfortunately the square tubing I am using is slightly bent, about a 1/16" over 48" so I can't really use any neck I press on it. I just wanted to eliminate pressure as a variable. Last night I didn't use the press at all. I just used the two neck jigs I mentioned and 32 clamps. Neck is straight and gap free. I'm gonna machine that neck press down flat and parallel, though. It was too easy to use. Edited May 15, 2021 by thekt88killedjfk Quote
Bizman62 Posted May 15, 2021 Report Posted May 15, 2021 2 hours ago, thekt88killedjfk said: looks like I did not use enough glue on the previous necks but this one came out great. That's good news! You're learning! A semi-see-through film on both surfaces is fool proof, the same on one surface should suffice when you know how much is enough. Rather a bit too much than too little. And I repeat, don't overdo with the pressure. For what I've heard a perfect joint should be doable even without clamps! That said, even high end professionals use them just for sanity as you never know how the wood will react with the extra moisture of the glue. The high pressure clamping systems are for industrial thicknesses where 2x4" blanks are glued to beams up to 10x50" or even bigger. Quote
thekt88killedjfk Posted May 27, 2021 Author Report Posted May 27, 2021 On 5/15/2021 at 1:27 PM, Bizman62 said: That's good news! You're learning! A semi-see-through film on both surfaces is fool proof, the same on one surface should suffice when you know how much is enough. Rather a bit too much than too little. And I repeat, don't overdo with the pressure. For what I've heard a perfect joint should be doable even without clamps! That said, even high end professionals use them just for sanity as you never know how the wood will react with the extra moisture of the glue. The high pressure clamping systems are for industrial thicknesses where 2x4" blanks are glued to beams up to 10x50" or even bigger. Oh yeah no way I'm gluing two pieces of wood together that I didn't think jointed perfectly before. We're on the same page on that. Thanks man. 1 Quote
thekt88killedjfk Posted October 7, 2021 Author Report Posted October 7, 2021 (edited) Okay I've worked on this for months until I've became consistent. I have some unavoidable truths I had to realize: 1) the short porter cable bench jointer I was using was not very good. Its aluminum tables and composite frame flexed easily with the loads I placed on it. I did not notice until I put a dial gauge on it and checked, it easily flexes 10-20mil. Not acceptable. To make matters worse, its length is just too short for planing 48" long pieces of wood. It works, sometimes. 2)Most of the woods I use need a sled when being used in the planer, period. 1" poplar flexes inside the planer and causes numerous issues. Attaching the poplar to a 2" thick walnut countertop sled has taken care of any issue I had with the planer. 3)Typical tonewoods have proven much easier to work with than the poplar I was experimenting with, even more so since I've switched jointers and now use a sled 4) using a jointer is a skill and requires being able to read the wood to see what will be the most effective approach. Learning this skill requires turning a bunch of boards into wedges lol. Hopefully this helps someone. Edited October 7, 2021 by thekt88killedjfk 1 Quote
Bizman62 Posted October 7, 2021 Report Posted October 7, 2021 Whoa! A 10-20 mil flex sounded like a LOT to me until I checked how much it is in millimetres. Agreed, on a short table even that still is plenty and with larger pieces the issue accumulates. A sled used with the planer is common practice and you can improve it by attaching a sacrificable piece in front of your workpiece. Often the conveyor system tends to lift the piece when it grabs, making the plane chew deeper than expected. That happens with the huge cast iron professional ones as well. Poplar can be a bi**h to level! The fibres are long and strong grabbing in planer blades and in between there's the very soft stuff that seems to sand off by looking at it. Using a jointer is a skill indeed. One might think that a bigger jointer would make the job easier, but at least the one I've been using isn't fool proof. Despite being big, about 3 metres long and sturdy as can be there's still things to consider. It was on the second winter at the course when I realized that the piece had to be fed slowly through to prevent the small waves on the surface and when I told about it I learned that the fellow builders had been struggling with the same issue! Our Master then just said that he may not have pointed that out clearly enough during the introduction of the machinery. Quote
thekt88killedjfk Posted October 19, 2021 Author Report Posted October 19, 2021 On 10/7/2021 at 3:01 AM, Bizman62 said: Whoa! A 10-20 mil flex sounded like a LOT to me until I checked how much it is in millimetres. Agreed, on a short table even that still is plenty and with larger pieces the issue accumulates. A sled used with the planer is common practice and you can improve it by attaching a sacrificable piece in front of your workpiece. Often the conveyor system tends to lift the piece when it grabs, making the plane chew deeper than expected. That happens with the huge cast iron professional ones as well. Poplar can be a bi**h to level! The fibres are long and strong grabbing in planer blades and in between there's the very soft stuff that seems to sand off by looking at it. Using a jointer is a skill indeed. One might think that a bigger jointer would make the job easier, but at least the one I've been using isn't fool proof. Despite being big, about 3 metres long and sturdy as can be there's still things to consider. It was on the second winter at the course when I realized that the piece had to be fed slowly through to prevent the small waves on the surface and when I told about it I learned that the fellow builders had been struggling with the same issue! Our Master then just said that he may not have pointed that out clearly enough during the introduction of the machinery. Yeah I've had some more time with the dovetail floor planer this week. I disassembled and cleaned it, then shimmed it to make sure the outfeed and infeed tables were co-planer. A lot of work! However, I was able to create laminations that have less that .008" of gap over 48", which results in a gapless glue up after running the wood through my planer. I'd like to get those gaps down to .005", should be possible? I've got a better straight edge on order. Right now all I have is a level from lowes and a feeler gauge set. Quote
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