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Posted

Ok, I'm about to place an order on stew mac to buy carbon fiber reinforcements,

would a couple carbon fiber rods help in keeping the neck from moving sideways??? I use 2 way truss rods so i can adjust the neck if it moved up or down, but, i need now to be sure the neck won't move sideways... thanks guys!

And yes, the neck wood is dry, but i had to toss a laminated 3 piece purpleheart neck to the bis, because it moved sideways ...it was quartersawn and all...dry as a bone...and it moved :D

Posted

Bone dry, Laminates(thinner pieces that a single), well quartered. Straight grained(longtitudinal)? Bone dry(and I am assuming you would have mentioned if it was exposed to a lot of moisture during construction). All that and it moved sideways :D . Any chance the laminates were not straight and they were clamped and glued straight? Man I could even see that happening if there was pent up tension and then you carved, but this is a lam(smaller straight pieces don't usually hold much tension).

I think you either overlooked something(you would think that much tension would have made one of the lams crooked, given they were fully dried), or are really unlucky. I sure hope you have better luck on the next one :D

Posted (edited)
Bone dry, Laminates(thinner pieces that a single), well quartered. Straight grained(longtitudinal)? Bone dry(and I am assuming you would have mentioned if it was exposed to a lot of moisture during construction). All that and it moved sideways :D . Any chance the laminates were not straight and they were clamped and glued straight? Man I could even see that happening if there was pent up tension and then you carved, but this is a lam(smaller straight pieces don't usually hold much tension).

I think you either overlooked something(you would think that much tension would have made one of the lams crooked, given they were fully dried), or are really unlucky. I sure hope you have better luck on the next one B)

well, the purpleheart was figured, it was very straight grained but figured, not much but the figure was there, also, there were small glue line between the joints, the laminated pieces were3 pieces of 2 cm wide each... Moisture, i think that's the problem, it's been raining like crazy all these days, and while my guitar was inside my house, there's no way to let the moisture out..but during the construction of the neck there wasn't raining, so the neck was complete when it moved on me :D

Also, i laminated a mahogany blank ( south american mahogany) a few months ago, and no, it wasn't humid while i made it, 3 pieces of quartersawn, very straight grained mahogany, the outerpieces are like an inch wide, and the center one is 1.5 cm and it has moved sideways as well...so that's why i asked if the carbon fiber would work...there's no need to mention and it's also very dry, when i bought it it was around 10% humidity content maybe 8% and the pieces of 6 cm x 4 cm x 100 cm sat in my house for 4 1/2 years...

Edited by eddiewarlock
Posted
Bone dry, Laminates(thinner pieces that a single), well quartered. Straight grained(longtitudinal)? Bone dry(and I am assuming you would have mentioned if it was exposed to a lot of moisture during construction). All that and it moved sideways :D . Any chance the laminates were not straight and they were clamped and glued straight? Man I could even see that happening if there was pent up tension and then you carved, but this is a lam(smaller straight pieces don't usually hold much tension).

I think you either overlooked something(you would think that much tension would have made one of the lams crooked, given they were fully dried), or are really unlucky. I sure hope you have better luck on the next one B)

well, the purpleheart was figured, it was very straight grained but figured, not much but the figure was there, also, there were small glue line between the joints, the laminated pieces were3 pieces of 2 cm wide each... Moisture, i think that's the problem, it's been raining like crazy all these days, and while my guitar was inside my house, there's no way to let the moisture out..but during the construction of the neck there wasn't raining, so the neck was complete when it moved on me :D

Also, i laminated a mahogany blank ( south american mahogany) a few months ago, and no, it wasn't humid while i made it, 3 pieces of quartersawn, very straight grained mahogany, the outerpieces are like an inch wide, and the center one is 1.5 cm and it has moved sideways as well...so that's why i asked if the carbon fiber would work...there's no need to mention and it's also very dry, when i bought it it was around 10% humidity content maybe 8% and the pieces of 6 cm x 4 cm x 100 cm sat in my house for 4 1/2 years...

Man, if it has happened twice, with good quality wood. I suspect it would be best to get to the root of the problem first. How much movement are we talking about? How much and what kind of glue are you using when you laminate the wood? After you cut the wood for laminations maybe allowing it a couple days to move if it going to would be telling. Wood that has stored tension will move when it is cut(as the balance of tension has changed). If it is a humidity issue, then you may need to figure out what measures you can take to even the transitions out. Do you have a meter in your shop to test your ambiant humidity?

Carbon fiber rods will improve stiffness and stability. However they are not going to stop wood that wants to bend(if it becomes a high tension situation something will give, and it won't be the rods).

Peace,Rich

P.S. it sounds like you are paying attension to drying you wood very well, and you are also paying attension to your selection. You are on the right track. There is just a glitch in the process somewhere.

Posted

Well that mahogany, despite being very high quality, had always had issues with movement, very weird, since mahogany is one of the most stable woods available ( and yes it is mahogany :D ) that's how i started laminating necks, to avoid this problem, so i used that mahogany, laminated it and problem solved. The neck is still stable and straight as an arrow.

So i used the last piece i had, it had moved a bit but well, it had sit for 4 years so i thought that was normal, I surfaced both sides, planed it, sliced down the middle and glued another piece ( from another blank a bit older than that piece) and glued the whole thing together. I used regular titebond for this blank, the wood joint looks very good, no glue lines and almost invisible wood joints, i planed the fretboard surface and the oppossite to it, but left the sides untouched, well, about 4 months later, the neck blank has moved to one side, it's not much, but you can clearly see it, same as with the purpleheart neck blank.

So i guess the wood wanted to move anyways, but hell, it's dry, straight grained, laminated, and it's the last piece i have ( mahogany can't be found here anymore ) :D

What i'll try to do is, finish the neck blank, plane both side and see if it moves again, if it does....then i guess i should toss it to the bin...

With the purpleheart blank i used high quality wood glue, not titebond since it can't be found here, but i've never had a problem with it, it's PVA glue, and it smells the same as titebond, except it is white.

The new neck i'll build, i'll use 2 ton epoxy, slow curing, made by Devcon...

Posted

Do you store the wood in the same space you build in? On the off chance you store the wood say in a nice dry attic to season it, and then bring it down to your shop there could be some equalizing going on. You mentioned going to Epoxy to remove the water from the equation(that sounds like a good idea). There is also the chance that you have some case hardened wood that is trapping moisture, but if you have cut the wood and tested it with a moisture meter(you mentioned some specific percentages of moisture so I am assuming you used a meter) then you have ruled that out. If it is not a humidity or moisture issue, then you are left with stored tension or compression in those pieces of wood. That is a hard situation because you may not be able to detect it until you remove material. Best thing I can think of to deal with that is to pre-shape as much as possible, allow it to set, surface for your fretboard and attach it.

I must say though that with all the laminates, and the fact that you also glue a fretboard on a different plane. Side to side movement should be very rare. Two in a row though... You can't get around the facts.

BTW, What are your seasonal humidity levels like? and how radical are swings(not day to day, but week to week averages).

Peace,Rich

Posted
Do you store the wood in the same space you build in? On the off chance you store the wood say in a nice dry attic to season it, and then bring it down to your shop there could be some equalizing going on. You mentioned going to Epoxy to remove the water from the equation(that sounds like a good idea). There is also the chance that you have some case hardened wood that is trapping moisture, but if you have cut the wood and tested it with a moisture meter(you mentioned some specific percentages of moisture so I am assuming you used a meter) then you have ruled that out. If it is not a humidity or moisture issue, then you are left with stored tension or compression in those pieces of wood. That is a hard situation because you may not be able to detect it until you remove material. Best thing I can think of to deal with that is to pre-shape as much as possible, allow it to set, surface for your fretboard and attach it.

I must say though that with all the laminates, and the fact that you also glue a fretboard on a different plane. Side to side movement should be very rare. Two in a row though... You can't get around the facts.

BTW, What are your seasonal humidity levels like? and how radical are swings(not day to day, but week to week averages).

Peace,Rich

Hmmm i mentioned those levels because that's what was on the weather channel, i have no moisture meters... probably is stored tension, because the mahogany blank has moved towards one side, not much, i checked it, but hell it is laminated, i didn´t however, laminated the pieces with the grain running against each other, what i did was split the piece by the half and glue another piece in the middle, guess i should re do it and this time turn that side around?

Week to week avergaes i don't know, it's been a pretty irregular season, it didn't rain for like a month, then rained a lot a week, then 2 weeks with no rain, then 2 days in a row raining, and so it goes...no idea on how much it is now though...

my house is 2 stories high, the upper story is what i would call the attic, that's where i keep my wood, it's hot, and i would say dry, but you know there are windows...and even though they are closed all the time they aren't airtight...from time to time we turn the a/c on, but just to cool it off, we never let it on that much of a time to drastically chage the temp, the avg temp on there should be around 75- 77 ºF...i keep the wood in a room where the air conditioner doesn't get there ( no vents there) I have never had that kind of problem in a laminated neck, but granted, i never had a neck blank with glue lines...maybe it's that?

Posted

Thank you so much for that link Mattia! That is a great one to have. I've been needing to grab some, but I just didn't know where would be the best price and so far that is the cheapest I've seen. I've looked a bit locally, but haven't had much luck, this link seems by far the best route for me. Anyhow, that is a great link, very nice prices and I love the fact that they can angle it at 15 degrees for headstocks if you want, for a buck. Thanks again man. J

Posted
i didn´t however, laminated the pieces with the grain running against each other, what i did was split the piece by the half and glue another piece in the middle, guess i should re do it and this time turn that side around?

Jup, that is essential. By reversing one of the pieces you will have the laminations countering the movement of the opposite laminate.

Thought experiment:

Split a blank in two. Lay them down as they were before you split them. Turn one of them upside down. Glue them together. Now if the left lam would like to bend one end up (due to changes in humidity or whatever) the other lamination will try to bend the same end down. In a perfect world those forces will equalise each other and the blank will remain straight.

Posted
i didn´t however, laminated the pieces with the grain running against each other, what i did was split the piece by the half and glue another piece in the middle, guess i should re do it and this time turn that side around?

Jup, that is essential. By reversing one of the pieces you will have the laminations countering the movement of the opposite laminate.

Thought experiment:

Split a blank in two. Lay them down as they were before you split them. Turn one of them upside down. Glue them together. Now if the left lam would like to bend one end up (due to changes in humidity or whatever) the other lamination will try to bend the same end down. In a perfect world those forces will equalise each other and the blank will remain straight.

That's what i did with this last lamination, i drew up arrows indicating the direction of the grain so i wouln't mess that up when i had the separate pieces so far so good, i just umclamped it...oh and i glued it with epoxy :D 2 ton epoxy by devcon

Posted
i didn´t however, laminated the pieces with the grain running against each other, what i did was split the piece by the half and glue another piece in the middle, guess i should re do it and this time turn that side around?

Jup, that is essential. By reversing one of the pieces you will have the laminations countering the movement of the opposite laminate.

Thought experiment:

Split a blank in two. Lay them down as they were before you split them. Turn one of them upside down. Glue them together. Now if the left lam would like to bend one end up (due to changes in humidity or whatever) the other lamination will try to bend the same end down. In a perfect world those forces will equalise each other and the blank will remain straight.

This looks nice too - but depending on the board, it can make it a pain in the arse to plane without tearout.

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