# Joining boards along their length



## 1fizgig (Feb 11, 2018)

Hi folks

I'm going to start building a 1600mm long buffet in the coming weeks, but am having difficulty sourcing the laminated wood sheet for the base of the cabinet in the dimension I want. So, in order to give me plenty to work with, I'm considering joining two pieces along their length and cutting off what I don't need. 
I can only get 405mm wide, and I need 450mm wide in the pre-laminated sheets I want to use for this. The manufacturer won't make a custom sheet. Both boards would be 18mm thick.

Given I have limited tools and (at this stage) experience, I was thinking to join them by cutting a rabbet along the edge of both boards and gluing them together. Then, because there will be supports in the middle of the underside, making the join about halfway across the width and cutting the sides off to make my 450mm wide baseboard. This seemed a simple solution to me, and as the laminated sheets have proven very stable, I don't anticipate movement to give me any real grief.

This to me seemed a better option than having the possibility of the boards just side by side, as they would have a tendency to shift independently. I have no biscuit joiner, or dowel alignment jig, so have no confidence in going down that track (and they're not in the budget). I also have no tongue & groove bits for the router. Strapping them underneath by putting small bracing strips doesn't meet with approval from my client (wife).

I'm just posting this as a curiousity, wondering how you might suggest other methods that may be achievable given my sparse fit-out of equipment. If you have any other suggestions, I'd love to hear them so I can learn other possibilities. I've tried to give it some thought, but I'm all for learning other methods.

Thank you in advance.


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## Stick486 (Jan 4, 2013)

spline it instead of rabbeting...
better face alignment. stronger, easier and less waste..
use BB for the spline...

,


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## Stick486 (Jan 4, 2013)

use a slot cutter for the spline...

.


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## 1fizgig (Feb 11, 2018)

Okay, what's BB?
Hadn't thought of a spline. That would be a long spline, almost 1600mm long. Have you ever done that? 
Would you cut both slots at the same time, i.e. have the boards both clamped and cut just the once running the cutter up the middle?


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## Biagio (Mar 2, 2013)

@1fizgig, Stick probably offers the best solution, but I notice you say you do not have tongue-and-groove bits. Do you have a slot cutter? If not, take a leaf out of JOAT’s book, and make yourself a very simple dowelling jig. Instructions on the internet.
Provided you register the jig against the “bookmatch” faces of both boards (as opposed to face of one and back of the other), the faces should be well-aligned. Do a dry-fit before glue-up, and re-drill any dowel that is problematic. A slight longitudinal discrepancy will not matter, since you will be trimming to length anyway.
In my humble experience, the “affordable” dowelling jigs are not better than homemade.

Regarding the position of the glue-line,
1. Will it be visible inside the cabinet?
2. Will the board be weight-bearing?
3. Are there any other structural members to give support?
4. Exactly what material are you using? If by laminate you mean melamine-faced, it is darn difficult to get an invisible glue line. In that case, you might want to position the glue line as far towards the back as possible. Also, the factory edges will possibly be more chip-free than you or I can achieve by cutting. Ditto for the edging. If the laminate is wood veneer, it may not matter so much.

Perhaps post a sketch?


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## Stick486 (Jan 4, 2013)

1fizgig said:


> Okay, what's BB?
> Hadn't thought of a spline. That would be a long spline, almost 1600mm long. Have you ever done that?
> Would you cut both slots at the same time, i.e. have the boards both clamped and cut just the once running the cutter up the middle?


BB = Baltic Birch...
how about 40 feet...
been making splines since I was kid...

nothing says you have to have a continuous spline... segment it...
blind it if you don't want it visible at the ends...
a Slot cutter is the most effective simplest easiest (least amount of work) and economical way to get where you need to be...

I'd cut one edge at a time and all from the face/show side...
when you assemble the joint the face pieces will auto flush...
make one from some scrap...
it will all come together and make sense to you...

FWIW..
a tongue and grove bit is a different fit up vs the spline...


spline...
























T&G...

.


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## mgmine (Jan 16, 2012)

You are asking how to make the boards longer not wider. The way it is done is with finger joints. You can buy a bit or do it on a saw.

https://woodgears.ca/box_joint/fingerjoint.html


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## sreilly (May 22, 2018)

mgmine said:


> You are asking how to make the boards longer not wider. The way it is done is with finger joints. You can buy a bit or do it on a saw.
> 
> https://woodgears.ca/box_joint/fingerjoint.html


Evidently the material available is equivalent to maybe our 4' stock where his needs call for 1600mm (62.99213") length boards. Stick certainly gives you the methods best to use and as he stated the splines don't need to be continuous but need to be at both ends to be concealed. As Biagio asks, more information is really needed to determine what if anything else should be considered.


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## Cherryville Chuck (Sep 28, 2010)

I splined 2 seven plus foot birch boards together once for a mantle top using a 1/2” wood spline. You need to get the glue in as fast as possible at that length so more hands can be an asset.


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## Biagio (Mar 2, 2013)

mgmine said:


> You are asking how to make the boards longer not wider. The way it is done is with finger joints. You can buy a bit or do it on a saw.
> /QUOTE]
> 
> I understand it to be that he wants a board 1600mm long and 450mm wide, but the standard width is only 405mm. Hence he wants to join two boards of 405mm along their long edges, and then cut off the extra. The question is whether to have the joint in the middle of the board, or to one side (i.e. one of the joined boards would land up being only 45 mm wide).
> If this is the base of the cabinet, and not particularly visible from the inside of the cabinet, I would opt for the simplicity of the unequal widths.


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## Stick486 (Jan 4, 2013)

1fizgig said:


> Hadn't thought of a spline. That would be a long spline, almost 1600mm long.





mgmine said:


> You are asking how to make the boards longer not wider. The way it is done is with finger joints. You can buy a bit or do it on a saw.
> 
> https://woodgears.ca/box_joint/fingerjoint.html


to build for length an FJ butt joint is the way to go..
but I believe he wants to go wide...


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## Stick486 (Jan 4, 2013)

Cherryville Chuck said:


> I splined 2 seven plus foot birch boards together once for a mantle top using a 1/2” wood spline. You need to get the glue in as fast as possible at that length so more hands can be an asset.


use a slow set glue...

https://www.garrettwade.com/slo-set-glue-pt.html
Titebond Slow Set Wood Adhesive - Franklin Adhesives and Polymers

switch from yellow woodworkers glue (like Titebond or Elmer's Carpenters' glue) to a white all-purpose glue (such as Elmer's Glue-All). 
Another option is to use a hide glue or a powdered plastic (urea-formaldehyde) resin glue. 
Both of these glues set up slower than yellow glue and are just as strong.

go w/ an RF welder/curing...


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## Stick486 (Jan 4, 2013)

Biagio said:


> mgmine said:
> 
> 
> > You are asking how to make the boards longer not wider. The way it is done is with finger joints. You can buy a bit or do it on a saw.
> ...


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## DesertRatTom (Jul 3, 2012)

Given the sizes, I'd considr getting a 1/4 inch slot cutting bit--not expensive, cut the slot face down, or if you must do it freehand, face up with as wide a base as you can get on your router or at least an edge guide. This string has been very thorough.


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## Stick486 (Jan 4, 2013)

DesertRatTom said:


> Given the sizes, I'd considr getting a 1/4 inch slot cutting bit--not expensive, cut the slot face down, or if you must do it freehand, face up with as wide a base as you can get on your router or at least an edge guide. This string has been very thorough.


might want to think a bit more on using an RT... the board is a bit long for one and could easily become unwieldy...


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## Cherryville Chuck (Sep 28, 2010)

Stick486 said:


> use a slow set glue...
> 
> https://www.garrettwade.com/slo-set-glue-pt.html
> Titebond Slow Set Wood Adhesive - Franklin Adhesives and Polymers
> ...


Using a slower glue helps but even then the water in the glue can cause the wood to start swelling after a few minutes which can make a tight fit turn into too tight a fit. I think if I were to do boards that long again I would use a polyurethane glue (provided it has a long enough open time) and then spritz on the water needed for it to set and clamp it right away. I think the p u glue is less prone to make the wood swell than water based.


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## Stick486 (Jan 4, 2013)

Cherryville Chuck said:


> Using a slower glue helps but even then the water in the glue can cause the wood to start swelling after a few minutes which can make a tight fit turn into too tight a fit. I think if I were to do boards that long again I would use a polyurethane glue (provided it has a long enough open time) and then spritz on the water needed for it to set and clamp it right away. I think the p u glue is less prone to make the wood swell than water based.


PU glues has been discontinued here... 
I like weldbond or RF...


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## Biagio (Mar 2, 2013)

Stick486 said:


> PU glues has been discontinued here...
> I like weldbond or RF...


Interesting. Why has PU been discontinued? Environmental concerns or more basic reasons?


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## Stick486 (Jan 4, 2013)

Biagio said:


> Interesting. Why has PU been discontinued? Environmental concerns or more basic reasons?



discontinued in my shop, not in general..

Parts being glued with polyurethane need to have a tight fit to be strongly joined. polyurethane is not a good gap filler at all which compromises strength.
As it sets it froths up and the froth hasn't any strength.
In very dry areas (low humidity like here) it requires moisture to set or it can set very slowly and not reach it's full potential.
Because it is sensitive to humidity in the air and the wood's MC, setting times are all over the map.
Because it tends to foam and squeeze out. If not tightly clamped everywhere the parts can be forced apart by the foam, weakening the joint. 
The foam gives the illusion of gap filling, but there is no strength. 
I believe that it hasn't the strength of PVA glues......

After its cured it is very chemically inert and safe but the intermediate phases are it is toxic and an irritant. cause allergic reactions. This begets polyurethanes have to be handled carefully, kept off your hands and not breathed in too much. do a search for the MSDS's of various brands to get more information.

*Read the warning label*: Contains isocyanate containing polymers. Contact causes eye irritation. Prolonged or repeated skin exposure may cause allergic reaction, irritation and sensitization. Contact may stain skin. Do not allow eye contact. Avoid prolonged or repeated contact with skin.

short shelf especially after opening and they are *EXPENSIVE...*
It is messy and sticky to use and always seems to get on everything.
Polyurethane is difficult to clean off hands, (gloves are highly recommended). 
it takes Acetone or lacquer thinner to clean tools while still uncured.

it's not worth the extra work and hassles so I stopped using it all together...

this does does apply to construction adhesives such as PL Premium which I'm a die hard fan of......
and I'll stick w/ Weldbond...


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## Cherryville Chuck (Sep 28, 2010)

We used to see people on the forum say they used p u glue because it would foam up and fill the joint but you are correct when you say that the foam has no strength. It must be a tight fitting joint for it to work. The websites about it used to say as much but they removed those parts because people believed otherwise and they were selling more glue as a result. If you have a tight fitting joint then the foaming action is supposed to drive the p u glue into the wood grain making a stronger joint. But if it isn’t a tight fitting joint it won’t be a good idea. Then you need a glue with high solids content which I think might be be Titebond 3 but I’d have to check that to be sure. Lee Valley makes a GF glue (gap filling with high solids content) but if you use it on tight fitting joints you risk splitting them. Or having glue push out end grain on something porous like red oak from the hydraulic pressure in the joint. (VOE speaking here). This once again reinforces the statement that no one glue solves every problem and you need to use the right glue under the circumstances you have. I keep about 6 around that I consider essential but I might keep more if I could focus on woodworking all the time.


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## graeme.c.payne (Jun 21, 2017)

The only things I've used PU adhesive for is to bond different construction materials - such as steel stud channels to concrete. I don't think I've ever thought of using it for woodworking ... 

I have stuck mostly with yellow glue and it's relatives, or resorcinol when the bond had to be waterproof. I have experimented with epoxy on wood in the past week - I'm waiting to see how that works out.


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## Stick486 (Jan 4, 2013)

try Weldbond...

.


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## Stick486 (Jan 4, 2013)

graeme.c.payne said:


> The only *things I've used PU adhesive for is to bond different construction materials *- such as steel stud channels to concrete. I don't think I've ever thought of using it for woodworking ...
> 
> I have stuck mostly with yellow glue and it's relatives, or resorcinol when the bond had to be waterproof. I have experimented with epoxy on wood in the past week - I'm waiting to see how that works out.


are you referring to PU construction adhesive like PL400 and PL Premium...


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## 1fizgig (Feb 11, 2018)

mgmine said:


> You are asking how to make the boards longer not wider. The way it is done is with finger joints. You can buy a bit or do it on a saw.
> 
> https://woodgears.ca/box_joint/fingerjoint.html


Thanks Art, but no, I am trying to make a wider board, not a longer board. Length (1600mm) is not the issue, but I need that board to be 450mm wide. Currently I can source 405mm wide @ 1800mm long, so I can cut the length down, but it isn't wide enough.

Hope that makes it clearer.


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## 1fizgig (Feb 11, 2018)

Okay, I'll do my bit to answer a number of points made so far.

First though, thanks for all the input and discussion, very enlightening and I appreciate you all sharing your knowledge and experiences.
@Stick486: Thanks, that's a lot of good info. Baltic Birch isn't really available here in Australia so much (I haven't found much) and it's often made into ply with other woods, and not in thin sizes. @Biagio: I don't have a slot cutter at this time. Not to say I can't get one, so it's an option. 

I am concerned though that if the material I'm working with is only 18mm thick (not quite 3/4") that I would be hogging out quite a bit of material. Would I opt for say a 6mm thick spline?

Biagio: Regarding the position of the glue-line,
1. Will it be visible inside the cabinet? Yes it will
2. Will the board be weight-bearing? Yes it will
3. Are there any other structural members to give support? Yes there are, note I mentioned supports in the original post.
4. Exactly what material are you using? If by laminate you mean melamine-faced, it is darn difficult to get an invisible glue line. In that case, you might want to position the glue line as far towards the back as possible. Also, the factory edges will possibly be more chip-free than you or I can achieve by cutting. Ditto for the edging. If the laminate is wood veneer, it may not matter so much.

Steve: The laminate I refer to is glue-lam beech. No melamine involved 
I suspect hiding the glue line won't be an issue, nor will I need to hide the ends as they will be contained within the sides of the cabinet.
I've attached a sample pic of the glue-lam sheet I talk about for reference.

Biagio: I understand it to be that he wants a board 1600mm long and 450mm wide, but the standard width is only 405mm. Hence he wants to join two boards of 405mm along their long edges, and then cut off the extra. The question is whether to have the joint in the middle of the board, or to one side (i.e. one of the joined boards would land up being only 45 mm wide).
If this is the base of the cabinet, and not particularly visible from the inside of the cabinet, I would opt for the simplicity of the unequal widths.

Steve: Correct on the orientation of the board and cutting off the excess. I thought about unequal widths, however my concern about that was about the weight-bearing aspect and whether or not supporting it directly would prove stronger. I've attached also the sketch of the design to provide more clarity.
Note that the sketch is not entirely finished, but it shows the general design idea.


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## 1fizgig (Feb 11, 2018)

In the sketch you can see the two supports that will be underneath coming up from the stretcher along the middle. There will be a solid board in between the cupboards and drawers to which the baseboard will also be attached. All the grain/figure of the beech will be running horizontal across the piece (looking at it from the front).


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## Stick486 (Jan 4, 2013)

> First though, thanks for all the input and discussion, very enlightening and I appreciate you all sharing your knowledge and experiences.
> @Stick486 : Thanks, that's a lot of good info. Baltic Birch isn't really available here in Australia so much (I haven't found much) and it's often made into ply with other woods, and not in thin sizes.


that's what I was saying to use... BB plywood... (or comparable)...
https://dmkforestproducts.com.au/contact/
Richwise Australia Pty Ltd - Australian importers and wholesalers of Russian Birch Plywood
https://www.perthtimberco.com/plywood/
and there's Yates in Sydney, Mister Plywood and Amerind....

6mm is your target thickness..
3mm will work..
9mm is too much...



> I am concerned though that if the material I'm working with is only 18mm thick (not quite 3/4") that I would be hogging out quite a bit of material. Would I opt for say a 6mm thick spline?


spline thickness, as a rule of thumb, is usually 1/3 of the overall material thickness...
so you won't be hogging out too much at all..
a spline is a good fit and not gaped like a tongue and groove...



> I've attached a sample pic of the glue-lam sheet I talk about for reference.


perfect for splining....


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## Biagio (Mar 2, 2013)

Steve,
I am no engineer, and defer to greater knowledge and experience, but I would think that if you are only adding 45mm width at the back of the board, it is unlikely that you could put anything heavy enough on the narrow section, to cause a joint failure. You are not planning on putting 20kg barbell plates upright on edge, behind the soup bowls, perhaps?
As for the strength of the carcass overall, the full width of the 405mm board should be enough to support the top, dancing girls and all. Having a joint down the middle of the base would have no effect - it cannot increase the tensile strength above that of the unjoined material. You are supporting the base, as indicated in your sketch, so there should be no sagging. If you are worried, you might need to double up on the board (to 36mm thickness). Remember the load is not distributed just at the ends of the 1600mm length - you have an upright divider. If still unsure, ask Cherryville Chuck to calculate the forces for you.
Apologies, by the way, I noticed after posting that you had mentioned supporting members. And you are right about the glue line - you can hide it among all the other “glue lines” in the pattern.
I am envious that you can get birch lam - we can only get pine lam, and that is expensive enough. 
BTW, I looked up some of the suppliers Stick listed - looks like you would be in for a full sheet of BB in order to cut off a spline. Unless the barbell plates are a definite, I would stay with dowels.


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## Stick486 (Jan 4, 2013)

> I would stay with dowels.


If good dowel joints aren’t the oldest joints ever made, loose ones must be...
dowels overtime, fail/loosen because of conflicting dimensional behavior between the dowel and wht they are inserted into...
humidity change alone can cause self-induced loosening...
w/o a drill press or a jig, it is tough to get right alignment......



> looks like you would be in for a full sheet of BB


so use VG hardwood like maple or ash for short end grain pieces or flat/rift sawn for long grain rips.....


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## Biagio (Mar 2, 2013)

@Stick486
I defer to your knowledge and experience. Always great to learn from you.


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## 1fizgig (Feb 11, 2018)

@Biagio I can promise, no barbell weights behind the soup bowls 

I understand what you're saying, and it would also mean less "wastage" from having to saw off both sides, so I can see the value.

If I truly have nothing to worry about there, then perhaps salvaging the larger amount from the sheet (for future use of course) may be the better option.
Now I just have to "nail" down the option to use for joining 
@Stick486 I too had a look at some of those sites, thank you. At least 1 didn't have anything less than 25mm in any ply, and most of them are not local to me, meaning a bit of a trip. 
I did discover some AA grade marine ply at our local Bunnings (big box store) that could be a good option. I'm already considering buying a sheet for the back, because the colour of the outer veneer sheet closely matches the beech so would be a good match.
The downside is it's 12mm, so a bit wide for a spline in this case. I don't know if trimming it back down to 6mm is even worth trying. I've gotta go there anyway so might look for spline options at the same time


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## Stick486 (Jan 4, 2013)

resaw the plywood...
rip the ply to width 1st...
use featherboards...


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## Stick486 (Jan 4, 2013)

Biagio said:


> @Stick486
> I defer to your knowledge and experience. Always great to learn from you.


 @Biagio...
please don't...


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## Biagio (Mar 2, 2013)

@Stick486
In spite of my deference, I would still go for dowels in 1fizgig’s stated case. A matter of matching the Positional and strength requirements of the joint, the available materials and tools, the time required, and the expected overall longevity of the furniture piece. And in my case, limitations of ability. I have even found biscuit joints to be trickier than advertised.
@steve, if you go the splined route, remember to have both lengths good face down on your router table when you cut the grooves for the spline - that way, even if there is a mild discrepancy in thickness of the boards, it will be on the underside of the joint. I don’t think you need to worry about stopped splines, unless the edge of the board will be exposed as part of your design.
BTW, how are you planning to join the top and bottom to the sides and divider of the carcass? If you are planning mitred corner joints, it may then pay you to do those as splined mitres, in which case it may be worthwhile investing the setup time and learning curve for splined joints. I think you will need a table saw - I don’t have one, so have used a biscuit joiner to cut the spline. I chickened out of trying it on my radial arm saw.


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## Stick486 (Jan 4, 2013)

> I chickened out of trying it on my radial arm saw.


good move..


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## 1fizgig (Feb 11, 2018)

@Biagio
Check out option 3 for cutting a spline slot in this woodmagazine article:
https://www.woodmagazine.com/woodworking-tips/techniques/joinery/plywood


Since I have no slot cutter, this would be a way I could cut the slot. And given I already have a mortising jig that I could use for this, that could work. I certainly have smaller cutting bits.

I'm still wondering about the rabbet idea, especially since the baseboard will be fixed to the sides and divider. The divider will be screwed and glued from underneath. The sides and back, well I haven't decided yet. I want to avoid screws from the outside on the sides. The back may well get screwed on like the divider.

Given the amount of support the baseboard will get, and that the amount of weight it will support is likely to be a number of porcelain platters, I'm not sure that the join needs to be in the middle like Biagio was suggesting. In which case, how much weight is it likely to have on it, and what does that mean for the style of joint required?

Mostly thinking out loud and wanted to share where I'm at.

If I chose to do a spline, does it have to be A grade ply? Could I use a lower grade ply since it will not be visible? Given the length involved, even if there was a few voids, it shouldn't make a lot of difference you would think?
By rabbet, in this instance it would be a "double rabbet", in that both pieces would get a rabbet to increase surface gluing area.


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## Stick486 (Jan 4, 2013)

1fizgig said:


> 1... Since I have no slot cutter, this would be a way I could cut the slot. And given I already have a mortising jig that I could use for this, that could work. I certainly have smaller cutting bits.
> 
> 2... I'm still wondering about the rabbet idea, especially since the baseboard will be fixed to the sides and divider.
> 
> ...


1... yes that would work..
support the router so it doesn't rock ot rip as you are routering...

2... baseboard???

3... the top needs to '''float''.. consider it to be a table top..
https://www.canadianwoodworking.com/get-more/table-tops-and-wood-movement

4... what you are doing should hold up several adults..

5... no...

6... no...

7... the joint is called a ship lap... this joint will move/open up...
you will get more gluing surface w/ a spline...


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## Biagio (Mar 2, 2013)

@steve,
Perhaps you need to think out the base-to-side and top-to-side joints, before proceeding. There is the matter of aesthetics. The divider could be a simple dado, as you suggest, perhaps stopped at the front.
Regarding the back, you might want to consider setting the back into a rabbet all around the inside edge of the carcass - hidden from view, may add a smidgen of structural support to prevent the carcass going out of square. In such case, cut the divider slightly narrower than the sides, by an amount equal to the rabbet depth - otherwise you will be exercising your expletive vocabulary.
I have a jig like in the article you referenced, but frankly prefer to do it with a 6mm slot cutter on a router table. Stability is the thing.
How are you going to edge the front of the cabinet?


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## 1fizgig (Feb 11, 2018)

@Stick486:
Baseboard: this is made of the boards I need to join and the topic I've raised. It will form the base of the cabinet. The top is a single piece and I already have that, as the beech laminate comes wide enough in 26mm thick sheets. But due to the weight of the entire piece (and that one day I'll have to move this out of a multi-story house with no lift), we're trying to avoid using 26mm thick material for the bottom board of the cabinet.

I have found this material to be very structurally sound with minimal movement, but yes, I'm planning on treating the top like a table for sure! Thanks for the reminder though, I don't want to forget in the heat of the moment. I was thinking about some "Z-clips". 
@Biagio:
I was planning on rabbeting in the back, or at the least mounting it inside the outer edge of the carcass as you suggested already (wife appreciation factor again). I had already figured that would give a bit of structural integrity. Plus, that's why I could screw up from the baseboard into it.

The front of the cabinet will not need edging: the material being used shows off its beech timber beautifully, as it's not ply. No veneers or anything required: solid wood. It will remain "plain", meaning not given any features other than maybe softening the edges.


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## graeme.c.payne (Jun 21, 2017)

Stick486 said:


> are you referring to PU construction adhesive like PL400 and PL Premium...


Yes. I don't remember the specific one I used, it was 8 to 10 years ago.


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