Joining thin boards

[Anonymous]

I'm joining some thinner stock - 1/4" - and it's fun! The method I used was to cut a thin groove the length of the board on the table saw 1/10" wide, i.e. the thickness of the tablesaw blade, and then to cut a fillet just a fraction thinner than 1/10" and join the boards with it.

Seemed an easy concept but I had two main problems.
1. Not easy to get the saw cut in exactly the same place on each board, which meant the jointed boards had to go through the planer (12" wide when joined)
2. How on earth do you successfully clamp thin boards during glue-up? Uisng regular clamps simply collapses them if you put enough pressure on to make sure there's squeeze-out of the glue. I tried using clamps on the joint and then clamping across, but not succesful.

I have one good joint, one fair and one with lots of filler!

These boards aren't huge - unjoined they are about 18" long by 4" to 6" wide - but they have gorgeous bookmatch patterns that I'm trying to take advantage of. They were made from resawing thicker stock that had interesting patterns. One might turn into an interesting looking musical instrument...

Any suggestions?

 

[Chris Knight]

Brian,

I frequently join boards of this thickness for drawer bottoms, backs of casework etc. I never try to position them with any kind of groove etc. I simply clamp them (in K bodies or just flat on my bench (on waxed paper) and if they show signs of shifting, put light clamps or weights across the junctions between boards.

I also frequently use hide glue for joining smaller boards and a rubbed joint sticks with no need for clamping.

 

[Anonymous]

Hi Chris. How strong are the joints when you're done? Would they take significant pressure OK? I'm thinking of up to 20kg/cm2 at some points which is why I used a reinforced joint.

 

[Chris Knight]

Brian,

Like most edge to edge joints they are at least as strong as the native wood - if you try to break them, they will always break somewhere other than the glue line.

I am not quite clear how you are measuring the pressure you want the boards to handle but if a wide board could take it, then so could ones joined to a similar width in the manner I have described.

 

[Chris Knight]

Brian,

A fiurther thought. I have happily edge joined wood much thinner than this - down to veneer thicknesses. For the really thin stuff I just lay the boards edge to edge and run packing tape up the join, then "open" the joint like a book, put glue in it, close the joint and leave it flat till the glue sets.

You could try this if you fnd clamping difficult

 

[Guest]

Brian, if you run the boards over the table saw from each end you will finish up with a groove dead centre.

 

[Bean]

I have done the same as chris but with wide masking tape, so far successful. I have not tried packing tape but will do so its cheaper than masking tape.

Bean

 

[devonwoody]

I successfully joined some thin boards last month .
I put a sheet of chipboard on bench covered with a sheet of plastic sheeting, glued the board edges and put 3/4" screws through each board to hold everything down(also had wedged boards at sides previously)
I did finish with screw holes, but over length boards could have had screws put in a waste area.

 

[Anonymous]

Thanks for all the suggestions. My prior experience in simply edge gluing with no fillet or biscuits hasn't been 100% successful - admittedly a long time ago though. Practice makes perfect?

I've calculated the pressure that needs to be handled from the tension in the wires that will have to be supported on small areas of the board, and added 25% just to be safe.

 

[devonwoody]

This afternoon I glued up 4 x 1/2" Thick boards but instead of screwing them down I have laid a bag of gravel (aggregate) on top inaddition to wedgeing the sides of boards.
Let you know tomorrow end result.

 

[Bean]

devonwoody Is it me or does that seem a little extreme, I have just finished glueing up some 1/4" boards, I'm only using 2" Masking Tape to hold them together, I will also report tomorrow.

Bean

 

[devonwoody]

TO Bean
It gave me confidence, I left the workshop saying to myself it won't lift up overnight
It did make my elbows ache though lifting up the sack (it was wet).

Very successful end result by the way.

 

[Bean]

Devonwoody
Mine also, I had cut some oak to 1/4 thick and edge jointed it for the base of a liftout tray. It had not moved appreciatively at all. I have just finished giving it a quick plane over to make sure it is nice and flat.

Mind you last weekend I was making some suitcases for a local dance troop who are going to tap dance upon them, the ply I skinned them with was anything but flat and I placed a small engineer's vice on them to get the ply flat enough for the glue to bond to the strengtheners :shock:

So I suspect your method is good :wink:

Bean

 

[tx2man]

Aaah, they were the All singing, All dancing suitcases
someone was telling me about :lol:

TX

 

[Bean]

Hey is there still a space where the front passenger should be in cabs for trunks, or did that advantage go with my youth


Bean

 

[tx2man]

No, it's still there, but it was originally for a bale of hay
to feed the old nag :shock:

TX

 

[Bean]

Ere what you doing with my LOL then !!

Bean

 

[tx2man]

I'll set 'em up, you knock 'em down!

TX