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General Forestry => Drying and Processing => Topic started by: stumpy on December 30, 2011, 06:25:45 PM

Title: Thick slab glue up
Post by: stumpy on December 30, 2011, 06:25:45 PM
I'm looking for some ideas on improving my method.  frequently I need to glue up slabs as thick as 2", wide as 12", and long as 8'.  The problem is getting a good edge on them so they glue up clean and seamless.  I use biscuits and Tightbond 2 glue.  The problem is, if I rip them on the mill, they're fairly true, but not good enough.  I tried running them thru my joiner, but they're just to big to handle.  I tried the table saw, but because they're so big, it's hard to control the cut.  Any ideas????
Title: Re: Thick slab glue up
Post by: tyb525 on December 30, 2011, 06:37:38 PM
Circular saw and good blade, with a long, stiff straightedge (metal or hardwood). Clamp the straightedge to the board and run the base of the saw against it.
Title: Re: Thick slab glue up
Post by: Ianab on December 30, 2011, 07:20:09 PM
I've mounted my big router on the mill carriage. Put a large flat cut bit in the router and you can joint and plane pretty much any  size board, and get it as true as your mill's rails.

(https://forestryforum.com/gallery/albums/userpics/10460/P1040630.jpg)

Ian
Title: Re: Thick slab glue up
Post by: shelbycharger400 on December 30, 2011, 08:18:36 PM
i use a pro's edge  (menards) and a skill saw. 
I must add,  pro cabinet shops use LONG toe and foot boards on their jointers
Title: Re: Thick slab glue up
Post by: Nomad on December 31, 2011, 06:27:47 AM
     Try a long, wide straight edge made of something thin and hard clamped to the board.  Use a router with a 2" long pattern/trim bit.  You can get them with the bearing either on the top, bottom, or both.
Title: Re: Thick slab glue up
Post by: LeeB on December 31, 2011, 09:00:17 AM
You can also use the skilsaw/straight edge combination by laying the two boards to be glued side by side. Use some cleats and wedges to lightly clamp them together. Position the straight edge so the cut will be centered on the seem down the middle. Any discrepecies will be mirrored from one edge to the other.
Title: Re: Thick slab glue up
Post by: Rooster on December 31, 2011, 10:28:46 AM
Stumpy,

Here are a couple ideas:

Build portable workbenches on lockable casters that will double as infeed and outfeed tables for your table saw.

Use a 18" x 96" ripped slice of 1/2" cdx plywood, and clamp your 2" stock to the top...use the factory edge of the plywood against your fence. Carraige bolts, wing nuts, and some hardwood blanks can be used to hold the stock in the correct position.

Also, there is a company in Madison called The Workbench Tool Company
http://www.workbenchtool.com/
...and they may still have a straight line rip saw.  It takes rough sawn lumber and edge cuts automatically.   Might be worth the trip "Out West" to get a quality product that you don't have to fight with...and get a good seamless glue-up.

Good luck,

Rooster
Title: Re: Thick slab glue up
Post by: purple otter on December 31, 2011, 06:14:35 PM
A few years ago I built a dining table out of 3" thick white oak.Like you said it is HEAVY.In order to handle the planks I built infeed and outfeed tables for my jointer.They were only as wide as my jointer and have adjustment screws onthe legs.The tops were melamine to help the material slide better.I also ripped everything to 6",this not only made it easier to handle ,but allowed me to true  up one surface on the jointer before planing them.I know it sounds bad ripping a nice 12" piece in 1/2,but when they are glued back together you honestly can't see the joint.Good luck!
Title: Re: Thick slab glue up
Post by: scsmith42 on December 31, 2011, 10:11:35 PM
Depending upon your budget, I would suggest two options.

Option 1 - Festool track saw (the larger one).  Expensive, but phenominal quality.
Option 2 - a high HP router with a straight bit and an edge guide.  Less $ than the Festool, and more versatile.

Option 2 is probably the most commonly used option for achieving a straight edge on longer boards.
Title: Re: Thick slab glue up
Post by: beenthere on December 31, 2011, 10:17:46 PM
The slightes change in moisture content will likely change any straight edge obtained.
So quick assembly after straightening the edge will be important as any crook will not likely be removed by clamping.

purple otter has a very good idea for thick material.  ;)
Title: Re: Thick slab glue up
Post by: Norm on January 01, 2012, 08:24:16 AM
I have the festool track saw Scott talked about and it works great.
Title: Re: Thick slab glue up
Post by: red oaks lumber on January 01, 2012, 09:09:36 AM
finding someone in your area that has a straight line rip saw will be the cheapest, fastest, most accurate option :)
Title: Re: Thick slab glue up
Post by: purple otter on January 01, 2012, 05:21:15 PM
Here is a  picture of the jointer extention ,and the dining table.

 (https://forestryforum.com/gallery/albums/userpics/20947/DSC02111.JPG) 

 (https://forestryforum.com/gallery/albums/userpics/20947/DSC02101.JPG) 

 (https://forestryforum.com/gallery/albums/userpics/20947/DSC02109.JPG)
Title: Re: Thick slab glue up
Post by: beenthere on January 01, 2012, 06:13:10 PM
I have similar jointer extensions for long pieces on the jointer as well.

I see you are getting some top shrinkage in the table but have allowed for it to slide in the end caps.
Title: Re: Thick slab glue up
Post by: stumpy on January 01, 2012, 06:33:38 PM
Thanks for all the input.  I'm reminded why I'm a member here.  keep it commin 8)
Title: Re: Thick slab glue up
Post by: purple otter on January 01, 2012, 06:54:13 PM
Beenthere,the 3"oak airdried for7years and the 40"top shrunk 1/2",not too bad.
Title: Re: Thick slab glue up
Post by: SwampDonkey on January 01, 2012, 07:03:28 PM
Like beenthere says about truing up the edges, make sure you use it soon or it will move out of square over a few days.
Title: Re: Thick slab glue up
Post by: Magicman on January 01, 2012, 08:21:19 PM
Yup, you gotta allow wood to do what wood does.  I built a Grandfather clock out of Pecan once.  Well, I should say "was building".   :-\  I finally had to scrap the entire project because I did not allow enough room for shrinkage with some wide raised panels.
Title: Re: Thick slab glue up
Post by: WDH on January 01, 2012, 08:29:29 PM
Purple Otter,

The sliding dovetail on the breadboard end is a very nice design feature!
Title: Re: Thick slab glue up
Post by: Ironwood on January 01, 2012, 08:36:17 PM
Well, others have said this but, for what is worth I make my living building with BIG thick material. Delivering a 22' walnut bartop to downtown Pittsburgh tomorrow morning. Tree was lightening struck lightly, see the check in the pics. Also, it is in priamrily two pieces with a third center "marque"

The straight edge router is THE way to go. Skip Festool (sorry guys) unless you have other uses for their system(s),...$$$

Go to an aluminum supply shop and get/order a 1/2" or 5/8" x 4" piece of high tensile aluminium (40/20 I think)  "flat bar" , Mine is 12' long and it get used frequently for just this purpose. Forget about add-on tables (although I have them on my 16" Oliver jointer) the straight edge is the way to go. I even have a hidden hole in the wall on the outfeed side of the jointer for the boards to go out if they are longer than 9' or so ::)

It stays true and will last and last. mine was $150 many years ago. Pic looks shiny, it dulled down when it dried (I HATE shiny)

Ironwood



 (https://forestryforum.com/gallery/albums/userpics/11262/camera_121_180.jpg) 

 (https://forestryforum.com/gallery/albums/userpics/11262/camera_121_201.jpg) 

 (https://forestryforum.com/gallery/albums/userpics/11262/camera_121_200.jpg)
Title: Re: Thick slab glue up
Post by: metalspinner on January 01, 2012, 10:09:19 PM
I use the router and straight edge trick,too.  But one thing is different in my process.

The straight edge is clamped to the first piece and edge routed.  Leave the straight edge in place and clamp into position the second board so a gap 1/16" smaller than your cutter diameter is between the two boards.  Now run your router the opposite direction of your first cut jointing the edge of the second board.  This will leave a mirror image on the second edge and your peices will mate perfectly.  Any irregularity in the straightedge will not matter as the defect will "key" into each other..

A couple more tips... make sure to run the same spot of the router baseplate against the straight edge for each cut.  One smooth motion and speed the entire length of cut will also produce better results.
Title: Re: Thick slab glue up
Post by: Larry on January 02, 2012, 09:51:54 AM
Another straight edge/router guy.  When you get a straight edge buy two.  One about 10' long to rip and another 3 or 4' long to make your crosscuts.

Title: Re: Thick slab glue up
Post by: stumpy on January 02, 2012, 10:10:02 AM
I'm thinking the straight edge is the way to go.  I have tried it with a 1x2 oak, but had trouble with the saw fence slipping under the edge.  Do you guys have a problem with the straight edge flexing cause it's only clamped on the ends of long pieces?
Title: Re: Thick slab glue up
Post by: Ironwood on January 02, 2012, 06:04:31 PM
That is the reason for the better grade of aluminum AND the thick dimensions I stated, mine is HEAVY, like 40 pounds or so. DOES NOT MOVE.

Ironwood
Title: Re: Thick slab glue up
Post by: shelbycharger400 on January 02, 2012, 07:42:19 PM
stumpy..  most straight edges are 4 inches wide, and are extruded with some sort of profile in them
http://www.menards.com/main/tools-hardware/power-tool-accessories/router-bits/pros-edge-cutting-guide/p-1487305-c-10080.htm