Glue for the sandwich panel

[S. Heisley]

When using TitebondIII to glue plywood to your stick frame, wet and wring out a cloth so it is just damp. Then, if you wipe down the frame with it before you apply the glue, it will buy you extra time. Some of my plywood skins were glued in 90 to 100 degree heat with as low as 8% humidity and, with this method, I had plenty of time to position, clamp, and weight my skins. Also, I used enough glue so that it just started to drip when I clamped it. (Keep damp and dry paper towels on hand to wipe off the drips and use wax paper as a liner under your work so you don't glue something that you don't want to glue.)

[Cody Pendant]

Cody,

Welcome to the forum...... Please don't make me watch the video and search for the results..... just tell us.........

Thanks for the welcome!

But your not tricking me! You will have to watch and read, sorry.

I see we have some astute observers here also....S. Heisley and Mauleskinner.

The strength of regular yellow glue blew me away.
Their findings on the types of glue JOINTS was for me just or maybe more informative to me. I think we waste a lot of time on fancy woodwork that in reality, does more harm than good.

Unfortunately they did not test PL Premium. (Gorilla glue is similar but is NOT the same. I have tested it.)

So without further adieu, I will muck up the waters further!

http://www.woodenboat.com/forum/showthread.php?t=6799

http://www.solowoodworker.com/wood/glue.html

http://www.simplicityboats.com/pl_premium.htm

http://www.woodweb.com/knowledge_base/C ... sives.html

Happy reading and head scratchin'

[planovet]

Where I had good, close tolerance mating surfaces and could apply glue and clamp quickly, I used TB III (for example, in the sandwich construction of my floor and sidewalls).

Where there was less close tolerances and I need some working time, I used PL glue (for example, bending and fastening plywood to roof spars.)

+1

[S. Heisley]

If you mix a little sawdust in with the TBIII, it works really well for those joints that have less close tolerances. In fact, doing that makes those joints sounder than the ones that have a close tolerances.

[Cody Pendant]

Looking for some opinions. I'm about ready to glue my skins to my 1x framing. I've got Titebond and PL adhesive. Any preference? I thought the PL would be better. Do we have to worry about any fumes emitted after it's cured? We are in an small space.

You asked for opinions so heres mine.

My personal preference is for the PL Premium for the structural assembly and use the Titebond 3 for the joinery / cabinetry.

Both adhesives are great, but the PL P is awesome and is used allot in small boat building. ( a similar pursuit)

I posted the links to various tests that have been preformed to get at your basic question. To me that comes down to the best product for the right job. Their is no single best product. They all have strengths and weakness.

And for the last ?, no I do not think you need to worry / about off gassing.
However, I am not a doctor or scientist , though I play one on TV.

[wannabefree]

I used Titebond 3, which was a real challenge. To extend open time I thinned the glue as much as I dared, wet the wood, and sprayed down the glue I had applied to keep it from skinning over.

When (if) I ever do another I'll use epoxy thickened with fumed silica (Cabosil). Working time is an hour or better, which is what you need.

[Rock]

The shocking thing about TB III or any other conventional yellow wood glue is the clamping force required for maximum strength. In that article I think they applied over 100 pounds/square inch of joint.

I did use TB III to glue my walls together. For my little 4 X 8 walls I had 600 lbs of concrete blocks on top of the clamping cauls. Guestimating at the surface area of my framing, I'm guessing that I got barely 1 PSI of clamping force. The walls have not fallen apart yet but it's only been on one trip.

If I had vacuum bagged, I would have gotten 14 PSI max - still far short of the recommendation. We would need a giant hydraulic press (Terminator fans out there know what I'm referring to) to get the 100 PSI recommended for max strength. But then again, our walls should never see the kind of stress that they applied in the article.

Eric

[S. Heisley]

Rock wrote:

The shocking thing about TB III or any other conventional yellow wood glue is the clamping force required for maximum strength.

How true! It took a bit of trial and error before I found what worked best for me. Around the edges of the wall, I used only good, sturdy/strong clamps and strips of unused or scrap wood, clamping down each end of the scrap wood board, using that board to hold down the plywood in between the clamps. If it was a long section and a long clamping board, (more than 3 or 4 feet) I used a clamp or two in the center of the length of the clamping board. Be certain to position your clamp with the working mechanism up, not down, so that glue drips won't clog up your screwing or ratcheting clamp mechanism. In the center areas, (away from the edges, where I couldn't clamp) I used gallon milk jugs, filled with water (better yet, sand).

TitebondIII and PL...I like both! Each has a purpose for which it is best suited. PL may have not need as many clamps but it also has a drawback in that unnoticed drips and errors are harder to remove. Dried Titebond sands off much easier.

[Cody Pendant]

The shocking thing about TB III or any other conventional yellow wood glue is the clamping force required for maximum strength. In that article I think they applied over 100 pounds/square inch of joint.

I did use TB III to glue my walls together. For my little 4 X 8 walls I had 600 lbs of concrete blocks on top of the clamping cauls. Guestimating at the surface area of my framing, I'm guessing that I got barely 1 PSI of clamping force. The walls have not fallen apart yet but it's only been on one trip.

If I had vacuum bagged, I would have gotten 14 PSI max - still far short of the recommendation. We would need a giant hydraulic press (Terminator fans out there know what I'm referring to) to get the 100 PSI recommended for max strength. But then again, our walls should never see the kind of stress that they applied in the article.

Eric

Howdy Eric,
Been some time since I read the article, but I do not remember them using any exotic clamping methods. If I remember correctly they used regular wood workers clamps. Correct me if I am wrong. (May have to dig up my back issues)
There was a lot of pressure applied during the destructive test by the press to the force meter, but thats a different matter.

1 US ton per square ft = 13.888 psi is a apx measure for the force equivalent of vacuum bagging. It depends on your altitude and vacuum pump and quality of the bag seal. Thats a lot of tonnage to have to equate for by weighted means, thats why it is so attractive.
Its a uniform pressure across the entire surface and is hard to duplicate otherwise. It would also be very inefficient for joinery. A hand clamp would be more than sufficient. It (vacbagging) is extremely efficient for panel construction however.

[Rock]

They did apply over 100 PSI. I think they used 1 1/2 wide sticks of wood. For a half lap joint (the strongest type in their tests - stronger than mortise and tenon) that would amount to 1.5 X 1.5 = 2.25 square inches. That amounts to 225 pounds clamping force for the glue up. That's easily attainable with a stout woodworking clamp.

I would like to know how much strength the glue has at much reduced clamping forces. I think that as long as the gap is minimal we'll be fine. We're not building chairs. I did take the time to flush up my framing with a hand plane, and used 1" MDF as clamping cauls. I think it'll be OK.

Eric

[john curtis]

I have just gone through 3 cases of Tight Bond III.Set up very quick in the heat,better working time when it's cooler.Once it sets thats it you don't get what ever you have glued apart.I like it better than PL.
John