Glue Tests

[Birdhunter]

I've received a great deal of excellent information from this forum on building a bunch of outdoor benches out of Ipe.

I was researching glues for Ipe and I found an article in a July/August 2007 Fine Woodworking issue testing 6 different glues in 3 types of wood, each with tight, snug, and loose bridle joints. Each joint was scientifically tested to failure. The title is "How Strong Is Your Glue".

One of the 3 wood types was Ipe. The other 2 were white oak and hard maple.

The glues in order of success were Titebond III, T88 epoxy, Elmer's Carpenter's Glue, Old Brown liquid hide glue, Moser's hot hide glue, and Gorilla Glue. The average measured joint strength in pounds of pressure at failure for each glue in the above order were 2024, 1994, 1924, 1595, 1531, and 1164. So, Gorilla glue (in these tests) came in about 1/2 as strong as TB III.

There was very little difference in strength between TB III and T88 epoxy. The ease of use of TB III factored into the equation.

Based on this information, I plan to use TB III for the tenons as they will not be getting wet and epoxy on the areas that will get wet. I'll back up the critical glued areas with stainless steel screws.

 

[grbmds]

I use Titebond III for everything. It isn't necessary in most applications, but it's easy to use, for me spreads and sets up like any other similar glue, and I never need to worry about the joint failing, inside or outside. I used Gorilla polyurethane when it first came out, but the fact that it's hard to clean off your hands and, I find, more difficult to work with, makes it less desirable. Titebond III just seems to be the best glue all-around.

 

[Neathawk Designs]

Birdhunter - a little off subject, but I was wondering if you are sanding your Ipe?  If so, what sander and grit?  I just picked up some Ipe decking today.  I like to remove the mill marks, so I'm sanding to 100 grit using the Rotex 125.  Sometimes I start at 80, them go to 100. This seems to be a decent selection, so most of it I can remove the marks with 1 pass in rotex mode at 100 grit, and then a second pass in the random orbit mode.  Then I'm coating with Messmers.

By the way...

Is titebond III safe for outdoor use?  I use it almost exclusively -but I don't think I've ever used it for outdoor projects. 

Thanks!

 

[Birdhunter]

I'd appreciate having the forum point out flaws in my plans!!!!!

I have built a prototype of the benches out of select pine just to get the dimensions and methods of construction right. I'm still waiting for the load of Ipe to arrive so you are ahead of me.

My research says Titebond III with an alcohol pre-wipe to remove oils is strong enough, works great with sipo tenons, and is water resistant. My research says the epoxy with an alcohol pre-wipe to remove oils is strong enough and give extreme weather protection.

I plan to use Titebond III on the tenons as they won't be exposed to rain. The 3 1X6X6'top sections will be "Dominoed" only, no edge gluing. The legs will be doubled 1X6X18"  and I plan to use epoxy between the boards AND joined with 4 stainless screws. I plan to wipe the glued surfaces with denatured alcohol immediately before gluing. The understructure is a 5' long by 10" box made of 1X4s joined with tenons backed by stainless screws.

All my joints are either mechanical (8mm by 80mm sipo tenons) or glued with stainless screws. None of the construction relies totally on glue. Well, I guess the 8x80 tenons rely on glue to hold then in.

I'd appreciate having the forum point out flaws in my plans!!!!!

When I see the condition of the Ipe boards, I'll decide on sanding. These are outdoor benches so they don't need to be fine furniture sanded. Just don't want splinters in the butts.