Exterior domino joinery with epoxy questions

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Apr 8, 2017
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I’m planning on using my DF 500, sipo tenons and West Systems (105/205) epoxy to join black locust boards. The end product will not be finished with anything (oil, varnish, etc) and it will be outside in direct sun and rain.  I called West and they gave me the following information:

1. Sand joint faces with 80 grit to open pores
2. Wash joint faces with alcohol
3. Apply epoxy to both faces, allow to tack up
4. Apply 2nd coat epoxy to one or both faces and join with light pressure

Please add any other information to the above if I’ve missed something.

What I would like to know from fellow FOGgers is what to do with the domino mortises and tenons?  Same procedure as joint faces (except the sanding)?  Any additional info is appreciated.

Thanks!
 
I built 10 outdoor benches out of Ipe. I used Sipo tenons. I used West epoxy on some tenons and Titebond III on others. I cleaned the mortises with naphtha just before gluing in the tenons. I puttied in the epoxy around each tenon, top and bottom, as a shield against any moisture invading the wood.

The benches still look really good after many years outside with no surface treatment.

I can’t tell any difference between the exoxy joints and the Titebond III joints. The joints on all the benches are still tight.

Titebond III was a lot easier to work with than the epoxy.
 
I built a mailbox out of IPE.
I cut my own Dominoes out of the same IPE to make sure to not have differing movement between the species etc.

Used a local woodglue similar to titebond 3, with alcohol washing of the glue faces before application. Works fine so far (2 years?)
 
Pretty sure I’m going to use Tite Bond III.  Talked to a few others today and the general consensus is to use wood glue.
 
That sounds easiest. My understanding (I might be way off base) is that epoxy was the way to go before the advancements in glue that lead to the development of glues like Titebond III.
 
Birdhunter said:
I built 10 outdoor benches out of Ipe. I used Sipo tenons. I used West epoxy on some tenons and Titebond III on others. I cleaned the mortises with naphtha just before gluing in the tenons. I puttied in the epoxy around each tenon, top and bottom, as a shield against any moisture invading the wood.

The benches still look really good after many years outside with no surface treatment.

I can’t tell any difference between the exoxy joints and the Titebond III joints. The joints on all the benches are still tight.

Titebond III was a lot easier to work with than the epoxy.
[member=15289]Birdhunter[/member] I am surprised that you have had such excellent results with TB III and Ipe.  Due to high oil and silica content I have heard of epoxy being the only go to for long term bonding Ipe, but your results are refreshingly contrary.  TB II and III have been my standard go to adhesives for years. I don’t have a lot of epoxy experience and I’m not really excited about reinventing the wheel.

Thanks for weighing in with your experience. It is really helpful. 
 
Depending on temperature, humidity, and complexity of the joint epoxy will give you more working time and strength. T-3 is a great glue but when it's warm you really have to hustle to get parts together before the glue skins over. We use a lot of West Systems epoxy and it is our glue of choice for doors, shutters, exotic hardwoods, and any complex glue ups.
Cheers
Curt
 
Curt Boyer said:
Depending on temperature, humidity, and complexity of the joint epoxy will give you more working time and strength. T-3 is a great glue but when it's warm you really have to hustle to get parts together before the glue skins over. We use a lot of West Systems epoxy and it is our glue of choice for doors, shutters, exotic hardwoods, and any complex glue ups.

This is a great thought. Thanks for posting.

I’ve used West epoxy and it is a PITA. For a normal glue up I’d never consider it...however, after reading this, for a difficult glue up this makes a lot of sense. Working time probably goes from 15 minutes to 45 minutes and the bond strength is increased.  [cool]  very  [cool]

For that matter, any epoxy would work well because the open/working time is increased to such a large degree. I’ve used JB Weld and that can still be placed and prodded after 2 hours.
 
I’m in the research phase of an IPE gate/door build I will be doing in mid October when I visit my parents in Southern California.  My original plan was to use TightBond 3 but after a good deal of reading over the last few weeks I’m leaning towards West Systems G Flex 650 in this thread: http://festoolownersgroup.com/building-materials/glue-for-ipe/?all

Not sure if I will be taking my Domino with me as the truck is already pretty loaded w other equipment :(. Might have to go old school on this job.
 
One other factoid on my Ipe benches. I did about half the Domino joints with Titebond III and half with two-part epoxy.

I added a stainless steel screw through each half of each tenon after the joint had been glued and clamped. I drilled a hole for the screw going from the underside of the joint, through the tenon, and into but not through the upper half of the board.

I was pretty sure the glue and tenon would hold the joint together, but I knew a mechanical (screw pinning each half of the joint) lock would guarantee my benches would stay together.
 
One big difference between Glue and Epoxy is the gap filling capability where a glue joint needs to have a maximum gap of approximately 0.15mm whereas epoxy can have a gap approximately 1.0mm.  I believe that the domino as cut will be tight enough but for the glue application if you go sanding with 80 grit (or other very course grit) you might open the gap too large.  Conversely if you don't sand with the epoxy application the joint might be too tight.  These are just observations from years of experience and not based on any testing data.
 
I've used Titebond III in several applications with Ipe including post wraps and caps and have had no failures after 4 years of exposure.
 
curt boyer said:
Depending on temperature, humidity, and complexity of the joint epoxy will give you more working time and strength. T-3 is a great glue but when it's warm you really have to hustle to get parts together before the glue skins over. We use a lot of West Systems epoxy and it is our glue of choice for doors, shutters, exotic hardwoods, and any complex glue ups.
Cheers
Curt
When you glue up stiles and rails for doors, in what order and where all do you apply the epoxy? In both the mortise and on the domino or just one or the other? And do you also apply epoxy to the mating joint surfaces of the stile and rail?
 
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