? about multiple M&T glue-ups

[GaryMc]

Think ladderback chair with curved uprights, three curved back pieces, a 1X2 seat support, and a bottom rung.  That's 10 M&T joints (20 glue applications) that need to be glued up at the same time.  The dry fit went together (finally) but it took these old hands quite a while, and I'm concerned about getting it all together without glue drying up or getting it all over me and everything else - despite using Titebond III with a decent set time.  Given the configuration, I do not think just doing one side at a time is feasible unless the second side follows immediately.

I'm thinking about applying glue to the tenons first, especially the end grain that normally needs two coats anyway, then the mortices.  This might mean that some of the tenons could be partially dry before completing all the joints.  Do you think this is will not compromise the strength of the joints?  Any other ideas?

[jteneyck]

Think ladderback chair with curved uprights, three curved back pieces, a 1X2 seat support, and a bottom rung.  That's 10 M&T joints (20 glue applications) that need to be glued up at the same time.  The dry fit went together (finally) but it took these old hands quite a while, and I'm concerned about getting it all together without glue drying up or getting it all over me and everything else - despite using Titebond III with a decent set time.  Given the configuration, I do not think just doing one side at a time is feasible unless the second side follows immediately.

I'm thinking about applying glue to the tenons first, especially the end grain that normally needs two coats anyway, then the mortices.  This might mean that some of the tenons could be partially dry before completing all the joints.  Do you think this is will not compromise the strength of the joints?  Any other ideas?

Epoxy.  Long open time; no stress.  Squeeze out is easily cleaned up with white vinegar.  

John

[GaryMc]

Epoxy.  Long open time; no stress.  Squeeze out is easily cleaned up with white vinegar.  

John

I'm familiar with 5-minute epoxy but have never used the slower stuff.  Any recommendation for a product?  Note I do not need a gallon of it.

[jteneyck]

I'm familiar with 5-minute epoxy but have never used the slower stuff.  Any recommendation for a product?  Note I do not need a gallon of it.

West System 105 is often considered the gold standard, but Total Boat and System Three make great products, too.  I've used System Three T-88 for the house doors I've made.  It has a working time of at least 45 minutes at temperatures below 70 F.  Another useful feature with epoxy is that it acts like a lubricant, so the joints slide together easily and also are easy to reposition, if needed, unlike yellow glue which begin to set immediately.  

System Three T-88 is available in small quantities up to gallons.  

John

[cpolubin]

Old Brown Glue has a 30 minute open time. A second advantage is it's reversible in case you make a mistake. Titebond liquid hide glue has a 10 minute open time if you think you're faster. I only use hide glue for all my projects. The reversablity has saved my butt at times. It also lubricates so the joint slides together easier.

Cliff

[FrankAtl]

Epoxy.  Long open time; no stress.  Squeeze out is easily cleaned up with white vinegar.  

John

Thanks for the tip, John. I didn't know this.

[Petertaylor]

Can someone else work with you? One putting glue on the tenons, one in the mortises. Then both of you pressong all the parts together.

[Bill Holt]

I'm familiar with 5-minute epoxy but have never used the slower stuff.  Any recommendation for a product?  Note I do not need a gallon of it.

I'm sure someone will disagree, but I doubt the brand is important.  I use epoxy in a several situations.  The 24-hour epoxy might be very handy for chair assembly.

I had no idea epoxy squeeze out could be cleaned up with white vinegar...that's a great tip!!!!!!!!!!!

[msalomon]

Old Brown Glue is a life saver for complicated glue ups.

[GaryMc]

Well, this morning I did the glue-ups using System 3 T-88 as recommended.  Two assemblies so 20 joints total, all done with the same mix.  Couple things - shop temp was about 55 F so both parts and even the mix were very viscous and difficult to pour and apply.  Next time I will warm things up!  Also (uncertain about how much would be needed), I mixed up about 3 times too much.

This afternoon after about 6 hours, I noticed the glue was still somewhat sticky, both the squeeze-out and the leftover amount, probably a temperature thing again.  Couple hours later it was nearly solid.  I intend to leave it in clamps for more than a day to make sure.

I found the vinegar tended to just smear the squeeze-out when wet, so gave up on that and hope it works better when set.  While tacky, I did remove most of it with a chisel.