Need help with gluing M&T joint. - Woodworking Talk - Woodworkers Forum
 
Thread Tools Display Modes
post #1 of 9 Old 09-20-2012, 02:54 PM Thread Starter
Junior Member
 
Join Date: Sep 2012
Location: Eastern PA
Posts: 4
View dan-o's Photo Album My Photos
Need help with gluing Loose M&T joint.

Hi guys, new to the forum. I've been lurking and reading for quite a while but haven't had a reason to sign up until now. I'm working on my first "real" piece of woodworking in the form of a craftsman inspired mirror frame. I've attached a picture of the mockup I made earlier out of some pine and scrap cedar strips. The final version consists of a cherry frame and Peruvian walnut for the accent detail.

I'm using loose tenon joinery to join the rail and style. I thought everything was going well until I did some reading today on gluing the joint together. I was reading that if the mortise is pretty close to the end of the piece on the style, it was best to keep extra material there and then trim to the desired length after glue up to help prevent splitting. I didn't account for this, and all my pieces are exact length. The mortise ends approximately .5" from the end of the style.

Any thoughts? Will clamping the ends of the styles while gluing help to prevent the split, or is a split inevitable as the tenon swells up due to being so close to the end? I'm at the point of glue up with the final piece and want to cover my bases.

-Dan
Attached Thumbnails
Click image for larger version

Name:	Mirror-Detail.jpg
Views:	180
Size:	97.6 KB
ID:	51352  


Last edited by dan-o; 09-20-2012 at 04:05 PM.
dan-o is offline  
Sponsored Links
Advertisement
 
post #2 of 9 Old 09-20-2012, 03:18 PM
Senior Member
 
Dave Paine's Avatar
 
Join Date: May 2012
Location: Eastern PA
Posts: 7,222
View Dave Paine's Photo Album My Photos
If you are using loose tenons, I would recommend 2 part epoxy for the glue. Yellow glue is not intended to be gap filling. The Titebond III claims it can fill gaps "up to 1/64in", however, best not to try.

Another benefit of epoxy is no swelling of the wood so you should not have stress in the joint while the epoxy sets.

I have not read about leaving extra material to have more stock to resist splitting during gluing due to expansion.

I have done a number of M&T joints and never added extra length. Perhaps I have just been lucky.

Edit - forgot to say this is a nice looking design.

Last edited by Dave Paine; 09-20-2012 at 03:19 PM. Reason: comment
Dave Paine is offline  
post #3 of 9 Old 09-20-2012, 04:04 PM Thread Starter
Junior Member
 
Join Date: Sep 2012
Location: Eastern PA
Posts: 4
View dan-o's Photo Album My Photos
Thanks Dave! I'll try to post up a larger post with some pictures I've taken along the way once it's finished. Might have to recreate some of the points to fill in the timeline gaps.

With regards to the gap filling comment. The loose tenon's are sized to be a snug fit into the mortise. There is no gap along the thickness of them. There is a small gap at each end of the mortise where end of the slot is with a full radius. Are you talking about filling those gaps? I was assuming that it woudn't need to be filled to the brim with glue, as the joint won't be seeing stresses like a dresser or bench would have. My initial plan was to lightly coat the mortise and tenon with glue and assemble, trying not to put any glue onto the shoulder to eliminate some squeeze out. Does this make sense? Would it be a similar process for epoxy?
dan-o is offline  
Sponsored Links
Advertisement
 
post #4 of 9 Old 09-20-2012, 04:43 PM
Senior Member
 
Dave Paine's Avatar
 
Join Date: May 2012
Location: Eastern PA
Posts: 7,222
View Dave Paine's Photo Album My Photos
Quote:
Originally Posted by dan-o View Post
With regards to the gap filling comment. The loose tenon's are sized to be a snug fit into the mortise. There is no gap along the thickness of them. There is a small gap at each end of the mortise where end of the slot is with a full radius. Are you talking about filling those gaps? I was assuming that it woudn't need to be filled to the brim with glue, as the joint won't be seeing stresses like a dresser or bench would have. My initial plan was to lightly coat the mortise and tenon with glue and assemble, trying not to put any glue onto the shoulder to eliminate some squeeze out. Does this make sense? Would it be a similar process for epoxy?
If the tenon is a tight fit in the mortise, then yellow glue is fine. Some folks make these rather loose.

I have never worried about getting glue on the shoulder of the mortise.

I like to see squeeze out with any glue.

I normally apply blue masking tape on either side of the glue line. Easier to clean up. If you use epoxy I consider the masking tape highly beneficial to prevent the epoxy filling the grain around the joint, which can prevent any stain from being consistent.

I use the blue masking tape since I have found it will come off with minimal issues of pulling splinters out of the wood and will not leave any residue.

The brown masking tape can be very difficult to remove, especially if you clamped over the tape. Sometimes it will leave residue.

If you use epoxy, I recommend having some acetone on hand. It is the only solvent to clean up epoxy. It is so easy to get some epoxy where you did not intend. Been there - done that - too many times.
Dave Paine is offline  
post #5 of 9 Old 09-20-2012, 10:16 PM
In History is the Future
 
firemedic's Avatar
 
Join Date: Dec 2010
Location: South Louisiana - Gonzales
Posts: 6,423
View firemedic's Photo Album My Photos
Don't worry about cracking your work, the amount of moisture imparted to the the pieces from glue is minimal. Your tenons should have a friction fit... not to lose not the tight, obviously both are bad. Hardwood is obviously the best choice for a loose tenon but not essential. How are you cutting the mortices?

Dave, I laughed out loud about the lose tenon thing... good times...
firemedic is offline  
post #6 of 9 Old 09-21-2012, 01:44 PM Thread Starter
Junior Member
 
Join Date: Sep 2012
Location: Eastern PA
Posts: 4
View dan-o's Photo Album My Photos
Quote:
Originally Posted by firemedic View Post
Your tenons should have a friction fit... not to lose not the tight, obviously both are bad. Hardwood is obviously the best choice for a loose tenon but not essential.
I made the tenons out of scrap cutoffs of the Cherry I used in the frame. I also oriented the long grain to match up with the direction of the mortises.

Quote:
Originally Posted by firemedic View Post
How are you cutting the mortices?
I used my router table and a custom fence setup to help support the rail's when I was standing them on end. I'm using different thicknesses for the styles and rails, and doing it this way allowed me to justify everything off the back of the parts, keeping the alignment consistent. It worked out really well. I snapped a few pictures along the way and will need to start a build thread.


I'm making two identical mirrors and glued one of them up last night. I fine tuned the tenon's to slide in place easily yet not fall out if I flipped the piece over and then put a decent amount of glue over eveything. This morning I unclamped the piece and there were no cracks present! I'll glue the other mirror up sometime this weekend.

Last edited by dan-o; 09-21-2012 at 01:45 PM. Reason: Added information.
dan-o is offline  
post #7 of 9 Old 09-21-2012, 06:17 PM
Senior Member
 
Join Date: Jul 2012
Posts: 327
View Wood4Brains's Photo Album My Photos
Quote:
I used my router table and a custom fence setup to help support the rail's when I was standing them on end.
If you do this again, would you mind terribly posting photos so us noobs can see what you are doing? It would really help all of us out who are interested in learning about jigs.

Thanks in advance.

I'm An Expert In Ugly!
Wood4Brains is offline  
post #8 of 9 Old 09-21-2012, 06:25 PM Thread Starter
Junior Member
 
Join Date: Sep 2012
Location: Eastern PA
Posts: 4
View dan-o's Photo Album My Photos
Quote:
Originally Posted by Wood4Brains View Post
If you do this again, would you mind terribly posting photos so us noobs can see what you are doing?
You're in luck! I took pictures of this when I built the prototype. I'll post them later tonight for you.
dan-o is offline  
post #9 of 9 Old 09-21-2012, 11:42 PM
Senior Member
 
Join Date: Sep 2011
Posts: 576
View Midlandbob's Photo Album My Photos
The problem is often over glueing causing hydraulic damage or messy squeeze out. A mirror frame has very little stress on it especially if you use a bit of silicone to hold the mirror and prevent rattle.
If the fit is right, only a bit of glue in the mortise will make a clean strong joint. Where there are grater forces, a dowel pined in a hole is good. It can be decorative in view or hidden in back. I put them in while clamps are still on. Square dowel ends look good in some applications.
I have just put in a pin or two in with a pin nailer if I'm sure I won't want to disassemble.
Midlandbob is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Woodworking Talk - Woodworkers Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
How to make this joint (i think its called a knapp joint) Upstate Joinery 6 12-23-2011 11:30 AM
rabbet joint/rebate joint klr650 General Woodworking Discussion 3 03-22-2011 12:07 PM
Gluing & Joints: How sloppy can a joint be before it is un-usable dejones General Woodworking Discussion 3 01-10-2011 10:19 AM
Gluing LadyLihai Woodturning 10 01-15-2010 10:43 AM
Butt Joint vs Reverse glue joint nblumert Joinery 3 07-30-2009 09:32 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome