glueing veneer

[Charlie Fox]

i am glueing roughly 18x18" veneer to 1" mdf. i shied away from the contact cement the hardwood shop recommended because like many things some people swear by it while the next guy swears at it. so i did a couple of test pieces about 2"x4" with TBIII and it worked great - i put a piece of stock over them and weighed it down.
so i just had the TBIII on hand, i need to do 6 pieces so should i stay with the TBIII or TB Original ok? i know they make a veneer glue but read an old post on here that it is funky to work with.

i dont have a vacuum press. was planning on placing another 18x18 over it and 200lbs of evenly distributed weight (four 50lb dumbells i am no longer able to curl lol) i know this doesnt equal 150 psi but it pressed well with the test pieces. i could use cauls and clamps - but that center area aint easy to get equal pressure to.


or should i just use TB original and the iron-on method?

[Kevin Jenness]

Your plan will work as long as all your surfaces are reasonably flat. Contact cement is a bad idea. I like a rigid glueline and Titebond Extend is the stiffest of that product line, but I pressed hundreds of square feet with Original with no problems. I would avoid TIII unless you need a highly water resistant bond, in which case plastic resin glue would be a better choice (and an excellent choice in general, but it does require mixing, a minimum temperature and a longer cure time, plus most formulations contain formaldehyde).

[John TenEyck]

What Kevin said. No to TBIII. Yes to TB Original, TB II, or Extend. TB III will likely work fine, but the glue line is not nearly as rigid as for the others, so if you have seams you likely will feel them over time as the humidity changes.

And another thought. Epoxy and Unibond 800 are excellent veneer glues and neither requires high clamping pressure, making both a great choice for veneering w/o a vacuum press or other means of applying relatively high, uniform pressure.

John

[Richard Coers]

Remember you need a balanced glue up for the panel to stay flat. Both sides of the mdf needs a layer of veneer on it. I don't like to glue down burl veneer with Titebond, but I too have had success with flat veneer. My unusual pressure technique back in the day was to cut some low grade wood to length to allow bracing up to the ceiling to my bench. Bowing and wedging to the ceiling generates a lot of force. I now have a vacuum bag system.

[Charlie Fox]

well, this is for the bottom of a chess board. the top has 1/4" shop veneer glued on with TBIII. i realize i ideally should have the same thickness on both sides but thats just not possible. i figure the glue will form some degree of moisture barrier, and both sides will get at least 3 coats of poly, and it will always be in a controlled envoronment.
also entertaining the idea of painting or sealing the mdf before the veneer. probably will have a lot of varied opinions on all this.....but so far TB original it is

Remember you need a balanced glue up for the panel to stay flat. Both sides of the mdf needs a layer of veneer on it. I don't like to glue down burl veneer with Titebond, but I too have had success with flat veneer. My unusual pressure technique back in the day was to cut some low grade wood to length to allow bracing up to the ceiling to my bench. Bowing and wedging to the ceiling generates a lot of force. I now have a vacuum bag system.

[Charlie Fox]

Remember you need a balanced glue up for the panel to stay flat. Both sides of the mdf needs a layer of veneer on it. I don't like to glue down burl veneer with Titebond, but I too have had success with flat veneer. My unusual pressure technique back in the day was to cut some low grade wood to length to allow bracing up to the ceiling to my bench. Bowing and wedging to the ceiling generates a lot of force. I now have a vacuum bag system.

good idea on the ceiling brace - a simple 2x4 and a bottle jack and i'm there. my joists in the garage are easily found because i have so may tools etc hanging from it... ;-)

[Richard Coers]

well, this is for the bottom of a chess board. the top has 1/4" shop veneer glued on with TBIII. i realize i ideally should have the same thickness on both sides but thats just not possible. i figure the glue will form some degree of moisture barrier, and both sides will get at least 3 coats of poly, and it will always be in a controlled envoronment.
also entertaining the idea of painting or sealing the mdf before the veneer. probably will have a lot of varied opinions on all this.....but so far TB original it is

It's been discussed before, but I was taught that 1/4" has solid wood characteristics and is not a veneer. You will get seasonal wood movement issues with 1/4"

[Kevin Jenness]

well, this is for the bottom of a chess board. the top has 1/4" shop veneer glued on with TBIII. i realize i ideally should have the same thickness on both sides but thats just not possible. i figure the glue will form some degree of moisture barrier, and both sides will get at least 3 coats of poly, and it will always be in a controlled envoronment.
also entertaining the idea of painting or sealing the mdf before the veneer. probably will have a lot of varied opinions on all this.....but so far TB original it is

If it's flat after layup and remains in a stable environment it should stay flat, otherwise you likely will see problems over time. Balancing panels is a rule arrived at by long and bitter experience. Glue in general and Titebond in particular will not bond reliably to paint, and differing thicknessses of veneer will fight each other. If you think this is just an opinion you should do some tests to see what works in your shop.

[Charlie Fox]

i understand, but i was told that 1/4" max on the veneer on 1" mdf should be ok, and it is actually a 32nd or so less. with 1" mdf i am going to trust it wont move.
clearly if i leave it outside in the rain it will fail horribly, and if i send it into the vacuum of space it will last forever - there has to be a goldilocks zone in there - the layer of glue and 3-4 coats of poly will retard some moisture for sure but how much is anybody's guess, my guess is not enough will get in to be a problem. i hope.
will TB adhere to the mdf if it has a sander sealer on it?

If it's flat after layup and remains in a stable environment it should stay flat, otherwise you likely will see problems over time. Balancing panels is a rule arrived at by long and bitter experience. Glue in general and Titebond in particular will not bond reliably to paint, and differing thicknessses of veneer will fight each other. If you think this is just an opinion you should do some tests to see what works in your shop.

[Mel Fulks]

In the old books anything that is 1/8th is a “ facing”, not a veneer.

[John TenEyck]

i understand, but i was told that 1/4" max on the veneer on 1" mdf should be ok, and it is actually a 32nd or so less. with 1" mdf i am going to trust it wont move.
clearly if i leave it outside in the rain it will fail horribly, and if i send it into the vacuum of space it will last forever - there has to be a goldilocks zone in there - the layer of glue and 3-4 coats of poly will retard some moisture for sure but how much is anybody's guess, my guess is not enough will get in to be a problem. i hope.
will TB adhere to the mdf if it has a sander sealer on it?

Not if you seal it completely. It needs to be porous enough for the glue to penetrate and bond to.

John

[lou Brava]

It's been a long time since I worked with any veneer but years ago I used contact cement on a few large projects & had no problem. What is the reason that pretty much every one is saying don't use contact cement ?

[Richard Coers]

i understand, but i was told that 1/4" max on the veneer on 1" mdf should be ok, and it is actually a 32nd or so less. with 1" mdf i am going to trust it wont move.
clearly if i leave it outside in the rain it will fail horribly, and if i send it into the vacuum of space it will last forever - there has to be a goldilocks zone in there - the layer of glue and 3-4 coats of poly will retard some moisture for sure but how much is anybody's guess, my guess is not enough will get in to be a problem. i hope.
will TB adhere to the mdf if it has a sander sealer on it?

I have 51 years of woodworking experience, 24 of those were as a professional. Who told you the 1/4 acted the same as a veneer, and how much experience do they have? The internet is filled who people that tried thick veneer and had failure. From contributor B:
I did this on a project with 1/4" thick hard maple. They were 9" x 12" plaques with the hard maple thick skin applied onto an MDF backer. When these plaques were placed in heated rooms (low humidity), the maple curled and pulled away from the MDF at the ends. This was a serious failure. You could place a damp cloth on the face of the curled plaque face overnight and in the morning it would be lying flat again.I then tried the same thing with 1/8" hard maple. Whereas the wood was no longer strong enough to pull away and curl at the ends, it still failed. This time the maple split in the center.
https://www.woodweb.com/knowledge_ba...Too_Thick.html

[Kevin Jenness]

It's been a long time since I worked with any veneer but years ago I used contact cement on a few large projects & had no problem. What is the reason that pretty much every one is saying don't use contact cement ?

Because there have been so many failures and it is impossible to repair them. Using a flexible thermoplastic adhesive on wood can work sometimes, as your experience shows, but I think you lucked out.

[Richard Coers]

It's been a long time since I worked with any veneer but years ago I used contact cement on a few large projects & had no problem. What is the reason that pretty much every one is saying don't use contact cement ?

Contact cement never really gets hard. Put a piece made with contact cement near a south facing window and the heat from the sun can soften contact cement and edges can curl.