Stave core door glue for 1/4" veneer?

[Terry Patrick]

Building a mahogany entry door 1 3/4" thick. I am making stave cores for the stiles and rails, and will be facing them with 1/4" mahogany. The entry door is facing the east north east, pretty far under the entry way overhang. Its in the northern Illinois, we get the worst of all seasons. I have been researching what glue to use to adhere the veneer with and pulling my hair out with all the different answers. I will been using a shop made press (two 5"x8' pieces channel iron and clamps). I'm leaning toward Weldwood plastic resin. but i have read other forums that say plain old white glue is fine also. The staves are glued up with Titebond 2 and now after reading a lot of good and bad things mostly bad about Titebond 2 and 3, was that the right thing to use. I've always used Titebond 1 for interior work in my shop forever. So i'm confused now on which way to go.

[Mel Fulks]

I've made lots of doors like that. Once 30 plus for one house. We used mainly plastic resin glue since its thin and
spreads easily. But we had to make the faces a little thick so that we could straighten after gluing. Clamped them up
with paper between them to make sure they didn't stick together. For one door I would use Titebond 2 undiluted . Put it
on both surfaces. With no water in the glue you might get perfectly straight stiles,but make the faces a little thick to be sure.

[David Sochar]

I would avoid adding water to all that wood. It will swell, get pressed, then shrink over the next few weeks. What happens next is conjecture, but not likely to be good.

I would only do it with urethane glue or another solvent based glue. Epoxy. Do not add water.

Also, the 1/4" thick Mahogany is precariously closer to solid wood than it is veneer. If it decides to act like solid wood, you are doomed. Thinner - even 3/16" would help - is what you want for veneers.

David R Sochar
Acorn Woodworks

[Mark Bolton]

I've made lots of doors like that. Once 30 plus for one house.

Wow, 30 exterior entry doors in a single home? Thats one massive house.

[Brad Shipton]

If you don't mind the cost of the glue, I would go with West Epoxy. Their six ten dispenses using a standard small caulking tube that has a nice mixing head. That material is thicker than their other epoxies (without filler) and that seems a good fit with your clamping plan. The tubes do not yield a lot of material due to the head for mixing, but they are very handy. If you don't like the cost of that, I would use a polyurethane. David has endless discussions on the woodweb about his experiences with different TB versions. I highly recommend you read those. Search the site using his name and you will find them.

[Mel Fulks]

Brad, that is interesting. But PL Premium is an adhesive ,not a glue. However next time I use some I will "put the
"squeeze " on a sample and see what it does. Thanks.

[Mel Fulks]

Wow, 30 exterior entry doors in a single home? Thats one massive house.

Yep, we had sign that read : We Serve Claustrophobics ! We don't get unhinged over oddballs, we unlock the inner
self. Never went off the rails and did any stile. And we kept sharp with panel reviews.

[Mark Bolton]

Brad, that is interesting. But PL Premium is an adhesive ,not a glue. However next time I use some I will "put the
"squeeze " on a sample and see what it does. Thanks.

West, or any epoxy, is an adhesive "not a glue" isnt it?

[Mark Bolton]

My assumption has always been that something considered as a "glue" had a viscosity thin enough to do some penetrating into the material. An adhesive kinda sits on the surface. Hide glue is really an adhesive other than for the tiny bit of penetration it achieves only from being applied hot. The term glue or adhesive is somewhat pointless in that modern adhesives may well outperform glue in every aspect and vice versa a glue in a certain application may crush an adhesive?

[Brad Shipton]

Mel, I did some tests with PL Premium when I was making some floor border that was made up of 3/16" skins over a 1/2" baltic birch. The samples (1 polyurethane glue, 1 epoxy, and 1 PVA) were pressed in my vacuum bag. I submerged the un-finished skins in water, and let it become fully saturated over a period of a day or more. The substrate, and opposite skin were above the water line. Neither the epoxy samples nor the PL premium skins came off, but the PVA samples did pop off. It was not an overly realistic test since the border will never see that level of abuse, but I was curious. Living in the boonies I sometimes use it because it is on the shelf of the hardware store. I would expect the polyurethane is more flexible than the epoxy, but I believe its strength will exceed a PVA made using similar clamping methods. The last I bought epoxy was an eye opener cost wise.

Here is the spec sheet for Polyurethane:
https://www.lepage.ca/content/dam/uac/lepage/canada/1-8/1-8-1-PL-Construction-Adhesive/LePage%20PL%20Premium.pdf

[Mark Bolton]

Mel, I did some tests with PL Premium it when I was making some floor border that was made up of 3/16" skins over a 1/2" baltic birch. The samples (1 polyurethane glue, 1 epoxy, and 1 PVA) were pressed in my vacuum bag. I submerged the un-finished skins in water, and let it become fully saturated over a period of a day or more. The substrate, and opposite skin were above the water line. Neither the epoxy samples nor the PL premium skins came off, but the PVA samples did pop off. It was not an overly realistic test since the border will never see that level of abuse, but I was curious. Living in the boonies I sometimes use it because it is on the shelf of the hardware store. I would expect the polyurethane is more flexible than the epoxy, but I believe its strength will exceed a PVA made using similar clamping methods. The last I bought epoxy was an eye opener cost wise.

Here is the spec sheet for Polyurethane:
https://www.lepage.ca/content/dam/uac/lepage/canada/1-8/1-8-1-PL-Construction-Adhesive/LePage%20PL%20Premium.pdf

Brad,
How to you apply and spread the PL?

[Richard Coers]

I hope you are using quarter sawn mahogany, because 1/4" thick veneer acts just like solid lumber. It seasonally moves just like solid lumber and your core won't. I think you'll find commercially made doors like that have veneer of 1/8" or less so it really acts like veneer.

[Terry Patrick]

By the time I’m done, veneer should be down to 3/16”, maybe a little less. What about using Unibond 800?

[Mel Fulks]

Unibond is good. I'd use Titebond 2. Check what kind of quantity you would have to buy. "Be sure you are right ,then go
ahead"

[Brad Shipton]

Mark, I have applied with a standard caulking gun. I experimented with a few different trowels to spread it out. I found the 1/16" or 1/8" v worked best. You need to carefully clean after or you only get one use out of that trowel.

Unibond 800 is great stuff (older version was better) with the correct amount of clamp force. I have used it many times in the vacuum. I am not sure I would go to this amount of work and use TBII, but I respect Mel's opinion and experience.

[Mark Bolton]

I'm in agreement about any pva. Run.

[John TenEyck]

I've made a few exterior stave core doors. I used TB2 to glue up the stave cores. I used 1/4" QS Sapele on some of them and 1/4" rift sawn white oak on some others, and glued them to the cores with Weldwood PRG. If you can't apply a lot of pressure, however, I would use epoxy. FWIW, the Germans use 7 mm skins on many of their exterior doors, which gave me confidence 1/4" would be OK. If you make the cores and skins from the same wood or from woods with similar seasonal expansion/contraction, with the same grain orientation, they will move together. In any case, I have had no trouble with doors that face N or are completely shielded from sun exposure. I did have trouble with one door that faced S and had a storm door over it, not surprisingly. The 12" wide bottom rail veneer split. I replaced the bottom rail (not easy), vented the storm door, and had 3M reflective film applied to the storm door and have had no further troubles with it.

John