type of glue for stave core

[mreza Salav]

Quick question: would Titebond III be good for glue-up of stave core (for a door) as well as the veneer/skin over the core?
I also have west system epoxy (but is messy and would rather avoid). I hear other suggestions (resin type) but wonder if can
get away with Titebond III.

TIA

[Chris Padilla]

I think it would be my #1 choice for gluing up the door but I'd be leery of using it for securing veneer. How thick a veneer are we talking? For veneers, you generally want a glue that dries very hard like a plastic resin glue or any of the veneer glues joewoodworker offers on his site.

[mreza Salav]

Chris, the veneer is 5/32" thick (so half way between 1/8" and 3/16"). I suppose you mean Titebond III for your #1 choice?
I have never worked with plastic resin glue. Would epoxy (west system) be a good choice here? I was thinking of using that for the M/T joins anyway.

[John TenEyck]

I used Weldwood Plastic Resin glue when I built some stave core doors, for everything - glue up of the stave cores, gluing on the veneer skins, and gluing the M&T joints. I didn't want to take a chance with the creep that can occur with Titebond and other aliphatic glues. Epoxy would also be a good choice for gluing the joints, but I wouldn't use it for the other areas. FWIW, I wouldn't go any thicker with your veneer.

John

[Mel Fulks]

Titebond is fine for the staves and faces. I like plastic resin glue and have made many doors using it for the whole job.The
stiles are straighter with the faces glued with Titebond because its not water based . If you insist on using plastic resin use
the Unibond 800 two part glue. Its specific purpose is for jobs where water should not be introduced. Titebond can be thinned with water for some jobs ,but not stile faces. Bringing in water ,you will get some stiles too bowed to use regardless of how straight the cores ,cauls,and presses are. It's the water.

[jack forsberg]

Mo

tite bond III for the core and Resorcinol for the face stock Very easy to work with and water clean up. this is a full water proof glue type I

its a powder(has a shelf life)you mix with water and has an long open time. you only mix what you need as it a catalyzed cure. so deep laminations cure well and it will cure under water too i believe.

very little creep if any. I use it for bent lams because the spring back is almost nothing

[Mel Fulks]

I know the creep issue is often mentioned ,but unless the use of the word has changed it exists mainly with white glue.
White glue shrinks as it cures and can actually cause a slight misalignment of surfaces. I know its frustrating to get conflicting advice ,consult the manufacturers.

[Peter Quinn]

Your choice for the staves. But if you use a water based glue you need let it rest to fully equilibriate post glue up, and titebond III takes 72 minimum to fully cross link, so glue them up, pull clamps, scrape and wait, a week is a good idea. I finger jointed my individual staves, for that I used tite bond III on suggestion from Jor Callhoun, idea being that the water swells the fingers and locks the joints, worked like a charm. I also used tite bond for the edg glue of the staves IIR. But for the skins I used tite bond PU glue, no water, and I didn't wet one face, plenty of moisture in kd lumber to cure urethane glues as it turns out, and minimal foaming. I would have used unibond, but its minimum operating temp is around 70 degrees, I glued the staves in winter and my shop is low 60's on a good day. Skip the epoxy, very expensive, massive overkill. Probably work fine but hardly required.

[jack forsberg]

Your choice for the staves. But if you use a water based glue you need let it rest to fully equilibriate post glue up, and titebond III takes 72 minimum to fully cross link, so glue them up, pull clamps, scrape and wait, a week is a good idea. I finger jointed my individual staves, for that I used tite bond III on suggestion from Jor Callhoun, idea being that the water swells the fingers and locks the joints, worked like a charm. I also used tite bond for the edg glue of the staves IIR. But for the skins I used tite bond PU glue, no water, and I didn't wet one face, plenty of moisture in kd lumber to cure urethane glues as it turns out, and minimal foaming. I would have used unibond, but its minimum operating temp is around 70 degrees, I glued the staves in winter and my shop is low 60's on a good day. Skip the epoxy, very expensive, massive overkill. Probably work fine but hardly required.


Peter i do not have any of the problems you mention with water glues during glue up of cores and faces all in one go. I let them set a bit but have never had a week do so. As to water glues or any glue ups like this it needs to be balanced so both faces are the same material and glued at the same time. every thing get worked again to final size anyway after the staves are made.

Now if there really wide i can see some concern there. I do so little stave that i just use full length core stock in #2 pine 4/4 KD. Of all the glues i have use for exterior PU is the only one that has failed for me. i find it a mess to work with a frankly not very strong IMO. I would use type III way before i would use PU because it just has not held up for me to weather.

[mreza Salav]

hmmm...it seems I would be fine with Titebond III for stave cores and possibly for the skins. I don't thin it (straight from the container).
I hate PU glue and the mess it creates. I have plenty of Titebond III and have west system epoxy and if I don't have to buy another type of glue for this task
I'd rather use what I have.
Stiles are 6.5" wide and the rails are between 6.5"-9.5" wide (top one to the bottom one). Since I don't hear any objection to TB III I suppose
I'll be safe to use it for the veneers too, but if I'm better off with epoxy I don't mind doing an overkill here (it's only one entry door I'll ever make!).

[John TenEyck]

It's not really the water that causes the staves to bend/bow, etc. it's the unbalanced construction people often use. Regardless, I don't use yellow glues for the staves because they do creep, despite what some may have posted. The are unsuitable for bent laminations for this very reason, which, to me, means they are unsuitable for any application where constant stress is being applied, like a door hanging on its hinges. Many people have successfully built doors with yellow glue, however, so the actual stresses may be pretty low. Still, why take a chance, the resorcinol glues are easy enough to use and cheap enough as well.

John

[Mel Fulks]

Jack,the company where I learned to make stave core doors used water based pr glue for many years before I got there .
We had a large old acme thread press and often made all the doors for the better jobs. We glued them up 1/8 inch thicker than finish size in order to do straightening where needed,a few would be too bowed,and we would use those for top rails.By using Titebond unthined I can make straighter stiles than before.
You wrote you don't make many,glad you have had good luck. A test :,take a thin strip of wood and trim it to where it fits and is held between two points without deflecting. Now remove it, dampen it and put it back. It will be bowed but you will not be able to measure the tiny bit of lengthening caused by the water. It doesn't take much. The glue makes that increase permanent. The pu glues have been well tested and some have been certified by independent labs to be used under water for structural use.The messiness is mainly due to excessive foaming from adding water. I know water is
reccomended on some of the labels but it is only needed for extremely dry wood. The added water can also reduce the
strength. Check with the technicians .

[mreza Salav]

Ok, I'll have to find a place that sells that plastic resin glue then (here in Canada).
Any tip/warning I should be aware of using that for the first time in an important project? I don't want to screw up the parts after so much time invested in preparing them (let alone I want to preseve my stock of Honduras Mahogany as much as possible).

[jack forsberg]

Ok, I'll have to find a place that sells that plastic resin glue then (here in Canada).
Any tip/warning I should be aware of using that for the first time in an important project? I don't want to screw up the parts after so much time invested in preparing them (let alone I want to preseve my stock of Honduras Mahogany as much as possible).


LV used to sale it but any boat repair shop would have it Mo.

[mreza Salav]

Jack, is this what you are talking about: http://www.amazon.ca/00203-Weldwood-Plastic-Resin-1-Pound/dp/B001003J16

Given the different suggestions on what to use for the veneers (avoid water based glues or not) I'm a bit confused/concerned.
My understanding was Epoxy is the ultimate (stronger than all resin glues) and would be Ok in this application (although pricy). I'm Ok with that if it is a safter choice here....

[jack forsberg]

Mel

i heard the watering down PVA glue makes it weak?


i have been building exterior work for over 30 years and of all the glues that i need to count on PU is one i do not count on for strength.All the documents support even the new ones for glue lam beams. if I glue up something and its bends the wood is telling me not to use it . to many stress.

most my work is solid doors and windows for historic work but i have glued up plenty to know what to use.
BTW are your doors not painted ? I can see you keeping the moisture out of the glue up maybe for stable during but glues are designed to move with the wood through a wet cycle IMO, and once cured they become stable. stave core stock by nature is unstable by grade(the very point to make them that way is to use low grade core and high grade face stock)so the point of water based glues reveling this is a good indicator of it future stability.

Point is woods warps and so does stave core once it hit water. If you know how to work wood it not a problem.




Jack,the company where I learned to make stave core doors used water based pr glue for many years before I got there .
We had a large old acme thread press and often made all the doors for the better jobs. We glued them up 1/8 inch thicker than finish size in order to do straightening where needed,a few would be too bowed,and we would use those for top rails.By using Titebond unthined I can make straighter stiles than before.
You wrote you don't make many,glad you have had good luck. A test :,take a thin strip of wood and trim it to where it fits and is held between two points without deflecting. Now remove it, dampen it and put it back. It will be bowed but you will not be able to measure the tiny bit of lengthening caused by the water. It doesn't take much. The glue makes that increase permanent. The pu glues have been well tested and some have been certified by independent labs to be used under water for structural use.The messiness is mainly due to excessive foaming from adding water. I know water is
reccomended on some of the labels but it is only needed for extremely dry wood. The added water can also reduce the
strength. Check with the technicians .

[Jeff Duncan]

Jack, is this what you are talking about: http://www.amazon.ca/00203-Weldwood-Plastic-Resin-1-Pound/dp/B001003J16

Given the different suggestions on what to use for the veneers (avoid water based glues or not) I'm a bit confused/concerned.
My understanding was Epoxy is the ultimate (stronger than all resin glues) and would be Ok in this application (although pricy). I'm Ok with that if it is a safter choice here....

I'm not so sure of that? A little out of my experience range, but I was under the impression that Resourcinol (sp?), is just as good, (or possibly better?), for exterior applications? I haven't done any exterior, (don't want the liability), so can't offer more than that:o Just that a little research may be in order!

good luck,
JeffD

[Thomas Hotchkin]

Mreza
As Jack has not said anything yet, Yes that is plastic resin glue. You well like the open time of this glue, at 60 degrees F, you have almost 30 minutes. Make sure that you wear a dust mask when mixing glue with water. Tom http://www.amazon.ca/00203-Weldwood-.../dp/B001003J16 (http://www.amazon.ca/00203-Weldwood-Plastic-Resin-1-Pound/dp/B001003J16)

[Chris Padilla]

When is a veneer a veneer and when is hardwood hardwood? IMO and experience, 1/8" hardwood is still going to act more like hardwood and not veneer. In other words, it can move and be strong enough to cause problems if/when it does move. Veneer should not be strong enough to cause issues with potential moving because it is thin.

I have an example: I once laminated two pieces of 5/8" MDF together with a veneer glue (i.e. one that dries hard) that were about 16" x 36". They were nice 'n flat as you might expect. I next laminated some shop-cut walnut veneer that was 1/16" to one side of this sandwich. I use vacuum bags for all this and the same glue. The next day, that walnut veneer managed to pull the 1 1/4" MDF sandwich into an arch! It had raised nearly a 3/4" in the middle. I was totally shocked and it made me a believer in the power of wood and most importantly, to BALANCE veneers. I eventually glued the same walnut veneer on the other side and all was well but this was an interesting lesson.

[Mel Fulks]

Jeff is right rescorcinal has higher water rating than pr. Rescorcinal costs more and sometimes soaks in and stains an exposed surface. Was the water proof glue for years .

[Jeff Duncan]

Chris, unbalanced panels will almost always warp as you found out the hard way, even with veneer. Door skins however should be thick enough to absorb abuse. A 1/32" veneer on a door is not going to withstand any abuse and will show it's inner layers with the slightest dent or scratch. Of course more importantly the skins need to be the same thickness so the panel is balanced. As long as you have 1/8"+/- skins on both sides, your still maintaining a balanced panel;) Personally I like to call them skins.....as I'm not sure where lumber ends and veneer begins:rolleyes:

Here's a case in point.....every once in a while I'll get a batch of veneered mdf that will warp. In each case it's b/c one side of the veneer was sanded a bit more than the other. So we're talking about a difference of maybe a hundredth of an inch! With the thicker doors skins and glued up solid wood staves, there's a bit more wiggle room.

JeffD

[mreza Salav]

The veneers are all the same thickness and my plan is to have both sides of each stile and rail (yes, rails are also stave core) of the same wood piece but fliped over.


Jeff is right rescorcinal has higher water rating than pr. Rescorcinal costs more and sometimes soaks in and stains an exposed surface. Was the water proof glue for years .

That's one of my concerns about this (especially that Mahogany is porus and it might seep through the veneers). I've read a few who have had this issue (maybe the mix wasn't mixed well?).

Thought my (quick) question had a definite/clear answer. Seems far from it...

[John TenEyck]

Mreza
As Jack has not said anything yet, Yes that is plastic resin glue. You well like the open time of this glue, at 60 degrees F, you have almost 30 minutes. Make sure that you wear a dust mask when mixing glue with water. Tom http://www.amazon.ca/00203-Weldwood-.../dp/B001003J16 (http://www.amazon.ca/00203-Weldwood-Plastic-Resin-1-Pound/dp/B001003J16)


Yes, this is the same stuff I use. I buy it at my local ACE hardware for about $30 - $35 for a 5 lb pail. It works as well as Unibond 800, IMO, and I can get it locally, cheaper. In Canada, I'd try one of your local hardware/lumber distributors.

John

[jack forsberg]

ya Mo thats the stuff i would use. Your going to run the work through a sander after so you can be fairly messy when you just add water to the powder. The two part glues are the messy ones and i have no experience with the resin part two mix type for the powders Its is my understating that this glue is stronger than epoxy Mo and the least creep. it does not have gap filling property but you don't need that with what your doing. If you don't have a good press a stack of mdf works real good as one. at any rate box tape the mold for clamps. With the water mixing is easy and clean up is easy and you should have no staining if you send them through the sander and a wiped them clean(your wood is dark anyway).You can't work to finish size anyway and you should be over thick after glue up. Let them set for a day are two then send them all through to size.

[Chris Padilla]

Chris, unbalanced panels will almost always warp as you found out the hard way, even with veneer.

Well, I didn't find out the hard way so to speak as the build up of the panel required veneering one side (non-show) first...then edge-banding with 1/2" walnut...then veneering the show side (over the edge-banding). I was just surprised a 1/16" veneer could still pull something that thick and heavy out of flat. :)

[Mel Fulks]

Plastic resin glue must be used at 70 degrees minimum and kept at 70 or more until cured ,not set ,CURED. See instructions. At 60 degrees the open time is probably 14 months,or more.....

[jack forsberg]

yes it has to be used a 70 or higher but 70 is what your shop should be at for stable work.

here is a PDF on the in and outs Mo
http://www.cpadhesives.com/proper-urea-resin-use

[mreza Salav]

Called around a bunch of local places and none carries plastic resin glue (many have no idea what I'm talking about). A boat building supply says they bring it only in winter :confused: Given the shelf life of this product is relatively short, I'm not keen on ordering from Amazon.

I understand everybody has a different method of work and have different reasons for their choice but if I may ask, why TB III is not suitable for attaching the veneers over the core? I can see the reasoning behind not using it for the core (although some are saying I'll be fine).
Is there a reason epoxy is not suitable for attaching the veneer or even gluing the core strips?

[Mel Fulks]

According to the technicians employed by the glue mfgs.,I think this is the third time I have referred to them today,Titebond can be thinned 5 to 10 percent. 5 percent makes a huge difference in viscosity. They acknowledge the issues with adding water that I mentioned. The bowing I mentioned does not occur after exposure to water,it is immediately apparent when stile is removed from clamps. It's the WATER. We would just glue up a few extra and use the
worst ones for top rails,and we made them about a extra 1/8 thick .It worked ,but not as well as using an unthinned Titebond or polyurethane as they consistently produce a straighter product needing less or no correction. Some of the info for Unibond 800 mentions water free as a feature.

[Mel Fulks]

Again, TITEBOND unthinned is fine for either .Just pay attention to working time,and glue up a few at a time.

[mreza Salav]

Thanks Mel, I have never thinned Titebond and my question was using it without thinning. You obviously have had success with it.

There are some who think Titebond is good for both (like you). Some like Jack think it's Ok for the core but suggest a different glue for the skin
and I'd like to hear why? Others like John think TB has too much creep which I can see as an argument against using it for core strips.

Similarly, would like to hear why some (if any) think epoxy is not suitable or either (the core or skin lamination)....

[Mel Fulks]

I won't speak for others ,but I can think of no reasons why epoxy wouldn't work. It's expensive and might be overkill but if
You have some ...use it up ,especially if it has a "use by" date.

[John TenEyck]

You could use epoxy for any and all of it, but the stuff is expensive and an incredible mess to use. Doesn't Amazon ship to Canada? If you can't get some sort of plastic resin glue, I'd use TBIII before epoxy for bonding the veneer, just to cut down on the mess.

John

[Peter Quinn]

Called around a bunch of local places and none carries plastic resin glue (many have no idea what I'm talking about). A boat building supply says they bring it only in winter :confused: Given the shelf life of this product is relatively short, I'm not keen on ordering from Amazon.

I understand everybody has a different method of work and have different reasons for their choice but if I may ask, why TB III is not suitable for attaching the veneers over the core? I can see the reasoning behind not using it for the core (although some are saying I'll be fine).
Is there a reason epoxy is not suitable for attaching the veneer or even gluing the core strips?


I will go on record that if a failure has been had with PU glue, its generally user error or wrong application. I've been using it for 12 years and never had a single failure. Its really one of the strongest glues available, well tested and well proven, and it will flex more than any other water proof glue that does not creep. Yes, the skins can expand and not break the bond. As has been mentioned above, door skins still move like wood at that thickness. I don't have a ton of experience making stave core doors, but I have done a fair bit of engineered material with plywood core, gluing thick skins to a core. Problem with PU for bent laminations is clamping pressure. You can't achieve it, maybe with a vacuum bag and outside form, maybe not. Its not gap filling at all, which makes it a less than ideal choice for tenon or dowel joints too. For me tite bond wins there because it swells a tight joint enough to act as a clamp. But for edge glue ups and face laminations where the open time can be met and solid even clamp pressure can be achieved, rock solid option IME. Messy? Hardly compared to the alternatives, epoxy, urea formaldehyde (oh, did everyone forget to mention that plastic resin and resorcinol glues have a fair bit of formaldehyde in them and are known as urea formaldehyde glues?) You need to use gloves with any of them, PU squeeze is the easiest to clean by far, and not a deadly toxin to sand like UF glues. When machine sanded epoxy turns to bubble gum and eats wide belt paper, real joy at $65 each. So no glue is perfect. I certainly respect the choice to not use PU glue for what ever reason one choses, but its strength should not be one for them. I'll let you know how my door fares in a few years, the last door I did with PU was in the weather almost 7 years, it had a sloppy half hearted finish on it, was meant to be temporary, didn't even give up when the excavator ripped it off the building! I wouldn't use it for gluing up a cope and stick door, big mess there.

Mreza, the problem with epoxy is its brittle. No flex. spread some thin, let it dry, it cracks like potato chips, or shatters like lexan. A few long time door makers I work with swear it off because its too rigid, too brittle, does't behave like wood. The claim is that the wood will move and over time will eventually break the bonds placed on it. But epoxy will fill gaps, does not require much clamping pressure, makes an excellent water proof sealer. And lots of people swear by it. Boat guys love it, but they need the gap filling and are constantly maintaining the boats.

I think ultimately you are fine with titebond III for the skins, you have to move quickly to meet the open time, thats the main challenge. You can thin the glue with up to 5% water by volume without any impact on strength, this extends the working time up to 50% (straight from Franklin techs), but I'm not sure you want to be introducing more water to the process in this case. You can also chill it , it works down to 50 degrees? We used to throw a gallon in the fridge in the summer for an hour before glue ups to slow it down, sounds crazy but it works. The worst thing that can happen is you get a little creep on the edge of the stiles where the skin meets the core, just a hair line feather typically. Veneer guys that do high end tables or boxes or such complain about this, its a catastrophic failure in their case. For a door stile? A little creep will probably never even be noticed, and is of little consequence, so fear not. It really does take 3 days to fully cure, no point rushing, I'm conservative. Also I like to stand the parts I face glue on edge after pulling clamps so both faces are exposed to air and can dry equally, that seems to be the biggest factor in flatness, balance. The instinct is to stack it like lumber with stickers...don't. Not sure where that tip came from, but is sure does help.

Having gone through the glue question for a similar project almost 9 months ago, I can tell you there is no clear consensus. Frustrating. I searched wood web, the internet, PM'd people, did all the research I could. Everybody had a different opinion as to why their system was right, and why others had or would fail. For every glue one guy says is best I found another guy who swore he'd had a failure. I'm pretty sure they will all work, I've seen pictures of doors made with PU, UF, PVA, epoxy, and isoset. Oh, I threw that last one in just to poke the fire. Google isoset, its supposed to be the ultimate two part laminating adhesive, only comes in 5 gal buckets though, meant to replace toxic UF glues in places with strict VOC laws. UF glues are getting harder to get...something about causing cancer?

[Mel Fulks]

I've been googling this glue creep thing . Seems the definition has changed .It used to be the actual shift of alignment at a joint .It seems now to refer to misalignment due to stress on a joint ,I have not seen this happen. But I don't deny it could
happen. White glue is bad about shifting ,a perfectly surfaced joint could move over night and require more work. The
lack of that fault in yellow glue was frequently mentioned when it was new and was probably the main reason it replaced
white glue. I once glued two pieces of aluminum with white glue ,surfaced the joint as soon as the glue was dry. Next day
they were misaligned. Anyway I now have a better sense of how the word is currently used.

[jack forsberg]

UF glues are getting harder to get...something about causing cancer?

Peter we should all be dead.:cool:


Formaldehyde is found virtually everywhere, indoors and out, naturally occurring and man-made. It is a combustion product found in cigarette and wood smoke, natural gas, kerosene, exhaust from automobiles, incinerators and power plants. It is also widely used in building materials especially glue, Urea-formaldehyde foam insulation and pressed-wood products such as plywood, particle board, paneling and wood finishes. Many floor coverings contain formaldehyde such as carpet, padding and adhesives. Also used in furniture, paper products, cosmetics, deodorants, shampoos, fabric dyes and permanent-press fabrics, inks, disinfectants, air deodorizers and carpet deodorizers. Mobile homes, motor homes, and travel trailers are known for high amounts of formaldehyde since so many of their components may be made from particle board or pressed-wood products.

[mreza Salav]

Thanks to all for the comments/suggestions.

Peter I think you are right that everybody has his own preferences and that probably I'll be fine with either of the suggestions made.
I will likely use epoxy for the stave core strips (where I want a more stable joint) and might use TB III for the skins. I have already started it but it is still a long way to go. Will post some progress pics.

[Jeff Duncan]

How are you attaching the skins? If you have the ability/funds to invest in a vac press your job will be much, much, MUCH easier! Again I'm speaking from the position of doing interior doors so the glue may change, but the process is about the same. I use regular old yellow glue, (yeah I know it's not in fashion anymore:o), and a 3" glue roller and spread the glue fast on the stile. Add a skin, flip, and repeat. I can get a few done up at once, get them in the bag, and apply pressure before the glue sets. I've also glued up blanks for stiles and rails like this and the glue line is almost non-existant! It really gives you a much better clamp than any other technique I've tried in the past.

good luck,
JeffD

[Mel Fulks]

Gotta add one more ,too. In last nights googling I watched a Wood Whisperer video comparing water based plastic resin
glue with Unibond 800 . Might be helpful to "it's the water "deniers.

[mreza Salav]

I don't have a vaccum press. As I said I've started the project already and have done a few glue-ups so far without problems. There are two posts
(between the side lites and the door) which will be 6" wide and 4 5/8" deep plus a half column that will be attached over it (so it will be about 7 1/4" deep inside to outside). Here is the picture of the column I have "turned" using a jig and a router as I don't have a lathe that can turn a 101" long piece:

268974

and here are the two posts that I'm gluing a skin over the inside to cover the fact that it is made up of 3 separate 8/4 pieces; I have built an I-Beam for the glue up and use enough clamps, both posts are being glued at the same time:

268975

Here is another glue up: 3 lamination (to make 2.25" thick stock) for side lites, no stave core for them as they will be fixed between the posts and jamb. I used 2" thick stock on top to make even pressure of clamps down:

268973

So far things have come out of the form (clamp) quite nice.

[jack forsberg]

Gotta add one more ,too. In last nights googling I watched a Wood Whisperer video comparing water based plastic resin
glue with Unibond 800 . Might be helpful to "it's the water "deniers.

Mel

I am sure the water has something to do with it. I have never said it did not FWIW but i find its not a big deal is all if you rework the core flat. I have/use this practices for years to deal with flatness. As good as the wood whisper is:rolleyes: i find his video aimed at the novice and they lack any real experience from both sides or any sides IMO. Lets just say he has not walked the walk.

Many times in a production environment each process is scrutinized for quality/waste. Sometimes the process misses the end result in that its looks at the problems in an isolated way(general money saving). Sure there are ways to keep the stave flat with out water as there are way to get them flat with water. much of the new glues have to claim something new don't they like no water no VOC.:p

The point being is that when the doors warps because the its in the sun with a dark color paint and baking hot do you tell them its the paint? do you go over how you kept everything flat when you made them. These are extremes i know but that's were the problem lay IMO.

Stave core IMO is being pond off as the best when in fact its a way to use low grade lumber to get a product out that is very contestant. it riddled with as many problems as solid doors and as far as i can tell there still working on special machinery for it. many of the cheap paint grade stave core doors use hard board as faces(mind you they prime them so they don't look so cheep) This is not new as solid core has used hardboard for years and marshmallow cores for slab doors.

Given all the cores that have been used over the years like card board, partial. lumber,foam.,what the core is glued with is not as relevant as what the face is glued with. The face glue acts as torsion box so to speak and its stability is maintained by its bond IMO.

This is all just my opinion based on my years gluing and watching things fail and then just asking why.
I just don't trust the techs (customer relations pep)anymore as i have found them to be more of sales men. there may be good ones but its a craps game finding them.

I think peter is dead on that epoxy being a bad choose too. RG has a long history of working in very hard wreathing condition and i tend to trust history more than the future.

let me add boys i hope you don't think i was being a hard ass it just my nature and i assure you we would be having a good laugh if we were sitting around a fire with a beer or too sharing our thoughts.

peace out

[Mel Fulks]

Jack,thanks . I'm not a huge fan of WW but he did reference what others are telling him .Not sure I understand "rework
the core flat" I've never attempted to use any cores that were not perfectly straight. All went in clamps straight some came out bowed. At the time I was taught, there were not a lot of type 2 glues on the market. Now that we have Titebonds and polyurethane I just don't see any reason to use water based glue even if it results in only one bowed stile out of a job. A number of times we have made large doors and been paid well just because no one else around would make doors over standard.I still use pr for long open time jobs like circle stair trim work. As for claims ,what few there have been were made good. The sun thing has not been big because we warn about full exposures and don't take any job that doesn't make sense. Neither of us can easily avoid stave core doors. When red flat sawn red oak and such are wanted
it is the only way. Sometimes architects demand stave core for genuine mahogany doors and will not yield to mere facts.
We both know Pinus strobus is the most popular stave material and has a high stability rating. I have used other cores
including exterior mdf and was surprised at how well it worked. I agree some inferior materials are in the industry just to save money for mfg.

[John TenEyck]

Peter, from the strength test results I've seen PU glue was the weakest one tested, far below typical yellow glues. I'm sure it's plenty strong enough to build a durable door with, but it's not because it is stronger. Personally, it's awful stuff to work with and has a short shelf life; as such, I have no place for it in my shop but I'm happy it works well for you. As for UF glues being toxic, maybe if you breathe in deeply while mixing it. I do it outside or under the stove hood until it's mixed; once mixed, there is no further outgassing. Finally, about epoxy being too brittle, well yes, it is, just like UF glues. That's the point. In order to prevent creep the glue needs to be rigid. I'm not defending epoxy, I don't use it for woodworking, it's just too messy, but it will provide a very strong and durable bond that won't creep over time which, IMO, makes it perfect for door applications.

John

[Chris Padilla]

http://www.sawmillcreek.org/showthread.php?21822-Are-Your-Glue-Joints-Repairable

I think it might be a good time to bring up Bob Smalser's nice thread on glue. It is somewhat relevant here.

[Peter Quinn]

Peter, from the strength test results I've seen PU glue was the weakest one tested, far below typical yellow glues. I'm sure it's plenty strong enough to build a durable door with, but it's not because it is stronger. Personally, it's awful stuff to work with and has a short shelf life; as such, I have no place for it in my shop but I'm happy it works well for you. As for UF glues being toxic, maybe if you breathe in deeply while mixing it. I do it outside or under the stove hood until it's mixed; once mixed, there is no further outgassing. Finally, about epoxy being too brittle, well yes, it is, just like UF glues. That's the point. In order to prevent creep the glue needs to be rigid. I'm not defending epoxy, I don't use it for woodworking, it's just too messy, but it will provide a very strong and durable bond that won't creep over time which, IMO, makes it perfect for door applications.

John

The last comparitive strength test I saw was FWW, it involved a right angle, like a tenon or cope and stick, then they tried to break it apart by racking it in a press. Is that the one we are discussing? For that joint, I'd prefer PVA, if a tenon is loose enough to be assembled IMO it's too loose to maximize PU's strength. But an edge glue up, or a face glue up? Solid clamping pressure, well mated surfaces, minimal gaps. The PU then expands into the mating pieces and forms a tenacious bond you can't smash with a hammer. Mind you I have glued up doors with PU with good success, but only paint grade, it's a foamy sticky mess for sure on finished millwork, and I stay up at night worrying that if somebody ever puts my doors into a giant press it will give up a few seconds earlier than it would have if I'd used titebond III.:rolleyes: For door skins, I know I'm going to be cleaning the joints regardless of glue type, PU foam is by far the easiest thing to clean up, let it dry, it fluffs off with the lightest scrape, assuming its a glue up you can easily scrape and will be further dressing, not my favorite thing for assembly work.

I read a report regarding one part moisture cure PU glues for preparation of structural laminations like glue lams, prepared by the German building sciences department of something or other.....honestly can't remember the name, but its easy to find on the web, long detailed 10 yr study on the simple question, is PU suitable for structural glue lam production, simple conclusion...yes. Is PVA....says no right on the bottle. My reasons for using PU were longer open time and it met all my other build criteria, temp range, strength, water resistance, spreadable, hidden glue line.

On the UF glues, breathing the raw dust is bad, breathing the sanding dust is not a great plan either I've been told, but of course no dust is really great for your lungs, just that UF has that extra special ingredient. I know formaldhyde is omni present, but it's been identified as genuinely bad stuff even in relatively small doses, so all else being equal, I have to ask myself, do I want to subject myself to more of the stuff? Of course PU has some rank off gasing too, as does epoxy and isoset, maybe it's a wash? For me, worth considering. My sheet goods have formaldhyde free stamped on them now.

[Mel Fulks]

Most of the polyurethane glue bottles say waterproof and strong then add ,don't use for structural purposes under water .But at least one has been tested and I've been told its a very expensive thing .Tests for above water ,under water ,wet ,dry ,etc.
I trust that certification more than any tests done by any magazine.

[Peter Quinn]

The tests I read from the german board of something or other involved structural stresses above the water line, no mention of sub aqueous work. There was a comparison to epoxy, the issue was strength after repeated stress-release-stress cycles such as glue lam frames in snow load countries face. Epoxy is very strong, but brittle, so when it fails it fails big and quick. One part moisture cure urethane it seems is better able to roll with the punches, it flexes and returns with little or less appearantly loss of strength than many other options. Sort of like a willow versus an oak. And the bond strength is substantial too. I'll look for a link to the research later.

[Peter Quinn]

A little light reading, draw your own conclusions.

http://www.woodworking.org/WC/GArchive99/5_19FPLglutest.html

http://www.purbond.com/purbond/files/20-5-2009_13-43-42_10JahresArtikelEnglish95.pdf

[jack forsberg]

https://www.youtube.com/watch?v=OXEBES-wNfc&feature=player_detailpage

[Peter Quinn]

Jack, rofl, glad to see the folks at gorilla have a sense of humor and a good lab. I wish they made a glue with a longer open time though, I need more time to get my butter properly positioned, and the soap always seems to slip at the last minute. I'd like to see them glue a hot dog to a stick of butter then run the whole mess through a saw stop.:eek:

[John TenEyck]

Wow, that's amazing. They finally found a good use for Gorilla Glue ! :)

John

[mreza Salav]

As the OP of this thread I thank all for the contribution and discussion. Also the links provided were good read and source of knowledge. I am feeling a lot of these technical discussions might not really matter
in applications we are dealing with (who has the door submerged in water for 6 months?!).

[jack forsberg]

(who has the door submerged in water for 6 months?!).


this old wood worker could have used some glue like that MO.:D:D

269078

[Peter Quinn]

this old wood worker could have used some glue like that MO.:D:D

269078

They never did find that guys boat.....I'd guess he burned it to get rid of the smell after all those months with the animals in the hold? Or maybe built his house with it, would have been the only timber left that wasn't soaked.



Mreza, I'm often amused by the tests they concoct to test adhesives. I know they are trying to simulate what happens to an assembly over time, to speed the process up. But boiling the wood? Then baking it....then boiling it again? Or crushing it on a press?

The tests I linked are more pragmatic, a glue lam timber frame failure can kill a lot of people, and they have happened. How this relates to a door....probably not at all. But still, never try to use your door to hold up the roof of an under water skating rink under any circumstances.