Replies

1. 
   StanleyNiemiec | Jan 23, 2003 09:03am | #1

   Weldwood powdered resin is a urea formaldehyde adhesive that does in fact have a limited storage life.  I am surprised you did not test the adhesive before you went through all the effort of veneering the side rails.

   I am wondering why you chose this type of adhesive for veneering?

   The bond is not water resistant/proof so it is not now appreciably better than other available products.  If you are looking for something that has a longer open time, why not use the premixed liquid hide glue.  I have used it very successfully though you need to keep it in clamps for a longer period of time.  I use it for joinery and will release the clamps after about 12 hours and with my vacuum bag, I keep it "under pressure" for 30-36 hours to insure proper drying (as I have found that adhesive "drying" is considerably retarded in the vacuum bag).

   I use a simple test to determine an adhesive's 'quality'  --  I rub a little between the tips of my forefinger and thumb.  I then squeeze my digits together and then separate them a couple or so times.  I like to feel "tackiness" and/or see "threads" appearing.  The adhesive should also feel smooth.  The combined warmth of my fingers and the aeration of opening and closing the 'joints' provides a quick indication of adhesive properties.

   I don't know what the effect of the residual Weldwood might be on subsequent adhesives and joint strength.  If the formaldehyde has volitilized and all you have left is urea, it might cause problems with bonding and later.  All that nitrogen might be a good food source for the yeastie-beasties as well as interferring with the chemical bonds at the adhesive/wood interface.

   Beyond this simple attempt, you need to talk with a resin chemist.

1. 
   observer | Jan 23, 2003 09:28am | #2

   I use a powdered urea resin glue called UF 409 which is marketed as a marine adhesive. Are you saying that Urea Resin glues are not at the very least water resistant? Are urea resin adhesives not the same as urea formaldehyde adhesives?

1. 
   StanleyNiemiec | Jan 23, 2003 11:58am | #3

   I am a wood technologist (MS Penn St '79) and not a chemistry nerd or resin chemist.  I have also worked as a research wood technologist for the Masonite Corp and in an extension role at Oregon State University Forest Products Department (7 years).  As such my knowledge is related to past and general industry practces and therein may be limited especially when it comes to the attributes of specific products. 

   With that said, as I understand adhesives, my general perception has been that UF (urea formaldehyde) resins/adhesives are capable of being dissolved/softened when exposed to water.  This class/group of resins (as there are different formulations) are primarily used for interior grades of plywood (eg hardwood plywood) because they are less expensive than phenol formaldehyde (PF) resins/adhesives.  It is possible that there are formulations of UF resins that might have improved water resistance but I, personally, would never use them in a marine application even if the product label claimed such.

   If you wish to test the adhesive you can do so simply by placing a wet cloth on the surface and after several hours check to see if you have delamination.  If you do this with most grades of hardwood plywood, buckling will occur.

   The two primary industrial wood adhesives that are water proof are PF and resorcinol.

   For bed rails (or any interior application) I do not see the need for an adhesive to be either water resistant or water proof.  In my mind when I am veneering, one needs to have sufficient open time so that the adhesive does not begin to set up before assembly is completed.  Both white glue (PVA) and yellow glues (aliphatic) have a fairly short open time (ca. 15-20 minutes at best).  As such I prefer something like liquid hide glue that has an open time of at least 30 minutes.

   Beyond my technical expertise, I have had considerable practical experience in the trades.  I started working in a furniture refinishing operation 6 years before I entered into graduate studies and have continued to practice my trade (I consider myself to be a joiner) since I began in early 1972.  I have used just about every wood adhesive/glue with the probable exceptions of blood glue, fish glue and casein.  UF's are resins that I do not use and really, unless I am in some sort of very specific industrial situation, would not generally consider.  Aside from the fact that I think them difficult to work with, and their short storage time (including the implication that I don't know how long they have sat on a supplier's shelf), I am generally dissatisfied with bond strength.  Besides UF resins emit formaldehyde gas as a by-product.  The less I have to do with formaldehyde, the better I consider myself to be.   

1. 
   Jayhawker | Jan 23, 2003 07:17pm | #4

   Check out the following page on the Fine Woodworking Website:

   http://www.taunton.com/finewoodworking/pages/w00010.asp

   "A Working Guide to Glues."

   Look under "Chapter 3, Reactive Synthetic Glues.

   Urea resin glue is listed as being highly water resistent, and ideal for veneering and lamination, as it has high creep resistance.

1. 
   StanleyNiemiec | Jan 23, 2003 09:45pm | #5

   As far as I am concerned the water restistance of UF resins is overstated  --  it is not water proof or that resistant such that when exposed to water, buckling and delamination does occur. 

   Glue-line creep is a pretty nebulus concept  --  the only application where it might be a factor (based on my experience and knowledge) relates to free standing (unsupported/unrestrained) bentwood laminations.  In my 30 plus years of woodworking, I have never found creep to be a significant problem in any of the work I have done.  Low creep glue joints imply to me a brittle glue line and therein likely to fail over time especially when wood is exposed to large cyclical EMC changes. 

   I have used UF resins in both shop and industrial situations and feel that in most shop applications, there are better adhesives that are easier to work with.  I would use UF resins if and only if I had a large platen hydraulic press (preferably heated) and only cold press it as a second choice.  I cannot think of any application where I would use a UF resin when I vacuum press veneer.  I definitely would not use a UF resin to clamp veneer to a substrate because I am certain the subsequent glueline would have variable thickness.  Glue spread rate is critical in UF resins  --  too low and the joint is weak; too thick and the brittleness of the resin can contribute to glue line failure.  Also if the resin contains too much water, excessive absorption can occur leading to a glue starved joint.    

   This however is only my opinion and you are certainly entitled to yours; maybe you are more experienced with them than I.

2. 
   observer | Jan 24, 2003 09:27am | #9

   Thanks for your info. I've never had a problem, or more precisely, I've never been informed of a problem with anything I have used the adhesive on including a bent laminated rail for a bed on a boat. I think this calls for a couple of glue and soak experiments just to double check.

1. 
   dustytools | Jan 31, 2003 02:42am | #10

   I got some liquid hide glue (Titebond).  I used it on the edges.  It worked well and was more convenient than the Weldwood Plastic Resin Glue.  I got it at still another hardware store.  The employee at this store told me that he can no longer get Weldwood Resin Glue.  Has it been discontinued or taken off the market?  I noticed a sticker (apparently required in California) that warns about a potential cancer risk.  Does anyone know.  It wouldn't upset me too much if it were.  I will probably use liquid hide glue from now on, at least for projects with small gluing areas.

2. 
   dustytools | Jan 24, 2003 07:54am | #6

   Thank you for your response.  I could not wait to hear the responses to my question, so last night I opened a new container of Weldwood.  Boy, was it different!  Instead of the gritty light tan compound I ended up with the night before, it was almost like chocolate syrup.  When I unclamped it tonight it worked well.  For the powder residue that the previous attempt left, I sprayed it off with air.  That seemed to be enought, as the veneer was well adhered. 

   The reason I used Weldwood was that is what was recommended in a book by Paul Villiard titled A Manual of Veneering.  This book is old, copyright 1968, so I am sure adhesives have changed since then.  He does mention liquid hide glue as a good alternative, however, he mentions that it has a short shelf life also.  I had some Weldwood.  I did not find liquid hide glue at my local Menards.  So that is why I chose this product.  I knew I would need more glue than what I had so I obtained some more Weldwood at my local hardware store.  This was my first attempt at veneering and most stores open after work have few if any veneering supplies.  Unfortunately most of the workers didn't even know what Weldwood glue was.  I really miss the days that I could go into a hardware store and talk to someone who was an expert in many areas.

   Thank you for your response.  I never even thought of testing an adhesive prior to using it.  My good old yellow wood glue has always been faithful to me.  When I started planning this project, I had planned to use good old faithful.  None of the articles on veneering mentioned it, so I thought it might not be a good idea.  Next time I try veneering, I will consider liquid hide glue.  Thanks again.

3. 
   dustytools | Jan 24, 2003 08:05am | #7

   I would like to make a humidor sometime soon.  What glue recommendations do you have for veneering a project such as this?  What do you know about Spanish cedar?  Thanks again for your response to Weldwood glue!

1. 
   JohnCabot | Jan 24, 2003 08:20am | #8

   Talking about Formaldehide and other chemicals I just learned that smoked meat resist rotting because of two chemicals in the smoke: Formaldehide and creosote!

   Bon Appetit

   John Cabot