Replies

1. 
   JBD | Jan 05, 2004 09:04am | #1

   I haven't a clue to the case construction method you mention, but over ten years ago in my pro cabinetshop I discovered the absolute best (strongest), easiest and simplest method of plywood / melamine case construction for frame and frameless cabinets.  It is using butt joints glued with PL Premium polyurethane construction adhesive (100% solids moisture-cure urethane).  Before you laugh, I tested sample "T" joints using biscuits, dadoes, and drywall screws against the PL butt joint.  This test was using thermoset melamine, as many of my high-end clients wanted more money put into the solid wood effects, FF's, exotic inlays and custom ground crown moulding, so they often opted for melamine interiors, though this glue is superior for ply as I'll explain later. 

   The 4 x 4 x 4 test pcs were placed under an arbor press at the angle for breaking, and a scale was underneath recording threshold breaking weight.  The PL joint held strongest at around 47 lbs before break, as it welds to the melamine / HPL surface and rips the core right out - never glue joint failure.  The dado held next strongest (38-40 lbs) then the screws, then biscuits. 

   Then, I tried a PL butt joint with a glue block (cleat 3/4 x 1" x 4") shot under with pin nailer to hold in place simulating a cabinet bottom where it is common to do this, and is still faster than other methods.  It broke under 130 lbs.

   Since then, and a few seventeen grand kitchens later, this method blows away all other methods for speed and performance.   Most of the time, pinning the shelves in place til the glue sets is good enough (no clamp pressure necessary), but I wanted few fasteners showing at all, so I would pin the front and back to locate, then apply 10" reach deep throat Wetzler clamps to the inside.  Not much extra time.

   This may not appear to be FWW standards (I'm in Design Book Six, so I know the standards), but the time saved allowed serious fine woodworking on other parts like Wenge pinstriping on cherry etc (option that one client couldn't afford, til I offered melamine interior).

   Ply is great for this glue too - nothing better for end grain and voids than an EXPANDING adhesive that has stronger cohesion than any other PUR glue.  NEVER a glue joint failure that I can remember.  Best glue for solid wood-to-ply applications like FF to case.   Best adhesive for dissimilar materials like metal to wood, wood to glass, and wood to PVC (prime PVC,  Plex, or Lexan with PVC cement and bed wet PL into wet cement/plastic for a full-fledged weld).

   Waterproof too - Half my mahogony boat is glued with PL, the other is epoxy (f-glass sheathing, and below waterline).

    

   "The furniture designer is an architect." - Maurice DuFrenes (French Art Deco furniture designer, contemporary of Ruhlmann)

   http://www.pbase.com/dr_dichro

1. 
   Manchild | Jan 05, 2004 05:23pm | #2

   Thanks for the glue up method. I've knocked together carcases before with glue and a finish gun or screws. It was for cheap site built stuff that was fine for the job.

   I always had a hard time lining up the outside and shelves. I would end up with a box that was not accurate. Wouldn't the rabbits and datos make assembly go much smother?

1. 
   JBD | Jan 05, 2004 08:42pm | #4

   Hi David and John,

   Lining up butt joints appear to be difficult, but I made a quick "lining up" jig that is along the lines of a framing square.  I had two - one for uppers (11") and one for lower cabs (22").  They were long "U" shaped plywood panels, where I cut two pcs of 1/4" lauan about 8" x 11 or 22, and glued them together at one end, spaced with a piece of maple or poplar that was the thickness of the case material (3/4") real square and accurate.  This way I could slide this "U" over the edge of the case with one flap on the inside to line the shelf against, and one flap was on the outside as a guide to shoot the nails perfectly on center (held the rubber nose of the gun against the 1/4 lauan edge, that shot a nail 3/8" from the edge - perfectly on center of the shelf edge).    I also planed a slight wedge into the space block so that the lauan "toed" in, therefore snugly holding onto the case, eliminating movement.

   This jig allowed very accurate, fast case glueups, and I never had an alignment problem.  Using PL to attach FF's and 1/4" cabinet backs made a cabinet so solid, it could survive falling down stairways.

   I did double oven cabinets and entertainment centers where the main load bearing shelf was simply PL'd in place, and 2" x 3/4" cleats were glued and shot under the shelf.  These cabinets still hold well to this day - even with commercial ovens, and big TVs.  Imagine the shear strength required to remove the cleat?

   I've even veneered with this stuff.  Great for bonding wood to masonry too.

   John from UK - PL Premium polyurethane construction adhesive is made by OSI Specialty Chemical in Mentor, Ohio, USA.  Tubes are not in front of me, so when I get back to the shop, I'll get a phn #.   Its less than three bucks a tube (10 oz), and is a fraction of the cost of Gorilla Glue, yet higher performance.  The website is http://www.osisealants.com/PL/PL_products/PL_construction.htm and, Good News John - OSI is a division of Sovereign Specialty Chemicals HQ'd in UK.  Click the link to SSC on these pages for UK info.

   Lowes carries it, and I imagine HD does too.  Prior to three or four yrs ago, I had to order it from other sources.

    - JB             http://www.johnblazydesigns.com  

   "The furniture designer is an architect." - Maurice DuFrenes (French Art Deco furniture designer, contemporary of Ruhlmann)

   http://www.pbase.com/dr_dichro

1. 
   john | Jan 05, 2004 10:44pm | #5

   Thanks for all the extra info, John. Unfortunately I couldn't get the link to your site to work, I will try again later. Also I couldn't find the link to SSC, but I expect I can overcome that as well. The link to the actual product wouldn't work for me, but I assume that the actual product you are referring to in the premium PL construction adhesive? Anyway, the whole idea sounds good to me and I shall now see if I can trrack down some of this stuff

   John

2. 
   Scrit | Jan 06, 2004 06:09pm | #6

   Unfortunately Sovereign in the UK don't sell the PL range over here.

   John (UK) - I currently use H.B.Fuller PU which comes in at about 1/3 the price of Gorilla Glue and is every bit as good (I use 12 min and 1 hr set PUs) - call me picky, but I don't like the way the Gorilla Glue importer brings it in from the USA when it's made in Denmark. Direct Adhesives also sell good D4 (PU) adhesives. If you drop me an email I'll forward you the phone numbers and addresses of some suppliers.

   Scrit 

1. 
   john | Jan 07, 2004 01:11am | #7

   Scrit, I sent you an email through your profile, and ticked the box to send a copy to myself. That was several hours ago and I haven't had the copy come through yet.

   John

2. 
   john | Jan 05, 2004 05:32pm | #3

   Can you give me any more info about the PL adhesive? It sounds exactly what I need ( I make face frame cabinets, a bit unusual in the UK but that's the point with high end stuff)  I'd like to ty it but I am in the UK and may have trouble sourcing it, so may need to see if I can find the same thing in a different make

   John