Making Seams with High Pressure Laminate

Here are the tools, bits, lubricants, and techniques the pros use to cut a perfect HPL seam. April 11, 2008

This week I have to laminate some store displays. And there will be seams! What do I do to prepare them so I do this only once?

Forum Responses
From contributor A:
Router and a straight edge. Lay the two pieces of lam end to end as they will be applied and overlap them a little, then router through both sheets at the same time. I have tried many ways, but this is the best and you always get it right on the first try.

From contributor G:
Ditto. Make sure your straight router bit is good and sharp. I always mark the two sheets with a magic marker before I move them to show me just where the seam will match perfectly.

From contributor J:
Same as the responses above. Use a 7 degree bevel bit when cutting the seam. The slight undercut bevel makes the seam fit much tighter. I prefer laminate bits, both bevel and straight, that don't have a bearing. Your laminate distributor should have them by the box full. Just remember to use a lubricant with this type of bit when using any of your laminate edges as a guide so you don't burn it. I've seen WD 40, motor oil, vegetable oil, veggie oil, special wax pencils, etc. used. I use WD40. It also seems to clean up spray contact cement pretty good too.

From contributor G:

I have never used a bearingless router trim bit since I started playing with HPL. I've either used a straight trim bit or a seven degree bit, but all with bearings. What's the trick to using the bearingless bits? I just can't bring myself to use one - fearful of the friction buildup on the edge laminate. I take it you cannot even think about stopping... I still don't get it.

From contributor F:
Beaver Air Tools and Betterley both offer a seaming router. On vertical seams on the OD of cylinders they work like a dream. I can't think of a tougher test for an efficient method to seam HPL.

From contributor A:
For seaming on a curve, the Beaver tool is great, but I still prefer the straight edge method when length isn't critical. The Beaver tool only trims one edge, so if the other edge isn't perfect, there is no compensation. By perfect, I mean, if you cut to rough size on a table saw, the edge has a little wave to it, at least on my saws. When you route both edges, how perfect one edge vs. the other doesn't matter.

Contributor G, no, you can't stop with a bearingless bit. The thing I hate about bearing bits is the bearing builds up with crap and either makes you take a second pass or clean more off with a file. Just use a good lubricant and move at a steady pace. I have never used WD40 but since it contains distillates, I would be careful about it compromising the glue bond. Also, don't push too hard against the edge; let the router do the work.

From contributor J:
I had a hard time getting the guts to try one of those all carbide bits myself years ago. The best thing to do is get one and try it. You'll see they do a good job. I don't think they leave you with as much filing either. The goop like contributor A mentioned is a lot easier to keep off too.

I read about the WD40 on this forum a long time ago and had reservations about it myself since it will dissolve the glue. I liked the convenience of it. I've tried many times to get the bond to separate and so far haven't been able to. You certainly don't want to get it on your substrate before you put laminate down.

From contributor E:
Vaseline works real well and is easy to wipe off. Solid carbide bearing-less bits are the way to go. When I seam two sheets, I use a jig which consists of a 10" wide board. 3/4 thick MDF works well, with a 3/8 x 3/8 dado down the center. Board should be longer than or at least equal to the length of your seam/sheet. Butt both sheets together over the dado and clamp down at the ends. Run your router down the right side. A perfect seam every time.

From contributor J:
I make my seams the same way, only I made a jig with two pieces of MDF rather than making a dado in one board. I also laminated the inside edges of these MDF pieces to give the router bit something to ride against. Did you intend to say "run your router down the right side"? I normally keep my router to my left when cutting away from me.

From contributor E:
Yes, I pull the router toward me, and I also laminated the side of the dado for a smoother cut.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor S:
I have been using bearing-less (integral bearing) router bits for 26 years. Bearing burn in my experience has been extremely rare and it's been years since the last time it happened to me. These integral bearing bits do not collect contact cement globs as the bearing ones do, which cause you to stop the trimming operation and clean the bearing only to pick up another glob.

I use Johnson's Paste Wax that comes in a yellow can as a lubricant. It is quick and easy to apply (I use my index finger), it is easy to clean up and a single can will last a very long time. In my experience, the time and money saved using integral pilot bearing bits over regular bearing bits more than makes up for replacing an edge due to the extremely rare burn.

Comment from contributor R:
I totally agree with the mirror-image cut (have you ever laid wallpaper - same concept, heavier tools). The best lube/protectant I've found is Turtle Wax, applied as a thin layer a bit wider than your router plate. Let it dry (as if on a car) and it will not only let your router glide easily but will also protect the lam finish from scratches.