Attach desk edge to MDF

[Drew Sanderson]

I need to attach this profiled edge piece to a MDF core desktop. I had originally thought I would use biscuits and then tape while the glue cured. I'm feeling some doubt on this and wanted to see what ideas SMC people might have. Along with attachment, I'm a bit nervous about the inside miters on one piece... only one shot there.

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[Peter Quinn]

Is that counter fully installed? If so...thats not the way I would have done that, much easier to apply edge treatment in shop than in field. At this point I'd be making an investment in edge clamps...lots of them. I doubt tape is going to give you the kind of pressure you need to make a nice tight glue joint, which leads to gaps, and the first spilled cup of coffee wrecks you MDF substrate. I'd be looking at a water proof glue like tight bond 3. If you are using tape...a low pressure gap filling adhesive like epoxy might be your best bet, and dye it brown so it better matches your top. If there is any way to get the tops off the wall you can chase the molding around the edge with everything in place, make some registration marks on blue tape on the top and moldings, then pull the tops and clamp them on properly. Or you could shoot them through the face with 15ga 2" nails and fill.

[Gerry Grzadzinski]

If tape is your only option, use the packaging tape with string embedded in it. It's very sticky, and can apply quite a bit of pressure. This is recommended method for applying laminate bevel edges.

[Michael Moscicki]

Seems like some Rockler Bandy Clamps would be helpful in this situation. They are $19.99 a pair, so that is something to consider.

http://www.rockler.com/rockler-bandy-clamps-pair

[Drew Sanderson]

Those tops are definitely not coming out... I scored quite a few edge clamps in the great Lowe's Bessey closeout of 2014 so that is a good idea. What are thoughts on the biscuits? I don't have a lot of registration area on top of that profile. I might shoot the face if stuff starts going bad during glue up. Another thought is using several third hand poles (https://www.fastcap.com/estore/pc/3rd-Hand-c46.htm) and can push the two opposed edges away from each other creating great pressure.

[Steve Jenkins]

Biscuits will work fine but I think you should place them lower in the mdf and trim so they are opposite the vertical section on the trim so the edge clamps will be more effective. I too think that tape will be problematic.

[Justin Ludwig]

Along with attachment, I'm a bit nervous about the inside miters on one piece... only one shot there.
You have many shots. Grab some scrap stock of any material. I use stock that is wider than my molding as it shows deviations more clearly for setting the miter. Your stock looks to be 1-1/4", I'd use 2.5 or 3" boards for testers. Clean up that inside corner with a hand file. Cut two pieces at 45* and put them in the corner, notice if you have a gap at the counter (fence side of the cut) or near you. If the gap is at the fence side, increase your miter .25* and try again. Decrease your miter if the gap is close to you. Rinse lather repeat until your test pieces fit snug along their contact point (the whole miter). Use the same tape your measure the counter with as you'll use at the saw. Bam! One shot done. Next time mill extra stock. Best to have a little too much than not enough.

I would have attached the edge first and routed the laminate so i flowed over it for spillage reasons. You're past that now.

With what you have going on: using bisquits, waterproof glue, and a BUNCH of sticks that are 1" longer than the gap between counters.

1.) Do a dry run.
2.) Install bisquits, and edges and place oversized sticks between moldings that act as clamp forces.
3.) If all goes well and you get a warm and fuzzy, attach those 2 pieces and let dry.
3a) You could, as Peter stated, put some 16g or 15g nails in it. Running nails thru 1.25" of molding stock into MDF is not for the faint at heart, especially thru oak. Depending on grain, you could get some nails running out.
4.) Made it this far? Remove all sticks. Clamp a board running from the left knee area to the right. Use it as a backer for the kickers you'll use for pressure against the molding in the center.


That's what my brain is coming up with at 6am on 1.5 cups of coffee. Good luck.

[Drew Sanderson]

trim so they are opposite the vertical section on the trim so the edge clamps will be more effective. I don't follow... ???

[Justin Ludwig]

Another issue I just thought of. Keep the molding flush to the top of the counter. Bending kickers between the cabinets will provide the force, but you may have an issue of the glue allowing the molding to slide and shift.

Two options: 1) Rabbet the molding 1/8-1/4 deep and then it sits 1/16 higher than the top. Round over the lip above the counter so it's soft. This also provides so area if there is a spill. A thin line of clear caulk could save any spills from getting to the MDF.
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This method is tricky when cutting the miters. Your measurements have to come off the rabbet, not the top.


2) If you don't want the edge to be above the countertop, clamp a straight edge that will over hang. Something that the molding will hit. Beware of glue squeeze out sticking to it.