Help for settings for offset Domino in 18/19mm Melamine Butt Box Join?

[eddomak]

Hi,

I have been working a lot with sheet goods where it is 18-19mm thick (around 3/4 inch), and was wondering about the settings you use on a DF500 when butt box joining (eg cabinet carcass).

I have been choosing to use the 5mm x 30mm dominoes, but if I do a 15mm plunge then the 3mm remaining material with melamine facing is extremely brittle and can sometimes chip off, exposing the end of the hole for the domino.

So instead I have been using an offset of 12mm/20mm and ensuring I place the domino fully into the piece with the 12mm hole prior to insertion into the 20mm hole.

Is this good practice? Or should I use a 5mm x 40mm domino and do a 12mm/28mm offset arrangement instead?

Otherwise would you have any suggestions?

Thanks in advance.

 

[Sparktrician]

Do the 12/28 split and be VERY careful setting the domino into the 12 side.  Might even want to sand that end ever so slightly so it eases in nicely.  As you noted, the melamine is very brittle and cracks easily.  I'd even go so far as to suggest setting the 28 side first, then use a good hardwood block to gently convince the 12 side into place by tapping on the block to spread the pressure out over the melamine-covered surface.  When you clamp it up, use the blocks again to spread the pressure. 

 

[eddomak]

Thanks for that - I was just re-watching mrbigerock's series on kitchen cabinets and in using 19mm ply he suggests (in video 3) a 6mm x 40mm domino with a 15/25 split in ply.

I guess the 6mm is closer to the 1/3 rule, and 15/25 is also gives it a little more strength, but would start to make that thin edge even thinner. I will be sure to experiment on some test pieces first and see how it goes.

 

[Sparktrician]

When you're using melamine, the 15/25 makes the 15 side too thin and can potentially cause blow-out due to the hydraulic pressure from the glue being forced out.  I'd go with 12/28, just for added security.  This is why I suggested sanding the dominoes to lessen the resistance, making it easier to slide into place and allowing the glue to ease around the domino rather than have to try to rush out.  Hope that makes sense. 

 

[eddomak]

Perfect sense! Thanks for the wisdom and experience!

 

[Ivanhoe]

I second the 12/28 depths for melamine. Eric's videos are great learning tools but keep in mind he was using plywood in his project. Also, are you getting exactly 30 mm with your domino 500 with those settings? I have a 700 so I am not sure if your plunge depth actually exceeds your settings by 1 mm or so. You might want to check that for the glue squeeze out. I learned after my first project I need a bit more depth than the exact domino length.

 

[Sparktrician]

I second the 12/28 depths for melamine. Eric's videos are great learning tools but keep in mind he was using plywood in his project. Also, are you getting exactly 30 mm with your domino 500 with those settings? I have a 700 so I am not sure if your plunge depth actually exceeds your settings by 1 mm or so. You might want to check that for the glue squeeze out. I learned after my first project I need a bit more depth than the exact domino length.

Just remember that the dominoes are really 2mm shorter than the specified length to allow room for glue.