Laminating HPL with water base contact cement
I put together a very basic vanity counter top the other day and tried a few new different tricks which seemed to work quite well so I thought I would share them. I've been making counter tops for about 40 years as needed and when I started there was only solvent based contact cement which worked not perfectly, but reasonably well and with fair reliability. Then I tried water based when it came along, the green LePage's stuff and it worked beautifully the first time I tried it. The last time I tried it it was a dismal failure, so bad that I was able to peel the laminate back up without breaking it and reusing it after I cleaned the failed water based off.
I don't know why it failed so badly as I followed the directions implicitly. One of the issues every time I tried it was that I needed to put on more than one coat which is a problem when you brush it on. Some of the first coat tends to ball up when you brush over it with additional coats and I didn't want to risk ruining a spray gun which might have solved that problem.
When I went to laminate the top on my vanity I found a can of LePage's water based in my shop (don't remember how it got there) but this stuff is white instead of green so they may have changed the formula. Instructions were similar. If it doesn't dry glossy then you need another coat.
So this time I started by giving all the surfaces a seal coat of wood glue. I diluted the glue with a little water to get it to the consistency of average latex paint. I made sure the edges (MDF) got a heavy coat. This left all the surfaces a little glossy looking to start with. When it came time to spread the contact cement I just poured it on and used a brush to spread it. There was very little time for brushing before the rubber in it would start to ball up so you have to be quick. Some areas were quite wet while others looked a little dry. Any areas that looked like they didn't get covered well enough I poured more contact cement close to and used the brush to take that and dab it onto the dry looking areas without any brush strokes. Dabbing avoided rolling up balls of the rubber in the cement.
This method worked near perfectly. The only issue I had was with one of the first pieces, the face of a splash board, before I started dabbing more cement onto the dry looking areas. After I did that there were no more issues. The can of cement said that you can use a rubber mallet to stick the HPL down instead of rolling it. I tried that and that worked well too so if you have arthritic hands like I do you may find that easier. If you've had poor results using the latex based contact cement before there may be hope yet.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.