Laminating MDF with Contact Cement

[BigguyZ]

I've been wanting to upgrade to my final saw, but with my budget and the amount of time I have to devote to woodworking it's not really appropriate right now. So I'm sticking with my old C-man 80's contractor saw on the custom base I built.

It took two years, but I finally have the saw and the base moved from my old shop in the basement to the garage of my new house. Currently, the saw's in pieces, so I'm taking the opportunity to refurb it, and I'll obviously need to re-calibrate it as well.

Tomorrow I should have the PALS system from In-Line industries, to help align the trunion and lock it in. I have a new ZCTP, since I'm guessing my old one will now be slightly off. I also got the micro jig splitter system a while ago when it was on sale, so I'll be adding that as well. And tomorrow I'm going to Woodcraft to pick up some UHMW to re-face my old Beise fence (the original ply faces were warped from too much moisture).

In addition to all that, I'm building a new top extention that will double of a workspace, router table, and multi-function table to mount my other tools to (OSS, DP, Grinder, Buffer, Belt Sander). To that end, I bought a $10 piece of laminate for the top, and had a sheet of 3/4" MDF cut to size. The laminate isn't the exact type I wanted- I remember a thread about the laminate with the least amount of friction- but that would be something I'd need to buy in a large sheet from the distributor for $100 or so. Anyway, I'm planning on laminating 2 or 3 pieces of the MDF, then the laminate. Obviously contact cement is what you use for the laminate, but for speed's sake, I'm wondering if using that to laminate the 2 or 3 layers of MDF to each other would also work.

I'm excited to finally get my saw into my shop- and improved to boot.

Thanks!

[Nyeman]

I did that same thing for a router table top and had no issues with using contact cement for laminating the pieces of MDF together.

[cabinetman]

If you make a frame for ¾" MDF, one layer would be sufficient.

But, if you must laminate two sheets, cut one the size you ultimately want (I'll call that the smaller one). Lay it face down. Cut the second sheet ¼" larger all the way around. Lay the second sheet on top of the first sheet. Use a few spring clamps to keep them from sliding on eachother. Lay out a grid pattern to drill holes. Use a pilot drill and drill through the larger sheet into the smaller one. Mark the two sheets the way they are configured. Separate the sheets and use a countersink bit and countersink all the holes on the mating surfaces.

Blow off and clean off any debris from both sheets. Lay out yellow glue lines (not contact cement) on both sheets. Replace the larger sheet the way it goes. Use 1¼" coarse thread screws, and drive with a cordless drill on slow speed (cordless drills have more torque at slow speeds than electric drills). When near tight, just bump the trigger to tighten. Driving screws at speed can make them overspin and become useless, besides getting them hot, and having the possibility of snapping off the heads.

The countersinking of all the holes on the mating surfaces is done to make sure that when the screws break from one sheet and enter the second, that no debris will crumble out and interfere with a close fit. After all the screws are installed, Wipe off any squeezeout glue. Then use a flush trim bit and trim the larger sheet to the smaller sheet. It would be ready for plastic laminate, with which contact cement would be used. I like solvent based. Make sure you have good ventilation.

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[JimD]

My extension tables are made of melamine particle board with plywood stiffening ribs underneith. With a coat of paste wax, the melamine is quite slick. It is also durable. With the ribs, it does not sag. I also have a mount for a router in the primary extension.

I've used laminate and put it on mdf, particle board, and plywood. But it is a smelly, messy, tense process so when I don't have to do it, I don't.

Jim

[cwsmith]

As mentioned, laminating is a smelly mess.

I'm also concerned as to really how well it might adhere to this glue-up-of-dust that we refer to as MDF. Man, I really hate that stuff! There is absolutely NO integrity to it, whatsoever.

While maybe three layers of 3/4 MDF might stay off "the sags" for a short time, it will nevertheless sag in a comparatively short time, unless you've got a considerable amount of bracing as a foundation. (I've got a 6-yr old wall cabinet, with a 20-inch span of 3/4 MDF, with metal bracing back less than three-inches from the front edge, and it sags. Likewise my RAS table covering also sags at just the few inches where the MDF cover overshoots the 1-inch table.)

I've also not found that any kind of glue against an MDF surface is good. The MDF just separates, beneath the glue if there is any humidity.

Perhaps others have had better luck, but I won't go near MDF for anything.

CWS

[cabinetman]

Addressing a few comments...the OP already has the laminate and MDF. So the thrust of the thread is to use what he has. MDF is a very stable composite. It makes for a good substrate for plastic laminate, veneers, and paint. Working in South Florida, we can have humidity swings from 55% to 95% in an afternoon. I have not had any delamination problems due to humidity.

IMO, an extension table for a table saw could be done with Melamine, HPL on plywood, HPL on particle board, or HPL on MDF, without subsequent problems. I've used all of those combinations for similar projects. Supporting large substrates, or ones that will deal with heavy loads, can be done with framing or bracing with successful results.

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[chopnhack]

Awesome stuff bigguyZ! Please post your experience with the pals. I also saw that they sell a matched machined pulley set for a decent price. Good luck with your build and post some pics

[BigguyZ]

Thanks C-Man! I have to admit I was a little irked, as I stated the laminate and MDF are purchased already. I always appreciate feedback, but then parameters are given, advice is most appreciated when taking that into account.

I did choose to use the contact cement for both laminating the MDF and the laminate to the top. So far, I think it went well. The two MDF pieces are solidly together. The laminate seems to have bonded well, though there's a spot or two where I can hear a hollow sound if I tap on it. I don't know if continuing to try to roll it out will fix it or not, but the edges are solid and it's not causing a big deflection.

I took my Groz steel straight edge out and checked for flatness. It's not dead flat, but it's better than using the ply from the big box stores and for the TS extension it's plenty flat for what I need.

The top will be supported on all four sides- one to the saw via angle iron, the opposite side will have support sides from the base that will create a box for the router enclosure, and the other two sides will be supported by the 52" rails I have for my fence.

I got the PALS yesterday, but the instructions seem to be without any pictures at all. Does anyone have a link to something online or a video that shows them being installed/ used? I tried looking, and came up with a really old You Tube video that just talks about them.

I'll post pics once everything's set up. The laminate is the Wilsonart high rez stuff. For $10, definitely a steal. It looks nice, and it's plenty slick for the TS and router table surface.

[cabinetman]

I did choose to use the contact cement for both laminating the MDF and the laminate to the top. So far, I think it went well. The two MDF pieces are solidly together. The laminate seems to have bonded well, though there's a spot or two where I can hear a hollow sound if I tap on it. I don't know if continuing to try to roll it out will fix it or not, but the edges are solid and it's not causing a big deflection.

I recommended yellow glue, because with contact cement, you can't compress the two substrates sufficiently to get a good bond. The contact cement isn't as rigid a bond as with yellow glue. You may have trapped some air in the laminating of the two pieces. Likewise for the laminate, you may have some air trapped. If you warm up (not overheat) the top, and work from the center out with the edge of the board you may get out air trapped under the plastic laminate. You could use a hair drier, or a heat gun...but be careful not to get too hot, as the mica will blister.

Using yellow glue also allows an easier alignment of the parts, as you don't have the instant stick like with contact cement.

I got the PALS yesterday, but the instructions seem to be without any pictures at all. Does anyone have a link to something online or a video that shows them being installed/ used? I tried looking, and came up with a really old You Tube video that just talks about them.

Here is a video that may be of some help.

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[BigguyZ]

Thanks for the link!