I am building my own router table using laminated 3/4″ and 1/2″ MDF with a plastic laminate top. I’ve heard it is necessary to laminate the underside of the table with plastic laminate too although I’ve also heard that a lot of folks forgoe this step. Is it really necessary? If so, does glue adhere well to plastic laminate?
I chose MDF for the top because it is really flat. However, I did such a poor job laminating it (realizing now that my bench top is really not flat) that the bottom 1/2″ MDF slab now has a slight crown to it and the plastic laminate on top has one air bubble in it at the far side of the table- away from where I plan to put my router plate. The half of the table with the router plate appears pretty flat to me although I’m wondering if I should just start over- and use this “top” as part of the base to my router table or if having a top that is half flat and crowned on the bottom is really no big deal.
– Lyptus
Replies
They refer to this as balancing so that one surface does not loose moisture faster than the other, causing a cup or warping. I made mine with two pieces of 3/4 and HPL on top wraped with 1" oak banding. For the bottom I hit it with 3 coats of schellac (someone reccomended this) and I have not had a warp yet. That's my 2cw.
Lyptus,
Think about it....the flatness of your router table top is probably more important to good outcomes than the flatness of your table saw. Assume for a moment you want to put an ogee edge on a table top. If your stock is not perfectly flat or the router table top is not perfectly flat then the ogee edge will be spoiled.
I have a similar problem with a top I made for a sharpening station. I want it to be quite flat, to make sure my glass plates don't deflect.
I built up a 1" MDF core from two pieces of 1/2" I had on hand and laminated top and bottom. There is about a 1/8"-3/16" crown. Ick. I'm trying to figure out if angle iron on the bottom would work to flatten it, or if I should just toss it and start over.
Near the top of my list of shop stuff projects, now, is a dead flat assembly and glue up torsion box table, based on David Marks' step-by-step instructions here. Assuming I don't get too distracted ;-).
-robert
Compare the cost of MDF and laminate with the cost of furniture stock and your time.
It's cheaper to start over, no?
Regards.
I will add my voice to the "do over". The materials are cheap enough, and now that you know all the pitfalls, you shouldn't have any problem.
For my own router tables, I simply glue two pieces of 3/4" MDF together -- and I make sure the pieces I use are flat before I get started. Instead of clamping, I just screw the two pieces together -- and then later remove any screws that are in the way for your router plate. I also cut one of the pieces to the exact size I need, and slightly overcut the second piece, and then use a flush trim bit after the glue has set. That helps you avoid fussing to get the two pieces perfectly aligned.
You can eliminate the air bubble problem by rollering the laminate from the middle of the piece to the outer edges.
Technically, you are supposed to laminate the underside of the top (they even make a special, cheaper laminate for that purpose). But if you seal it up with something (water based poly, regular poly shellac -- almost anything), it never seems to be a problem. Two coats should be sufficient.
I think professional countertop makers laminate the bottom side because, for them, it is faster and cheaper than taking the time to brush or spray on a sealer coat or two.
Good luck.
********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Well you all have convinced me to do it over. I'll salvage the piece I started and use it for the base. I'll also try that trick of cutting the first sheet of MDF to size and then laminate the rest. I can't wait to actually get this thing built and running. I've never had a router table or table mounted router before and I'm tired of drenching my shop in dust every time I want to rabbet a picture frame with my plunge router.
Thanks for the advice.
- Lyptus
See design of this router table; it can be kept simple and still work. Indeed, scrap that top and make a new one.
I just finished making a 1.5" thick top using two 3/4" pieces of MDF. It came out great--dead flat, no gaps of any kind. I'm getting ready to put plastic laminate on it now.I think the reason it came out so flat is that this time I bought a 4' X 8' sheet of MDF (from Home Depot, nothing special) and had it cut down to roughly the size I needed (24" X 32"). The bigger sheets are always stored flat at Home Depot, which seems to minimize any warp or bow in the MDF. Then, I used contact cement (a lot of it, MDF absorbs it readily) to laminate the two pieces. It eliminated the problem I always have with laminated MDF, which is that I can't clamp it in the middle and any claming I do seems to throw the surface out of flatness. The contact cement really worked well, that's what I'll be doing from now on.Tom
I made mine with 3/4" Baltic Birch and when I clamped it up I also used a couple of 5gal paint cans fillied with water and a coupled of 15 lb anvils to keep pressure in center area1 - measure the board twice, 2 - cut it once, 3 - measure the space where it is supposed to go 4 - get a new board and go back to step 1
Gluing-up multiple layers for something such as a router top is easily clamped if you first cut out a roughed-out portion of the material where the insert plate will be located. Now you can locate clamps and apply pressure evenly spaced over the entire surface.
An alternative, and I think a preferable method since you can also use this for all glue-ups, are clamping cauls. Proper cauls are shaped with a curvature so when the clamping force is applied on the ends the high point of the curve in the middle of the surface causes the caul to straighten out applying roughly the same amount of pressure over the entire length of the caul. The amount of curve depends on the type of wood and the length.
I also seal the underside with lacquer or any similar material at hand.
Edited 11/2/2005 2:23 pm by DougF
Does it matter what type of glue you use for lamination. In my first attempt, I used yellow wood glue (Titebond I). I liked the fact that I didn't have to align the MDF and laminate perfectly at first, I could shift them slightly as needed prior to clamping. Others have advocated contact cement. Is there a best choice adhesive for laminating MDF or does it not really matter?
I built mine with Norm's plans except I used two 3/4 pieces of MDF. I used regular yellow glue (TBII), and screwed the two pieces together and have not had a problem. I have the PRL and PC7518 and no issues at all. HPL is the top surface and the bottom has three coats of Shellac (I had it left over). No Issues with it so far.
I used Titebond II. I also had questions about how secure the glue would be with this surface so I roughed the area with 80 grit before the glue-up. Once it set and I removed the clamps, just for good measure I used MDF screws on 4" centeres. I applied 2 coats of lacquer on the bottom and the edges of the opening for the router plate insert. The top's outer edges were sealed with Titebond before the 3/4" maple edge banding was applied. Then I applied the formica laminate on the top and beveled-trimed the excess. My top was made from two pieces of 1" MDF, very stable.
Just me and I have several shop made router tables.. All 3/4 or thicker MDF... I just sealed all edges with glue.. Ja know.. Rub in with your finger really good... Put on some shellac both sides and edges... I use MINWAX Paste Finishing Wax after ever use... Just the top.. Never had one warp.. That I know of.. Maybe I should check?...
I built Norm's new and improved router table. I asked the same question about laminating the underside. Several told me absolutely yes.
I then pointed out that I have never see the underside of kitchen counters laminated on the underside.
And, since I asked, I have read an article by one of the finishing experts who approaches the matter scientifically and practically, and he says no -- is not necessary.
However, in order to keep the mdf sealed, I put on 3 coats of polyurethane.
Planesaw- Alan
Planesaw, I just did the same thing. I had plenty of laminate left over after doing the top, but logic told me that poly would seal the bottom. If it warps I figure I can build a new top. So far, it's fine.
Roy
Planesaw,
I ain't no expert but I am working on my second top over Norm's router table. I did laminate on the underside and I think it makes sense. When you cut out the top to accommodate the plate insert (my second one is metal, the first was plastic) the weight of the router is being supported on about 1/2" boarder of press board or MDF...and that weight wants to pull the substrate away from the top lamination. So while it might not be much, the underside being laminated helps keep the substrate connected with the laminate...the underside laminate helps support the 1/2" cantilevered portion of the top.
Lyptus
save time and money? go to a kithcen cabinet shop and ask for a couple of sink or range cut-outs. Surface is smooth, slick and flat already, plus in a decent size for router table. Laminate or solid surface are easy to work with woodworking tools. You can get them for $2-3 dollars, or even free sometimes. The place I went said they save all their cutouts for this purpose.
This forum post is now archived. Commenting has been disabled