Pros discuss the merits of various materials for making router patterns, including MDF, plexiglass, phenolic board, and more. October 22, 2005
I am just wondering how well MDF holds up as a pattern material when using a pattern bit to cut dozens and dozens of parts. I would think the edges would crush after a while thus rendering the pattern useless. Of course, another pattern could be cut, but I would just as soon cut one set of patterns. Will MDF stand up to this use, or would solid wood be better? Is there another preferred pattern material?
FYI: This is for building several dozen chairs and tables to be used in cabin and condo rentals. It’s similar to Adirondack furniture with wide arm rests, curved seats, and backs. I know this just screams for CNC, but I just can't do it this time around.
From contributor D:
I would suggest making master templates with 1/4 MDF then use 1/2" baltic birch plywood (lumber core plywood) for your cutting template.
From contributor W:
I buy sheets of phenolic board in different thicknesses for a variety of purposes around the shop. One of them is durable templates. The material is nearly hard as steel, mills well with carbide router bits etc., and will not defect under the loads of guide bearings. Be prepared for the price - it's expensive, but does its job better than anything I have found. If you don't want to spend that kind of money you could edgeband your MDF with a piece of plastic laminate which is the same material as phenolic board.
From contributor F:
MDG doesn't hold up for very long. Phenolic sounds great. A less expensive material to use is plexiglass. Plexiglass can be machined with regular woodworking tooling. Make sure your router bit bearings don’t seize up because a stuck bearing will melt into the template.
From contributor J:
I agree with the plexiglass. Cut your master on MDF and use the plexiglass for your cutting templates. Like Contributor F said, keep and eye on your bearing or you'll smoke your template.
Something else I found quite by accident (because it's all I had) that works well is 1/2" Medium Density Overlay. If you're not familiar with MDO, it's an exterior plywood with some kind of real tough paper impregnated to one/both sides. It's really smooth and works great for templates. Mine have held up under lots of use.
From contributor E:
Plexiglass is ok for template material especially if you need to see through it to select best grain/ avoid knots. For serious use, though, the phenolic is the stuff to use. Plexiglass is comparatively soft and easy to damage/not easy to repair
From contributor M:
To contributor D: Baltic birch and lumber core are two different animals, not the same thing at all.
From contributor G:
What about using uhmw?
From contributor L:
I buy Alum from the scrap dealer for $1 a pound. He puts aside any sheet stock for sale because he only gets pennies for it in bulk.
From contributor K:
Contributor W wrote "you could edgeband your MDF with a piece of plastic laminate which is the same material as phenolic board." That's how I do it and I use epoxy in place of contact cement.
From contributor S:
To contributor G: How would you get your template to stick to the material that you are cutting?
From the original questioner:
I had thought about laminating edges with hpl but hadn't thought about phenolic board. It might be a little on the expensive side though. Wouldn't a seized bearing melt into the phenolic material as well? I don't think in this application that plexiglass would be the best material. There are too many parts for the bearings not to seize from time to time.
Alum sounds like a good idea. I should need to cut only one set of patterns and it would probably last indefinitely. I just have to watch the depth of the cut closely. I believe baltic plywood would be a good alternative, but I’m not so sure about MDO. I've seen some pretty good sized voids in it and I haven't seen true lumber core in years. I'm sure it's still out there, just not around here. I used to build cabinets, doors and all, out of it. There is lots of good help here at WOODWEB. I've gained a lot of good, useful information here over the years.
From contributor W:
To the best of my knowledge the phenolic board does not melt down, at least not the temperature the bearing is going to create. Phenolic is made with heating the material so I believe it takes a higher temperature to do anything to it. As for cost, yes it is pricey, but the value of long term durability needs to be factored in. How many templates of any other material available will you have to make for the dozens of parts you will have to make to equal one well made template of phenolic board?
From contributor G:
For the uhmw plastic template, you can use 2 sided tape or screws. The uhmw is slick but adhesive tape will stick to it when it is clean. A vacuum setup is the best way. If you are going to stick with an MDF type product then use 1/4" masonite. It is much harder and much more durable than the MDF.