MDF vs. Ply for jigs

[PeteM]

Most of the mags use 3/4 plywood for jigs. I use MDF ('cause it's cheaper!). Am I missing something? What, if any, are the benefits of using ply over MDF?

pete

 

[Ray Martin]

Pete,

Both MDF and ply are strong and stable, which are important traits for jigs. MDF certainly mills up very nicely... maybe a bit better than plywood.

With MDF, I think you have to be a bit more careful with the fastener you choose. I think nails hold better in ply. The wrong screw or too much torque on a screw can tear up MDF more easily than it would plywood.

I think if you pay attention to how you fasten the pieces, either material makes for good jigs.

Ray

 

[clowman]

MDF also makes one heck of a mess. (I use it for my jigs too, cause it's cheaper)

 

[lwhughes149]

Here is a hint for you. When you take your trash to the local trash dump look for scraps of plywood. You would be amazed at what someone will throw away. Just store it in a dry place and wait for the proper size jig to come along. Don't laugh, there is a lot of good plywood there.

 

[PeteM]

::..With MDF, I think you have to be a bit more careful with the fastener you choose. .::

I just read an article on fastening MDF. Basically it said to use sheet metal screws rather than wood screws (straight not tapered). Drill the hole in the top piece for a loose fit and countersink both sides of the hole. Seems like a lot of trouble but it would be worth it for a good jig.

Yup, it does make a mess. I generally cut it in the driveway and use my leaf blower to "spread it around".

I haven't been to a dump in ages! Brings back memories. When I was in the service we used to have a few brews and go down to the local dump and shoot rats. Ah, the good ol' days:lol:

pete

 

[DaveO]

I find that MDF is flatter and truer than most Plywood. As said before it's fastener holding capability is less. I'll often glue a hardwood strip to the MDF if I have to use any fasteners on or near the edge of it.
Dave

 

[SteveColes]

Becuase of the thundering chorus for my expert opinion, I'll add my 2 cents.:lol:

The biggest issue I have for MDF jigs is becuase of the way reacts to liquid spills. In my case, coffee. I have spilled coffee everywhere in my shop. And the one time I did use MDF, the coffee pretty much destroyed it.:-(

 

[DaveO]

Steve, that's why there should be no drinking in the workshop:slap:
If you give the MDF a good coat of poly or shellac you can avoid that problem also.
Dave

 

[Canuck]

Steve, that's why there should be no drinking in the workshop:slap:
If you give the MDF a good coat of poly or shellac you can avoid that problem also.
Dave:smile:

Not sure about that, DaveO. Steve likes his coffee pretty strong!!!!!:roll: :lol: :lol: :lol: :lol:

Wayne

 

[PeteM]

Steve - You must be tough on computer keyboards also:eusa_clap

 

[hannah01]

I prefer plywood. The mess from MDF isn't worth the trouble for me.

 

[McRabbet]

I've used both materials. But when I need a rock solid, gotta-be-flat surface, then I use 3/4" MDF or Baltic Birch. MDF takes a beautiful dado and if you use barbless t-nuts for any threaded knobs, it works great. Check out a few jig examples in my Photo Gallery.

Rob

 

[PeteM]

OK - So it seems the down side to using MDF is:
1. It makes a mess
2. You have to take care joining it.
2. You can't spill coffee on it.

The up side is:
1. It's flat
2. It's less than half the price of 3/4 ply.

So.........Poor as I am I think I'll stick with the MDF.

pete

 

[jglord]

One other problem I've run into with MDF is it will absorb moisture over time and swell. I had some 3/4" mdf stored for some time and when I went to use it I found it was now 13/16" or better. Sealing with a shellac based based sealer will help greatly but any rabbits or other cuts may swell over time - probably not doing any good for the accuracy of your jig.
I usually figure on plywood for long term jigs and mdf for single use.

 

[SteveColes]

Steve - You must be tough on computer keyboards also:eusa_clap

Yes on table tops, keyboards, shirts, rugs and on my marriage from the messes I cause.:eusa_danc

 

[PeteM]

Hey Steve - Maybe you should try one of these . . . :eusa_danc

No-Spill Travel Mug



You won't always have to put this travel mug directly into your cup holder to prevent spills just set it down on the passenger seat if necessary! To open the spout, simply press the lever with your thumb; release to seal it closed; works right- or left-handed. Includes a separate non-slip docking base to help stabilize the mug on your desk. Double-wall insulation keeps coffee hot up to three hours, and keeps a cold drink cold up to six hours. Easy-grip, stay-cool handle. Holds 14 ozs. Please specify color: brushed stainless steel or dark blue.

 

[SteveColes]

Hey Steve - Maybe you should try one of these . . . :eusa_danc

No-Spill Travel Mug



You won't always have to put this travel mug directly into your cup holder to prevent spills just set it down on the passenger seat if necessary! To open the spout, simply press the lever with your thumb; release to seal it closed; works right- or left-handed. Includes a separate non-slip docking base to help stabilize the mug on your desk. Double-wall insulation keeps coffee hot up to three hours, and keeps a cold drink cold up to six hours. Easy-grip, stay-cool handle. Holds 14 ozs. Please specify color: brushed stainless steel or dark blue.

My wife wants me to use one of those sippy cups that toddlers use. But I like what you just showed. Where can I get one

 

[sapwood]

What a marvelous suggestion Peter :icon_thum

For those that don't know, Steve has to carry two shirts wherever he goes . . . and there's usually a coffee stain on both :lol:

Sapwood

 

[PeteM]

I found th mug here:
http://www.shop.com/op/~No_Spill_Travel_Mug-prod-20950503
but be warned . . .it's a bit pricey :-(

 

[SteveColes]

I found th mug here:
http://www.shop.com/op/~No_Spill_Travel_Mug-prod-20950503
but be warned . . .it's a bit pricey :-(

I just ordered 2:eusa_danc