MDF for sled??

[Brent Romero]

How well does MDF hold up in high humidity situations? I am thinking about using MDF for my table saw sled and dont want to waste the time if it won't hold up long term.

Thanks

[Randy Rose]

I think MDF swells w dampness / doesn`t hold screws well / weighs a ton / creates horrible dust. I avoid it. JMO

[Peter Aeschliman]

I'm with Randy... People tout stability of MDF as a major benefit... And for certain uses, like panels in painted furniture and built-ins, it's great.

But anything that will get moved or bashed around, and anything that requires screws, won't hold up well if you make it with MDF.

[Brent Romero]

Thanks gentlemen. I would have suspected such out of MDF....but wanted to make sure....thanks again.

[Jerome Hanby]

I had no problems with my MDF sled...until my wife bumped it off the table saw. Then I had a two piece model! I think another 'creeker had the right idea for dealing with MDF in jigs. He touted using West system epoxy to toughen it up. Even so, I don't think I'd use it again in a big jig that could be placed on and off of another tool, just too easy to have a mishap and send it crashing to the floor. I do plan on using a stack of MDF as the core for my home made jointer's tables. It'll be wrapped in something , probably a hardwood, and may be topped with metal.

[Fred Voorhees]

I have to beg to differ with the general consensus here about using MDF for sleds. I have had a cross cut sled I made out of MDF ...jesus.....must be going on eight years now and the thing still cuts a true 90% and still gives me the satisfaction that it did the day I made it. I glued and screwed an oak runner for the tablesaw groove and the runner has never budged. Now, I don't know where anyone that has tried using MDF and had gotten unsatisfactory use from it lives, but I live in Central New Jersey and let me assure you that it gets pretty darned humid around here in the summer. That, added to the fact that my shop is on the second floor of my two car garage and it gets plenty hot up there anyway...well, I think my point is made. The sled is serving me well to this day. In fact, I used it just earlier tonight to fabricate some parts for a nightstand that I am currently making.

[Bruce Wrenn]

My Dubby (In-Line Industries) uses MDF core melamine for the actual sled. Been made that way as long as I can remember. I have several dedicated sleds that use melamine coated particle board. But it isn't the PB from the borgs. Rockler makes several sled type products out of melamine coated MDF.

[Jerome Hanby]

That pretty well matches my experience right down to the oak runner. Until it hit the concrete only complaint I ever had was that I should have made it larger. To be fair, no other material may have faired better from hitting the floor. Doing it over, I think I'd go with a material thinner than 3/4" just to cut down on the weight. I might use something more like Incra uses with the 5000... I bet a nice sheet of phenolic would work well, but ouch, at granger a 24" x 36" sheet of 1/3" is about $80


I have to beg to differ with the general consensus here about using MDF for sleds. I have had a cross cut sled I made out of MDF ...jesus.....must be going on eight years now and the thing still cuts a true 90% and still gives me the satisfaction that it did the day I made it. I glued and screwed an oak runner for the tablesaw groove and the runner has never budged. Now, I don't know where anyone that has tried using MDF and had gotten unsatisfactory use from it lives, but I live in Central New Jersey and let me assure you that it gets pretty darned humid around here in the summer. That, added to the fact that my shop is on the second floor of my two car garage and it gets plenty hot up there anyway...well, I think my point is made. The sled is serving me well to this day. In fact, I used it just earlier tonight to fabricate some parts for a nightstand that I am currently making.

[pat warner]

Just an aside. The flatness & thickness specs on phenolic, whether paper or fabric, are atrocious.
Don't trade one pile of misery for another.
Moreover, phenolic laminate is subject to suckin' up water vapor and changing shape, especially if one side is always down.
Incited me to go to nuthin' but ground aluminum jig plate for any substrate that demands flatness, seasonal dimensional stability and thickness uniformity.

[Bob Johnson Lake Geneva]

I made my sled with 1/2" Baltic Birch and then screwed down 1/2" MDF over the top (dual runner). Makes perfect zero clearance and when the kerf in the MDF is no longer zero clearance I can remove it and screw a new piece down. Don't have any humidity issues but if you do in your area just put a coat of shellac on it.

[Bill Huber]

I am in the MDF camp, I made my sled out of 1/2" MDF with oak fences and have had NO problem at all. I don't worry about it holding screws, all the screws that hold the fences are in the Oak and the rails have machine screws that hold them.

I did not put any finish on it, just wax on the bottom and top and that is it, mine is 4 years old now.

[Jim Finn]

I have to beg to differ with the general consensus here about using MDF for sleds. I have had a cross cut sled I made out of MDF ...jesus.....must be going on eight years now and the thing still cuts a true 90% and still gives me the satisfaction that it did the day I made it. I glued and screwed an oak runner for the tablesaw groove and the runner has never budged. Now, I don't know where anyone that has tried using MDF and had gotten unsatisfactory use from it lives, but I live in Central New Jersey and let me assure you that it gets pretty darned humid around here in the summer. That, added to the fact that my shop is on the second floor of my two car garage and it gets plenty hot up there anyway...well, I think my point is made. The sled is serving me well to this day. In fact, I used it just earlier tonight to fabricate some parts for a nightstand that I am currently making.

I have had a similar experience with my MDF jigs. Mine work well for me but we do not have a humidity problem here in West Texas.

[ian maybury]

Not sure about in the US, but over here there are considerable differences between the qualities of MDF available. The cheapish stuff from the big box stores tends to be one step removed from cardboard and inclined to fray, whereas there are much higher quality industrial grades around that seem to have a lot more resin or whatever in them. One of the local woodworking places does a specific brand that comes in colours too.

I've not checked them out because I don't like the stuff, but it's more a gut reaction to the feel/smell than anything very specific about its properties.

ian

[Phil Thien]

Someone makes 3/8" tempered hardboard that is S2S, I have seen it. But I've never found any place that sells it. I think 3/8" tempered hardboard would make a very good sled material.

1/4" tempered which is smooth both sides, which I can find all over the place, is too thin.

I've thought of laminating two 1/4" pieces, but instead I just used Baltic birch.

[Bill White]

Don't overlook exterior grade MDF. I have used a product called EXTIRA. Yep, it is heavy, but very stable. Also, it is moisture resistant (not submersable). This stuff is some kinda tough.
Bill

[Jerome Hanby]

Cool to hear a material like that exists. I was going to check on the availability and cost of MDO for some other projects, I'll check on this as well!


Don't overlook exterior grade MDF. I have used a product called EXTIRA. Yep, it is heavy, but very stable. Also, it is moisture resistant (not submersable). This stuff is some kinda tough.
Bill

[Myk Rian]

If you soak a lot of shellac into MDF, it holds up very well.

[Brian Penning]

Mine is made with MDF also -no complaints other than as I get older it automagically seems to get heavier..;)

[Guy Belleman]

Over the years, I followed several plans using MDF for tool tables, sleds, and fences, evening laminating it to plywood and adding wood banding. Maybe if I hadn't been in the military, moving every couple of years and having kids, or spouse, putting drinks on these items, living in areas where the humidity was 90% most of the time, the MDF items might have held up better. When the MDF starts crumbling or eroding, the item becomes unusable. Now, I make everything out of plywood and hardwood, and have not had a problem for six years or so. I would be interested to hear more about this exterior MDF though. Now, that I am retired, but still working for DOD as a school teacher and moving about every six years, I suppose I will use MDF again when I retire the second time and settle down for good.

[Carl Beckett]

If you soak a lot of shellac into MDF, it holds up very well.

+1 +1 +1

I have several MDF fixtures/jigs, and give them a few coats of shellac. Soaks in, hardens the surface, prevents severe moisture absorption, is quick and fast drying.

In fact, my outfeed table is just this, as is my router table top surface.

(I also have some baltic birch fixtures, some out of aluminum, some out of solid stock. With thoughtful design, the MDF is as durable as any. I would say they ARE susceptible to corner/edge impact if dropped on concrete (have dinged some corners) - but I wouldnt want to drop my hand planes or chisels either, so I dont necessarily design for this.

[Bobby O'Neal]

I can see people having good success with it as long as....whatever. Dropped, got wet, etc. I think it'd work great but take little, if any abuse. Mine is Birch ply, oak runners. Works great.

[Harvey Melvin Richards]

I don't drop any item that I expect to be precise.

MDF FTW.

[Richard Jones]

Both my cutoff sled and my miter sled are MDF. I have "many" jigs that are MDF. I live in Southside VA, and my shop is in my basement. It's always humid down there............... I have been very impressed with how all the jigs have held up, and MDF is usually my first choice for whatever. I have a bud with a cabinet shop, so scraps is not a problem........:)

Rich