First Project: Easiest material to use MDF?

[dndcollect]

Was wondering what material is recomended for a first timer?  i have read that mdf is hard to cut and has a ton of dust? is that true?  i am making a bartop, not sure if that matters.

[ScottS]

A 4'x8' sheet of MDF weighs over 100lbs, IIRC. Cutting it generates lots of dust. The dust contains formaldehyde, which is a carcinogen. That said, it's cheap and machines well. People like to think that it's easy to paint because it has a smooth surface. It sucks up paint (and wood glue!) like a sponge, however, so you'll have to take the time to prime and sand it.

MDF would be my last choice for building a cabinet. I don't like the weight, I don't like the lack of strength, I don't like the porosity, and I don't trust it's screw-holding ability.

My first choice would be Medium Density Overlay (MDO). My second choice would either be black melamine covered particle board or a decent plywood, depending on what I was doing. Melamine reduces finishing time (just slap on some artwork and you're done!), but is heavy and lacks strength. It also requires high-quality saw blades to avoid chipping the finish when you're cutting it. Plywood is light and is stronger than MDF or melamine. Finishing takes longer, though probably not much longer than priming and painting MDF.

Cost-wise, MDF is the cheapest thing you can buy. MDO and plywood are probably in the same ballpark. Melamine is somewhere in the middle.

[ChadTower]

A 4'x8' sheet of MDF weighs over 100lbs, IIRC.

Oddly enough, they're not that hard to carry if you have strength.  I pick them up and carry them over my head without a ton of problems.  Once you build something out of MDF, though, it is damn heavy for some reason.

[ScottS]

Oddly enough, they're not that hard to carry if you have strength.  I pick them up and carry them over my head without a ton of problems.  Once you build something out of MDF, though, it is damn heavy for some reason.

Right. You've built a cabinet out of three 108lb sheets, installed a 20" CRT that weights 85lbs, and probably thrown in 50lbs of 2x4 bracing like saint's book suggests... which gives you a finished weight of 350-400+lbs! That's significantly more than my cast iron 6" jointer weighs!

Even if you're strong, I think you'll have trouble with MDF. The weight, the size, and the lack of rigidity make it difficult to work with. Ever try to push a 4x8' sheet of it across a contractor's saw? Or tried to move sheets on a windy day? I've done both and recommend neither 

[ChadTower]

Heh, I did get blown over 6-7' one day carrying some across the yard.   

I'm not even talking about cabinets... even small stuff is heavier than it needs to be when you used 3/4" MDF.

[bigh4th]

Take it from these guys...MDF isn't a good choice for cabinets.   I used it for my cocktail (that I SHOULD be working on instead of on these forums) and its super heavy.

I foolishly went to the hardware store by myself planning to get the supplies I needed, including the sheet of MDF.  So I get the little cart and go over to get the sheet and about busted my arse getting it off the pile and on the cart, and I'm a stout dude (6'1").   Should've seen me get it ontop of my escort wagon.

Cutting it is another pain as it is rough on a saw, and has a tendency to pinch the blade.  Can anyone say kickback?  The dust is also terrible.  A dust mask is a must.

However, I haven't had any problems with screws holding into MDF.  My monitor is screwed into the MDF and its solid as a rock.

So do yourself a favor, go with plywood.  It costs more, but it will save your back, your saws ( I killed a jigsaw cutting MDF), and your lungs.

-Harry

[Kaytrim]

If you are going to be cutting a lot of MDF you need a respirator not a dust mask.  MDF dust goes through most dust masks.  Also do not cut that stuff inside the house unless the room is sealed off from the central air system.  The dust will get all over the house and will takes months to clean up.  If you think that cutting MDF is bad try using a router or belt sander on that stuff.  The dust is so fine it is a powder.

Yet we still use it.

TTFN
Kaytrim

[AcidArmitage]

A 4'x8' sheet of MDF weighs over 100lbs, IIRC.

Oddly enough, they're not that hard to carry if you have strength.  I pick them up and carry them over my head without a ton of problems.  Once you build something out of MDF, though, it is damn heavy for some reason.

ur a ---fracking--- beast!

[fixedpigs]

i recall a 4x8' sheet of mdf weighing more like 70lbs...

and if you are only using screws to hold your cabinet together...then don't expect much...you should be using glue...a good wood glue is stronger than the wood it holds together...

[Greenskein]

I'm almost finished my first cabinet...I used 5/8" SIS (sanded 1 side) poplar plywood...it's got one nice smooth side that you can stain or paint, and it's been great in terms of strength and ease of cutting.  If  you're just doing a small bartop, you can probably get away with 1/2", although I like the bit of extra width with the 5/8".  I didn't use any glue, I used #6 x 1-1/2" wood screws.  Make sure you take the extra step and drill the holes with a #6 countersink bit before you put in the screws.  Email me at kevingreen@rogers.com if you want me to email a few pics of the construction, I haven't posted them to a website yet...

[sstorkel]

i recall a 4x8' sheet of mdf weighing more like 70lbs...

I haven't weighed any of these materials myself, but the figures I recall are 60-70lbs for a sheet of 3/4" veneer-core plywood and 100+lbs for a sheet of 3/4" MDF.

[shardian]

4'x8' 3/4" MDF is definitely 100 lbs.
That horse has been beaten on this forum more than a few times.

[bigh4th]

I'm thinking MDF weighs more than 100 lbs., or at least the stuff I got did.  I've never had trouble lifting a 4'x8' of 3/4" plywood, but it was all I could do to get the MDF to move were I wanted it.   This was my first time buying MDF and the weight surprised me.

I brought it home ratchet-strapped to the roof of my stationwagon and didn't even try to get it down.  Had my dad help me and it STILL didn't feel any lighter.

-Harry

[ChadTower]

Average MDF is definitely about 100lb.  I think being able to carry it is as much about leverage as anything else.  The 4' width is good for a person's wingspan to stand it vertically, grab each edge, and just swing it up over head.  Then again I used to spend my nights and weekends grabbing weird shaped heavy ass stuff and carrying it around for fun.   

[michelevit]

dont use mdf.
its heavy, cheap to buy,
and not as strong.

i use oak plywood or baltic birch.

it makes a huge mess when you cut or route it.

mdf is for cheap shelves, not for arcades.

[Donkman]

   I use alot of MDF in my work. A sheet of mdf 3/4 inch weighs in at approx. 90 lbs each. I have been purchasing mdf in bulk for about 5 yrs. The screw holding in mdf is good from the face of the board but tends to split when screwed from the edge. The strength vertically is pretty good but even 3/4 will sag horizontally if spanned too wide.  I have built large cabinets, bookshelfs, and other units from MDF many times. If I were going to have a unit I wanted to move very often I would definitely go with plywood.
 If you use even 2 sheets of MDF for the exterior you are looking at 180 lbs before monitor or other hardware installation.
 Depending on your local suppliers you can find plywood in many different wood species and grades. The best plywood often has a good one face lamination. The best side of the plywood is cut to be exposed on the finished side. The lesser face is turned toward the inside of the cabinet. Often poplar plywood is a good choice for price and smooth finishing / painting.  
 MDF is still about 1/2 the cost of a good sheet of plywood in 3/4 thickness depending on the species. MDF is also a true .75 thickness where 3/4 plywood is usually undersized to 23/32 of an inch or sometimes less.  I recommend machining mdf outdoors if possible or with a good dust collection setup if working indoors. The dust will infiltrate your home if it enters the central air system, it also generates particles small enough to enter your lungs, coat your eyes, and cling to everywhere else.  Particle board covered with melamine is a good finishing option but still tends to be a little heavy in 3/4 sheets and will sag horizontally if spanned too wide.
Finishing mdf is easy enough with a good primer coat of latex paint. I use an airless sprayer to apply flat latex primer to all my mdf units.

[Namco]

MDF is also a true .75 thickness where 3/4 plywood is usually undersized to 23/32 of an inch or sometimes less. 

Aah, so that's why the back door of my cab sticks out a little bit. The MDF backdoor is thicker than the plywood the rest of the cab is made of 

I love the facts expressed in this thread. In just a few minutes I've learned the following:

• MDF dust when cut can give you cancer
• A sheet of MDF takes a beast to move
• MDF can't be moved on a windy day
• Wood glue dries harder than wood
• MDF dust will infiltrate your house if you aren't careful

• MDF will kill your jigsaw
• MDF will bust your arse

Great stuff guys, keep it coming!