Help with MDF

[JimD]

A good thing about a piano hinge is lots of screws. The holding power of individual screws into MDF is not as great as solid wood or plywood but it is not trivial either. With enough screws, it would hold significant weight. And as been noted, you could band that edge and screw into the edging. If it will need to bear a significant amount of weight (or be strong enough to withstand what kids have been known to do), you should probably screw into solid wood banding and reinforce the glue joint. Brads are the simplest reinforcement. Screws would be a little stronger. Biscuits or a spline is another way to reinforce the edging to MDF joint.

You can get 1/8 and 1/4 inch thick MDF but it is sometimes called tempered hardboard at that thickness. There may be some difference in the way it is made but at least one surface is smooth. My son's quickie college desk used 1/8 tempered hardboard for the surface over 5/8 particle board (I don't love particle board but we were making a large work surface on the cheap). It had 3/4 softwood edging. It survived several years in college and he was using it after finishing until he lost his job and moved back in with me.

Jim

[BasementDweller]

Ok, sorry for the lack of details. And for the long delay, I had to find a picture that told the story:




This is the function of what I'm going for. The hinge won't be in the pine it will be in the MDF as the MDF will overhang the apron by an inch or so. Then the "banding" (more like edging) will be flush top and bottom with the MDF but will stick out about an inch, not totally sure because I haven't made it yet.

My tabletop will lift much higher than the one in the picture as it is a easel table not a drafting table.

[JimD]

That project looks like a better application for melamine covered particle board than for painted MDF. Melamine might be a little more expensive but not much. The surface is much more durable. The accessory tables of my BT3100 are melamime and are holding up very well. Melamine is essentially thin formica. I think you can get it in colors but normally you only find white.

Edging can be as simple as iron on white plastic strips. Trim with a router or special hand tool. Or you could apply thin wood edging. I think the wood looks nicer but I've done both.

Particle board also is stronger than MDF so it would stay flat better and hold screws better.

If you do not like that idea, the local big box stores sell what appears to be tempered hardboard with a durable white surface of some sort on it. I used up a sheet of this on something but don't remember what at the moment. It is less than 1/4 inch thick so you could put it over plywood.

Biggest issue I see with MDF is the surface will not be real durable painted. And I think something this big will want to sag in the middle. If you must use painted MDF, I would think about a top coat with Resisthane, a water based finish you can even mix with latex paint.

Jim

[RayintheUK]

I don't think that sagging is an issue if it's going to be used as an easel - i.e., nearly vertical. However, there will be a weight issue with MDF, particularly ¾", so I'll withdraw my recommendation to use that, having seen the project requirements. I agree with JimD regarding the use of melamine, which will be altogether more suitable if you can source it readily.

Ray

[pelligrini]

I think you're going to have problems with MDF, probably sagging or warping, even 3/4" material. It'll probably happen between the hinge and vertical supports.

I did a infill table between a set of long rails extensions on my BT clone out of 3/4" MDF. It was quickly done and only supported with the 4 OEM wide table brackets, it sagged and warped. It was 48" long and only the depth of the opening between the rails (less than 24")

My wife acquired a large shop built table that was 1" particle board with a melamine finish. It sagged at the 18" cantilevers on the ends and sides. There was some 3/4"x2" oak banding around the edges but it still was bending.

I've got a couple Mayline drafting tables http://www.mayline.com/showcase/draf...eel_draft.html and the tops are 1" thick wood with steel end bands. If I needed to make another top I'd probably go with Baltic birch. Like JimD mentioned there is a hardboard product usually called 'White bathroom wallboard". We used that all the time to cover the old tables we had in architecture school.

[phi1l]

Interesting project..
Now, .. is this going to be an artists easel for painting?? If so, you may want to rethink the whole concept. Artists easels have a "mast" that locks down on the top of the object being painted. They also have a movable support to locate the work where it is most comfortable.

I think I would get/make an easel works like this: http://www.misterart.com/g8394/Best-...-Top-Easel.htm

Then either have a table top that would be hinged at the back and mount an erectible easel underneath the table to pivot up from the front or, adapt the works to hang or mount from the top of the erected table top.

If it going to be used for painting, I think you can expect it do develop extensive "character" over time from the paints being used. So I think I would go with a refinishable table top unless it is going to be removed during painting.

Of course, the simplest solution would be to just get a table top easel & build the table with a storage area under the desk top(either slide in from the front or side, or with the top hinged from the back like a school desk) for the easel When it is not in use.

[JR]

I have used 1/8" MDF for a number of shop projects, but nothing intended for other humans to see or use. It's just as smooth as the thcker variants.

A lamination of 1/8" MDF and 1/2" plywood might just do the trick for this project. If there's a concern about it being a bit wobbly, you could add a couple of stiffeners to the under side.

This brings us back to applying trim. My advice is to use your best judgement and leave me out of it!

JR

[BasementDweller]

The only suppliers I have in the area are LOWES and HD. So I'll have to check them out tonight and see what I can find. Thanks for all the ideas. I'll post some picks when I'm done! I'll have to see if I can find the white stuff you mentioned that would save me painting it! And Santa needs this thing for the sleigh loading in a hurry!

Thanks again!

- BD

[pelligrini]

My local Lowes and HD carry the white melamine covered 3/4" MDF, the lowes aslo carries rolls of the white iron on edge veneer too.