# Proper Screws for MDF



## antlersonly

Some of you may have seen my posts about making some antler plaques. I have gone back and forth between using solid wood and using MDF. Well, after purchasing a jointer, borrowing a small planer, and attempting to do some 'glue-ups' this past weekend, I have changed my mind. I am now settled on using veneered MDF. I do look forward to using my new jointer for other "woodworking" projects, but must move on now. I was really was trying to make a go of it with solid wood, but don't have the time (to learn needed skills) or money (to invest in a 15" planer, better calmps, etc…) in order to catch the already-upon-us deer season in Ohio.

So, I am now desperately in need a little help using MDF. The plaques I am making will be about 14" wide by 21" tall. They will be quite heavy once I get the antlers and picture attached, and am concerned about how to hang them. My plan is to use two standard mirror hooks on the back, with a piece of braided wire connecting them - from which the plaque will hang. I am using 3/4' oak veneered MDF. Now the question:

What kind of screws do I need to use to attach the hooks? Please keep in mind that the total weight could be pushing 40-50 pounds. Any help would be GREATLY appreciated.


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## mot

I wouldn't do it. MDF doesn't hold fasteners well at all. In my opinion, for the application you are describing, you'll need to through drill. With MDF, I'd even be concerned about counter sinking too much as it has a tendency of blowing out. I wonder how you feel about using oak veneered plywood. I think you'll be much happier for quite a few reasons. For one, the dust isn't as ridiculous as MDF, and second, plywood holds fasteners very well. I'm not sure of the cost difference for you.


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## antlersonly

Tom, thanks for the quick reply. I was afraid I would hear such a thing. My problem with plywood is the edges, and my inability to hide them. However, I may need to go back to the drawing board and reconsider using a design which would allow edge banding. Oh, well, back to the drawing board…


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## mot

I think that you'd be happiest in practicing and perfecting your technique of using solid wood, or you could use a solid wood edging on ply and then do some sort of routed edge affect on that. It might be hard with irregular shapes though.


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## North40

I'm with Tom - I wouldn't do it, especially for someone else. MDF doesn't hold screws well. However, a recent issue of Popular Woodworking (April 2007) has plans for a lathe chuck where they drill holes through a headstock nut and screw into an MDF faceplate. That seems like it would take some significant force. Not to disagree with the very knowledgeable folks at PW, but when I build the chuck, I'm going to drill and tap the holes in the nut and then use machine screws to go through the faceplate into the nut. But I digress.

If you really have to use MDF, you might consider using machine screws from the front side with nuts on the back. You could countersink the heads of the screws far enough that they could be covered with FastCaps or something. I don't know if I'm explaining well, so here's a little sketch of what I'm thinking …


Question: If you are using braided wire between two anchors, won't the weight of the antlers pull the top of the plaque away from the wall?


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## antlersonly

And therein lies the trick. The edge I created with a simple roundover bit, on both solid wood and MDF, was great. But on plywood "things" show up. If you are driving down the highway and you see a sign that has a state route number on it - well, that's the shape. It is sort of like a shield, and I think it looks great for what I am attempting to do. Perhaps I will try a smaller roundover so that less shows from the 'straight on' view point.

One complicating factor with solid wood is that I may need to create many (perhaps hundreds) of plaques in a very short amount of time. There is no way I could manage this, unless it is some sort of sheet good. Back to the shop…


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## antlersonly

Peter, we were posting at the same time. To answer your question, I don't know. I'm going to have to experiment. Perhaps a strip of 1×3/4 across the bottom of the plaque would help this?


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## mot

I see your dilemma, John. I think it's going to be a system that deserves flush mounting of some sort though. Include some anchors with the item or make sure it gets mounted in a stud. No sense impaling someone with it.


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## North40

John - you could try it, but I don't think so. You'd just be moving the center of gravity that much farther away from the wall. The shorter the braided wire, the less sag you'd get, but unless it's as tight as a fiddle string, you'll see a gap. And if it's that tight, it will be very hard to keep it on a nail. I'd consider regular picture hangers - they look like little metal saw blades, and come in a variety of sizes - or french cleats. I know you don't feel like you have time to figure out a new medium, but if you used ply or wood, you could just put a keyhole in the back and there would be no need for hanging hardware and no gap between the plaque and the wall. You might see if a local cabinet guy or woodworker would make some 14" wide by six or eight foot long glued-up panels for you, so you could just cut the plaques out of those panels.

Tom's got a good idea - what about two holes on the centerline of the plaque, one near the top, one near the bottom. Provide two heavy wood screws (maybe brass?) with matching decorative washers. Then the customer could put both screws into a stud, the mounting hardware would be part of the decoration, and you'd have a flush mount.

I hope you get it figured out.


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## boboswin

John, you can insert a piece of solid wood in the back of your plaque with a decent glue and mount your attachments to that if the thickness allows.
Like others have mentioned this too is not the ideal answer.

Bob


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## antlersonly

Okay, so let's assume I am now using veneered 3/4" plywood. In this case, I am afraid that using just one of the saw-toothed looking hangers may cause the plaque to 'lean' a little because of irregular weight on the part of the antlers. I figured a wire would allow adjustment for this when a 'customer' is in the process of hanging it on their wall. I am trying to avoid using two saw-toothed hangers because, well, I can remember going through a heck of a time myself trying to get them level. Not only that, but at only apprpximately 12 inches apart, they would only be able to get one of their hangers into a wall stud! I think I may have to use an extremely tight wire. I'll have to attempt this and see how it works…


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## North40

Hey, John - I'd be interested to hear how this worked out. Could be useful information!


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## antlersonly

Well, I'll tell you how I HOPE it works out. I just called the guy and told him it isn't working the way it is *suppossed to*. No amount of cleaning has helped. I'm taking it back to him today. He was reluctant, but if it doesn't work, then he should, as an honest man, take it back. I'll post the end result.


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## North40

John, you must be referring to the drill press. I hope the two of you can work it out and he does the right thing.

I was curious about your solution for hanging MDF plaques - did that work?


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## antlersonly

Well, he just called me back and was refusing to take it back. I had to work hard at convincing him that I did it no harm, and finally talked him into doing a trade for one of his remaining tools.

As for the MDF, well, in the end I had to go with 3/4" veneered plywood. I am having to paint the edges, but the plaque looks great. I still want to look into using MDF though, because I could subcontract out the routing and then assemble in my shop. Right now I am trying to find a company in my area (which is Pittsburgh) that would do the CNC routing for me. Any suggestions on how to go about finding a company that would do this for me would be *greatly appreciated*.


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## North40

You might try …
Tiger Sales in Sharon 724-342-3080
Lyndan Cabinets in Connellsville 724-626-9630
Country Furniture in Montgomeryville 215-362-3836
Springwood CNC in Larksville 570-371-2420


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## antlersonly

Peter, sorry for confusing the two forum topics, but I was pretty focussed on getting my money back today.

As for the MDF, like I said I am currently using plywood. I do hope to switch to MDF after I work out some fastening issues. On the plywood I ended up using ONE mirror type hook, which I turned vertical and place at the top of the plaque. I was amazed at how well the plaque stayed wherever I hung it, this was because of the tremendous weight on top, due to the antlers, compared to the bottom. Unlike a picture, which is loose on the bottom and will 'swing' on you, it would stay almost anywhere between 4 and 8 o'clock when placed in that position.

I stopped at a sign company today and they said they would be willing to CNC route for me! I couldn't believe it since they are only 5 miles from my house, versus the 50 miles to the Pittsburgh area. We'll see how it turns out.

I am going to start a new topic on this, since I now need a CAD drawing. Stay tuned.


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## Radish

How thick is the MDF? Could you use that new router to route keyhole hanging holes, the kind that capture the head of a screw. Toggle bolts should be able to handle a 40 lb load, and then the plague would hang flush against the wall. Just my two cents.


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## antlersonly

Hey guys,
I decided to test the MDF myself. I hung my MDF plaque with one mirror hook, turned vertically, and supported it with the two 1/2" screws that came with it. I then hung 165 lbs. of my son's weights from the plaque, which is at least four times more than the maximum weight I would ever hang on one of my plaques, including the weight of the plaque itself. It held for several hours and showed no sign whatsoever of wear and tear. I am now convinced that MDF will work just fine for this project - at least in terms of strength.

The issue of its safety…well, that I will handle by subcontracting out the cutting and shaping to a CNC company. Once again, all of your input was greatly appreciated.

Thanks for all your input!


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## mikef

Sorry for getting on this old thread again but I can't send a message yet (newbie!). John / others, I need to hang sheets of 9 - 12mm MDF that is 8ft x 4ft onto walls. I noticed the last post here saying that you'd hung 165lbs of boy from a single mirror plate! How was the mirror plate fixed to the MDF and what thickness was the MDF? What size srew fixed the mirror plate to the MDF? An 8ft x 4ft board is about half what you hung from a single plate and so this'd be awesome. I'm an artist painting onto MDF and so it needs to look neat and not ruin the surface of the board.


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## jims2

why are you using mdf to paint on? IMHO mdo plywood would be a much better choice for painting does not require priming like mdf would.


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## mikef

could any responses be in answer to the question please? MDF is the only surface that will work for what I require (my work sells for £15,000 each and I'm extremely experienced in this area, usually the boards are mounted on a frame first then covered in canvas but this is something different.
Just the answer would be great, thanks!


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## mikef

apologies if that seemed a bit rude..! It's just that this is the 3rd forum I'm trying as EVERY other one I've tried ends up with people commenting on the use of marine ply or MDO etc rather than just answering the question. On the use of MDF for acrylic paintings, it's safe to assume that I know what I'm doing. As for trying to hang it straight to the wall with mirror plates, that could be a great new solution to a query if I can find out how best to do it and prevent my work falling off the gallery wall (which could very quickly result in a drastic drop in reputation..!)
Cheers


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## Belg1960

Mike, if I was going to hang something like you describe I would use a french cleat system, if your going to use mdf for everything use glue and confirmat screws to attach the piece to the back of the "art" and cut it at a 30 degree angle. Attach the other cut off piece to the wall with some screws long enough to catch wall studs under the sheetrock.
heres a link to how to do it.
http://lumberjocks.com/zlatanv/blog/14907


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## Gofor

Mikef: Just saw this thread. Could you router a 1/2 or 3/4" wide stopped dado on the back side and glue in a 3/8 to 1/2 thick piece of hardwood into which you can anchor the eyelet screws for the wire hangers? The hardwood could sit out proud of the back if you want the screws to go into the top edge of it. A small spacer surface glued on the lower area would keep the plaque from rocking forward when hung. the hardwood inserts could be all the way across, or just in the screw location.

If the hangar screws go in from the top, inset a 1/2" dowel from the back about 1/2" from the top edge and about 5/8 deep. A screw going through the top sideways through the hardwood dowel will hold a lot more weight than just into the mdf. Screws could then be of your choice. Dowel holes could be made with plunge router or a brad point bit. For a large production run, I would advise using a carbide tipped up-cut router bit, as it will last much longer than a HSS brad-point bit in MDF.

I would not anchor the screws into the end grain of a dowel, as they will tear out much more readily.

Just some ideas.

Go


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## jmichaeldesign

For that much weight I'd build the plaque up to double thickness using two layers of ply. Only build up the edges in back so you have a hollow area to put in a french cleat. This way it's flush against the wall and definitely strong enough. In addition it's just easier to hang things from french cleats. Screw a small piece of wood to the way, then just set the larger piece on top, no fussing with things to get them flush, level, or centered.


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## Gofor

After all I said, I still did not answer your question: "What kind of screws do I need to attach the hooks?"

Check out these two links, which should answer your question:

http://www.norbord.com/images/screws-MDF.pdf

Note the statement "more length is stronger than larger diameter"

and these that meet the description:

http://www.ultimategarage.com/spax.html

Hope this helps

Go

PS: My apologies. I try to make it a point to answer the question first and offer alternatives after. Failed miserably here.


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## Clarence

Ho)w about milling a keyhole into a thin (1/32) metal plate of some size (2" x4", say), and attaching it to the back of the board with several screws. The keyhole would match up with a hole you've routed into the back of your board. This would allow a flush mount, and you would have several screws, not just one, supporting the weight with no fear of tear-out.


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## mikef

This is officially the best site with the best knowledge base…! Thanks to all, the french cleat system is something that I would never have thought of but I perfect! Thanks for other suggestions too but I can see how mounting half of the cleat onto a wall and the other to the back of the mdf will make it really easy to mount the work level. 
Last question, what's the best glueing to MDF to support the 40kg weight of the board? (I can imagine this could result in a mix of answers?!)


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## RetiredCoastie

Early on Peter had the answer, but I would recommend along that same idea of using machine screws but instead of plain nuts, use "T" nuts epoxied into a drilled recess cut with a forstner bit. You can get fairly small "T" nuts at most hardware stores. They wont pull out and can hold a lot of shear weight.


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## mikef

Thanks RetiredCoastie, I have gone from despair to the perfect solution in under 24 hours thanks to an amazing bunch of experts - I'll be sure to use this site for all wood related issues in future instead of stressing out with my lack of experience and knowledge..!
Thanks all


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## Gofor

PVA glue should work fine for MDF to wood or MDF to MDF. I would use Titebond II or equivalent unless it would be in an outdoor or unheated situation (like a cabin) in which case I would use Titebond III (more moisture resistant). If just gluing the french cleat to the smooth back, I would augment with a couple screws or dowels into the back.

If using a metal cleat, 2 part epoxy rated for both metal and wood would be better, although may not be needed if you are using mechanical fasteners. Won't hurt though.

IF the glue is being used to attach the antlers, the PVA type glues won't work well unless the mating surfaces are flat and smooth. I have never done that, and I know others here have, so would wait for their input as to the best method unless you have already researched that and have that covered.

I would seal the back of the final product whether using wood or MDF for the plaque, just to keep moisture out. Both weaken if moist, with MDF weakening severely. Spray can poly wood coating should serve this purpose nicely, altho brush or a wipe-on (thinned brush on mix) would be cheaper. A couple coats is all you need.

Go


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## drewnahant

the T-nuts are great, but I have had problems using them in MDF. if you keep the teeth as shown, you significantly weaken the mdf, and often create bumps of displaced mdf fibers, and mdf does not hold epoxy well because it has no penetration, and mdf delaminates so easily, the top layer which is glued just peels off. maybe others have figured out how to use these, but I gave up on them. I would set up a template and use a router with a bushing base to hollow out an area big enough for your hanging anchors, and the antler attatchment as well in the mdf, 1/2" deep should be about right. then you can cut a piece the same size and glue it in with slightly dilluted wood glue to aid penetration, I would actually do this from the front if you plan to veneer over it anyway. as for level hanging, I have found that using two sawtooth hangers, both angled up toward center works well. by angling the hangers, you give an easy leveling method, if you move it left or right, you are moving up one, and down the other, tilting it slightly. ( install them like this, but a much lower angle / \ )


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## antlersonly

mikef
Sorry it took me so long to reply. I ended up using the following to secure the mirror hooks to the back of my MDF plaques:

Heavy duty mirror hook - one that allows 2 screws
Sheet Metal Screws - Pan Head - Phillips
#6×5/8 (since the board is 3/4 and I wanted to penetrate as far as possible)

Rather inexpensive and simple to attach


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## gwiener

Check out This guy: Hangman Products at www.hangmanproducts.com

He has a great assortment of trick hanging fasteners, including a double headed screw.


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