Reptile & Amphibian Forums

3/4 MDF

Drilling Pilot Holes 2 inch screws

Using some sort of bracket on each end of the shelf

Using a router to make slots in the sides of the MDF to allow the shelf to slide in

Some kind of adhesive

Attaching a solid back, and drilling pilot holes screws along the back of the of shelf and sides

Those are just a few ideas Ive had, not sure what the most common one is...

Any of the ways mentioned could be used. I personally use the first, drill pilot holes, but I don`t use over 1 5/8" drywall screws on the 3/4" stuff. For 1/2" mdf I use 1 1/4" screws. I have built racks and cages out of mdf, and am pleased with both. The main thing is drill your pilot holes to match the length of your screws and don`t over tighten the screws. If you over tighten the screws, that is when you will have trouble with splitting the mdf. Go to www.finegtps.com and look at how he builds his cages, I use a modified version. I do agree with Chris Harper who points out that contact paper isn`t what it used to be. But I have used and still use it, it is a cheap way to water-proof cages. But I haven`t tried the contact vinyl everyone is talking about, I can pick-up the contact paper at Wal-mart. By the way, I used a lidded rack system, don`t have to waterproof the mdf when using lids. Just my 2 cents.

Vampire

Here is some pics, 1st is a MDF 4' X 2' cage for my A. p. conanti, 2nd is stack of MDF cages 24" X 12" X 12", and last is a MDF lidded rack for juvie Agkistrodon. Please excuse the mess, they are empty and need cleaning.

Vampire

The best way would to be to combine many of the methods you mentioned.

One trick I learned on a woodworking forum for MDF is to drill pilot holes in both panels. In the case of a rack, having a counter-sunk area on the shelf helps prevent splitting as it gives and area for the MDF to expand into. Works well.

I think confirmat type screws work well for MDF, but you should double check.

So...

1) 3/4" MDF

2) Dados (not absolutely necessary).

3) Predrilling pilot holes in both the side and shelf.

4) Confirmat style screws (double check to see if recommended for MDF).

5) Either standard yellow glue or polyurethane glue.

6) A solid back (only necessary for a larger rack).

Personally I think all of the above would be overkill, but you did ask for the best way.

Great, thanks for the response. I did read on a fastener website that confirmat screws were best for MDF, but I will double check.

I "may" lean away from using glue, as any sized shelf of MDF will be somewhat bulky and heavy, and I would rather have the option of easy disassembly.

thanks again!

If you're thinking no glue then you might use some knockdown hardware of some sort. I think Rocker sells some.

I would also use dados and a back panel (also with dados) if you're thinking no screws.
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Current snakes:

1.1 Gonyosoma oxycephala - (Silver/Yellow)

2.2 Gonyosoma oxycephala - (Green)

4.3 Gonyosoma janseni - (Black)

I was always told that the only purpose for nails and screws was to hold the wood in place until the glue dries.

The most important part of using screws is the pre drilling. If you are screwing into a shelf through the cabinet side, your should drill a hole through the cabinet side (shank hole) big enough that the screw will slip through without touching. That hole should be counter sunk. For 1 5/8 #6 drywall screw, that would be a 3/16" dia hole. There should then be a hole drilled in the end of the shelf (pilot hole). This should be of a size that the threads of the screw will engage the wood but the shank of the screw just touches. Again, for a #6 drywall screw, this would be a 7/64" diameter hole. This hole shold be as long as the screw so the screw won't bottom out.

The thing that causes MDF or any wood for that matter to split is because you are trying to force a screw into a place where there is no space for it. Something has to give. If you predrill first you will never split a board.

Another thing I like to do with MDF, is put some Tite-Bond glue on the screw itself. Then as the screw cuts through the wood the dust and particles you create will be glued back together and will form "threads" in the wood you screwed.
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Wade's Weptiles & Wodents

Thanks for the exact numbers Wade!

So I would drill a bigger hole in side so that it doesnt really grab at all, but then grabs into the shelf...

I definitely want to be able to take it apart in 4 years, unless by then the lifetime of the wood would be exceeded for a rack.

"So I would drill a bigger hole in side so that it doesnt really grab at all, but then grabs into the shelf... "

That's right. Then when you tighten the screw it will pull the side tight to the shelf.
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Wade's Weptiles & Wodents

Is the best way to make a dado to use a router and make the groove?

I only have a circular saw, dremel, jigsaw, drill at the moment, so anything fancy like that would be rough (though a good way to do it! Especially in 3/4 MDF

If i forgo the dados and the glue, do you think the screws alone would be enough to hold it together, especially with a solid back and a few thin boards nailed down the front for support?

Thnx

If i forgo the dados and the glue, do you think the screws alone would be enough to hold it together, especially with a solid back and a few thin boards nailed down the front for support?

I doubt it and certainly don't recommend it, especially if this is a big rack.

So we've gone from that entire list being "overkill", to taking out 2 components and it not being enough.

Would dados, screws, solid back to screw the shelves into, boards down the front to support the front in 3 places be enough?

>>So we've gone from that entire list being "overkill",
>>to taking out 2 components and it not being enough.

It's just that you took out two important components, at least for a large rack that you want to be able to disassemble and put back together if needed.

>>Would dados, screws, solid back to screw the shelves
>>into, boards down the front to support the front
>>in 3 places be enough?

For how large of a rack? I don't remember everything you have posted, but you seemed undecided but leaning towards a large rack.

Are you still leaning towards MDF with confirmat style screws? If so, I'm uncertain because I have never used confirmats in MDF.

In fact I question the ability of any sized MDF rack to be able to witstand being taken apart and put back together more than once.
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Current snakes:

1.1 Gonyosoma oxycephala - (Silver/Yellow)

2.2 Gonyosoma oxycephala - (Green)

4.3 Gonyosoma janseni - (Black)

One trick I learned on a woodworking forum for MDF is to drill pilot holes in both panels.

I don't think the above really explains what I meant. Typically when you predrill a hole you countersink an area for the screw head to fit into. It forms a conical shaped hole of sorts in the side of a rack (we'll say rack for the sake of this discussion). It allows the screw head to fit flush or slightly below the surface of the panel.

But with MDF some professional woodworkers take the extra step of countersinking the other hole as well (the hole in the shelf of the rack for the sake of this discussion). The reason being that when the screw is tightened the MDF distorts and the joint can separate. The countersunk area in the shelf gives space for this distortion to ocurr without pushing the boards apart.

I have not tried this myself and I don't know if it's also recommended for confirmat style screws.

Countersink the bottom hole as well. It sounds strange, but as you tighten the screws, the mdf distorts (pulls up) and will separate the joint. The countersink on the bottom piece creates a space for this distortion to occur without pushing the boards apart.