adauria

OK, my kids need one and I have lots of extra 1/2" MDF lying around. I have plans from a book that call for using bullnose stair tread for the 2 steps and 3/4" birch plywood for the sides. Instead of the plywood, I figured I'd try to use the MDF I have.

Question - Do you think I should substitute a single layer of 1/2" MDF for the 3/4" plywood for the sides, or would it be better to double up the MDF and have 1" thick sides? I have the material, just not sure how strong MDF will be in that situation.

For the record, the heavier kid is ~30 lbs, but I could see 50 lbs on there if both kids try to crowd each other.

-Andrew

adauria

Oh, I should point out that it looks something like this (at least the basic design with 2 steps and fat L shaped sides):

http://mommylife.net/step%20stool.jpg

The stretchers underneath each step are narrower than that on my design.

-Andrew

Gerry KIERNAN

I would be cautious about using mdf for anything that will come under a load. Doubled up on the sides it would probably be adequate. Keep in mind that mdf can break out quite easily because of the nature of the material. It is basically compressed sawdust, and has very little structural integrity. The plywood would be a much better choice. My other concern would be that even though the step stool is intended for children's use, sooner or later an adult is going to grab it and use it.

Gerry

adauria

Thanks Gerry. Maybe I will double up the legs with plywood, using the MDF for the outside of the legs and the plywood for the inside. Hmm... Need to give it some thought.

-Andrew

cabinetman

If I were making it for my kids it would be all plywood, or all solid wood.

frankp

Are these small children? Are they expected to be able to move it easily? I'd say use real wood just for the weight savings alone. MDF is really heavy and while great for things it's good at. I'd expect a step stool for children to be near sinks or toilets though, which would mean water. Water and MDF simply don't mix well. Just one more thing to consider.

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adauria

Thanks for the advice guys. I had already started the project before some of the recent comments. On thing I have noticed is that using MDF for the supports that run from one side to the other is a problem because it splits very easily when screwed on the end (at least 1/2" MDF does when using #8x2" screws). I tried replacing those parts with 3/4" plywood (CDX) but found that even that splits! I was able to control (not eliminate) the splitting by putting a few clamps around the piece when driving the screws and using a little soap on the threads. Anyway...

With the basic structure built I dry fit the treads on the frame and stood on it. I weigh 150 lbs and am the heaviest member of this family by far. Seems reasonably sturdy. More testing is in order, but I think it might be OK as is.

I plan to prime (2 coats) and spray paint it (2 coats enamel). Hopefully that will help with the water resistance.

The kids shouldn't have to move it, so I'm not too worried about weight (seems around the same weight as the one I bought in Target last year... maybe a touch heavier).

I will do more testing though, before I unleash it on my little daughters. If it needs re-enforcement, I'll do that. I'll post pics when done.

In any case, it may end up just being a good practice project for me. I had scrap I had to use. Win or lose, I'll come away with knowledge here.

Thanks again!

-Andrew

maplehillfrm

[quote=adauria;88371]. On thing I have noticed is that using MDF for the supports that run from one side to the other is a problem because it splits very easily when screwed on the end (at least 1/2" MDF does when using #8x2" screws). I tried replacing those parts with 3/4" plywood (CDX) but found that even that splits! I was able to control (not eliminate) the splitting by putting a few clamps around the piece when driving the screws and using a little soap on the threads. Anyway...



Predrill your holes , you can use a contersink / drill bit all in one and have the screws recessed,, that would eliminate your splitting, good luck with your project,pat

adauria

For those who want to see the final product:

http://tinyurl.com/nrks2f

-Andrew