Stand material suggestions needed

[Kevin Stanford]

Hey my name is Kevin and I'm working on a project right now.

The stand will be made with cinder blocks and a board on top, this way it is easily movable which is nice because I will have to move this from my house and my dorm. There are 3 8x8x16 cinder blocks stacked on top of each other, and another 4x8x16 cinder block on top of that. This will reach a total height of about 26". Then there will be a board on top of that.

The designs of the board I attached as an attachment. As you can see, there will be two 5.5 gallon fish tanks over it, they will weigh roughly 50 lbs each. There will also be holes that will be drilled into the board for the plumbing and airlines. The two tanks are sitting centered on top of the cinder blocks so most of the weight should be on the cinder blocks.

So my question is, what material shall I use for the board? I was thinking 3/4" plywood, but then someone suggested I use MDF instead because that will lead to cleaner edges for both the sides and the hole. Also he said that MDF is more rigid then plywood which is what I need here. The only problem is I need a way to seal it to protect it from saltwater and freshwater. So what material do you suggest and how would you seal it?

Thanks

EDIT: Oh i just realized i didn't attach it, why didn't anyone mention it?

[Jamie Buxton]

Plywood would be a better choice than MDF. Your friend is wrong about the relative stiffness: plywood is stiffer than MDF of the same thickness. On top of that, MDF behaves badly if it gets wet. It swells, comes apart, and generally turns to mush.

If you use plywood, you can varnish it or paint it to give it some protection from spills.

[Kevin Stanford]

Okay thanks, what about the edges and holes

[John Schreiber]

Okay thanks, what about the edges and holes

+1 on MDF being a bad choice anywhere near water. It swells up and flakes and looks awful.

The edges of plywood will look like plywood, but you can cover that with iron on wood tape or you could add a hardwood edge which would also add strength.

Actually, if you are building with cinder blocks, the appearance of plywood edges won't be your major aesthetic concern.

Your design looks like it will handle the weight of the tanks just fine, but I would worry about lateral forces. What if someone bumped into the table from the side? If the floor is flat and the blocks are heavy, I think it would be ok, but if there's carpet under the blocks it just might be too tippy.

Most of my college furniture was built from milk crates, so that looks stronger than my approach.

[sean m. titmas]

to give the stand a little insurance against falling over you should use a plywood base that is slightly bigger than the footprint of the two CMU stacks. attach 2 lengths of 4x4 to the plywood base so that you can thread the CMU's over the 4x4's. cut the 4x4 so that they are flush with the top of the CMU stack. than you can screw down through the top board into the 4x4. this will make the entire stack act a one unit.

depending on your budget for materials you might want to consider MDO or MDX which is water resistant MDF. it goes by the brand name of Extira.

http://www.extira.com/

for a finish you might want to use a good quality marine varnish on top of a pigmented base.

[Shawn Pixley]

+1 to Sean's advice about the 4X members through the cores of the CMU. Consider Marine Ply around the Aquaria. If this were to be more permanent, I'd suggest glassing and creating a "tray" for the tanks. Raised sleeves for the penetrations.

[Kevin Stanford]

@John Schreiber Thanks for the iron on wood tape suggestion, I will probably do that. You need an iron for this correct? because the heat makes it bond, so what would I do for the holes then? Also haha, cinder blocks don't look THAT bad :P

@sean m. titmas Well the reason why I close cinder blocks is so when I then need to move this stand, I can take the top board off, and move each cinder block on it's own, therefore easy to move from house to dorm. Attaching everything together would increase the strength laterally, except it would cause it to be a much bigger hassle to move. Thanks for the suggestion of Extira, do you have any idea around how much a 2'x4' .75" MDO or MDX costs? Marine varnish would work.

I have another question though, I was thinking of using a garage floor epoxy such as the http://www.rustoleum.com/Product.asp...ct_id=56&SBL=1 to seal the plywood, would this work also or am i better off with the marine varnish?

[sean m. titmas]

@sean m. titmas Well the reason why I close cinder blocks is so when I then need to move this stand, I can take the top board off, and move each cinder block on it's own, therefore easy to move from house to dorm. Attaching everything together would increase the strength laterally, except it would cause it to be a much bigger hassle to move. Thanks for the suggestion of Extira, do you have any idea around how much a 2'x4' .75" MDO or MDX costs? Marine varnish would work. or am i better off with the marine varnish?

krvin,

4 screws to prevent the the possible loss of a couple hundred $ is not that big of a hassle. in the end its your decision but speaking from experience you should seriously reconsider the 4 screws.

check with your local building supply house (not home despot or lowes) and ask for pricing. all things considered its not that expensive.

marine varnish is the best choice for a number of reasons,
1 inexpensive compared to epoxy
2 easy to apply
3 performs exceptionally well under harsh environments

if Extira is not available than regular MDF with 2 coats of varnish will hold up just fine under the abuse you plan for it.

[Kevin Stanford]

krvin,

4 screws to prevent the the possible loss of a couple hundred $ is not that big of a hassle. in the end its your decision but speaking from experience you should seriously reconsider the 4 screws.

check with your local building supply house (not home despot or lowes) and ask for pricing. all things considered its not that expensive.

marine varnish is the best choice for a number of reasons,
1 inexpensive compared to epoxy
2 easy to apply
3 performs exceptionally well under harsh environments

if Extira is not available than regular MDF with 2 coats of varnish will hold up just fine under the abuse you plan for it.

Alright and do I need primer for this? or just straight varnish, and could I paint it a color over it?

So which one of these would I need then
http://www.rustoleum.com/CBGProduct.asp?pid=4
http://www.rustoleum.com/CBGProduct.asp?pid=8
http://www.rustoleum.com/CBGProduct.asp?pid=7
http://www.rustoleum.com/CBGProduct.asp?pid=6

seams the first, topside paint is the best choice

[sean m. titmas]

Alright and do I need primer for this? or just straight varnish, and could I paint it a color over it?

So which one of these would I need then
http://www.rustoleum.com/CBGProduct.asp?pid=4
http://www.rustoleum.com/CBGProduct.asp?pid=8
http://www.rustoleum.com/CBGProduct.asp?pid=7
http://www.rustoleum.com/CBGProduct.asp?pid=6

seams the first, topside paint is the best choice

the marine varnish is more than adequate. and you can paint it first than seal it with the varnish.

[Eric Sutton]

Kevin,

What about adding a second shelf for added lateral strength? Perhaps a smaller shelf than your top could be placed between the second or third blocks to help tie the two towers together? You would also get an added bonus of storage space for your supplies and equipment.

[Marty Paulus]

When checking on the pricing consider spar urethane. This can be bought at the borg. I think I just got a quart for about $15 as compared to marine varnish at over $30 a quart at the marine supply store. Keep in mind that any time you attach the word 'marine' to anything it inceases the price by at least 50%.

That being said why couldn't regular varnish or urethane be used? I am sure those would be more then adequate for the 'temp' furnishings here. The stand will not be outdoors in the sun, wind and rain so why spend the extra money on a finish when it can be better spent on school supplies?

[Kevin Stanford]

Kevin,

What about adding a second shelf for added lateral strength? Perhaps a smaller shelf than your top could be placed between the second or third blocks to help tie the two towers together? You would also get an added bonus of storage space for your supplies and equipment.

That's a pretty good idea, I'll look into that actually

@ others, I don't want the protective coat to be clear, I was hoping the finish would be a flat smooth color