help with enclosure plan

rwg · 12-31-03, 04:16 PM

Hello all,

I'm thinking about trying my hand at building an enclosure. I'm going to base it on HetForHuman's melamine design (http://www.ssnakess.com/forums/showt...threadid=25282), but I'm going to need some advice on a few things.

First of all, he (she?) lists the litter dam cuts as being 2 1/2" X 18 ", and I'm pretty sure the 18 should be 36 right?

Next, I'd like to use plywood rather than melamine. Any idea what thickness I would need to do a 36" x 18" x 18" enclosure? Also are plywood thicknesses accurate in canada? I know lumber depends on wether it's rough or planed, and since the floor cut has to correct for the thickness of the end walls, I really need to know this one.

Plywood grade: My plan is to use a crappy grade, but trowel in some wood filler to smooth it out to make cleaning easier. Anyone see a problem with this?

Finish: what kind of paint should I use? I'm not completely sure what I want to house in it yet, so I'd like something that will hold up to humidity.

My plan is to seal and paint all pieces before assembly, and then screw and silicone together.

Glass tracks: How strong is silicone for gluing in the tracks? I would like to make sure my 2 year old is not capable of pushing the glass and tracks in too easily. I guess I could just use some screws in the bottom of the track, and sink them well so they dont scrape against the glass.

rg

MistyDaze · 01-08-04, 02:00 AM

By the time you fork out for paint, sanding sealer, putty etc, it will be cheaper just to go with melamine and cheaper yet (particularly if you want to paint it) would be MDF. The thinner sizes of plywood are pretty hard to get flat/strait over any decent area so you probably need to be looking at the 15-18mm thickness. I don't know about Canada but the possible (but unlikely) 1mm difference between sheets in your case is irrelevant. Litter dams? Just use a bit of common sense for this one. The idea is to plan your cut list to get as many cuts from the one sheet as possible, so make your plans around this.

rwg · 01-08-04, 01:08 PM

After pricing out some materials, I'm looking at melamine after all. It's just cheaper. I never thought about using MDF. How is it to work with?

rg

Linds · 01-08-04, 03:48 PM

MDF is the same as melamine, only uncoated. I hate melamine for just about everything. The only pro to it is convenience (you can skip out on applying a finish).
I used OSB to build <a href="http://www.ssnakess.com/forums/showthread.php?s=&threadid=27408">my enclosures</a>. It isn't the best due to all the little nooks and crannies (could be fixed), but it works fine and the price is more than fitting

If I had a bit more to spend I would have chosen an exterior grade plywood. If you want something suitable for humid environments, and something with long-lasting durability, stay away from urethanes. You can use a marine enamel or an epoxy. Epoxies will give you a hard-as-nails finish that can hold water, instead of just providing a degree of resistance.
I wouldn't use silicone as a bonding agent, but rather as a finishing sealent. Carpenter's glue is stronger than anything. I would assemble the enclosure using a combination of screws and carpenter's glue (the screws mainly act to clamp the pieces together).
As for the glass tracks, I only have one enclosure with sliding glass so I can't comment on which method is best for that. I've heard people use both methods.
5/8" would probably be a good choice to go with in terms of thickness for that type of enclosure. You could go a bit thinnner, however I would try to stay above 1/2".

MistyDaze · 01-08-04, 07:04 PM

You can find MDF coated with melamine but most melamine is chipboard, totally different material. In the event that you do find it it's usually more expensive because MDF is a very stable substate (meaning because it is not made of wood you get very little movement within the material) thus when veneered with timber or melamine the product is more stable and delamination is not an issue. Normal MDF is fine to work with and painting gives you a perfect finish (very smooth, no preparation required). It comes in all the stardard thicknesses and it is cheap. Unless you want it to hold water or very high humidity, polyurethane clearcoats will work fine (marine spar is used to seal decks on boats so this will well and truly stand up to regular misting) and plural component urethanes are much harder than standard urethanes, you can even get polyurethane that will set-up as a solid hard plastic like your computer case.

Invictus · 01-08-04, 08:00 PM

First off, MDF is NOT the same as Melamine. Melamine is particle board. MDF is fibreboard. The difference is, MDF is literally dust and glue, where as Melamine has larger paritcles from various hard and softwoods and glue.

MDF is way heavier, and in my opinion is an absolute waste of time, because it won't even hold a particle board screw. I have built things from MDF before, and if you try to put a screw into it and put any pressure on it whatsoever, it will fall apart even easier than melamine. Sometimes it may hold a nail though, but you still have to be very careful.

As for the silicone, I use 100% pure rubber silicone for my cages, including on the glass tracks, and they are about as steady as you can get. Wood glue doesn't work very well because you're gluing plastic to wood - it becomes brittle and will flake apart with no effort. Same goes for model glue, except it won't adhere to the particle board correctly. Silicone is your best bet.

For waterproofing, I'd recommend Epoxy if you do go with MDF or plywood. That creates a seal that is harder than plastic. Failing that, Marine Enamel is great too, but takes a long time to dry and stop offgassing, and is extremely expensive.

For thickness, I agree with Linds - 5/8" for anything over 2 feet on any dimension. This also gives you enough width, if you are working with melamine, to drive in a particle board screw without the wood splitting. Remember to always ALWAYS predrill!

Hope this helps.

MistyDaze · 01-08-04, 09:50 PM

OK, here are some links so you can verify this yourself. These links are from the companies that make the material.

QUOTE: In general the screw holding strength of MDF is at least two times higher than in normal particleboard, in some cases it is nearly the same as in some wood species.
SOURCE: http://www.hochstrate.de/micha/reports/repmdf.html

Check this site for a guide to correct screws, pilot hole size and screw gauges for the different MDF thicknesses.
http://www.cullitytimbers.com.au/prod_mdf.asp

I agree that MDF is heavy but epoxy just like polyurethane comes in a variety of hardnesses.

Lisa · 01-10-04, 11:09 PM

Personally I like melamine, it's prefinished and easy to work with. I know when I did BJ's cages (oak) I spent about 4 times the amount of time and work on them then I do on melamine cages.

MacGyver · 01-14-04, 10:19 PM

Invictus, I dont agree with you on the MDF not being able to hold a screw. I've built speaker boxes out of MDF for years and have never had a problem with it coming apart when screwed. The key is to make sure that you pre-drill the holes properly and do not try and overtighten them.

rwg, I build my BCI enclosures out of melamine with great success Here's a pic them

Will