Working with Melamine MDF Panels

[Greatwhitewing]

I want to fabricate "cabinet like" boxes from single sided 3/4 melamine MDF panels with smooth surface inside. Top and bottom panels about 60x33 and side panels about 36x33. I want to use 1/4 melamine for rear panel again with smooth surface inside. I am probably going to use 1x4 PVC trim boards for a traditional face frame. I need these boxes sealed well at all the internal seams. These will need thorough cleaning with wet cleaning rags often.

Like ideas for how to seal and fasten this project. I need to make about 9 of these boxes.

One idea I had was a good silicone sealer at the joints, let it squeeze out and fillet the internal corners and fasten with screws. Concerned about the pull out of screws into the sides of MDF panels. I am not too concerned with external appearance so pocket screws on the outside of the boxes are acceptable if they hold.
Would I be better off with PL construction adhesive and silicone caulking the seams? The most structural stress these will see is transporting into position where they will be stacked in various configs and fastened together.

Not sure what to do about doors yet but will have to have something like a 1/2 wire mesh for ventilation.

Side question- would I be better off using traditional plywood and applying a durable epoxy or polyurethane finish?

Thanks in advance for your advice

 

[kyrbz]

Melamine is never going to last long exposed to moisture. I would use “MDO” plywood (medium density overlay) also referred to as sign board. It’s resin impregnated with a smooth paper surface. It’s designed to last for years outdoors. Typically it comes in 1/2” and 3/4” with paper on 1 side or 2 sides. I would biscuit or domino your glued connections. It helps with proper alignment and adds strength to your boxes.

 

[Greatwhitewing]

I don't think I will need this too long, maybe 5 years. Tried to find someplace within 100 miles to buy that MDO and so far no luck.

Thanks

 

[The Cobbler]

MDF doesn't hold screws well in the "end grain " maybe use some thin gauge angle on the outsides so you can screw into the field of the MDF for better hold of the screws

 

[Greatwhitewing]

MDF doesn't hold screws well in the "end grain " maybe use some thin gauge angle on the outsides so you can screw into the field of the MDF for better hold of the screws

Never worked with MDF but that was my impression that it wouldn't hold well in the end grain.

 

[jar944]

I've not seen mdf core melamine.

 

[mike93lx]

I've not seen mdf core melamine.

Me neither, also never single sided melamine.

 

[Greatwhitewing]

I've not seen mdf core melamine.

This doesn't specifically say one side only. This is what I was looking at

Veranda 3/4 in. x 4 ft. x 8 ft. Melamine White Particleboard Panel 461877 - The Home Depot

Melamine White Panel is ideal for making cabinet carcass, desk tops, closets, store fixtures and furniture. Easy to maintain and clean.

www.homedepot.com

 

[mike93lx]

This doesn't specifically say one side only. This is what I was looking at

Veranda 3/4 in. x 4 ft. x 8 ft. Melamine White Particleboard Panel 461877 - The Home Depot

Melamine White Panel is ideal for making cabinet carcass, desk tops, closets, store fixtures and furniture. Easy to maintain and clean.

www.homedepot.com

Ah, yeah, that is particle board, not mdf.

 

[Greatwhitewing]

Ah, yeah, that is particle board, not mdf.

So that's a false description? aka a lie?

 

[acer66]

I wouldn’t consider that lie just wrong wording.

Happens and in the description it actually says particle board and the pics also show particle board.

And like it was said before not that easy to work with and just the thought of moisture will make it crumble away.

 

[gungatim]

So that's a false description? aka a lie?

Yes.

 

[mike93lx]

So that's a false description? aka a lie?

Someone checked rhe wrong box. The description and pictures are all particle board.

Particle board is little chips, mdf is powder

 

[WoodsTruck]

MDF: multi density fiberboard

It is manufactured using several different size particles with the largest/coarsest material in the core with ever increasing smaller particles used on the faces to create a smooth surface.

 

[mike93lx]

MDF: multi density fiberboard

It is manufactured using several different size particles with the largest/coarsest material in the core with ever increasing smaller particles used on the faces to create a smooth surface.

MDF is Medium Density Fiberboard

 

[Greatwhitewing]

MDF is Medium Density Fiberboard

I do understand the acronym. Seems I might be better off using a marine grade plywood and a durable finish

 

[cgrutt]

I hate particle board and it's not a great choice with frequent exposure to moisture from cleaning. That said I would rabbet the sides at top and bottom leaving about 3/4" at top and bottom and rabbet the back of all pieces leaving about 3/8" and assemble with waterproof (resistant) wood glue and staples. Don't need to staple back but you can glue some small triangular shaped wood (such as quarter round trim) into exterior corners on back and top/bottom for added strength. Not sure if silicone is going to adhere to the melamine or not you're going to have to try it. Maybe a polyurethane sealant such as OSI or 3M 5200 will work better but they cost more than silicone.

 

[mike93lx]

I do understand the acronym. Seems I might be better off using a marine grade plywood and a durable finish

i was just correcting the previous poster.

what kind of environment will these cabinets be in? have you made cabinets before? purchasing prefab will save a ton of time and may not be materially different in price.

 

[Greatwhitewing]

i was just correcting the previous poster.

what kind of environment will these cabinets be in? have you made cabinets before? purchasing prefab will save a ton of time and may not be materially different in price.

The boxes would house small animals temporarily needing daily wet rag or squeegee cleaning in controlled humidity environment. Not a typical cabinet environment but far from hose down conditions. Maybe closer to a high volume restraunt environment.

Currently have regular plywood with a low VOC paint that *****

 

[cgrutt]

The boxes would house small animals temporarily needing daily wet rag or squeegee cleaning in controlled humidity environment. Not a typical cabinet environment but far from hose down conditions. Maybe closer to a high volume restraunt environment.

Currently have regular plywood with a low VOC paint that *****

Not sure what kind of animals you're talking about but I would think particle board would be a particularly bad choice for a variety of reasons. What about a plastic animal dog/cat crate?

 

[speed bump]

Melamine is fine for your application. Maybe silicone the corners if you are really worried about it. We have melamine lab surfaces at work that are 20+ years old and still look new.

When I build shelving or cabinets out of 3/4 melamine I rabbit it with a router, throw a little wood glue in the rabbit and **** it tight with some #6 fine thread wood screws.

 

[acer66]

Nice router and dust control setup.

Plus cool bikes, what is the year and model of the Kawasaki?

 

[wyb2]

Melamine is fine for your application. Maybe silicone the corners if you are really worried about it. We have melamine lab surfaces at work that are 20+ years old and still look new.

When I build shelving or cabinets out of 3/4 melamine I rabbit it with a router, throw a little wood glue in the rabbit and **** it tight with some #6 fine thread wood screws.

I would second this. That stuff will probably work fine if you seal the seams. As mentioned, particle board has terrible water tolerance, but the melamine veneer is reasonably water resistant, so you just need to keep water away from the exposed panel edges.

I’ve been using the same stuff as a countertop in a trailer and it’s been fine. It doesn’t get constant abuse, but I’ve had condensation from a cold drink sit on it for hours without issue.

If you go with plywood, don’t waste money on marine ply, focus on finding a waterproof finish. I would use boat epoxy because that’s what I have, but I’m sure there are other options. The selling point of marine ply is its resistance to rot/delamination when soaking wet. It sounds like for sanitation reasons you want the boxes to not soak up water in the first place.

 

[WoodsTruck]

I stand by my definition. We used to have a division of our company that made this product. Toured the mill and watched it being laid down.
Note the texture differences from face to face of the product.

 

[wyb2]

I stand by my definition. We used to have a division of our company that made this product. Toured the mill and watched it being laid down.
Note the texture differences from face to face of the product.

Sounds like your company made a product called multi density fiberboard.

The common usage of the acronym MDF that most people know is medium density fiberboard.

Medium-density fibreboard - Wikipedia

en.m.wikipedia.org

 

[cgrutt]

Sounds like your company made a product called multi density fiberboard.

The common usage of the acronym MDF that most people know is medium density fiberboard.

Medium-density fibreboard - Wikipedia

en.m.wikipedia.org

I think it's mostly semantics. Technically multi density fiberboard might be industrial terminology that includes what most people think of Medium Density Fiberboard (I don't ever recall it being called anything else) but also LDF and HDF (low and high density fiberboard respectively). There are other products that may fit here as well including fireproof boards and ultralight composites used for moldings, etc. I think we're all saying the same thing here.

 

[wyb2]

I think it's mostly semantics. Technically multi density fiberboard might be industrial terminology that includes what most people think of Medium Density Fiberboard (I don't ever recall it being called anything else) but also LDF and HDF (low and high density fiberboard respectively). There are other products that may fit here as well including fireproof boards and ultralight composites used for moldings, etc. I think we're all saying the same thing here.

Agree, semantics. Just pointing out that “medium” isn’t any less correct, and it’s what probably 9/10 people will picture in their heads.

Well 9 of the 10 out of 100 that will have any idea what you are talking about.

 

[The Cobbler]

googling MDF brings up Medium Density Fibre board.
googling Multi density Fibre board brings up medium density fiberboard
safe to assume MDF is commonly known as medium density fibre board .

 

[The Cobbler]

I stand by my definition. We used to have a division of our company that made this product. Toured the mill and watched it being laid down.
Note the texture differences from face to face of the product.

that to me is commonly known as particle board

 

[Greatwhitewing]

Melamine is fine for your application. Maybe silicone the corners if you are really worried about it. We have melamine lab surfaces at work that are 20+ years old and still look new.

When I build shelving or cabinets out of 3/4 melamine I rabbit it with a router, throw a little wood glue in the rabbit and **** it tight with some #6 fine thread wood screws.

Do you rabbit for glue surface area or to mill away the melamine for the glue? Both?

 

[mike93lx]

Do you rabbit for glue surface area or to mill away the melamine for the glue? Both?

Glue won't stick to melamine. Maybe there is an epoxy that would, though

 

[yhprum]

I have done several things to seal up the cut ends where water can get in.
Paint or varnish the edges
Run a bead of glue on it and rub it in with your finger. Let dry
This generally will stop water ingress unless it’s underwater. I like the idea of caulking any inside corners to further slow it down too.

 

[jar944]

I stand by my definition. We used to have a division of our company that made this product. Toured the mill and watched it being laid down.
Note the texture differences from face to face of the product.

Commodity mdf


Commodity particleboard


Commodity melamine with a particleboard core



Op, titebond and roo glue make melamine adhesive. confirmat screws are the industry standard for screwing melamine boxes together.

 

[macgyver37]

Agree with confirmat screws, they are engineered to be used in particle board.

My main concern at this time is the span of 60", will the top be supported in the middle at the front at all? At 30+" deep, I'd expect the top to sag before too long.

1/4" thick back is fine unless the animals get rowdy and it's particle board, I don't think that would be the best choice. An mdf core melamine 1/4" would be fine. Now, if the back is flat against a wall where it is fully supported to not allow any flex it shouldn't matter either way.

Also, pro tip, find a shop and or wholesaler so you can buy 5x8ft melamine. It will drastically improve your yield. You aren't going to get it at a big box store that I know of, but a commercial supply house will have it.

Idk where you are, but a couple examples would be Liberty Hardwoods in KC and Paxton Lumber also in KC.

I'd also run the exposed edges through my edgebander with 3mm. Seals it up and makes it nice to look at.

 

[Greatwhitewing]

Agree with confirmat screws, they are engineered to be used in particle board.

My main concern at this time is the span of 60", will the top be supported in the middle at the front at all? At 30+" deep, I'd expect the top to sag before too long.

1/4" thick back is fine unless the animals get rowdy and it's particle board, I don't think that would be the best choice. An mdf core melamine 1/4" would be fine. Now, if the back is flat against a wall where it is fully supported to not allow any flex it shouldn't matter either way.

Also, pro tip, find a shop and or wholesaler so you can buy 5x8ft melamine. It will drastically improve your yield. You aren't going to get it at a big box store that I know of, but a commercial supply house will have it.

Idk where you are, but a couple examples would be Liberty Hardwoods in KC and Paxton Lumber also in KC.

I'd also run the exposed edges through my edgebander with 3mm. Seals it up and makes it nice to look at.

I do plan to have a face frame on the front but it would only be PVC and only offer a little stiffness. These boxes would be stacked 3 high so except for the top one there would be TWO 3/4 panels which I can fasten together to get a 1-1/2" thick panel. Probably have a center vertical member of the face frame to keep the door size manageable. Bottom box would sit on a 3-4" high base to provide toe space like a cabinet.

I can add stiffeners to the back panels if the 1/4 MDF/Melamine panel is too flimsy. I can't get the "stack" firmly against the wall.

In my application any visible sides or edges where the MDF or fall-aparticle board would be visible isn't a concern but a trim panel is not out of the question.

When you say a 5x8' melamine are you saying a thin panel with no backing like a sheet of Formica?

Thanks for the 411 on the screws

 

[mike93lx]

Careful on the cut edges as the melamine will be sharp

 

[Greatwhitewing]

Careful on the cut edges as the melamine will be sharp

Like most us here, I assume, i far too often find my blood on my project not knowing I was even cut.

 

[macgyver37]

By melamine, I meant a sheet of particle board with melamine on both sides. In my world, that's standard when someone says melamine. Just brought it up as most people not in the commercial wood world know 5 ft wide material is available. It makes for much better usage of material than 4x8 when dealing with cabinet size parts. If you can't get it easily, it may turn into more drama than just using 4x8 that would be easier to get locally.

 

[Greatwhitewing]

By melamine, I meant a sheet of particle board with melamine on both sides. In my world, that's standard when someone says melamine. Just brought it up as most people not in the commercial wood world know 5 ft wide material is available. It makes for much better usage of material than 4x8 when dealing with cabinet size parts. If you can't get it easily, it may turn into more drama than just using 4x8 that would be easier to get locally.

Thank you for clearing that up. For my project I would prefer 3 foot wide panels to reduce waste

 

[rharman]

@speed bump - I was thrown by your description of using fine thread wood screws. In particle board? I was thinking something like Spax.

Just curious.