Melamine

[Ned Trout]

First of all I'm too deep into this to rethink my choice of melamine. Having said that, these are storage shelve/boxes that are, roughly, 79" long, 12" deep and 15" tall. Each unit is divided by into 3 compartments. I have cut dados 1/2" wide by 3/8" deep into the horizontal pieces. Planning to cut corresponding tongues on the end of each vertical. I'm going to use Roo glue in those joints. My question is, should I add pocket screws to the joints? I built a smaller base and used only the glue and it feels pretty sturdy. Of course, it won't be subjected to the stresses that the upper units will. These are for the grandkids toy storage. TIA. Ned PS the end verticals are inset 2"

[handi]

I personally do not believe that pocket screws will add much if anything to your structure. melamine is terrible at holding screws.

If this is an upper shelf/cabinet, I would be more concerned with the hanging system. Having it mounted securely to the wall provides a LOT of the support of upper cabinets.

I would either go for a thick back and screw it to the wall studs or good cleats top and bottom.

Ralph

[Paul K. Murphy]

Glue.
No screws.

[Ned Trout]

Thanks for the responses. They won't be hanging. They will go on a base and sit on the floor. Toys will go on baskets. I hadn't given much thought to a back, but I might add one....sounds like a good idea. Thanks again.

[ruffcutt]

I've build a lot of stuff out of melamine. Conformat screws hold good in melamine.

https://www.quickscrews.com/catalog/conf...CFYdefgodQLII8A

[Ned Trout]

Thanks.

[Ruler2112]

Glue and nail a back on IMO. (A back provides a lot of rigidity that's otherwise lacking.)

[AzFred]

+1 for the Confimats for joinery and wood glue at board joints if you wish. I have no faith in gluing the Thermo fused plastic surface. Every brand of melamine glue fails on at least one board manufacturers product. JMHO

[Paul K. Murphy]

It's possible that it would be a good idea to talk a little bit about screws, and a little bit about particleboard.
By the way, with regard to your first question, I still think you'll be fine without screws.
Screws:
The tread on a screw is best viewed as a wedge. In the example of a screw, the wedge is wrapped in a circle around the cylinder of the shank of the screw. I don't intend to get into the niceties of thread pitch, but please understand I'm trying to compare apples to apples. Reasonable readers will know that thread pitch is a variable worthy of their consideration.
Confirmat screws, and 5 mm System screws were developed for use with particleboard. They can be used elsewhere, but their chief virtue is the ability to join particleboard well.
If you were able to unwrap the thread from a screw's shank, the larger diameter of the Confirmat, or System screw would be a long thread. They also do not diminish to a point. This means that the calculation diameter times pi is consistent throughout the threaded portion of the shank. It isn't reducing to zero as the screw tapers to a point. Bottom line: the engineers tweaked the screw's anatomy to cram as much thread in as possible.
Particleboard:
Looking at it with a magnifying glass, the material looks like Corn Flakes, stuck together with molasses. A small screw, fastening something to this material is pinpoint in its precision. It zaps into one or a few of these little Corn Flakes chips. It's local; limited in what it ever grabs a hold of. If that particular flake fails, the attachment fails.
The larger diameter of a Confirmat or System screw distributes the purchase of the screw to a broader area. More has to fail (more or less simultaneously) for the fastener to fail.

[Admiral]

I lined my master bedroom closet with melamine "boxes" for storage, and larger ones for hanging shirts, suits and dresses, and used the Confirmat screws, no glue, and they are solid as heck 6 years later. I also used a back, which I think gives it the rigidity it needs. Those screws worked well.