Wood is too expensive - use cardboard

[luvmytoolz]

Hollow core doors used to have honeycomb cardboard cores that were bonded to 1/8” thick plywood. They were a cheap and acceptable product.

But when I bought one severall years back, the honeycomb core was not bonded to the plywood skins, just placed inside and left loose.

The “plywood” skins were not plywood at all, but rather wood veneer over cardboard.

My mistake was using a water-based poly.. The water content must have penetrated the wood veneer and and caused the skin to bow inward so you could see the wood parts of the door telegraph through the skins.

Take enough cost out of a product you will be left with junk.

If the core wasn't bonded to the skin, someone definitely stuffed up and forgot the glue.

 

[Packard]

If the core wasn't bonded to the skin, someone definitely stuffed up and forgot the glue.

I don’t think so. I went back to the store and all the door skins flexed about the same. Also, look closely at the edges and you will see the cardboard with a wood veneer bonded to it for the skins.

I’d have to buy a new hollow core door to prove the point, but it is possible that they got so many complaints that they had to improve the quality. It could be that current production bonds the honeycomb to both skins.

I worked for a company that made SIPs (Structural Inslulated Panels) well before that term was in vented (1970 to 1974). They bonded cardboard honeycomb that had been treated for fire resistance, to aluminum skins. These panels were used for “3 season” rooms. Basically sun rooms with auxiliary heat. Light weight and durable, they made an excellent product.

Our completion made panels with foam interiors and wood structure and composition board interiors and exteriors. They were heavier, carried less weight, were more difficult to install, and their fire resistance claims were bogus (they used an inappropriate test for their rating as “self extinguishing”).

So I have great respect for honeycomb construction. And bonding it to the skins would have made a superior product. But I don’t think they ever intended to do that. I mean they were using cardboard for the door skins. Really?

 

[luvmytoolz]

The core is absolutely supposed to be glued to the skin in doors, otherwise you end up with the deformation described. These are usually done on an assembly line which produces consistent results in very fast time.

When I worked at Corinthian Doors, a major supplier country wide here, the doors would come out of the press at the end of the line as fast as we could stack them on the pallets as the process was so fast.

Made properly despite being as cheap as they are, honeycomb doors are amazingly robust when not abused.

 

[Packard]

Made properly despite being as cheap as they are, honeycomb doors are amazingly robust when not abused.

Yes, I’ve used older hollow core doors that had actual plywood skins, as portable tabletops on saw horses. Light weight and easily moved, these were ideal for light duty assembly. But the newer cardboard skins damage quickly, even if the manufacturer remembers to glue the honeycomb core in place.

This is another case where the buyer (Home Depot) puts so much pricing pressure on their vendors, that the vendors cut costs to meet that pressure. The result is that so much quality is cut from the product that it is rendered useless.

“When is a door not a door? When it only looks like a door at Home Depot.”

 

[smorgasbord]

I had a hollow-core door as my desk during grad school for years. I think it had a masonite/hardboard skin. Put in a corner with a couple of 2x4s and one 2x4 leg.

When I moved, I used it as a ramp for heavy things, mostly slid on blankets but even a dolly once in a while. It was my moving ramp for several moves. I forget what happened to it, but I don't think it got destroyed in such use.

Haven't moved in 30 years. The doors in my house are all solid wood with ball-bearing hinges. I do wish I had thought to put lightweight rubber strips on the mouldings for more sound-proofing (smallish house, hard surfaces) but as my son has moved out, not so much need anymore.

 

[rst]

The glazing company I’m part timing at selling hundreds of thousands of dollars fire rated glass to what used to be Masonite Doors and buys for the commercial jobs we do. Fire rated glass is ungodly expensive, a full lite door glass can be $900.00. Anyway, we receive the glass crated, protected by 1/2, 3/4, 1, or 2” corrugated sheets. We recycle the cardboard, but I save the large sheets for cutting with a track saw. They are also great for mats working on the ground whether auto or construction.