Custom MDF door frame

[phatboy]

Thanks for the advice chief.
If they are indeed rated at 120kg I'm inclined to glue 2x18mm MDF sheets (~60kg) for a thicker sturdier feel. Not sure what you guys think about that?
Cheers

You may struggle getting the screws to bite in the end of mdf. I did 1 18mm thickness of MDF for a loft hatch, and a year later I opened it and it came crashing down as the 50mm screws tore out. And that's a hatch thats opened once a fortnight at most.

 

[Mr Chibs]

Think I'd go along with phatboy, with that weight it's going to be difficult to keep screws in mdf.

I think I'd make a frame out of something like 25x50 (layed flat, possibly 25x75 on the hinge side) with 2 or 3 middle rails (going straight across, very simplified torsion idea) then use D4 wood glue to bond onto frame 12/15mm mdf/ply... yes you'll have a thicker door, but you'll have something with decent timber you can screw into.

I'd use rawl plug frame fixings to attach frame to wall, I'm not a fan of masonry screws, (no plug) if you overtighten they are then loose.

Just my ten pen'th.

Let us know how you get on, post some pics.

 

[Gerrydelasel]

I'm thinking of sacking the whole MDF door jamb idea and just getting some good timber, which will probably accept the hinge screws better as well.

You can use MDF for smoothness and convenience, but glue some timber behind the jambs for extra screw bite-ing-ness. I've made a couple of doorframes this way.

 

[paulrockliffe]

The way to avoid screws pulling out is to use machine screws instead. MDF taps a thread brilliantly and gives a very good fixing, certainly better than anything you'll achieve with screws. If you have to use screws, plasterboard screws are better than wood screws. But use something with a thread on it.

 

[CrazyFool]

You may struggle getting the screws to bite in the end of mdf. I did 1 18mm thickness of MDF for a loft hatch, and a year later I opened it and it came crashing down as the 50mm screws tore out. And that's a hatch thats opened once a fortnight at most.

Think I'd go along with phatboy, with that weight it's going to be difficult to keep screws in mdf.

I think I'd make a frame out of something like 25x50 (layed flat, possibly 25x75 on the hinge side) with 2 or 3 middle rails (going straight across, very simplified torsion idea) then use D4 wood glue to bond onto frame 12/15mm mdf/ply... yes you'll have a thicker door, but you'll have something with decent timber you can screw into.

I'd use rawl plug frame fixings to attach frame to wall, I'm not a fan of masonry screws, (no plug) if you overtighten they are then loose.

Just my ten pen'th.

Let us know how you get on, post some pics.

Thanks for the insightful comments fellas

I like the frame idea, but I fear the door will become too thick.
25mm timber rib + 10mm MDF face + 10mm MDF face
= 45mm
:S

Instead of screwing into MDF end grain what if I drill some holes on the edges where the hinges will be and glue some dowels.
I can screw straight into the dowels.
This way I'm not screwing into the mdf end grain.

Yes, I will be gluing into the end grain of the dowel but it can't split as any splits will only wedge the dowel into the MDF.

What do you guys think?

Here's an interesting video on screwing into MDF end grain:

Cheers

 

[Gerrydelasel]

I like the frame idea, but I fear the door will become too thick.
25mm timber rib + 10mm MDF face + 10mm MDF face
= 45mm

Too thick for what? I prefer regular-sized doors to be ~40mm thick, so 45mm for an imposing 8 foot door sounds about right to me...

 

[CrazyFool]

Hi guys.

I'm picking this project up again. Thanks for all the great advice.

I was getting ready to make the torsion box but then realised I need an offset lip for both doors to meet in the middle.
This is going to be really awkward with a torsion box.

If I glued together 2 x 18mm MDF sheets the lip would be perfect however I understand that the hinge screws wouldn't bite into the side of the door.

How do you guys feel about doing the above, and drilling good quality 25mm dowels into the side of the MDF where the hinge screws would go?
Would that solve the problem?

If yes, any recommendation on dowel thickness and type?

Thanks again

CF