Tall MDF doors

[n0legs]

Some comments and advice please folks.
I need to make two doors 2.4m high by 450mm wide. They are to have sand blasted acrylic panels inset to make them opaque.
The doors need to have a high gloss finish applied by spray painting to continue a fitted wardrobe project for my daughter. All the furniture is high gloss.
I intend on making the doors with mortice/mortise and tenon (panel door joinery) construction.
My issue being, would 25mm thick MDF be up to the job over such a long length. I've made a few MDF doors this way in the past but not this length.
I've considered timber but it's the finishing of timber that concerns me, I don't want any grain showing through the paint.

 

[Drudgeon]

I've always found 22 or 25mm MDF is more than adequate for these length of doors, but I'll try to use a panel of minimum 9mm or maybe even 12 and rebate the back of the panel, although if you are using acrylic, I guess you will have a 6mm panel?

 

[n0legs]

Hi Drudgeon.
It's going to be either 6 or 10mm acrylic, depends if I can get a half sheet, but in half in the long dimension rather than across the sheet. Most of the people I've spoken to offer a 1200 x 1200 sheet in 10mm but not the other way.
Would you think gluing in the acrylic, to try and make it structural a good idea ?
What about 3 maybe 4 hinges over the length ?
Thanks for the reply.

 

[Drudgeon]

I think the 10mm would be ideal, and if it was me, then yes I would use a silicone (clear) to glue the panel in place.

As for hinges, assuming you are using concealed type hinges, (Blum/Grass etc) I would use a minimum of 4, on a 2.4m door, perhaps even 5.

Would be interesting to hear others' views, but that is what I would do.

Really like the idea of the acrylic panels though, sounds great.
Dan

 

[katellwood]

What are the widths of stiles and rails?

 

[n0legs]

I think the 10mm would be ideal, and if it was me, then yes I would use a silicone (clear) to glue the panel in place.

As for hinges, assuming you are using concealed type hinges, (Blum/Grass etc) I would use a minimum of 4, on a 2.4m door, perhaps even 5.

Would be interesting to hear others' views, but that is what I would do.

Really like the idea of the acrylic panels though, sounds great.
Dan

I like the idea 5 hinges and yes they will be Blum ( clip/screw on kitchen cabinet ) type hinges.
The acrylic panels are the girls idea and to be honest I think they will look great. Fairplay she has got pretty good taste.

 

[n0legs]

What are the widths of stiles and rails?

Hi Katellwood, Probably around the 120mm mark for stiles and rails at around 150-180mm. I don't really fancy going any narrower, but I am open to suggestions.
Thanks for the interest.

 

[mailee]

i agree with the above. I have made large MDF doors in the past and used 22mm MDF. Anything over 2mtrs and I use 5 hinges per door. Should work fine with loose M&T's and the acrylic panel silicone'd in place. :wink:

 

[n0legs]

i agree with the above. I have made large MDF doors in the past and used 22mm MDF. Anything over 2mtrs and I use 5 hinges per door. Should work fine with loose M&T's and the acrylic panel silicone'd in place. :wink:

Hi Mailee, thanks for the input.
I'm feeling a lot more confident about using the MDF and I'm pleased to hear the hinge suggestions.

 

[chippy1970]

I've got some 2200 x 600 panel doors on my own wardrobes that are 18mm and have been fine. I built them with 18mm mdf stiles and 6mm mdf panels years ago before I went over to using 22mm. I will admit they were floppy on the bench but when fitted with 4 concealed hinges they are perfect.

So your 25mm ones will be fine.

 

[n0legs]

Well here's an update about these doors.
I got some 25mm MDF cut and machined up the stiles and rails. Jointed using the loose tongue method ( I think JasonB's idea/method ??)
I bought some 10mm thick clear cast acrylic (Trent Plastics absolutely excellent service, delivered in 2 days from order and came very well packed without any marks)
One side was sanded with 180 grit discs to get the level of obscurity my daughter wanted, we practised on some offcuts.
The doors were primed with 2k high build primer, flatted down to 800 grit and I sprayed them this weekend with High Solids 2k paint. they were allowed to air dry in the spray booth. On Monday morning I gave them a light flat and polish.
I'm really pleased with the way they've turned out and I have many many brownie points with eldest daughter.
Just gotta get the cabinets assembled and fitted, no rush dad but yesterday would be good :roll:
Thanks to all for the advice earlier in the thread =D>

 

[Alexam]

Nice work which looks most professional. Just one question, why didn't you get the acrylic panels sand blasted by the supplier before delivery?

Alex

 

[MrYorke]

They look great. What did you use to polish the rails and stiles?

I mainly use 18mm MR MDF with no problems at that sort of lengthy so interesting that you and others have gone thicker. Did you use you a spindle moulded or router table?

 

[custard]

The problem with MDF on large doors isn't that they'll come off the hinges, but that MDF's inherent lack of stiffness means the door will flex when it's opened, which doesn't make the furniture feel particularly solid. Especially if there's no rail at or about door handle height, if the catches are overly strong, or if the hinges are resistant. Whether or not this is considered a problem is entirely down to the client, but I'd guess that psychologically we're more likely to accept that flexing on a wardrobe door than anywhere else.

 

[n0legs]

Nice work which looks most professional. Just one question, why didn't you get the acrylic panels sand blasted by the supplier before delivery?

Alex

Thank you.
After looking at some samples we were undecided on whether to leave them clear or not. Also the level of obscurity became an issue, my girl thought the sand blasted was too much for her taste.
I have access to sandblasting equipment so we trialled a few pieces, we even painted a few pieces which gave (in my opinion, but what the hell do I know when it comes to kids) a lovely look a bit like the glass splash backs for kitchens. In the end we started the sanding idea, which she ended up preferring over everything else.

They look great. What did you use to polish the rails and stiles?

I mainly use 18mm MR MDF with no problems at that sort of lengthy so interesting that you and others have gone thicker. Did you use you a spindle moulded or router table?

Thank you.
I used Farecla G6 polishing compound after flatting back with 1500 wet and dry. Let them settle for a couple of hours then final polish with Farecla G10.
I used a router table (home made) which has a 2000w Erbauer router installed permanently in it. I used a 10mm straight cutter and on the final pass for all parts I moved the fence a little to give me a little bit of wiggle room for the acrylic to be installed.

 

[Tierney]

Very smart.

DT