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Mdf panel in pine frame interior barn door

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Forum topic by ronstar posted 08-10-2017 12:28 AM 430 views 0 times favorited 9 replies Add to Favorites Watch
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ronstar

429 posts in 3547 days


08-10-2017 12:28 AM

I’m building a barn door for the interior of our house. Frame and panel construction. MDF panels and pine frame. Frame is sandwiched 3/4” pine, with the MDF panel in a dado in the rails/stiles. It will be painted.

I’m wondering if I can glue the MDF panel to the frame, and also if I can wait to paint the whole door after assembly. Or should I leave the MDF panel float and paint the panels before assembly.

The top MDF panel is huge – 43”x43”. I understand that MDF has no movement, but still wonder if its ok to glue to the frame. It would help with stability if I could glue it.

-- Ron, Northern Illinois


9 replies so far

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Jerry

2452 posts in 1485 days


#1 posted 08-10-2017 12:44 AM

I’ve glued MDF with a variety of glues, and it never makes a secure joint, at least not for me, but maybe a construction type glue like liquid nails would work. I have a concern about the weight of the MDF as opposed to the strength of the pine, and the strain all that weight is going to put on your hinges and door frame. wouldn’t it be just as cost efective to use 1/4” ply? it would glue well, probably be cheaper, take paint better, and be lighter.

-- There are good ships and there are wood ships, the ships that sail the sea, but the best ships are friendships and may they always be. http://www.geraldlhunsucker.com/

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ronstar

429 posts in 3547 days


#2 posted 08-10-2017 01:04 AM

Great comments Jerry. I considered thinner mdf and plywood, but I’m routering v groove (simulated tongue and groove) on each side for decoration and the v groove will require the extra thickness.

I haven’t worked with 3/4” mdf before and I am amazed at the weight of this stuff.

Weight should not be much of a factor (hinge wise) because I’m using sliding barn door hardware where each stile is lag bolted at to the barn door rail.

Weight could be a problem on the frame itself, but I added some loose tenons. I’ve got the door ready to insert the panels now, so I really can’t change the design.

I’ll used liquid nails on the panels and hopefully the frame can handle the weight.

This is what the door hardware looks like.

-- Ron, Northern Illinois

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Loren

9627 posts in 3484 days


#3 posted 08-10-2017 01:20 AM

I would glue it.

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tomd

2122 posts in 3607 days


#4 posted 08-10-2017 01:30 AM

I would leave the panel floating, the MDF will not move but the frame will. If it is 3/4 inch MDF that’s going to be a very heavy door. Also MDF does not glue very well.

-- Tom D

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ronstar

429 posts in 3547 days


#5 posted 08-10-2017 01:43 AM

I’m wondering if I should put in plywood instead of the MDF.

But I calculated the weight of MDF in the door at 60.9 lbs. The same amount of 3/4” plywood would be 43.1 lbs. 17.8 lbs doesn’t seem like much of a difference.

But if I use 1/2” plywood, the panel weight would be 28.8 lbs. That’s a 32 lb less than 3/4 mdf.

But if I cut 1/8 deep grooves back to back in 1/2” ply, I only have a 1/4” thickness where the grooves are.

Hmm – what to do

-- Ron, Northern Illinois

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Loren

9627 posts in 3484 days


#6 posted 08-10-2017 01:48 AM

Heavy doors are nothing new.

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Rich

1980 posts in 426 days


#7 posted 08-10-2017 02:22 AM

I’m with Loren. When I first started building doors, I swore the hinges couldn’t support them, but I’ve hung entry doors that weigh well over 100 lbs without a hitch. The fact that yours are hanging on barn door hardware makes it even less of an issue.

That said, if I were building the door, I’d use alder. Clear or knotty, depending on the look you’re going for. Even if you paint it (aargh) it will look better. The v-groove in the MDF is going to expose the core of the material, which does not paint well. You can seal it, prime it, do whatever, and it just won’t look as finished as real wood. Alder is harder than pine, while still being easy to work and pretty inexpensive.

Sorry for butting in, but I couldn’t help myself. I’ll shut up now.

-- No matter how much you push the envelope, it'll still be stationery.

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bobkberg

439 posts in 2910 days


#8 posted 08-11-2017 05:11 AM

Hi Ron,

If you’re going to paint it, I’d actually recommend poplar. It’s a good stable wood, but much lighter than MDF. I like MDF in its place (like veneer coated for cabinet carcasses). I also don’t think the thinness of the 1/2 MDF routed would be all that bad. If you are concerned, you could try to find a router bit with a wider angle “V” and not cut as deep. Good luck!

Regards,

Bob

-- Bob www.singularengineering.com - A sideline, not how I earn a living

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ronstar

429 posts in 3547 days


#9 posted 08-11-2017 12:24 PM

Thanks for the advice guys. I decided to change the panels to !”x6” pine boards routered to a tongue and groove. Then I’ll loose fit those into the frame. I’m painting the panel boards first.

I should have used poplar, but I would have to drive a ways to get it.

-- Ron, Northern Illinois

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