bJ

23/06/2004 10:07 AM

Novice needs help with MDF boards

Hi,

I am totally new to woodworking and I am thinking of building an
inexpensive wall cabinet out of cheap MDF boards. My questions are:

1. Is MDF boards strong enough to be used in a wall cabinet ? Can it
even hold it's own weight ? Or should I add some real lumbar as
reinforcements ?

2. What is a easy way to join boards at right angle ? Can I simply use
screws / gule and wood filler to patch the hole ?

3. When you paint the boards, do you need to use a primer first ?

Thanks in advance for your advise.

JW


This topic has 9 replies

tT

in reply to [email protected] (JW) on 23/06/2004 10:07 AM

23/06/2004 5:24 PM

JW wrote: >Hi,
>
>I am totally new to woodworking and I am thinking of building an
>inexpensive wall cabinet out of cheap MDF boards. My questions are:
>
>1. Is MDF boards strong enough to be used in a wall cabinet ? Can it
>even hold it's own weight ? Or should I add some real lumbar as
>reinforcements ?
>
>2. What is a easy way to join boards at right angle ? Can I simply use
>screws / gule and wood filler to patch the hole ?
>
>3. When you paint the boards, do you need to use a primer first ?
>
>Thanks in advance for your advise.
>
>JW
>
Hi, JW. Check out FINE WOODWORKING's recent issue(June 04 #170) for joining
MDF. Plus, there're some good tips on finishing the stuff. Tom


Work at your leisure!

TF

"Todd Fatheree"

in reply to [email protected] (JW) on 23/06/2004 10:07 AM

23/06/2004 12:30 PM

"JW" <[email protected]> wrote in message
news:[email protected]...
> Hi,
>
> I am totally new to woodworking and I am thinking of building an
> inexpensive wall cabinet out of cheap MDF boards. My questions are:
>
> 1. Is MDF boards strong enough to be used in a wall cabinet ? Can it
> even hold it's own weight ? Or should I add some real lumbar as
> reinforcements ?
>
> 2. What is a easy way to join boards at right angle ? Can I simply use
> screws / gule and wood filler to patch the hole ?
>
> 3. When you paint the boards, do you need to use a primer first ?
>
> Thanks in advance for your advise.
>
> JW

MDF is strong enough for a wall cabinet, but it wouldn't be my first choice.
I'm working on some face frame shop cabinets right now made from 1/2"
meranti. 1/2" meranti runs about $22.50 per 4x8 sheet here and 1/2" MDF
(regular weight) gets $15. For me, I'm able to get 5 18x30x12 wall cabinets
out of two sheets of ply, so the difference in material cost is not that
great. Unless you make the lengthwise cut 1/2" too narrow and have to go
back and get another piece. DAMHIKT. With that said, here is the gist of a
paragraph on the subject from "Building Your Own Kitchen Cabinetry", by John
Paquay. MDF is stable, uniform, and very smooth-surfaced. It's
inexpensive, paints well, and makes strong glue joints. The downside is
that MDF can be damaged easily, particularly at corners and edges.

todd

km

in reply to [email protected] (JW) on 23/06/2004 10:07 AM

23/06/2004 6:05 PM

[email protected] (JW) wrote in message news:<[email protected]>...
> Hi,
>
> I am totally new to woodworking and I am thinking of building an
> inexpensive wall cabinet out of cheap MDF boards. My questions are:
>
> 1. Is MDF boards strong enough to be used in a wall cabinet ? Can it
> even hold it's own weight ? Or should I add some real lumbar as
> reinforcements ?
>
> 2. What is a easy way to join boards at right angle ? Can I simply use
> screws / gule and wood filler to patch the hole ?
>
> 3. When you paint the boards, do you need to use a primer first ?
>
> Thanks in advance for your advise.
>
> JW

Depends on the width of the cabinet and how much weight you anticpate
loading.I prefer Plywood myself , but I have a tip or two if you do
use mdf. Several joints will work, biscuits, loose tenons , simple
butt glue and screw. Dado or rabbet joints, shallow about 1/4" or less
deep help line up your parts. When you drill mdf , drill thru the
center line of the rabbet or dado, use a bit that is about 3/4 the
diameter of the screw. Countersink slightly on the dado or rabbet
INSIDE. This is very important for mdf, mdf when screwed leaves a
little hill, the slight counter sink gives the broken fibers a place
to go without pushing the board away. Naturally you want to
countersink or counterbore the face side too. A coarse thread drywall
screw is well suited for this work. There are special screws for mdf
and hardboard, can't comment on them because I've never used them.
I have found that bondo or water putty is the best filler for nail or
screwheads in mdf. Both can be sanded when hard, bondo is best ,
invisible under a coat of paint. I believe Rockhard Water Putty is the
other fillers name,works good but not always invisible.When I paint
mdf I spray a primer then two coats of finish. Brushing takes too many
coats , at least four including primer to cover. Other posts make help
more on the painting aspect, I never liked brushing paint on mdf,
maybe it's my technique.
As far as the other questions, you do not need to reinforce mdf with
lumber.Last thing,remember if you need full sheets , have the yard rip
or crosscut them for you to a rough dimension. Full sheets are very
heavy.

mike

bJ

in reply to [email protected] (JW) on 23/06/2004 10:07 AM

23/06/2004 3:47 PM

Thanks to everyone who have responded to my questions. You guys are very helpful.

Ww

Woody

in reply to [email protected] (JW) on 23/06/2004 10:07 AM

23/06/2004 9:40 PM

JW wrote:
> Hi,
>
> I am totally new to woodworking and I am thinking of building an
> inexpensive wall cabinet out of cheap MDF boards. My questions are:
>
> 1. Is MDF boards strong enough to be used in a wall cabinet ? Can it
> even hold it's own weight ? Or should I add some real lumbar as
> reinforcements ?

If your concerned about shelving, the maximum length for droop-free
shelves is about 32". If you add a 1"x2" wood banding to the front, that
will extend to about 40". This per "Trim Carpentry and Built-Ins" by
Clayton DeKorne.
>
> 2. What is a easy way to join boards at right angle ? Can I simply use
> screws / gule and wood filler to patch the hole ?

If you're making shelving/carcasses, you can dado the vertical pieces
and then glue and screw the pieces together.

>
> 3. When you paint the boards, do you need to use a primer first ?

Yes, but if you've milled any of the MDF (e.g. edged it with a router)
*don't* use a latex primer. You'll raise the fiber something fierce and
spend hours sanding it down. On unmilled, flat surfaces, any primer
should work fine. I learned this the hard way with some raised panel
wainscoting I made from MDF. Spent 3 days sanding down the routed edges
of the panels, rails and stiles.
>
> Thanks in advance for your advise.
>
> JW

As an aside, veneered MDF (e.g cherry, maple, etc.) is becoming
increasingly popular as material for cabinets and shelving, so it must
be okay.

~Mark.

UC

"U-CDK_CHARLES\\Charles" <"Charles Krug"@cdksystems.com>

in reply to [email protected] (JW) on 23/06/2004 10:07 AM

23/06/2004 5:29 PM

On 23 Jun 2004 10:07:07 -0700, JW <[email protected]> wrote:
> Hi,
>
> I am totally new to woodworking and I am thinking of building an
> inexpensive wall cabinet out of cheap MDF boards. My questions are:
>
> 1. Is MDF boards strong enough to be used in a wall cabinet ? Can it
> even hold it's own weight ? Or should I add some real lumbar as
> reinforcements ?

MDF is reasonably strong if it's reasonably well supported. What are
you planning on holding up? Try loading a length with the kind of loads
you anticipate. Is the deflection acceptable? If not, add a support to
the middle.

> 2. What is a easy way to join boards at right angle ? Can I simply use
> screws / gule and wood filler to patch the hole ?

Ty and Wynn use glue and a brad nailer, iirc. I think if they had a
more reasonable timeframe, glue would be sufficient with a decent clamp
time.

I would try to arrange things so that all my load-bearing was done under
compression, rather than tension.

> 3. When you paint the boards, do you need to use a primer first ?

In general, primer is MUCH cheaper than paint, so that's a resounding
YES.

I'd use oil-based primer, but check the paint manufacturer's
recommendations for their product. Makers of quality paint want you to
feel happy with their products, so they tend towards conservative
recommendations, application-wise.

MM

"Michael Mcneil"

in reply to [email protected] (JW) on 23/06/2004 10:07 AM

23/06/2004 5:33 PM

"JW" <[email protected]> wrote in message
news:[email protected]

> I am totally new to woodworking and I am thinking of building an
> inexpensive wall cabinet out of cheap MDF boards.

Say no more; find your way over to uk.d-i-y. Anal retention is not
rquired there. Also the chat is actual hands on stuff not stuff on
hands.

> My questions are:
> 1. Is MDF boards strong enough to be used in a wall cabinet? Can it
> even hold it's own weight? Or should I add some real lumber as
> reinforcement?

Any shelf needs support at 3 foot intervals for a section 1" thick. MDF
has been used for a long time now. It is common on stair risers for
example and the beloved media of house make-over programmes on the TV
over here

> 2. What is a easy way to join boards at right angles? Can I simply use
> screws, glue and wood filler to patch the hole?

Space some strips on each side piece to set the shelves on. Put them
tight to the back and stop them short of the front and cut the front
edges of them at an angle. MDF has to be pre-drilled for screws and a
countersunk bit used to bury the head of the screws. Over here in the UK
the trade named filler is Pollyfilla. Any wood filler will do. Follow
the instructionson the packet.

> 3. When you paint the boards, do you need to use a primer first ?

Yes. Acrylic then undercoat then gloss if that is what you want for a
finish. It will look OK with 2 or 3 coats of acrylic.


--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

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Andy Dingley

in reply to [email protected] (JW) on 23/06/2004 10:07 AM

23/06/2004 10:40 PM

On 23 Jun 2004 10:07:07 -0700, [email protected] (JW) wrote:

>1. Is MDF boards strong enough to be used in a wall cabinet ?

MDF is strong enough for almost anything. However it's not very stiff.
It won't break, but it'll sag like crazy if you're not careful.

I like it for built-ins and kid's furniture, but I'd not use it for
bookshelves.

>Or should I add some real lumbar as reinforcements ?

Just choose the right thicknesses and get the design right. 1/2" thick
is OK for shelving and put a back on it, screwed from the back. You
can go to 3/8" thick if they're not too deep and you know what you're
doing.

Another tip is to saw the front edge into a gentle curve. If it does
sag, it makes it much less obvious.

>2. What is a easy way to join boards at right angle ?

Biscuit jointer. If you're in the UK, try Screwfix's Ferm cheapie.

Avoid screws for the carcase. Getting them to hold edge-on to a board
is a thankless task. If you must do this, use the right screws -
parallel shanks, with narrow thread ridges and a fairly big spacing
between them. You can find these as MDF, chipboard or even drywall
screws.

>3. When you paint the boards, do you need to use a primer first ?

Yes, and it needs to be MDF primer. Anything with water in it raises
fibres and
--
Smert' spamionam

tb

terry boivin

in reply to [email protected] (JW) on 23/06/2004 10:07 AM

27/09/2004 2:44 AM

On 23 Jun 2004 10:07:07 -0700, [email protected] (JW) wrote:

>Hi,
>
>I am totally new to woodworking and I am thinking of building an
>inexpensive wall cabinet out of cheap MDF boards. My questions are:
>
>1. Is MDF boards strong enough to be used in a wall cabinet ? Can it
>even hold it's own weight ? Or should I add some real lumbar as
>reinforcements ?
>
>2. What is a easy way to join boards at right angle ? Can I simply use
>screws / gule and wood filler to patch the hole ?
>
>3. When you paint the boards, do you need to use a primer first ?
>
>Thanks in advance for your advise.
>
>JW
Hello JW,

MDF is a fine substrate for most low to mid range cabinets. It takes
paint very well, machines nicely and will accept veneers of wood and
metal . Exposed edges do not paint very well so be cautious in your
design details. But above all, please wear a back brace cause that
stuff luvs gravity!


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