JE

"John Emmons"

16/08/2006 6:44 PM

Weatherproofing MDF?


Howdy,

Anyone have any ideas as to how I can weatherproof, as much as that's
possible, some 1/2" MDF?

I'm planning a new portable slot car track to replace my current one and I
want to make this one a routed track, it will be attached to the top of a
torsion box that is then mounted onto a utility trailer.

I'm not locked into using MDF, but it is the recommended material amongst
track builders.

I know it soaks up moisture like crazy. I won't be using it in the rain or
snow, it will be stored outdoors with a cover on it. I live in SoCal so
there's really only a couple of dozen days of rain to deal with.

Any thoughts or ideas welcomed.


--
John Emmons


"when hatred calls with his package, refuse delivery..."


This topic has 16 replies

d

in reply to "John Emmons" on 16/08/2006 6:44 PM

16/08/2006 5:16 PM


John Emmons wrote:

> Anyone have any ideas as to how I can weatherproof, as much as that's
> possible, some 1/2" MDF?

You can't.

If you _must_, then replace the MDF with Valchromat -- an extra resin
MDF that's soid colour all the way through and significantly more
resistant to moisture. I use it for bathroom fittings, but I'd still be
wary of real outdoor use.

bb

"bf"

in reply to "John Emmons" on 16/08/2006 6:44 PM

16/08/2006 10:42 PM


John Emmons wrote:
> Howdy,
>
> Anyone have any ideas as to how I can weatherproof, as much as that's
> possible, some 1/2" MDF?

I don't think it's possible. Why not use exterior grade plywood?

tj

"the_tool_man"

in reply to "John Emmons" on 16/08/2006 6:44 PM

19/08/2006 6:19 PM

Hi John:

As others have said, MDF isn't really a good choice for outdoors.

A few years ago, I would have been in the "use MDO" camp, but my
experience of late has changed my mind. MDO is indeed regular plywood,
with a waterproof resin-impregnated paper bonded to one or both sides
(you can buy it either way). The surface is waterproof. However, the
plywood inside is not treated against decay. Any unprotected edges or
holes will allow moisture inside, and become trapped between the
waterproof surfaces. Unless you are VERY careful about sealing all
exposed edges and holes, moisture will find its way into the inside and
begin rotting it from the inside out. Perhaps if you are meticulous
about painting it, and you keep it covered, and don't drive through
puddles, etc., you'll be fine with MDO, but I thought you should know
that it's not without risk.

My recommendation would be to get exterior-grade plywood, or even
pressure-treated plywood. It's typically not very flat, but if you're
going to mount it to a torsion box, you should be able to get it flat
and keep it that way. Non-treated plywood will still need painting,
but it shouldn't have the same level of moisture entrapment as MDO.
Pressure-treated plywood should last many years.

Regards,
John.

Cc

"CW"

in reply to "John Emmons" on 16/08/2006 6:44 PM

18/08/2006 4:33 PM

So, now that you have all these answers from people telling you that if you
remove a piece of MDF from it's protective building and take it outside, it
will dissolve, I guess it's up to me to tell you the real truth. I've had an
unfinished MDF box sitting outside, unprotected, in Seattle for over a year.
No, it's not in very good shape but it's still around. In your case, since
you are going to keep it covered and the weather is as good as it is where
you are, there is no real need to do anything special other than put SOME
kind of finish on it. BTW, I wonder how people get their MDF home since, as
they claim, it decays when taken out of a building.

"John Emmons" <[email protected]> wrote in message
news:[email protected]...
>
> Howdy,
>
> Anyone have any ideas as to how I can weatherproof, as much as that's
> possible, some 1/2" MDF?
>
> I'm planning a new portable slot car track to replace my current one and I
> want to make this one a routed track, it will be attached to the top of a
> torsion box that is then mounted onto a utility trailer.
>
> I'm not locked into using MDF, but it is the recommended material amongst
> track builders.
>
> I know it soaks up moisture like crazy. I won't be using it in the rain or
> snow, it will be stored outdoors with a cover on it. I live in SoCal so
> there's really only a couple of dozen days of rain to deal with.
>
> Any thoughts or ideas welcomed.
>
>
> --
> John Emmons
>
>
> "when hatred calls with his package, refuse delivery..."
>
>

MD

"Morris Dovey"

in reply to "John Emmons" on 16/08/2006 6:44 PM

19/08/2006 4:56 AM

John Emmons (in
[email protected]) said:

| Anyone have any ideas as to how I can weatherproof, as much as
| that's possible, some 1/2" MDF?
|
| I'm planning a new portable slot car track to replace my current
| one and I want to make this one a routed track, it will be attached
| to the top of a torsion box that is then mounted onto a utility
| trailer.
|
| I'm not locked into using MDF, but it is the recommended material
| amongst track builders.

It might be worth your trouble to investigate Extira, a product that
looks and machines much like MDF, but isn't vulnerable to moisture. I
use it for outdoor signage and it has worked well for me.

It's a bit heavier than MDF (90#+ for a 3/4 x 4 x 8 sheet) - and it's
definitely harder on router bits - but it may be a good solution for
you.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

LH

Lew Hodgett

in reply to "John Emmons" on 16/08/2006 6:44 PM

17/08/2006 2:24 AM

John Emmons wrote:

> I'm not familiar with MDO, what is it?

Plywood for outdoor signs.

Has a paper coating bonded to it.

Since you are in SoCal, check Gahnal<s/p>, know they have it.

Lew

PH

Peter Huebner

in reply to "John Emmons" on 16/08/2006 6:44 PM

17/08/2006 11:16 AM

In article <[email protected]>,
[email protected] says...
>
> Howdy,
>
> Anyone have any ideas as to how I can weatherproof, as much as that's
> possible, some 1/2" MDF?
>
> I'm planning a new portable slot car track to replace my current one and I
> want to make this one a routed track, it will be attached to the top of a
> torsion box that is then mounted onto a utility trailer.
>
> I'm not locked into using MDF, but it is the recommended material amongst
> track builders.
>
> I know it soaks up moisture like crazy. I won't be using it in the rain or
> snow, it will be stored outdoors with a cover on it. I live in SoCal so
> there's really only a couple of dozen days of rain to deal with.
>
> Any thoughts or ideas welcomed.
>
>
> --
> John Emmons
>

If you can avoid chips and dings, a water based primer and 2-3 coats of oil
based enamel will work just fine. The moment you break the paint you will have
to redo that spot or you'll be up the creek the moment it gets seriously wet.
Rounding over the edges and corners will help greatly to preserve the integrity
of the paint.

I'd probably use plywood. The better grades should do the job just fine. (More
layers for the same thickness is what makes it a better grade as a rule).

h.t.h. -P.

--
=========================================
firstname dot lastname at gmail fullstop com

JE

"John Emmons"

in reply to "John Emmons" on 16/08/2006 6:44 PM

16/08/2006 7:44 PM

I'm not familiar with MDO, what is it?

John

"Lew Hodgett" <[email protected]> wrote in message
news:[email protected]...
> John Emmons wrote:
>
> > Anyone have any ideas as to how I can weatherproof, as much as that's
> > possible, some 1/2" MDF?
>
> Doubtful, IMHO.
>
>
> > I'm planning a new portable slot car track to replace my current
> one and I
> > want to make this one a routed track, it will be attached to the
> top of a
> > torsion box that is then mounted onto a utility trailer.
> >
> > I'm not locked into using MDF, but it is the recommended material
> amongst
> > track builders.
>
> I don't know about track builders, but how about MDO?
>
> > I know it soaks up moisture like crazy. I won't be using it in the
> rain or
> > snow, it will be stored outdoors with a cover on it. I live in SoCal so
> > there's really only a couple of dozen days of rain to deal with.
>
> Since you are in SoCal, forget about trying to seal using epoxy, the
> sun's UV will kill it.
>
> Varnish is probably best.
>
> Lew
>
>
>

JM

"J. Mohnike"

in reply to "John Emmons" on 16/08/2006 6:44 PM

16/08/2006 3:54 PM

what about fiber glass? you can use the cloth or just the resin. it would
help if you did all surfaces and then painted.


"John Emmons" <[email protected]> wrote in message
news:[email protected]...
>
> Howdy,
>
> Anyone have any ideas as to how I can weatherproof, as much as that's
> possible, some 1/2" MDF?
>
> I'm planning a new portable slot car track to replace my current one and I
> want to make this one a routed track, it will be attached to the top of a
> torsion box that is then mounted onto a utility trailer.
>
> I'm not locked into using MDF, but it is the recommended material amongst
> track builders.
>
> I know it soaks up moisture like crazy. I won't be using it in the rain or
> snow, it will be stored outdoors with a cover on it. I live in SoCal so
> there's really only a couple of dozen days of rain to deal with.
>
> Any thoughts or ideas welcomed.
>
>
> --
> John Emmons
>
>
> "when hatred calls with his package, refuse delivery..."
>
>

EP

"Edwin Pawlowski"

in reply to "John Emmons" on 16/08/2006 6:44 PM

16/08/2006 8:23 PM


"John Emmons" <[email protected]> wrote in message
news:[email protected]...
> I'm not familiar with MDO, what is it?
>
> John

A plywood like material made for outdoor use. Many road signs are made from
MDO. Comes in 4 x 8 sheets

PB

Pat Barber

in reply to "John Emmons" on 16/08/2006 6:44 PM

16/08/2006 8:43 PM

There is always waterproof MDF which is weather proof...

http://www.sierrapine.com/products/mdf/medex/default.asp

MDO might be a better option and can be bought from a
local sign company....

There are "many" versions of MDF, not just the one you
saw at Lowes or Home Depot.

John Emmons wrote:

> Howdy,
>
> Anyone have any ideas as to how I can weatherproof, as much as that's
> possible, some 1/2" MDF?
>
> I'm planning a new portable slot car track to replace my current one and I
> want to make this one a routed track, it will be attached to the top of a
> torsion box that is then mounted onto a utility trailer.
>
> I'm not locked into using MDF, but it is the recommended material amongst
> track builders.
>
> I know it soaks up moisture like crazy. I won't be using it in the rain or
> snow, it will be stored outdoors with a cover on it. I live in SoCal so
> there's really only a couple of dozen days of rain to deal with.

gg

gka

in reply to "John Emmons" on 16/08/2006 6:44 PM

19/08/2006 2:19 AM

MDO medium density overlay

it's a resin coating that is fused by heat to the plywood.

LH

Lew Hodgett

in reply to "John Emmons" on 16/08/2006 6:44 PM

16/08/2006 7:17 PM

John Emmons wrote:

> Anyone have any ideas as to how I can weatherproof, as much as that's
> possible, some 1/2" MDF?

Doubtful, IMHO.


> I'm planning a new portable slot car track to replace my current
one and I
> want to make this one a routed track, it will be attached to the
top of a
> torsion box that is then mounted onto a utility trailer.
>
> I'm not locked into using MDF, but it is the recommended material
amongst
> track builders.

I don't know about track builders, but how about MDO?

> I know it soaks up moisture like crazy. I won't be using it in the
rain or
> snow, it will be stored outdoors with a cover on it. I live in SoCal so
> there's really only a couple of dozen days of rain to deal with.

Since you are in SoCal, forget about trying to seal using epoxy, the
sun's UV will kill it.

Varnish is probably best.

Lew


Rr

Roy

in reply to "John Emmons" on 16/08/2006 6:44 PM

24/08/2006 3:25 AM

John,

I'm catching up on threads. If you haven't bought anything yet, why not post this question on
www.slotside.com ? One of the folks in the hobby may have already faced this problem. I assume
you're painting the track in blackboard paint.

I've got a few drawers full of memories that date back to 1962-3. Still have my old Cucaracha and a
Cox Lotus 40.

Regards,
Roy

On Wed, 16 Aug 2006 18:44:41 GMT, "John Emmons" <[email protected]> wrote:

>
>Howdy,
>
>Anyone have any ideas as to how I can weatherproof, as much as that's
>possible, some 1/2" MDF?
>
>I'm planning a new portable slot car track to replace my current one and I
>want to make this one a routed track, it will be attached to the top of a
>torsion box that is then mounted onto a utility trailer.
>
>I'm not locked into using MDF, but it is the recommended material amongst
>track builders.
>
>I know it soaks up moisture like crazy. I won't be using it in the rain or
>snow, it will be stored outdoors with a cover on it. I live in SoCal so
>there's really only a couple of dozen days of rain to deal with.
>
>Any thoughts or ideas welcomed.

Pn

Prometheus

in reply to "John Emmons" on 16/08/2006 6:44 PM

17/08/2006 8:24 PM

On Wed, 16 Aug 2006 19:44:50 GMT, "John Emmons"
<[email protected]> wrote:

>I'm not familiar with MDO, what is it?

As far as I could tell looking at it at the lumberyard, it's regular
old pine plywood with a very thin layer of veneer-like hardboard on
each side. I'm assuming it's for projects that are going to be
painted- can't think of any other good uses for it offhand.


JE

"John Emmons"

in reply to "John Emmons" on 16/08/2006 6:44 PM

17/08/2006 3:49 PM

I'm leaning towards trying that. MDF is the preferred material for what I'm
trying to build, it's flatness and ease of routing the slots and you can
bend it for banked turns.

My track will be basically flat and I need the weather protection more than
the other attributes so it sounds like MDO which has been recommended by
several people will be the way to go.

John

"bf" <[email protected]> wrote in message
news:[email protected]...
>
> John Emmons wrote:
> > Howdy,
> >
> > Anyone have any ideas as to how I can weatherproof, as much as that's
> > possible, some 1/2" MDF?
>
> I don't think it's possible. Why not use exterior grade plywood?
>


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