Large sign

[James RS]

Hello
I've been approached to carve a 48" x 36" sign
For outdoors. I was wondering about material, would
MDF work with a sealer applied? The sign will
Be painted also I found the July 2009 tips PDF

[lawrence]

First off, congratulations on your possible commission!

If you use MDF, I HIGHLY (HIGHLY) suggest either ordering one of the more waterproof of MDF types or a different material (signboard, marine ply, (poss check into MDO) or a man-made material. You can seal MDF off so that it does not leak, but if any penetration of the seal occurs, MDF will soak in moisture and then become very "flaky" like wet cardboard (DAMHIKT!)

Again, I'm not saying it can't be done, I am saying that the risk is high.

V/r
Lawrence

[unitedcases]

I've done a couple big signs (4x4) and I have used cypress with great results.

Sent from my ADR6300 using Tapatalk 2

[mtylerfl]

Hello
I've been approached to carve a 48" x 36" sign
For outdoors. I was wondering about material, would
MDF work with a sealer applied? The sign will
Be painted also I found the July 2009 tips PDF

No professional sign maker I know of would use MDF for an outdoor sign. It will always fail (swell) over time. Paint is designed to 'breath' and no amount of sealer under the paint will protect the MDF long-term from moisture soaking in.

Here is a link to a professional sign maker website forum. They have folks with decades of experience that can advise you on what materials are suitable (and will last). http://www.3dsignforum.com/index.php?action=forum

Also, our own Doug Haffner has a good deal of experience with making signs (it's a crime to call them signs...they are works of art). Perhaps Doug will see this post and give you a couple tips, too.

[dehrlich]

Cedar and White Oak are the best outdoor woods. As has been said, I would be REALLY worried about MDF. Any water that gets in it and it will fall apart.

[ktjwilliams]

No MDF outdoors PERIOD !!!!

[lawrence]

just to clarify my "highly recommend" that I made-- the marine grade MDF is not one that you can get from your home store- it is a specialty item that is usually only available by special order from marine stores/lumberyards and is suitable for outdoor use. I was given a small piece by my local lumberyard and it is more akin to signboard in feel/texture than standard MDF. It is cheaper than signboard, however, at the prices they listed, there are MUCH cheaper options (a 4x8 sheet was $275-$400ish depending on thickness) I appreciated the sample, but will stick to other materials. The only advantage I could see over the standard "sign material" samples that I've gotten is that primer seemed to seal the pores quicker with the water-resistant MDF than with the signboard.

Point being, there are a LOT of guys here on the forum that do a lot more work on outdoor signs than I do - I trust their experience more than I do my own in this regard and I would advise you to do the same!

Lawrence

[Digitalwoodshop]

My vote would be to do it from the Professional Sign Foam that many Sign Shops use.... OR something that I have had some good luck with... PVC Board... I need to get the finished pictures of 2 signs that I helped to do... Both had PVC Letters and one had a Plywood backing and the other a PVC backer board. The TRICK is that if you used the PVC on a regular wood board backer, the Expansion and Contraction would cause the More Rigid PVC to SNAP.... I found this out when I inlay-ed a Ceramic Tile into a outdoor sign... The Tile snapped in half in length of the board due to expansion of the board in width.

Two trains of thought with the PVC letters. In both cases I used my machine to cut the letters. It took a long time. In retrospect, I highly recommend cutting hardboard letters and attach the hardboard with double stick tape of fine brads. Rough cut the outline and with a bearing router bit cut the final letter. This will be smoother than the machine as last from my experience. I round over the top of the letter and paint then apply. In my case I only cut the letters someone else did the install and painting.

With the Rohman Park letters, I cut one set and the installer made a 2nd with a bearing bit I gave him.

Good Luck,


AL

[James RS]

Thanks, but the sign I am to do the letters won't be cut out.
I'm carving the design as you would a pattern, I just figured
Mdf might work sealed and primed and painted.

[tierman]

100% NO on the mdf. You will end up with a swelled up piece oy yuck after the weather gets to it ,an unsatisfied customer and nothing but a bad reference for your work. Don't use it outside. I would suggest the composite materials such as Azek or Trex (these are the ones I am familiar with)They can be purchase in 4'x8' sheets in varios thickness. They are designed to be used in the elements and with hold an exterior finish very well and also carve great.

[henry1]

MDF is a no no don't matter what sealer you put on or paint your looking for trouble

[Digitalwoodshop]

You put hours and hours of work into designing, carving and painting the sign and making it from MDF. You SEAL it and Paint it....

Then the guy installing it uses Screws and Bolts to PUNCTURE the MDF..... Water gets in and the MDF turn to OATMEAL at the puncture.... A Stiff Breeze pulls your sign off the posts and on to the ground....

As for Marine Grade MDF.... Could work...

And since we are talking SIGNS.... IF you mount the Sign.... YOU take on the Responsibility..... For a Hanging Sign over a Sidewalk, the choice of some Home Depot EYE Screws that let the sign fall on someone..... The Lawyers will LOVE that Pain and Suffering.... You could loose your HOUSE.... Work SMART.... That is why I don't do Installations except for the small 4 x 4 post signs.

Good Luck,

AL (Grumpy...)

[James RS]

I've decided not to use mdf, I have a friend who makes signs and can get me HDU.
He's used it for quite sometime for all f his signs