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Tonyfavs
03-28-2012, 11:27 AM
I am doing a MDO sign and in the past I have sealed the edges with bondo. I have been trying to get ideas and asking around and no one really seals the edges of MDO around here.

Any ideas on what is the best was to seal the edge of MDO?

thanks all

StarSign
03-28-2012, 11:28 AM
We just paint them, never have any problems.

J Hill Designs
03-28-2012, 11:30 AM
latex caulk, or wood glue

tsgstl
03-28-2012, 11:30 AM
I rarely use MDO anymore. First I switched to Alumilite and now mostly Grimco's Max Metal or Proveers Tru Stock? But to answer your question I always just painted the edges. You can buy trim cap (plastic framing) but I actually think it traps more moisture speeding up delamination.

Tonyfavs
03-28-2012, 11:32 AM
would love to not use MDO but the town requires wood. Lucky me.

john1
03-28-2012, 11:38 AM
I've just painted them before with no problems that i have heard of anyway.

I have also used Elmer's wood filler, sanded it smooth then painted over it. Fills the voids and keeps moisture out good.

Gino
03-28-2012, 11:40 AM
^^ :thumb: ^^

After filling in with the Elmer's wood filler and sanding them, a good coat of prime would be beneficial before top coating.

john1
03-28-2012, 11:43 AM
Oh yeah, don't forget the primer! I forgot about that, It's been a while since i have done a MDO sign.

weaselboogie
03-28-2012, 12:11 PM
I recently made some Mdo signs with a non-exterior Mdo ( I thought all mdo was exterior, but apparently not. ) I primed and painted with latex and an automotive sprayer. Each side received 2 coats of prime and 3 coats of paint. Because I hit the edges at a 45 degree angle of spray, all edges received about 8-10 thin coats of paint. By no means was this a thick coating of paint. These were installed and I noticed a bit of a wave to these signs within 6 months. Within a year, one sign had completely delaminated through ALL layers of the board and was just a wobbly mess.

After talking with my plywood supplier, I found out that these were not an exterior glue. What still baffles me is that even with those 8-10 coats of paint on the edges, water was still able to penetrate through the edges. These were painted with Sherwin williams super paints. Needless to say after eating that job, I'm a bit gun-shy on using mdo without marine grade or a ridiculous amount of edge sealing.

TwoNine
03-28-2012, 12:30 PM
Elmers Wood Glue (Or your favorite brand)

Then (if you want to go a bit further) place some plastic u-channel on the edges. Your supplier should have it in 8' lengths. Comes in 1/2" and 3/4".

signguy 55
03-28-2012, 01:03 PM
Primer and paint always worked for me. I would take the extra step of hand sanding the primer coat and knock the sharp angle off the edges. If the paint is going to fail it's going to be there.

AUTO-FX
03-28-2012, 01:10 PM
Ease the edges and then "paint" them with 2 part epoxy.( I've done this and learned it from friends who've been doing it at their shop for years and years.) Next day sand and paint.

Fred Weiss
03-28-2012, 01:13 PM
I read years ago a tip sheet from one of the plywood manufacturers. They recommended the same sorts of filling as mentioned here already. But they also recommended spraying the edges with any standard aluminum metallic paint such as Krylon. Something about the aluminum flakes evidently works better. I have always used that technique and have never experienced an MDO failure.

SD&F
03-28-2012, 02:17 PM
My two cents....I use wood glue and primer.

ddarlak
03-28-2012, 02:17 PM
MDO is so 1980....

TwoNine
03-28-2012, 02:59 PM
MDO is so 1980....

ANOTHER insightful post. Thank you DDarlak....Awesome input!!! :noway:

Kottwitz-Graphics
03-28-2012, 04:22 PM
I also learned that if mdo is going to fail, it will be on the sharp edge, so I run a 1/8" round over on the edges, then fill with a (2) part wood putty (made by bondo, but made for wood). Sand smooth, prime, then paint.

Malkin
03-28-2012, 04:31 PM
I also learned that if mdo is going to fail, it will be on the sharp edge, so I run a 1/8" round over on the edges, then fill with a (2) part wood putty (made by bondo, but made for wood). Sand smooth, prime, then paint.

We do this, and add some coats of Titebond III (mixed 50/50 with water) before the primer.
Also a coat of paint on the edges every time you paint a side.

TammieH
03-28-2012, 07:05 PM
We use to use a brush/roll on Elastomeric Paint (water sealer) on the edges works well
But nothing lasts

Jillbeans
03-28-2012, 07:15 PM
Two coats of Titebond2 wood glue, then two coats of Kilz primer, then whatever I'm coating out the rest of the panel with.
I try to avoid using MDO.
Love....Jill

k.a.s.
03-28-2012, 07:23 PM
I still prefer to use MDO in situations where I am mounting in between two posts. We slightly round the edges and fill any holes with wood filler. We then prime with XIM or Jay Cookes and paint two coats of Ronan Paint.

Kevin

Deaton Design
03-28-2012, 08:07 PM
I use the heck out of mdo and havent had a failure in a long time. I used to use wood filler, but had some problems with that, used caulk but took to long to setup, also used wood glue which did okay, but the best thing is to prime and paint. That, imho is what seals it best. I have signs up that are ten years old and the mdo is still good.

insigniagraphics
03-28-2012, 08:51 PM
I've had great results with simple exterior spackle as filler. The key is to be sure and sand the edges smooth first, especially any cut ones. Then fill, and ROLL a good exterior latex primer, such as glidden gripper, or even Behr. something with a high-solid content. 2-3 coats of that stuff before you paint works wonders. Spraying tends to leave any paint or primer on the surface, while a good ol' fashioned roller actually presses the paint into the voids. Also, I try to use 3/4" MDO as opposed to the 1/2", as it seems to have 10 times the longevity. I get an average of 6 years of life from contour-cut, 3/4" MDO before we notice any warping or water infiltration. Some people even go further as to finish the painted edges with a thin swipe of clear silicone sealant for good water resistance.

Of course, all that being said, I've discontinued MDO altogether because of the extraneous steps required to preserve it!!!

bob
03-28-2012, 09:54 PM
MDO edges are the reason not to use MDO.

Without taking ridiculous and/or heroic steps the MDO will fail. Even going through all of the nonsense you have to go through in dealing with the edges there's still no reasonable assurance that it won't fail.

MDO: Nice surface, bad edges. There's so many products whose superiority to MDO is measured in light years as well as a panel not weighing more than water buffalo, why would anyone want to beat up on themselves by using the a product that requires a level of preparation totally out of proportion to the results?

infinitesign
03-30-2012, 08:35 AM
MDO edges are the reason not to use MDO.

Without taking ridiculous and/or heroic steps the MDO will fail. Even going through all of the nonsense you have to go through in dealing with the edges there's still no reasonable assurance that it won't fail.

MDO: Nice surface, bad edges. There's so many products whose superiority to MDO is measured in light years as well as a panel not weighing more than water buffalo, why would anyone want to beat up on themselves by using the a product that requires a level of preparation totally out of proportion to the results?


What are you using for a substrate when you have to do a free standing install?

jsmoritz2000
03-30-2012, 09:07 AM
We seal our mdo edges first with Plastic Wood putty. I think Dap makes it. The putty fills any of the large voids between laminates and dries quickly. Then we seal the edges all over with Titebond wood glue. Then we prime with Zinsser oil base primer and top coat with 3 coats of Rustoleum professional oil base enamel. We also round the corners prior to any finishing to shed water away from the edges of the sign.

royster13
03-30-2012, 09:43 AM
By the time you do all that remedial work on MDO is it still worth using?....

Gino
03-30-2012, 10:01 AM
By the time you do all that remedial work on MDO is it still worth using?....


Good question. Yes, indeed.

When one knows what they're doing, you can fill all the voids, seal the four edges, in less than five minutes. Sand the edges flat, knock off the corners, dust it in about another 5 minutes. Prime the edges in maybe 2 more minutes.

Top coat the three edges and face in about 5 or 6 minutes, drop down and paint the last edge and the other side in maybe 6 or 7 more minutes. According to your air conditions, when it's dry, sand both sides and repeat the coating of the edges and faces. When dry, if you want give it a third coat repeating the same steps.

All total, you're at about 45 minutes and you have a nice shiny board that will last 15 years.

If you're doing two at a time... you'd add maybe a little more time, but as you get good at it and are doing these routinely, we would have 10 or so at any given time all finsihed with the filler, sanding, priming and one top coat already on. We generally used a kinda grey first top coat. That's a good color that anything will hide when going overtop with your second and third coat.... even white.

When we're doing baseball signs, we have 20 or so up on horses and can only paint one side at a time, because of space. 640 square foot of boards takes up a lota space cause of getting in-between them. Using this process we can paint all 20 in about 5-6 hours 3 coats top side, 1 coat back side. Usually prep in the morning and get the back coat on. Flip immediately and do a top coat, then sand, tack and re-coat at end of day and a third coat the next morning. :rock-n-roll:

royster13
03-30-2012, 10:09 AM
Gino, thank you for that "great" reply.....

bob
03-30-2012, 10:27 AM
...All total, you're at about 45 minutes and you have a nice shiny board that will last 15 years...

45 minutes in a perfect world, double that in the real world. Even at that, had you chosen a laminate you'd have a nice shiny board that would outlast the next ice age for an investment of 0 minutes. Moreover you could wrangle it all by yourself.

At anything resembling a reasonable hourly rate the cost difference betwixt MDO and a civilized laminate panel, if there were any with which to begin, is negated.

I have a 4'x5' drop of pre-coated 3/4 MDO sitting up against the back wall of my shop. It's been there for years. Whenever the situation arises I offer that chunk of board for free vice a sheet of 10mm laminate. After I explain the differences between the freebie chunk of MDO and the $191.00 sheet of laminate, everyone offered this deal has chosen the laminate.

Gino
03-30-2012, 11:42 AM
No doubt the composite aluminum or even sheet aluminum is less hassle, but have you ever seen how badly the aluminum composites oxidize in just two or three years.... especially if you leave a white background. If it's colored ahead of time, they just fade out. No, we don't really sell these aluminum composite boards as high end signs. They're usually considered quickies at a high cost for materials.


For us, we do a fair amount of MDO, aluminum composites and sheet alumninum, banners, sandblasted, electrical and trucks, so we use it all. Also, a big seller is all the various PVC's for interior signs, so we generally use the substrate most fitted and best for the project and don't worry about taking the easy way out, but to each their own.


Oh, and it must be a somewhat perfect world around here or we're just good, but I've never seen...... even an employee, take over an hour to paint one board and that includes opening, stirring and closing the cans.

By the way, we also still have quite a bit of lead oil-based 1-shot lettering and bulletin on hand. It's not like the snot in the cans most are buying these days.

signage
03-30-2012, 02:03 PM
Gino does OSHA know you are having employees using lead paint?

Are you informing your clients that the boards are painted with lead paint?

Gino
03-30-2012, 02:04 PM
Gino does OSHA know you are having employees using lead paint?

Are you informing your clients that the boards are painted with lead paint?


Yep. :thumb: Just filled out another OSHA sheet a few days ago.

jsmoritz2000
03-30-2012, 02:54 PM
I just prefer to work with MDO because it involves a lot of hand craftsmanship and no shortcuts. When I can pick up a sheet of 3/4" at Menard's for $50, cut it, route it, fill and seal it, paint it, and put some nice graphics on it, it makes my job very enjoyable and I can preserve a bit more pride in the finished product.

Different strokes for different folks.