I'll bet you ain't using REDWOOD for a routed substrate anymore!

[tuck]

I can't even find it around Atlanta anymore. 10 years ago it was plentiful enough, although rather expensive even then. Unless customers just had to have redwood, it was easy enough to sell them on clear-heart cedar, which routs/blasts almost (I said ALMOST), as well. But heck, even clear cedar is very expensive nowadays. Plus, for larger signs, ya gotta glue-up the boards and do some considerable prep work (sanding) before you can even rout the lumber, and then do more sanding afterwards before the necessary priming and painting, etc...

I love HDU (foam) because it eliminates most of the prep work and is just about "bullet-proof" as far as the elements are concerned. You don't have to prime it (at least I don't), and it cuts like butter. But the price of HDU is climbing steadily (already discussed in another thread), and may get completely ridiculous soon enough because of rising oil prices. I'm no chemist, but I'm told that HDU is petroleum based. Makes sense. Ain't everything?

So, what's left for exterior signage applications? Exteria? I've heard both bad and good. My only experience with this product was a bad one, but maybe I need to take another look at it. The only time I tried it was to rout down some small, as in "tiny" (3/4") copy in it and it did not do well. It delaminated and the tops of the letters popped off and chipped during the final passes on my Bot. I'm thinking it might still do well for larger signs with larger copy, but I've read in here about paint adhesion problems due to the fact that Exteria has oils in it and the amount of oils can differ from sheet-to-sheet,...causing paint adhesion problems on it's smooth and non-porous surface.

Any feed-back is always much appreciated. We can help each other as we help ourselves! :-)

[rookie432]

Mark,
I've been using extira for a year or so now and like you said everything has it's good and bad points. I havn't had a paint failure yet but maybe that's just me. I prime and use latex enamels from Sherwin williams. I think the big key here is the price. HDU is just so darn expensive but is irreplaceable in some applications. However have had my issues with HDU. It paints well but leafing it is a bit tough I have found. Those darn open cells are tough to completely fill to get a perfect smooth surface without extra special primers and fillers. This is not to say that extira is the answer but just easier to get a smooth finish with off the shelf materials.
Extira is HEAVY and dusty. HDU is light and dusty. Neither on holds a screw perfectly.
As you said...redwood is gone...cedar hard to get clear and expensive, HDU getting more expensive, Extira is just a much cheaper but dirtier alternative. Trupan may be the answer but you have to seal it pretty good. I just don't think there is a perfect material out there. When I sit down and look at a sign project I'll weigh all of these and pick the material best for the job.
For example If I was gonna use smalts I would probably use extira, however a textured wood backround 3d milled with the router would probably go HDU.
I can say that I'm to a point where I think I want to bondo all my substrates just to try and get a smooth finish. I Need to find a good high build primer that dries hard and sands smooth and fills in all the little pores or scratches.

Extira may have been a bit too soft for those 3/4" letters. It just mills fuzzy and would be tough to mask and sand letters that small maybe.

B

[brian_harnett]

I have had good luck with spanish cedar it's just under $4 a board foot.
If you like real wood it weathers very nicely.

[tuck]

Bill,
Bondo all you're substrates? C'mon, man. You gotta be pullin' my leg! Haha! Bondo is an excellent filler for certain applications, but DAMN! I can't IMAGINE covering a 4' x 8' sheet of "whatever" with that stuff, sanding it smooth, then routing it! NO WAY! I ain't gonna do it! ;-)

As far as gold leafing goes for a smooth surface on HDU, you might try this:

http://www.alumapanel.com/view_product.cfm?step=1&lines_ID=79&name=FSC%2D88% 20WB%20Hi%20Build%20Water%20Based%20Primer

I don't do much leafing (hell, who can afford THAT?) so I can't swear by it, but the primer looks to be a pretty good product.

Any screw will hold just fine in almost any substrate if you put a little dab of Gorrilla Glue on the screw shank before you drive it in. You may never be able to get the screw back out, but hey, it's an imperfect world!

Personally, I'm leaning towards MDF (another dusty substrate), as a new (to me), and affordable (for the customer) alternative. It's cheap enough and readily availabe at Home Depot, Lowe's, etc., in 3/4" x 4 x 8' sheets at about $22.00 a sheet the last time I looked. If your project/job requires 1 1/2" thick material, then it goes without saying that you'd have to double it up with laminating 2 pieces, but that in itself is no problem. The problem is,...how do you make the MDF truly "bullet-proof"? Zolatone primers come to mind. (See my thread "Zolatone Industrial Coatings for Sign Making") These primers are "water-proof" within themselves, but not cheap,...about $75.00 a gallon.

Hmmm...I think some experimentation may be in order...

[bleeth]

Bill: I used Durabond for years as a sandable high build that sprays with ease. Check your Auto Body store. Often the first coat will go on and result in rough finsh appearance, but then after sanding and applying the second coat it sands to glass. This was the build up primer of choice for fairing boat plugs and for all I know still is.

Dave

[rookie432]

Thanks for the tips guys.
haha.No I probably wouldn't bondo a whole sign just expressing frustration with a lack of a glass smooth finish on some projects no matter how much I sand. I will buy a can of that Durabond today if you think it works Dave.

Mark standard MDF may not be a bad tester. I have an actual sign sample made out of it and hung it on the exterior of my shop. Been up there about 3 years now and the only sign of wear is the paint fading a bit, but that could just be the paint. However it is somewhat protected by the eave of the roof so it does not get the full brunt of rain,snow etc. That being said I still have been surprised by its stability when painted. Still afraid to try it on a fully exposed sign though.
Your right about the MDF benifits being cheap and avaialable. I can get both MDF and Extira pretty easily and very cheaply compared to HDU. The best thing about this for me is...ahem... I have been capable of screwing up royally. Misprogram or didn't set my z-depth right ...well the list can get extensive (blush). With MDF if I screw up it may only cost me 30 bucks to start over. With HDU it's a much bigger OUCH!

The biggest negatives are the dust and weight.
The dust is awful. As a matter of fact I am building a new shop this year and am budgeting quite a bit for dust collection. MDF just leaves a film on everything and if enough dust gets in the air its an instant headache for me anymore.
I can get Trupan delivered to me now but I have to buy at least 20-30 sheets to make it worth while to pay freight. Waiting until the new shop is up so I'll have storage in the old shop.
MDF doesn't keep my bits sharp either but like you said it's an imperfect world.

The weight has both worked for me and against me. I have handed potential clients a sign sample out of extira and when they hold it, it FEELS substantial. They Feel like they are getting their $75-100+ per sq ft worth. HDU just doesn't give them the same comfort. Despite all of the benefits. However hanging MDF is a pain in the booty somedays. I always need a helper on anything over 10-15 sq ft.

I laminate both extira and mdf with gorilla glue and if necessary well placed and hidden stainless screws for clamping power on larger signs to cure glue tight. Liquid nails exterior has worked well too.

o.k. I have run on enough I hope this gives some insight on my experience with mdf. It's a love- hate relationship.

Bill

[tuck]

Here's the deal with any "high build" sandable primer, be it sprayable or not...it's only going to be at it's best on a routed deminsional sign with a raised background and routed-down copy/graphics. For instance:

A V-grooved sign on HDU; Raised background, routed-down letters. You can apply a sandable "sealer-primer" thick enough onto your HDU and sand all day until it's smooth as glass. Then you clean it, paint it, and apply a masking agent like "Grip Mask" before you rout it. All very time consuming and labor intensive, but I've seen it done and the results were,...well,...like glass.

By the same token, if it's not a large sign with large (wide and deep V-grooved letter stroke) copy, you can use expanded PVC and skip the sandable primer/filler, but you still need to mask for a V-grooved, of course.

But if your sign is a "raised letter, routed-down background" thing, no amount of sandable primer/filler is gonna help. Why not? Because, you can't get to it (the background) to sand it and make it glassy smooth. You simply can't do it. Any tool marks from your router bits are gonna show on the background and I've YET to find an workable way around that. It never comes out "perfectly smooth". My best solution is to at least make all of the tool marks "consistant",...in other words, all going in the same direction...horizontially. In SignLab, it's called an "S-Sweep" toolpath.

Bill, yes, MDF is some heavy and dusty stuff to cut/rout but I'm still thinking it can be the ultimate solution for MOST (not all) applications if I can satisfy myself that I can make it truly "bullet-proof" with primers and paints. The primer is the main thing. If I Google "waterproof primers", I mostly get primers for cinder block/basement water-proofing. I think ya gotta trowel that stuff on! Not good! I ain't gonna do it! LOL!

There's a solution out there. We just haven't found it, or no one has told us yet!

Shellac, Joe Crumley? Can ya spray dat stuff? Will latex stick to it?

Peace! :-)