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View Full Version : Extira Vs. Medex



joe
12-12-2004, 11:31 AM
Howdy Botters,

Hope my note finds you all in good routing spirits.

I'm posting this note to assist newby's who are not familiar with these two products.

Medex came to the market a few years ago an Exterior Fiber Board. It was smooth, heavy, and glued and cut much like MDF. It didn't stand the moisture test however and many sign company's got hurt real bad. Our included. That was our fauld for not testing better. Although we left Medex behind, I will probably start using it again as we could waterproof it outselver.

The hard surface of Medex and chrip routed edges made it a dream to finish.

Now comes Extira: We are using it and think it has real possiblities. We have finished a dozen or so, large carved signs.

However there are problems.

First of all Extira is a SOFT cardboard pulp product which has been soked in a good adhesive water resistant solution, not unlike Resourcinol and or Phenolic Resin. Probably an Isomer, like Catecin, Any way it is much more water resistant than Medex and is real, real heavy. 4'X8'X .75" weighs a helty 120lbs.

The dust left behind the roter is oily. This is clue #1.

Water based glue doesn't soak in very well to oil. Remember this is a water repellant product. So all you guys that are interested in deep penetration, Titebond 111 or Plastic Resin Glue or any other waste based adhesive should be looked at with suspecion. Also water based primers aren't the best either. WE KNOW by several failures. O yes, we've followed Extira's Officical Specifications Sheet, and grouched them out pretty good too for not doing the prelimenary tests. A Good company any way as they are buying back some of the faileres. Acorn Graphics is in that process of re-embursment for latex primers and paint coming of the surface.

There is a fuzzy and hard side. The fuzzy one is the one we have had the best results with. Surface stregnth is where we concentrated. If you put a knife under a corner and lift, you will see how soft Extira is, so it seems important to stregnthen the surface. To do this we have been applying epoxy cut with acetone as a surface wash. Then follow up with another epoxy coat, then prime and paint.

There must be many solutions for glueing and painting Extira, but I'm frustrated with SB posters who give unqualified recommendation. I beg you guys don't, give un tested suggestion about products and proceedures you haven't even tried.

I will be posting a photo or two of my glue board showing the results of different adhesives on Extira.

Hope to save someone the mistakes we have made.


j
www.normansignco.com (http://www.normansignco.com)

Gorilla glue should also work well but am concerned with the softness of the product.

billp
12-12-2004, 01:07 PM
Joe,
I agree with you about Extira's "dual personality". It IS strong, and probably as weather proof as they say ( I have no long term experience to base that on however..).
I'm in my 4th day of cutting some glued up blocks of the material for this fairly large ( 6"thick in two "slices")3D piece. The weight of the material has been a royal pain in the butt, but by building a wheeled staging table I have been able to muscle the parts back forth to the 'Bot.
I went to the Atlantic City Sign Show and grilled the folks from Extira about gluing laminations. Their suggestion of Gorilla glue has proven to work so far. I have laminated four layers at a time, and I am doing fairly intricate 3D cuts without any signs of glue failure or slippage.
A pleasant surprise has been the fact that while I have a fairly severe reaction to cutting MDF ( BAD sinus headaches within minutes of breaking through the surface..) I have had NO problems with Extira. Of course the flip side of that is that the dust is almost as bad as MDF and I'll be cleaning my shop for the next few months after this job is done.
Of course ANY 3D file will remove a lot of material from the initial stages to the final cut, but so far the differences I'm running into are major. I will try to attach a picture of the pieces I have completed to date. The "tail"section on the left was 36 pounds as a "block'of Extira, when machined it became 16 pounds. The "slice"on the right was 83 pounds, and now it's 32 pounds. The good news is that means my final piece will be lighter than I had originally thought, the bad news is that the rest of that material is decorating the floors, walls, etc. of my shop... I'm now cutting the main body which was 200 pounds when Iloaded it onto my table, and I REALLY hope that becomes more manageable..
Of the 3 similar materials,so far I like cutting Medex the best. Crisp lines, and no formaldahyde headaches. Of course each material has it's strengths/weaknesses...
5085

joe
12-12-2004, 01:43 PM
Bill,

Thanks for the reply.

We seem to get crisper, sharper detail by lightly topcoating the material before carving. It doesn't seem to make a lot of difference as what we use, often from a spray can of Shellac.

I have noticed batch differences. Some seem accept adhesives differently than other. Must be from the saturation of the Phenolic Resin, or what ever they use. To be sure this is a much different product to work with than MDF, Trupan, or Medex/

Wish I could have made the Atlanta show. SB used a few photographs of our work and would have liked to see there new display booth.

Isn't it amazing how the dust from this product seems to settle and stay right where is lands.

J

elcruisr
12-13-2004, 07:59 AM
I've really been wondering about the difference in batches. We did quite a few signs in Extira for a local RV park. We cut them and they wanted to paint them. I gave them all the Extira advice for painting them which they promptly ignored. They painted them with a cheap exterior latex without primer and left the backs unfinished. They've been in the weather since early summer and I went by and checked them last week. The paint is adhering excellently and not a peel or chip anywhere. I even tried to scrape some off a corner and had no luck at all.Makes you wonder...

Eric

joe
12-13-2004, 08:31 PM
Eric,

I'm getting a few interesting messages like yours, some having no problems and others with disasters. Lee Bentley and myself have run extensive test which come out differently each time.

We have soaked one end of a piece in water for about a week and saw very little swelling so, if you get the paint to stick on one side I don't think it will not be affected by the un-painted side.

The fuzzy side of the board should be the best for getting a good physical bond.

Because our clients are upper end and expect their signs to last for a couple of decades, we get very nervious when the paint pulls up, while in the shop, with standard masking tape.

I just don't know where to go with this product so will move back to HDU and Medex.

J

elcruisr
12-13-2004, 10:20 PM
Joe,
I know what you mean! With all the different results out there I'd be a bit nervous myself to use it again untill there are more consistent results. HDU has it's own quirks but it's a great, if expensive, product. We still reccomend it to people who ask.....

Medex is harder to get in our area.

Eric

joe
12-14-2004, 08:21 PM
Eric

I am wondering if a good surface scrub down with a strong soapy solution would prime Extira for a better surface adhesion. This notion came to me today and haven't had a chance to test it out.

Perhaps someone had allready tried this.

J.

elcruisr
12-15-2004, 07:22 PM
Joe,
maybe something strong like TSP? Or even a solvent but that might attack the binder....

Might be worth a test.

Eric

Mayo
12-15-2004, 11:55 PM
Just another opinion, but...
any material requiring more prep work than scuff sand, primer and paint just to get it to NOT fail, shouldn't be worth all the extra labor time unless the cost of the material is so low that the extra labor cost doesn't put it out of range of similar products.

Another somewhat new product I have seen at Home Depot is called Intecel/Inteplast. It's used for indoor or outdoor trim. It's a mixture of PVC and wood fiber that looks similar to MDF but it's lighter weight and it comes primed. It appears to only be available in standard trim sizes - not 4'x8' sheets, and only 3/4" thick.

I plan to try some tomorrow to see how it routs.

fleinbach
12-16-2004, 06:22 AM
Mayo

I'm interested in hereing your opinion on this material as I purchased some about 3 weeks ago but just have'nt had time to test it.
Thanks

Brady Watson
12-16-2004, 09:53 AM
Here's the link (http://www.inteplast.com/40site/4.0.htm) for the too lazy to Google people...

Here's a link (http://www.inteplast.com/40site/products/worldpak/intefoam.htm) for InteFoam and InteCel (http://www.inteplast.com/40site/products/worldpak/intecel.htm) ...Plus Specs (http://www.inteplast.com/40site/products/worldpak/spec/foamspec.htm) on Intefoam.

Looks to me like InteFoam is a nice product...Frank & Mayo, what kind of price are we looking at? Where can we get it?

-Brady

paco
12-16-2004, 10:24 AM
Look interesting... I might tryed to find a near retailer.
Thanks for sharing that Brady!

Brady Watson
12-16-2004, 12:08 PM
See...I KNEW you were one of the lazy people!!!




-Brady

paco
12-16-2004, 01:31 PM
First time I joined this threads... to say thanks... and I'm considered lazy?!

Well OK! Lazy me!

fleinbach
12-16-2004, 06:39 PM
I go out and work hard all day. For what! Just to come home and listen to all this bickering.


By the way as soon as I get a little energy or time I'll look into that stuff I picked up.

paco
12-16-2004, 06:53 PM
It's Brady who begin...
I'm just... being nice...
and polite.

Brady Watson
12-17-2004, 08:25 AM
Hey Papa Frank, what kind of price are we looking at? Where can we get it?

rookie432
12-17-2004, 09:33 AM
I'm interested too, so I called the company direct. They sell through distributors and I have a call in to my closest distributor for a price on 1/2" 3/4" and 1" thickness 4x8 sheets.
4x8 sheet is standard size. the stuff at home depot is special cut for home depot.
avail in 2 colors. plain brown (I ussume like mdf)
and white hardcoated for signage ( for direct application of vinyl)
1 3/16" is the thickest avail.
The listed distributor in my area didn't have any in stock, but will call me back for a price.

Alice at World Pack advised that if I were to buy 15 sheets or more at a time they could sell direct to me. She is willing to send out samples to serious inquiries if you call her at 1-800-452-2117 ext 8036
I just told her I was gathering information for our cnc users group so reference that conversation to get a sample. Nice lady and seemed excited to find buyers, so I assume the stuff isn't too cheap. As soon as I get a quoted price I will post it here.

Bill