Not HDU Again "CRACK"

[joe]

We did a U turn when I saw this one.

http://i38.photobucket.com/albums/e115/jcrumley1/DSC00123.jpg

Don't you know the sign company who sold this sign told the City of Roswell they were getting a fool proof material that will last for years!

This sign was 4"X4'X10' and what do you know it's CRACKED. Most of us using these materials have found the best way to use them. We've glued aluminum, angle iron, and MDO in HDU trying to overcome it's weaknesses.

I've come full circle by returning to wood as the major substrate for all my signs. The only time I use HDU is for detail carving on logo's and lettering.

The helmets aren't part of the sign.

Joe Crumley

[sebago_signworks]

Joe, not sure if it the climate or not, but we dont have too many issues with HDU here. I have many 4x6' signs, hung in-bewteen 2 poles using steel as the brackets that have been up for years now. One of the few changes I have made on double sided signs using HDU is instead of using one sheet for both sides, I will use two 2" sheets with alumalite as the core. So far (knock on wood) we have not had any HDU failure. That being said we were in Southern PA (Pittsburg) going to W. VA on a job and we noticed multiple HDU signs that did not hold up. Maybe here in the north the elements dont effect HDU the same way it does where the sun shines brightly all year long.

[joe]

Sounds like you've done well with this product however there are limits.

HDU takes special techniques when using screws. Screws expand and contract, HDU doesn't which leads to failure
It will not span distances without interior braces.
Paint preperation is a true pain.
It's way too expensive.
Outside borders will not take any abuse and if the interior is exposed UV will does damage.
Do Not glue up one sided sign with DiBond. It will warp like a potato chip.
You can not refurb an old HDU sign because the material gets brittle.

Gees I could go on for ever. But, what every material you choose has thumbs up over here. Should I show more photo's of HDU failure?

Now don't get me wrong I use Duna. I have a 6K order of 20lb. That will be for small exterior signs on a present job.

Joe Crumley

[sebago_signworks]

When it come to inserting screws, we ream the hole a bit and insert epoxy to allow for expansion/contraction. I agree with the paint, we use the 18lb foam which is a bit easier to paint with Matthews or House of Kolor which gives it a nice look. Even then you do see a dimple or two..three. Never used di-bond, Signfoam recommended alumalite. It has worked well. I wouldn't do more then a 4x6' before going back to wood or another substraight. I do agree with your theory... there is a place for HDU. Wood is king. I am still looking for alternatives to Acrylic for raised lettering/etc. Lots of people using PVC which I am unfamiliar with and would like to learn more about.

[joe]

O well here is a 5K job that went wrong with DiBond and HDU. I posted on this when it happened and was told I used too much glue. You Sure! The brand name isn't important. All of these panels are made the same and expand at a different rate than HDU. I'm sure you know that. Good to see your pocketing for screws. That's essential


http://i38.photobucket.com/albums/e115/jcrumley1/IMG_2228.jpg

http://i38.photobucket.com/albums/e115/jcrumley1/IMG_2227.jpg

http://i38.photobucket.com/albums/e115/jcrumley1/IMG_2224.jpg

I'm not sure you can tell the amount of warpage by the last shot. I could have let it go for a while to make a point but I'm not wanting to punish a customer. We've made five of these and scared to death there will be more failure. All are at ground level and student damage may be an issue. When I make these from Redwood or YP they are much tougher. And I don't worry about them.

Should I post more HDU catastrophes? OK I will.
The one thing I'm trying to do is protect Sbers from errors .

Joe Crumley

All the maroon letters are cut from 1/4" PVC and glued down with silicone.

[sebago_signworks]

Very nice sign... And dont get me wrong Joe, I dont disagree with HDU is a pain in the ass. We used Alumalite due to its 6mm thick vs Di-Bond. Also, its hard to tell in your pic but we never mount HDU into wood, we always use steel as a buffer for expansion and contraction. Wood and HDU have different expansion rates. Also over time if the wood checks it will warp, leaving your sign warping with it. Its allot of work, but in the pics below we would have a steel brace to mount to the poles, then mount the HDU to the steel. The steel can handle the shift/check of the wood that the HDU cant. And the Steel and HDU have a similar expansion rate. I have allot of respect for you Joe, and look forward to meeting you at SignCamp in June... Im not picking a fight! You forgot more about the sign business then I ever knew! That being said I can see some room for failure where the HDU and the wood are mounted together with no buffer. Somebody made a SF sign down the road from us, used steel against wood, the top of the sign extends about 30" above the steel and come to a peak, its all warped above the steel??? That sucks I would like to see S.F.'s answer to what that happend. I think its only been there for 2/3 years now. We have been lucky.
http://i949.photobucket.com/albums/ad336/dmfahie/RMVP.jpghttp://i949.photobucket.com/albums/ad336/dmfahie/MF.jpg

I know its hard to see in these pics, but we have steel to buffer the wood and hdu.

[sebago_signworks]

Joe, the background in the University sign, is that blasted with a grain frame or similar or CNC'd? And the lettering, looks like 1/8.. what is your choice of material for that?

-----Joe, sorry just looked at your post again and saw it was PVC...

[joe]

I also see MDO and HDU glued together all the time. Like you, I've never felt comfortable with that process but I have to say it seems to work. The important thing HDU needs special attention or it will fail. I'm expecting to see lots more along this line.

I'm glad were having this discussion because I know there are Newbees who need to know.

Newbee's won't be making signs like mine because the process is too involved. And If you haven't seen someone making up large panels it would be tough. They will have to go with board like materials.

For me HUD is a three letter word!

Joe

[knight_toolworks]

Joe your ok with pcv as letters and such glued to a backing board? of course they have to be painted right? what paint sticks to pvc the best?

[joe]

Steve,

That's the great thing about PVC, I haven't seen any paint that won't stick to it. I like good old flat house paint. Except on dark colors. For that I use OneShot with their hardner.

Devin,

These signs are routed. No sandblasting.

Joe Crumley

[sebago_signworks]

Awesome Joe.... I hope we touch base on routing the sandblasted look in June. Love your work, I have followed you over my time in the business. What brand PVC do you use/recommend Joe?

[joe]

D.

I'm no good at that. Perhaps JO has the answer. I'm still looking for a good example.

J.

[tuck]

HDU has its' place but it is overpriced, easily damaged or broken, and not all it's "cracked" up to be. ;)

Duna is the best in my opinion and they were the least expensive when they started marketing their product. Now they are the most expensive, at least around these parts. $324.00 for a 4 x 8 x 1 1/2" sheet of 15 lb. Geeeez!

Gimme some PVC.

[Ajcoholic]

Since I build furniture and cabinets, and do millwork - I am unfamiliar with the terms "HDU, MDO, Dibond, etc" can you explain?

I am assuming some kind of plastic material?

AJC

[knight_toolworks]

HDU is high density urethane foam. mdo is Medium density overlay it is a paper faced waterproof plywood. you see it on highway signs and such.
dibond is a plastic core with aluminum faces. it is pretty handy stuff to build with waterproof and fairly light weight. here it is where I cut through the face.
http://i154.photobucket.com/albums/s266/knighttoolworks/posting/d0c35f05.jpg

[Ajcoholic]

HDU is high density urethane foam. mdo is Medium density overlay it is a paper faced waterproof plywood. you see it on highway signs and such.
dibond is a plastic core with aluminum faces. it is pretty handy stuff to build with waterproof and fairly light weight. here it is where I cut through the face.
http://i154.photobucket.com/albums/s266/knighttoolworks/posting/d0c35f05.jpg

OK makes sense. Ive brought in the kraft paper coated fir plywood for a few sign makers... that is what you call MDO.

The HDU, is that similar to the expanded urethane foam insulation? If it is so prone to cracking and so forth, isnt there some substitute or no?

AJC

[tuck]

Since I build furniture and cabinets, and do millwork - I am unfamiliar with the terms "HDU, MDO, Dibond, etc" can you explain?

I am assuming some kind of plastic material?

AJC

HDU = http://www.norvaplastics.com/precision-board.asp

"Precision Board" is just one brand and type of many.

[knight_toolworks]

OK makes sense. Ive brought in the kraft paper coated fir plywood for a few sign makers... that is what you call MDO.

The HDU, is that similar to the expanded urethane foam insulation? If it is so prone to cracking and so forth, isnt there some substitute or no?

AJC

yes not sure on the HDU may be the same but denser.

[letterman7]

Wow...in fifteen years of doing this and using both SignFoam and Duna I've never had a material failure other than paint, and that was lack of prep on my part. I've glued 3/4" mdo to backs of single faced signs and as a core on double face.. using 18# SF each time. Without more info on the Roswell sign it's hard to see why it cracked.. but I doubt it happened all by itself. Your university sign Joe... the back was painted dark versus the front - of course it's going to warp. Not picking a fight either... that just wouldn't have been my method of installation. And pvc? Only for small stuff. I use 1" for quite a few projects and it will warp in a heartbeat no matter how it's prepped on anything larger than 2' square. Interesting to see how stuff "works" across the country.

[kevin]

Joe thanks for the heads up .
I know there no price tags on your experince

[joe]

Rick,

I'm setting on the edge of my seat. After fifteen years of no failures, you gotta show us what you're doing. What I'm interested in is dimensional signs.

Do you have a website so we can see for ourselves. What's your company name and who are you?

Joe Crumley
www.normanssignco.com

[Ajcoholic]

Rick,

I'm setting on the edge of my seat. After fifteen years of no failures, you gotta show us what you're doing. What I'm interested in is dimensional signs.

Do you have a website so we can see for ourselves. What's your company name and who are you?

Joe Crumley
www.normanssignco.com


Joe, its in his details upper right hand corner...
http://www.tamartedesign.com/

[joe]

Thanks Andrew.

Joe Crumley

[letterman7]

I'll have to drive around to see if any of my old stuff is still up, Joe. I know I have HDU out there that's been hanging for at least that long.. I might be going by a couple places today - I'll try to get some photos.

[joewino]

We've never had a HDU sign crack but have had some run over by drunks...but that doesn't count as a failure to me.

Joe, you can look at my website or at any of the articles I've written. None of those have cracked. I've had some redwood panels crack, but never HDU, especially Duna.

[letterman7]

Ok, back from my morning run. I went by several locations to check my old signs and took some photos. Since we're limited to 5 photos per post, I'll break it down a little.
Oldest carved sign I have locally, 1.5" Signfoam, kerfed and curved, then laminated with a layer of 1/2" SF on the back to keep the curve before it went on the wall. Built in '97, measuring 2' x 4' and mounted with only two hanging brackets off the back, and looks almost as good as the day it went up - a little paint deterioration, of course:
14874

14875

Next one I could find was built in '98, double face 1.5" Signfoam with a 3/4" MDO core in the center, all glued and screwed. Brackets are only fastened from the ends. In the time it's been up it's been painted by the homeowner's group several times (and covering the gold leaf.. good plan there), but the structure itself is holding up fine. It measures a full 4' x 8'. There is some paint peel and a little delamination of the MDO, but nothing major considering it's 5' off on a major highway:
14877
14876

[letterman7]

Next set. This next sign is the only "failure" of material that I noticed, and it's the MDO I used as a backer. This was built in 2000, 2' x 6' x 1.5" hdu with a 1/2" MDO backer. I can't remember what I used to glue the backer on, but I obviously didn't get enough to it, nor did I fair in the edges like I normally do (must have been trying something different). The result is a warped MDO panel, but the hdu is just fine outside of really faded paint and some landscaper rash:
14883
14884

This next one was also built in 2000, again, 1.5" HDU double sided with a 3/4" MDO core. Letters are plastic Gemini stuff which are peeling color on their own, but the sign itself is basically the way I hung it, save for some lichens growing on the mdo! This one measures 60" x 32" (roughly).
14885
14886

And like Raymond, I've had HDU crack by someone vandalizing it with a baseball bat, but I've never had a failure of any just on their own.

[dan_nelson]

Hdu experts, If Im using this stuff for the first time and the sign is single sided hanging inside an alcove covered by a 12 inch overhang ,northern exposier. signs 30h x 60w your saying that it has to be backed with mdo? What glue do I use to hold it together? and stainless steel screws to cut down on the bleeding?Holes elongated and epoxied in? does it make since to sandwich the mounting brackets in the mdo since it wont be seen from the front? planning on using alum L brackets let into the mdo. Any other advice except to stick to furnature and cabinets?

[letterman7]

As long as you paint both sides equally and use either 1.5" or 2" 18# or 20# (preferred) I don't think you'll need a backer of mdo. I only back my signs for impact protection - much of my stuff is in neighborhoods where there are bored children. How exactly are you hanging this? Is it meant to not swing - can you use strap down the sides? My choice for hanging something like this would be a) long - I mean long (8" or better) screw eyes drilled and screwed right into the hdu from the top, then chain or whatever if it needs to move a little. For a permanent mount, I'd use the same width aluminum strap, 3/16" thick, and countersunk 2" stainless screws every 6 or 8" up both sides. Leave enough strap at the top to add either a hole to hang by or a piece of angle welded or bolted across each one to make it stationary. Paint the aluminum to match the sign up to the point it leaves the sign face.. you'll never see it.

[dan_nelson]

Rick thats exactly what I had in mind . The sign isnt going to swing. Hdu holds lags/screws well without epoxy? Thank You Dan Nelson

[letterman7]

I've never had an issue except on the lighter weights (15# and under). As long as you can get at least 2 1/2" of thread into the foam, you should be fine.

[joe]

HDU should never be a major structural element for a sign. I ALWAYS allow the sign to go along for the ride. Screws and chains will fail.

I'm not making this stuff up. Go to the website of Precision Board and read further about the proper ways to handle HDU.

Hanging Signs

"Do not attach a weight bearing screw or bolt directly into high density urethane. Because urethane has a cellular structure and doesn’t have grain, any weight bearing screw or bolt must have extra support around the threads. Hanging signs are typically hung from eye bolts that are either screwed directly into the sign or that are welded onto the supporting steel framework that is screwed into the periphery of the sign. Attaching eye bolts or weight bearing screws into urethane should be done by drilling a hole about 1 1/2 times larger in diameter than the eye or screw and about 1/4″ deeper than the length. Fill this hole with a very strong 2 part epoxy, such as EP-76 and insert the eye or screw down to flush with the surface. Try to keep the fastener in the center of the hole. Excess epoxy can be smoothed around the eye with any suitable tool dipped in mineral spirits. The epoxy holds the threads of the fastener and greatly increases the holding surface around the inside of the hole. This makes the fastener able to take much more load and eliminates the loosening effects caused by expansion and contraction of the fastener"

www.precisionboard.com/

I love using HDU as supplemental product. Here's an example of a Wood background, PVC white letters and gold logo from HDU. I'm not suggesting anyone follow my path with laminating up wood sign panels. I've been doing it long enough so the process is a pleasure. Also I have the equipment. The fact is, I Love Wood, and synthetics are just that. Poor substitutes for the real thing.

http://i38.photobucket.com/albums/e115/jcrumley1/IMG_2331-1.jpg

[sebago_signworks]

Dan, in my experience... and by all means Rick has done much more then I. Any fastener that is inserted into HDU needs epoxy/etc. joe, again... just beautiful.

[letterman7]

Joe, that is a beautiful sign! And you're right, the precision board site does say to pot the holes for hanging hardware. On the flipside, my own sign for my business is a 2' x 2' double sided all HDU panel with 6" screw eyes at the top, simply screwed in. It's survived almost three years so far hanging by itself... and surviving some powerful winds a year or so ago. To each their own, maybe I've just been lucky so far. By all means, if you feel safer potting the hanging hardware, go for it!

[gsmith]

I made a sign out of 1.5" SignFoam. We made an aluminum frame out of 1" square tubing. Drilled 6 holes and attached with stainless steel carriage bolts and put a nylon sleeve in the SignFoam. I have not noticed any problems, but we had a mild winter this year. We have two more signs we will be doing shortly.

[joe]

I think you're on the right trail. It takes something like what you've done to shore up the material.

It's a clean, professionally made sign. Good work. The double border is a plus.

Joe Crumley

[gsmith]

I forgot to add, we are changing the way we mount the 2 new signs.

4x4 with a vinyl cap. I will take pictures of the frame and post. The frame will run flush with the sign and then use a 2" angle aluminum and the attachment point to the post.

[joe]

I'm sure that will be a good idea. Again, I sure like the strong white double border.

If this was my project, I'd set the panel on their own massive posts, behind the sign, and have a flower bed below.

Joe Crumley

[sevans]

I haven't had any cracking problems with HDU. Not to say that it won't happen. I usually run 1/8" thick Aluminum Angle Brackets on the back of signs for attachment to frames. If they order double-sided, they get 2 signs...no if's and's or but's. Sometimes I back with Alumacore. I attach to HDU using the big fat wall drillers gorilla glued into panel. The work great. Up here there are way more wood signs that are bowed up just like the photo you posted, cracked, etc. My question to you is, where do you get wood that is cheaper than HDU? In my experience, wood has always been much more. I wish I had a better source. Are you gluing up your own panels? Best, Sarah Evans

[joe]

Sarah

I use HDU all the time and appreciate it for some work. It will warp like crazy if glued up to Aluma Pane, DiBond or any of the aluminum composite materials.

Your post has put me on that trail again. Tomorrow I'll glue up a stip and put it out in the sun and post the results.

The only reason I post on this forum is to help others like yourself. Please don't take any offence.

Joe Crumley

[Icarus]

I am going to attach this sign to a north facing wall above the front entrance to a pub. There is an overhang so there will be little exposure to elements. It is 15lb 2" signfoam. I was going to create a couple of small pockets in the back of the signfoam then attach a painted plywood backing, gorilla glued with bolts glued inside facing outwards and mount to side of building that way. (not sure if that's clear) There is an existing wooden sign with glued on letters, I thought I would just chip off the letters and use the flat wood already mounted to attach my bolts to. Any suggestions? Comments?
p.s. this sign still to be painted, so please no advice to paint... :)

[letterman7]

That looks fairly sizable, Ryan, and deeply pocketed. Gluing the plywood to the back is a good first step - personally I would use a minimum of 3/4" and nothing less. I'm not sure about the bolts.. sounds like it would work fine, but I think you might need more structure across the back if that sign is wider than 5'. Personally, I'd weld up a square tube frame to encompass most of the back of the sign (with the plywood) and put tabs off of that to mount your bolts to the existing sign. Use 2" tube, pre-drill it for 3/8" short lags in a few spots and epoxy it to the plywood. Find lag bolts that won't punch through the face in the spots where you pre-drilled and put those in place. Pre-drill those holes into the ply/hdu sandwich and put some epoxy in those holes before you anchor the lag screws. All that should give you a very strong (and heavy) sign that should not warp - ever.

Rick

[joe]

I'm not quiet sure about all that underlayment. Here is a simular panels that went up fast and has lasted for years. I bolted a back panel to the brick wall which is about an inch larger than the sign. I rounded over the edges and painted it black. The material is Extira. My sign is attached with four bolts which are covered up with the gold dots, top, bottom and sides.

http://i38.photobucket.com/albums/e115/jcrumley1/Hmeingways-Copy.jpg

Ryan,

I think a backer board larger than your panel would give you lots of flexability. I'd round it over and by painting is black or a dark color it would become a design element.

Joe Crumley
www.normansignco.com

[letterman7]

For some reason I missed the "bolted to the building" part. I thought it was a single face freestanding... not enough coffee today I guess. good lookin' sign there, Joe. Did you glue it to the Extira or just bolted it?

[joe]

You gotta allow it to move. No glue. I have a thick washer between these panels to allow moisture to escape. Looking forward to seeing the sign installed.

Joe Crumley

[chadagmsign]

I know that this post has not been very active recently but I wanted to post this since it is relative. I may make another thread to get some feedback just noticed post had almost 4600 views.

Let me know your thoughts!!

http://i896.photobucket.com/albums/ac166/chadagmsigncompany/100_7832_zps9121a6e0.jpg (http://s896.photobucket.com/user/chadagmsigncompany/media/100_7832_zps9121a6e0.jpg.html)

http://i896.photobucket.com/albums/ac166/chadagmsigncompany/100_7831_zps943de36c.jpg (http://s896.photobucket.com/user/chadagmsigncompany/media/100_7831_zps943de36c.jpg.html)

[gene]

Could the cracks be due to the size or does smaller foam signs crack also ? I have never made one from sign foam .

[joe]

Chad,

Good idea to start another thread on this topic.

When I first posted my concerns about HDU not holding up over time, it wasn't much of a concern. Today I use very little of this material because it's proven unworthy. I still like it for some 3D work but that's about all.

Many of us have tried all sorts of methods to get around the inherent it's softness and brittle qualities but it's just too much trouble. Some of the 15lb varieties are too time consuming to fill and paint. For those reasons I've moved on to cheaper and better products. One of them is .75" and 1"PVC.

The good things about the cracks, holes and chips with HDU, they can be filled, sanded and painted. It appears this sign is a free swinging one. If so I gotta tell you these are the most likely to have seperation problems.

Please tell us more about the project.