posted
Why is it everytime I see something on HDU everyone recommends backing it with Plywood?
I'm a red wood guy and I'm resisting HDU every chance I get (even tho I enjoyed playing with some HDU at Fred's meet this year)never the less I have repaired more than one HDU sign and it's always the same M.O. ? "ROTTEN PLYWOOD BACKER FAILURE"
In some of my repairs I have used 1/8" di-bond drilled full of holes then epoxyed it to the foam letting the epoxy oooz thru the holes and allowing it to set up.
Now I have something substantial to mount it with (you can even drill and tap it for easy removal)or even use tech screws for mounting purposes from the back ...even drill thru the foam and mount from the front side with a tech or lag screw then plug over the hardware with a copper plumbing cap or even a wood dowell.And the best part water can't get between the foam and the plate so...no rot.(not that the di-bind would rot anyway).
So again I ask... whats the point in using plywood when you know going in that it's doomed for failure?
Does anyone else have unique methods for backing HDU...ya never know I might want to do a HDU sign someday (when the redwood gives out)hey and thats another thing why can't they figure out a way to layer the foam when its ,made so when you blast it it looks more like wood...(I don't think much of the current method of "graining").
Just some questions that were on my mind
[ April 08, 2002, 08:04 PM: Message edited by: Monte Jumper ]
-------------------- "Werks fer me...it'll werk fer you"
First off.....we never use plywood as you speak of for the same reason you have noticed...We back all of our HDU panels with Aluminum......depending on size...anywhere from 080 up to .125. This also allows for an easy installation of the work.
We have been using the pelucid as a coating but have not yet tried the material after it has been outside. I am not totally convinced of it's effectiveness, but only because I have not checked it out after having been moisture cured.
We made our own grain frame and have found it to be pretty effective......the pouring or injection process for the effect you speak of would drive the price way over it's worth creating your grain value!
Hope that helps..also...did you get my email about the neats oil?
-------------------- Robert Beverly Arlington, Texas Posts: 1023 | From: Arlington, Texas | Registered: Jan 2001
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Every single one of our large mural carvings are backed with plywood. If it's mounted so you can see the back we use a finished birch on one side and no paint. We bond the panels, overlapping them, with PB240 & screws. Every single panel is double coated with Pelucid. We have large murals that have been up and exposed to our Montana weather for 6 years now, and they look like new. Sometimes Dad backs smaller carvings with Dibond, but if it's going to be 8' tall and 16' long, we use 3/4" plywood coated with Pelucid, painted or not.
Posts: 764 | Registered: Jan 2001
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I'm not going to endorse MDO as a backer either Monte. I've got some out there from years back, but for at least the last two years Dibond and PVC have replaced MDO totally, both as backers and as main substrates. We just installed two 3'x 8' Dibond panels today 10' up a pole - what a pleasure it was not to have to grunt up the ladder with plywood! I'm sold.
SONGPAINTER Original Sign Music by Sign People NOW AVAILABLE on CD and the proceeds go to Letterville's favorite charity! Click Here for Sound Clips! Posts: 1974 | From: Orleans, MA, Cape Cod, USA | Registered: Nov 1998
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Hi, sorry to barge in on the conversation but I'm going to do a carved HDU soon and had planned on backing it with plywood based on seeing a sign buddy doing the same thing.
Now I have second thoughts, but please tell me, what is "DiBond?" And what is "Pelucid?"
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I usually use Dibond. I have used .040 aluminum and when glued to HDU creates nearly the same strata (creates its own ply)... I'm wondering here???? has anyone used silicone as a sole adhesive, as opposed to pb40 or gorilla or pvc glues, as a laminating fastener with good life. I know the pvc types are totally waterproof, but don't care for their bonding power. Jack
-------------------- "Don't change horses in midstream, unless you spot one with longer legs" bronzeo oti Jack Davis 1410 Main St Joplin, MO 64801 www.imagemakerart.com jack@imagemakerart.com Posts: 1549 | From: Joplin, MO | Registered: Mar 2000
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About 6 yéars ago I made the same mistake backing HDU with plywood. I use aluminium too, either by routing into the back of the sign and then setting a profile in the groove, or by building a box section aluminium frame on the back to span the width and use to attach mounting brackets on the side, we also use plaster board fixings for all screws, works great.
Grain fraim signs always look too manufactured (uniform) We made our own frame that is much less uniform and gives more life to the "grain effect".
We tried to buy a container load of either PB or Sign Foam here between several companies, the main one being a tool maker, but neither US company was prepared to offer a discount, same price for 100's of sheets as it was was for 1. I guess we work abit differently in Europe.
We have now found a great HDU product that is much more dense than Sign Foam or PB no holes in it at all, Its abit more work to blast, but paints without fillerprimer and is much stronger out in the open.
Its a board that is also used for industrial prototype toolmaking, and comes in several densities, and sizes.
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I've been carving SignFoam for fourteen years. I was probably one of the first to back it up with mdo, and I still do it. No failures. No problems. It's all about sealing.
-------------------- Steve Purcell Purcell Woodcarving & Signmaking Cape Cod, MA
************************** Intelligent Design Is No Accident Posts: 900 | From: Cape Cod, MA | Registered: Oct 1999
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I use alumalite with silicon. The largest sign is 8x8 2 sided between 2 posts. No problems, yet. I also use silicon for plastic & metal letters. Have yet to have a failure. With alumalite, you can cut the sign 1 inch bigger on the sides and groove the posts to accept the alumalite, makes a nice clean install.
-------------------- Carper's Signs 594 Union School Rd. Mount Joy, PA 17552 carpersign@earthlink.net Posts: 157 | From: Lancaster, PA, USA | Registered: Aug 1999
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Bingo, Steve. It's all about keeping the damn water out. We use plywood or MDO on larger HDU signs, and ALWAYS seal up the edges with West System. I've also used West System and fiberglass cloth as a backup and stiffener, though admittedly it's more work. Lately I have also used heavy-gauge aluminum - dibond seems a bit pricey for a backup. Expecting paint alone to seal edges on plywood is asking for trouble.
Speaking of HDU, we are just finishing a 5'x8' DF carved sign, using two sheets of 1" HDU and a 1/2" plywood "core". The core is split in two places to allow for 1/2" stainless-steel rods that run all the way through the sign and stick out both sides. The ends of the steel are threaded so that we can bolt on our side brackets, which lag into the posts. The whole job took almost a gallon of West Sytem to glue up and seal the edges, but for a sign this size (and at this price) we didn't see any point in cutting corners.
-------------------- "A wise man concerns himself with the truth, not with what people believe." - Aristotle
Cam Bortz Finest Kind Signs Pondside Iron works 256 S. Broad St. Pawcatuck, Ct. 06379 "Award winning Signs since 1988" Posts: 3051 | From: Pawcatuck,Connecticut USA | Registered: Nov 1998
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Hey, can anyone answer Peter's question? I too would like to learn a bit. He asked what is Dibond and Pelucid and how are they used?
I am assuming that the "backers" that everyone is talking about are needed because the HDU foam being used is quite thin?
I have done only 3 sandblasted signs, but I used 2" Signfoam (high density)and didn't use a backer at all. The 2 larger signs were approximately 3' X 6' or 7' long. I'm a bit of a greenhorn when it comes to blasted signs and mounting systems.
All of the signs were mounted by the customer and amazingly, one of them which was very "wobbly" is still up....I'd post a picture but have no way to do it (that I know of).
So, I would appreciate anyone taking the time to outline their normal procedure, explaining products used, what these products are, and what purpose they are used for...right down to different mounting techniques.
I know this is a lot to ask...I would be very [humbly] thankful for the education.
Best regards to all,
-------------------- Todd Gill Outside The Lines Potterville, MI Posts: 7792 | From: Potterville, MI | Registered: Dec 2001
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Todd, Most HDU pieces of any size are flimsy in stature. There is nothing to substantial to get a hanger or screw to hang it with, without screwing directly through the face onto another stiff substrate or wall. I have heard of drilling 4 inch deep undersized holes into HDU, filling with some gorilla glue and threading in some 4 to 6 inch eyescrews. One sign man says it becomes one and works like a champ. I have never quite trusted it enough to take the gamble. To answer your questions, peludid is a product made by the people that mfg. POR 15, and is distributed by Pierre here on the bb. It is a tough clear coating. He can fill you in on the details, but a search engine will probably get you to some paperwork. Dibond is aluminum laminated on solid pvc plastic on both sides similar to alumalite, but in my opinion a much better and product at about the same costs. You can cut the edges into any shape and expect a nice edge to finish. It is less damageable overall, but is fragile. It comes in 2,3,and 4 mil which is equivelant to 1/2 thru 1/4 inch. I'm am currently doing a job for myself, where I am using all of these products, and will take photos for a step by step. This install will include a pair of steel hangers to attach to the Dibond (which is not strong enough for a heavy hang with the added adornments). They should prove to grab the sign like a pair of hands, and will hide in the process that I will show. Watch for this step by step in about a week. Jack
-------------------- "Don't change horses in midstream, unless you spot one with longer legs" bronzeo oti Jack Davis 1410 Main St Joplin, MO 64801 www.imagemakerart.com jack@imagemakerart.com Posts: 1549 | From: Joplin, MO | Registered: Mar 2000
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What we do here is either rout grooves into the sign back and insert some aluminum angle, usually two to three of them, depending on the sign, which adds a good deal of rigidity. Or we weld up a frame out of aluminum square tube and embed it in the back.
This second method works great on double faced signage as you can weld some flat stock to the frame to provide a mounting method. You can get a 3" thick sign this way by sandwiching two pieces of 1½" HDU together. Here's a pic. of a sample piece that we made to show to our clients.
We do not use MDO as a backer because the man hours involved to properly seal the stuff makes it cost prohibitive, but it can be done provided the MDO is sealed correctly.
-------------------- Jon Androsky Posts: 438 | From: Williamsport, PA | Registered: Mar 2002
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My Dad can't be here for a while because of Mom's surgery, but I think I can help about Pelucid. If you go to our website you can see how it works and read about it, but it's a one part clear that was made for Semi trucks frames to stop rock and sand from chipping the paint. If it works on Semis, then it works on signs that stand still. That's what my Dad thought 6 years ago and every one of our permanent signs, carved, painted and vinyl film get coated with Pelucid. We sell it to a Bus Stop Bench company that puts ads on all the benches where people sit. There's no more vandalism. If you finish coat anything with it, including plywood, it permanently seals it against any weather.
Posts: 764 | Registered: Jan 2001
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I'm with Todd on this one. The only backing I add is 2-2x4 horizontal cedar pieces with bolts thru and into an oversized hole in the HDU which is filled with West Epoxy resin. Pieces are clamped overnite and ready to be mounted the next day.
-------------------- Mario G. Lafreniere (Fergie) J&N Signs Winter did show up! Posts: 1257 | From: Chapleau, Ontario | Registered: Jun 1999
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Hey thanks everyone! I'm starting to visualize this a bit more. 2 HDU signs I did were bolted directly into posts with the third being mounted directly on the side of a pole building....
I am very interested in different types of mountings...
John, that is pretty cool how you add the aluminum....how exactly would the piece you have pictured be mounted? I'm a little fuzzy on this.
Jack...thanks for the advice. Please give me a "heads up" when you get your step-by-step done...I am really interested in checking it out...and will also keep a lookout for it.
How would one rig up a "hanging" type mounting system for HDU for say, hanging a blasted sign from a sign bracket or off an (upside down) "L" wood post type configuration?
Thanks everyone for the explanation on Pelucid and the backer boards.
By the way, how is the Dibond mounted to the HDU? Thanks.
-------------------- Todd Gill Outside The Lines Potterville, MI Posts: 7792 | From: Potterville, MI | Registered: Dec 2001
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Todd, In this example you'd mount the sign between two posts. Do you see how the flat stock extends beyond the ends of the signface? Well what you would do is drill through the flat stock perpendicular to the signface and screw through it into your post.
We've also done this for double faced hanging signs where the flat stock extends beyond the edge of the sign just enough to get your chain connector through.
For lighter hanging signs, I like big ol' eyehooks with the pilot hole filled up with epoxy.
For heavy double faced hanging signs, we've used machine eyehooks threaded into an interior aluminum structure, like this: The tops of the vertical aluminum tube supports are capped with either ½" or ¼" aluminum which is drilled and tapped to accept the eyehook.
-------------------- Jon Androsky Posts: 438 | From: Williamsport, PA | Registered: Mar 2002
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THe fixing I use is very similar to that pictured in Jonathan's post, if we use an aluminium frame on the back I then screw it on the sides as we weld brackets with spacers to the posts, and thru the back. I use plasterboard fixings, they are aluminium plugs that we screw into the HDU and then you can screw a regualr screw into them, they sit really tight, I have never screwed right thru a sign, I made some hanging signs that were 2" thick I then mounted a stainless band around the sign, and welded hooks on the top side. I have also made HDU with a stainless frame slid the whole block into it and thén attached an end piece and finished off with dome nuts.
posted
Thanks for these descriptions Jonathan and Ken....the drawings and visuals really help in addition to your explanations too.
Looks like I need to learn how to weld. Although, a buddy of mine is pretty good at it.
Now....what do you guys use to glue the two halves of the HDU together? I have heard of Gorilla Glue being used. Is this what you would recommend to "sandwich the two sections of HDU around the aluminum framework?
I don't do signwork as my full-time job....it's kind of a hobby that directly relates to my "real" job. I mainly work in vinyl....but like the artistic and dimensional qualities of HDU stuff. Maybe I can get to a meet sometime and see you pro's in action.
Tell you what...I'm gonna email you a photo of one of the signs I did out of HDU....please feel free to critique it for me. I like constructive criticism....it's how you learn and get better right?
Thanks again.
-------------------- Todd Gill Outside The Lines Potterville, MI Posts: 7792 | From: Potterville, MI | Registered: Dec 2001
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thanks for putting out the call to get those questions answered. The reason HDU is backed is not because it's thin, but because it's brittle.
The first HDU I naively did was not backed and mounted between two posts for a library. Some kid came along and karate-kicked it in half. How did he know it would snap?
Another time I had a 3x8 on the shop bench which hadn't been backed (it was going flush on a wall so didn't think it needed to be backed). I just finished carving it and called for someone to help me flip it over to begin priming the back.
As we turned it over and let it down on the table, one corner landed (gently) on a half-pint can of One Shot on the table. You just heard a *snap* and we looked at each other in disbelief. That little bit of stress cracked a one-foot section off the end of the sign, right through one of the carved letters ( where the sign was even weaker because of the thinner carved area). You wanna see a grown man cry?
posted
Jonathans' method works great for 2 sided signs. I used 2 inch wide by 5/8's steel instead of aluminum. This also stiffened the sign considerably.
Another method for a single sided sign with poles set apart narrower than the sign width is to route two channels in the back a little deeper than the thickness of the steel. The channels should be a little longer than the distance between the outside (or inside, whichever side you want your mounting flanges) of the poles.
Weld a 3 inch plate, (drill your bolt holes first) to each end. Now you have the equivalent to an "L" bracket at each end. Mix up some West System Epoxy or SignShine Resin and pour a thin layer into the channels. Drop in your steel, align them parallel and square. Then fill the channel flush to the surface with more epoxy. Brackets and stiffener in one piece.
My local machine shop makes these brackets for me cheap.
-------------------- Dave Sherby "Sandman" SherWood Sign & Graphic Design Crystal Falls, MI 49920 906-875-6201 sherwoodsign@sbcglobal.net Posts: 5397 | From: Crystal Falls, MI USA | Registered: Apr 1999
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Thanks guys....this has been a real education for me. The descriptions are great, but if you get a chance to post or email me a photo of the different techniques you are describing...that would be icing on the cake.
I tend to be real visual...show me a drawing or picture and I go, "Oh, I get it". Guess I'm kind of dense that way.
Thanks again.
-------------------- Todd Gill Outside The Lines Potterville, MI Posts: 7792 | From: Potterville, MI | Registered: Dec 2001
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Although, a buddy of mine is pretty good at it.![[Confused]](confused.gif)
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