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Dimensional Sign with HDU

cschinny

New Member
Hello everyone,
I am working on an outdoor dimensional letter sign. I have never worked with HDU before but would like to use it for this project instead of MDO.
Plan on using 15# or 20# HDU 1 1/2" thick with 3/8 Threaded rod placed every 8".
The Sign will Standoff 1 1/2" from the wall with vinyl siding and 1 1/2" OSB under the siding.
Will HDU warp over time without using a back support?
Can I use 15# HDU or should I use 20#.
Can I use Epoxy to Attach the threaded rod and Will it hold in HDU?
I have attached a photo of what I am Looking at
Thanks
Cory
 

Attachments

  • WCS Front Dem.pdf
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Gino

Premium Subscriber
What is the overall size of the backboard/sign itself ?? Your dimensions show the letter sizes, but not the board. Or, are these just gonna be cut out letters, painted and mounted directly to the wall ??
 

cschinny

New Member
What is the overall size of the backboard/sign itself ?? Your dimensions show the letter sizes, but not the board. Or, are these just gonna be cut out letters, painted and mounted directly to the wall ??
They are going to be mounted directly to the wall
 

GB2

Old Member
I am working on an outdoor dimensional letter sign. I have never worked with HDU before but would like to use it for this project instead of MDO.
I would never use MDO for those letters, almost anything else would be a better choice...HDU, PVC, Aluminum, ACM, Acrylic

Plan on using 15# or 20# HDU 1 1/2" thick with 3/8 Threaded rod placed every 8".
I'm not sure I understand, you plan on using an 8" grid to place mounting studs? That would be far too many on the larger letters and not appropriate on the smaller ones. You just need to use 2-6 studs appropriately spaced for each letter or unit. How are you proposing to use these mounting studs? Ideally they would have through bolted solid attachment to the wall with fasteners on the back side such as nuts or snap toggles. Do you have access to the back side?

The Sign will Standoff 1 1/2" from the wall with vinyl siding and 1 1/2" OSB under the siding.
If you will be standing off you will probably need some sleeves, tubing or something else to stand them off. That is unusually thick OSB.

Will HDU warp over time without using a back support?
It can but I don't think you'd have a problem with those letters as proposed.

Can I use 15# HDU or should I use 20#.
15# is fine, 20# is better but not necessary for this, depends on the budget and the desired result

Can I use Epoxy to Attach the threaded rod and Will it hold in HDU?
You can, it would probably be fine for what you propose. How do you plan to accomplish this, mount studs in the wall, put epoxy in pre-drilled holes in the back of the letters and then push them on to the studs or do you have access so you can epoxy the studs into the letters and then place them into pattern drilled holes in the wall so you can then secure them from behind with nuts?
 

gnubler

New Member
I worked on my first HDU sign recently and it was the most stressful nightmare project of the year.

You probably have more experience than me, but you need to have the right shop space and tools to work on it. Sanding, painting, etc. In my case it took over my small shop and caused much grief. It's also really expensive material, if something goes wrong.
 

cschinny

New Member
Gary,
Thank you for your response. I do not have access to the back of the wall, what I was thinking is templating and the drill holes on the wall. epoxying the the thread rod to the back of the letters (I would use spacers between the letters and wall) and then use PL Ultimate to secure the thread rod to the building. After reading you post this might not be the best idea.
 

cschinny

New Member
I worked on my first HDU sign recently and it was the most stressful nightmare project of the year.

You probably have more experience than me, but you need to have the right shop space and tools to work on it. Sanding, painting, etc. In my case it took over my small shop and caused much grief. It's also really expensive material, if something goes wrong.
Thanks for the input. I have a paint shop and was going to cut the letters with my CNC. In the past I used MDO but was hoping to cut done on the filling and sand time with HDU.
 

Gino

Premium Subscriber
Do you or the customer have a budget in mind ?? I mean did you get a feel from them if you haven't quoted ??

Using the hdu, you are increasing your costs on just about every avenue, from materials to handling, painting and installing. Regardless of what substrate you use, you're always gonna have a mess in the air til the cutting, sanding and finishing is completed. Finding all of this out beforehand is great.

Also, too much space between the 'W' and the rest of the word. What is the stroke on the 5" letters ?? Looks like you'll blow them apart with 3/8" studs. Ya might wanna rethink using 3/16".

If you re-group and mount this to a free-form back panel, I think you can do what you want for much less cost, but it'll still be expensive..... mistakes or not.
 

cschinny

New Member
the budget is $3000.00 but they do not want any back panel. They want the letters to look like they are floating.
 

Gino

Premium Subscriber
If that is their budget, that doesn't allow you enough to fab and instal it all and leave room for overhead, profit and taxes. That's at least a $6,500 to $8,000 sign according to your installation and time.
That'll barely pay for materials and time, let alone finishing things. I calculate, you'll need two sheets of hdu. I only know of it coming in 4' x 8' sheets. With hdu, it needs lotsa sanding with two coats of good thick prime and maybe 2 or 3 top coats. Calculating your studs for the back, making the pattern and drilling all those holes and setting them in, let alone doing it again on the building........... I'm afraid you short changed yourself.
 

gnubler

New Member
Agreed with above. I ate $hit on my HDU project not realizing how much production time it would end up taking, it was a major learning lesson.

There's a great series of Youtube videos about making HDU signs from a shop in California, Signs by Van. They make it look so easy...it wasn't!
 

kenkelsey

New Member
Hello everyone,
I am working on an outdoor dimensional letter sign. I have never worked with HDU before but would like to use it for this project instead of MDO.
Plan on using 15# or 20# HDU 1 1/2" thick with 3/8 Threaded rod placed every 8".
The Sign will Standoff 1 1/2" from the wall with vinyl siding and 1 1/2" OSB under the siding.
Will HDU warp over time without using a back support?
Can I use 15# HDU or should I use 20#.
Can I use Epoxy to Attach the threaded rod and Will it hold in HDU?
I have attached a photo of what I am Looking at
Thanks
Cory
We use HDU all the time. About $459 for a 4 by 8 15# sheet. Will not warp or wrot
Hello everyone,
I am working on an outdoor dimensional letter sign. I have never worked with HDU before but would like to use it for this project instead of MDO.
Plan on using 15# or 20# HDU 1 1/2" thick with 3/8 Threaded rod placed every 8".
The Sign will Standoff 1 1/2" from the wall with vinyl siding and 1 1/2" OSB under the siding.
Will HDU warp over time without using a back support?
Can I use 15# HDU or should I use 20#.
Can I use Epoxy to Attach the threaded rod and Will it hold in HDU?
I have attached a photo of what I am Looking at
Thanks
Cory
We use HDU all the time. 4 by 8 sheet, 15# cost about $430. I would use 15# for dimensional letters. If painted on all sides, front and back, it will not warp or wrought. Studs hold in well with 2 part expoxy. We use West System marine expoxy and 1/8 inch diameter studs, approximately 4 to 6 per letter. HDU does require sanding, but its soft material and sands quite easily. PVC would be less costly, but the sanding is much more time consuming. Agree with others, not use MDO. After it is machined into letter shape you have exposed wood edges which have to be sealed. Sanding MDO is much harder than sanding HDU.
 

Emidio

Your Source for Signs
Hello everyone,
I am working on an outdoor dimensional letter sign. I have never worked with HDU before but would like to use it for this project instead of MDO.
Plan on using 15# or 20# HDU 1 1/2" thick with 3/8 Threaded rod placed every 8".
The Sign will Standoff 1 1/2" from the wall with vinyl siding and 1 1/2" OSB under the siding.
Will HDU warp over time without using a back support?
Can I use 15# HDU or should I use 20#.
Can I use Epoxy to Attach the threaded rod and Will it hold in HDU?
I have attached a photo of what I am Looking at
Thanks
Cory
Cory,

This is how I handle HDU Letters.
I use 1"dia pads from Gemini with 2" studs
I drilled a 1" diameter hole that was 1/2" deep at each stud location on the back of the letter.
First, I dry fit each pad and stud in its location to open the hole slightly.
Then I fill each hole halfway with 2 part epoxy and insert the pad and stud.
I attached a picture showing this with a 1/12: thick HDU Letter.

You can also just drill a hole that is slightly larger than your stud, insert stud and fill with epoxy.
 

Attachments

  • HDU Letter.jpg
    HDU Letter.jpg
    3.5 MB · Views: 19

cschinny

New Member
Agreed with above. I ate $hit on my HDU project not realizing how much production time it would end up taking, it was a major learning lesson.

There's a great series of Youtube videos about making HDU signs from a shop in California, Signs by Van. They make it look so easy...it wasn't!

Cory,

This is how I handle HDU Letters.
I use 1"dia pads from Gemini with 2" studs
I drilled a 1" diameter hole that was 1/2" deep at each stud location on the back of the letter.
First, I dry fit each pad and stud in its location to open the hole slightly.
Then I fill each hole halfway with 2 part epoxy and insert the pad and stud.
I attached a picture showing this with a 1/12: thick HDU Letter.

You can also just drill a hole that is slightly larger than your stud, insert stud and fill with epox

Cory,

This is how I handle HDU Letters.
I use 1"dia pads from Gemini with 2" studs
I drilled a 1" diameter hole that was 1/2" deep at each stud location on the back of the letter.
First, I dry fit each pad and stud in its location to open the hole slightly.
Then I fill each hole halfway with 2 part epoxy and insert the pad and stud.
I attached a picture showing this with a 1/12: thick HDU Letter.

You can also just drill a hole that is slightly larger than your stud, insert stud and fill with epoxy.
Thanks for info. This is what I was thinking.
 

GB2

Old Member
That's an interesting method with the pad studs but the bigger issue is how you will secure the letters to the wall. You could drill pilot holes in the siding and OSB, thread the studs into the OSB, put expoxy in pre-drilled holes in the HDU letter backs and then press them into place over the studs in the wall with spacers on them. I always prefer some sort of mechanical fastening to the wall, which is usually code in most places too. Gluing stud mounted letters to a wall is generally an interior method of installation or possibly for exterior masonry installations with a product specifically approved for that purpose.
 

TSC1985

New Member
Have you looked into wholesale companies for HDU letters? ArtSignWorks in CA and Howmac are great providers.
 
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