Cutting HDPE panels

[Tom Bachman]

Hey guys...I was asked last night to cut some letters out to label a building. The letters will be about 12" tall and probably mounted to a Extira or another HDPE backer. I told them we could cut them out of the HDPE panels and the letters will be white, so I was thinking HDPE would be a good choice. Thinking I'll use 1/4" but maybe 3/8" would be better.

Any hints, suggestions or other help you can give me on cutting this material would be great. Does HDPE screw well? Thinking screws through the backing into the letters, so the fasteners don't show.

I could use Extira for the entire thing, but that would require maintenance down the road, and I think they are trying to minimize that.

[jerry_stanek]

I would use something other than HDPE for this as it is hard to glue up. We use Sintra for this and pocket the letters for easy assembly.

[chiloquinruss]

Jerry, if you pocket a sintra backer to place the letters into, how do you stiffen the backer? Is the stiffener part of the hanger for the backer? I love working with sintra but just for my models not for the signs I do. Just askin'! ;) Russ

[steve_g]

Use PVC… You can get it in white or black or it easily paints. You can prism cut or round the edges with Type 1 PVC… not so with the foamed products like Sintra.

SG

[Logan Y.]

I would use something other than HDPE for this as it is hard to glue up. We use Sintra for this and pocket the letters for easy assembly.

I agree. If by hard to glue up you mean almost impossible. The only way I've found to reliably join HDPE is to weld it together.

[jerry_stanek]

I use 12 mil PVC or Sintra and only pocket it .062 just enough to set the letters in. I also use the 6 mil for the letter that gives you a nice dimensional look. Most of the signs I do are mounted to a wall

[Tom Bachman]

OK, don't use HDPE.... Where to purchase the PVC or Sintra?

[Tom Bachman]

I like the idea of being able to prism the top of the letters.

[steve_g]

I get mine at Allied plastics… do you have a commercial plastic supplier nearby, or a sign supply house?
SG

[Tom Bachman]

No, I live in rural America. Was hoping that HD actually had the 3/4" PVC sheets they list on the website........no such luck. I'll check out Allied.


I get mine at Allied plastics… do you have a commercial plastic supplier nearby, or a sign supply house?
SG

[ron_moorehead]

What glue do you use to glue the Sintra to it self? Do you have problems with the Sintra expanding as it gets warmer or colder?

[jerry_stanek]

I use the pvc plumbers glue from the borgs

[robtown]

What glue do you use to glue the Sintra to it self? Do you have problems with the Sintra expanding as it gets warmer or colder?
Some years ago I worked on a project that required me to “laminate” a sheet of yellow 1/4” pvc between two sheets of white 1/4”. I initially tried pvc glue.
My first attempts were not successful as when I tried to cut parts from the laminated pvc sheets, a lot of them were delaminating.
I called the manufacturer of Sinatra and talked to an engineer, he advised me to try straight MEK, it actually melts the pieces together. Pvc glues, he said, contain fillers and additives that can get brittle.

[jerry_stanek]

The pvc glue that I use seems to melt the sintra togther

[gundog]

I make parts from HDPE all the time and screw them together I use Starboard it is UV stabilized and made to be in the weather. I use at least 1/2" thickness for screwing but it can be glued using 3M 8005 a fast setting 2 part epoxy it is not cheap and requires a special gun with mixing tips. I am not a sign guy so I can't say it is the best material for your application but it does hold screws well and can be glued.
Mike

[steve_g]

When I assemble Sintra, straight MEK has worked well with no color staining. So far when using heavy type 1 PVC I’ve mechanically fastened it…

These 1” thick letters were screwed into the cedar sign from the back

SG

[Tom Bachman]

That's an attractive sign Steve! Very nice.