Best fasteners for mounting alumacore

[Pixels Are Bad Mmmkay?]

We may be picking up our first large scale vinyl sign job and I need opinions on the very best fasteners to mount alumacore substrate to a galvanized steel frame. To better explain I've included a photo of the signs framework that the 4' x 8' sheets will be attached to. I would prefer a fastener that's not too noticeable but perhaps something that will self tap into the frame work. Also any advice for mounting alumacore like this would be greatly appreciated. The sign frame is 48 feet long and 8 feet high. We plan on using 6 full size sheets and 2 3/4 length sheets on the top. We would be doing two of these, as there is one on each side of the building, so 16 sheets total.

Thanks for any advice.

 

[OlsonSigns601]

I wouldn't use Alumacore as bugs, dirt, snow, ice, water will get into the holes. Plastic End Caps will get weathered, brittle and break off over time and only do so much to keep moisture out.

I would go with a 3mm or 6mm Poly - Metal.

Also, if you drive the screws in to much they will buckle the Alumacore.

Self Threading Screws strategically placed would be the way to install.

Using ones with Rubber Washers would be good if you are putting them over your vinyl. Be sure not to drive them in to much especially when going over your vinyl as it may cause your vinyl to rotate a little over your letter giving it wrinkles around your screw hole.

Also use a hex or square head (not Philips) head especially if you are using a ladder to get up there as it will be easier to control the drive.

Good Luck.

-Edit - Just notice you probably be able to stand on the roof. Which is good but I would still go with a hex or square head.

 

[DizzyMarkus]

Those screws (hex head) you are referring to are for steel roofing and can be bought in tons of colors at your local lumberyard. Self tapping with a small aluminum capped rubber washer. They usually use a 1/4" drive

Markus

 

[visual800]

if this were my job I would use .063 or .040 and get them 12' long. as i would overlap the panels about 1", not another substrate.
also depending on the frame I would use self tapping SS or run some SS 1/4" bolts with locknuts thru it. once again i said depending on the frame. we use alot of SS screws and fasteners cause there is nothing tackier than rust from these bolts you buy. either SS or galvanized

 

[OlsonSigns601]

if this were my job I would use .063 or .040 and get them 12' long. as i would overlap the panels about 1", not another substrate.
also depending on the frame I would use self tapping SS or run some SS 1/4" bolts with locknuts thru it. once again i said depending on the frame. we use alot of SS screws and fasteners cause there is nothing tackier than rust from these bolts you buy. either SS or galvanized

Good Point. I got 3 huge boxes all stainless steel "Steel Roofing" screws at an auction a couple years ago for $50. Sold 1, kept two still haven't opened the last box. It was a good investment.

The price on a sheet of Aluminum 12' long is going to cost at least 5x more than a 4x8 sheet of Poly Metal especially if you went with .063 and no one is going to notice the seem in the poly metal that high up.

 

[bob]

Go with the Nudo poly metal if you can.

If all you have available is Alumacore or some other product with a corrugated core it won't be the end of the world. It's not that crap gets into the flutes, if it does so what? It's that it's trickier to screw to anything without crushing or at east dimpling it. You can crush and/or dimple poly metal also but you have to try harder.

Use stainless fasteners. Never use ferrous fasteners with aluminum. The don't play well together.

Don't worry about rubber washers, you're not sealing anything.

If it were mine to to I'd pre-drill clearance holes in the substrate. You don't want the fasteners to take a bite out of the substrate.

I'd use 3/16 maybe 1/4 stainless self-tapping hex head sheet metal screws. You may or may not want to drill pilot hoes in the supporting framework. Depends on the physical position you have to assume and your balance when you're attaching the sheets.

If you use the corrugated core material then you really ought to use a fender washer on each fastener to spread the load. With the poly metal it's not necessary to use any sort of washer.

 

[Craig Sjoquist]

I found a plastic caps for screws at Ace hardware came in white & black all sizes.

Just found them had a alumcore signs to mount worked great for a cover up, I also just paint over & or vinyl over.

 

[Pixels Are Bad Mmmkay?]

Thanks for the great responses. We were figuring on going with stainless self tapping screws but I figured it wouldn't hurt to get other opinions. I had also considered the self tapping hex screws colored to match the ivory panels but I'm afraid those will be very noticeable even from the ground level. Then again, most people will probably be viewing the sign from at least 20 feet away so maybe I'm just being overly particular.

 

[J Hill Designs]

dont forget polymetal expands - make holes in poly metal larger than the screw's bore to allow for expansion, and only screw in hand-tight

 

[Mosh]

Use .040 and make it a "pan box", then there will be NO screws on the face at all.