Rails on my Leer topper - to drill or not to drill, through that is...

Okay...not sure if this belongs here but it is drillin and cuttin, just on a truck topper.

I just picked up a new truck and a Leer fiberglass truck topper and want to put my old Yakima system on to haul my yak around.  I picked up a set of the 60” rails to mount onto the top of the topper.  On my old vehicle I had a thin fiberglass top and when I installed the Yakima rails, I drilled all the way through following Yakima’s factory mounting instructions. 
I have seen a few factory installs on Leer / Snug tops where they used 60” Yakima rails and they did not drill all the way through the top.  It seems the eisther used self-taping screws, or only drilled into the first layer of fiberglass, not all the way through the top and it seems to be working.  My question(s) is: Does anyone have this set up?  What type of screws did you /they use? Have you had any issues with the install?  Anything you would have done differently?

I'd sure love some input before I start drilling holes into a $1,500 piece of fiberglass.

I have a older style LEER top from my Tacoma that I've since taken off, but can't figure out how you would only drill through a single layer of fiberglass, let alone screw anything to just that. If I'm not mistaken, the fiberglass is thick but is built up with several layers. The inside has outdoor carpet that is glued on.  For a clean secure leak proof fit, I recommend drilling all the way through and use stainless hardware.  On the top surface, I'd suggest a light sanding where the rack's landing feet will meet the gelcoat/paint.  Apply a thin layer of Marine goop to both sides of any gasket that will be used under the landings. Also, apply the Marine goop liberally to the threads of the bolt where they will make contact with the hole.  Use large wide washers on the backside of the hole, as well as Nylock nuts to secure everything from coming loose over time.

I drilled through the top of my Snugtop on my Tacoma to mount my Yakima system.  I used the "Landing Pads" and "Control Towers" so that I could take the rails off when I'm not carrying a kayak around.  I used a wax pen to make the measurements - I did a lot of eye-balling as well.  Make sure you check out the underside of where you plan to drill.  My Snugtop has a extra thickness section that is positioned directly underneath the most flat part of the roof.  If you happen to end up drilling on the edge of that, you'll have to bend some washers to make them fit against the ceiling properly (DAMHIK  )  As INSAYN mentioned, use a sealant on the topside.  I used Marine Goop and it works great.  I simply put a ring of goop around the hole and put a little around the bolt before slipping it through the hole.  I used nylock nuts as well.  Also as INSAYN mentioned, use all stainless.

I'm with Insayn, not sure how you'd drill through partially, much less get a secure hold. When I did mine, I drilled all the way through. Can't remember what Yakima parts they were (it's been over 10 years), but installation was easy, although drilling holes was scary. Think I just used the included rubber gaskets, but the layer of Marine Goop is a good idea. Another good tip I got was to use a wood block pressed against the back of the camper while drilling. Supposed to help minimize the vibration & splintering of the fiberglass.

Good luck!
Brian

Okay...not sure if this belongs here but it is drillin and cuttin, just on a truck topper.

I just picked up a new truck and a Leer fiberglass truck topper and want to put my old Yakima system on to haul my yak around.  I picked up a set of the 60” rails to mount onto the top of the topper.  On my old vehicle I had a thin fiberglass top and when I installed the Yakima rails, I drilled all the way through following Yakima’s factory mounting instructions. 
I have seen a few factory installs on Leer / Snug tops where they used 60” Yakima rails and they did not drill all the way through the top.  It seems the eisther used self-taping screws, or only drilled into the first layer of fiberglass, not all the way through the top and it seems to be working.  My question(s) is: Does anyone have this set up?  What type of screws did you /they use? Have you had any issues with the install?  Anything you would have done differently?

I'd sure love some input before I start drilling holes into a $1,500 piece of fiberglass.

I would call rack attack in Portland and ask them what the options are. This is all they do. http://www.rackattack.com/

Oh and be sure to use a nice sharp drill bit, and drill at a moderate speed. 

  Snug-top shells (At least mine) are made with a dual layer top, meaning there is a small air gap between the outter and inner layer.  I think it's filled with a  web'd or honeycombed material in between the 2 layers to help with strength.
  If you choose to go all the way trough, with the mounting hardware, just use some type of sealant and you'll be ok.  My yakima rack is installed on the sides of my shell, using the gutter mounts.  One advantage I've found by using the gutter mounts is I use the mounting bolts from both sides inside, to support a web rod holder ( Strap thingy with loops to support up to 7rods)
 

Thanks for all the input.  I do have the factory mounting system, so drilling through is what they suggest.  I called a local topper place, they suggested using stainless 1/4" self-taping screws in the double layer portion of the topper.  I asked about why and the guy replied "it looks a lot cleaner from the inside."  Cleaner is cool, but I'm partial to function over form.
 
I usually haul around an OK T13 on my yakima mako saddles, so weight is not on issue and wind push from the side is minimized, but I just can't stop thinking about how thin of bite that is.
 
So...I am leaning towards drilling through and following all the advice with the marine goop, sharps bits etc.
 
The next question I'll scratch my head over is how wide to make the stance of the rails.  I've been looking at 33.5" (basically the width of the hinges of the topper)and staying on the thicker part of the topper. 
 
Any advice on this aspect?
   

The next question I'll scratch my head over is how wide to make the stance of the rails.  I've been looking at 33.5" (basically the width of the hinges of the topper)and staying on the thicker part of the topper. 
 
Any advice on this aspect?
 

I think you're asking how far apart to put the front bar from the back bar.  Check out your kayak and where the scupper holes are.  Line up with these, especially if you're using saddles.  The kayak is structurally stronger here and you'll minimize any possible oil canning.

-Allen

If you are referring to stance as in width of rack itself, I would recommend at least 5' wide. This allows you to carry two 30" wide yaks side by side.   

Having multiple fishing buddies, I have used my rack to haul two yaks MANY MANY times and couldn't be happier with the width I chose to make it.   

You could go as wide as the bed of the truck, or even slightly wider as it will be above your head anyways.  It may even make it easier to get yaks up there if the rack sticks out a bit. 

I have 60" bars on my Subaru and the extra width is great.
But I think you are asking about hoe wide to space the feet. I would say place them as wide as you can and still mount have optimum mounting space from the inside.

My advice would be to put the rail feet as far apart from each other as they can go, but also in a position that makes sense with respect to the underside of the roof of your topper.  Like I mentioned before, there is a thicker section on the underside of the roof of my topper where it is mostly flat.  If yours is the same way, which I think you mentioned it is, I would position the rail feet just on the inside of the edge of that thicker section.  If your roof isn't this way and it appears to have uniform thickness throughout the underside of your topper roof, then I would position the rail feet a little bit inside of where the edge of the topper is or where the roof of the topper starts to slope down.  Best advice: put your rails together before you drill holes, set them on top of your topper and do a LOT of eye balling just to see what looks good.  Maybe even take some pics of it put together and positioned where you think you might want it, then put them on this thread and get some input that way.

   Thanks for all the help on this one. 
 
I ended up calling Leer and they recommended drilling all the way through the single layer portion of the topper near the outside edge for the following reasons:
-More able to spot leaks if they develop
-If you develop a leak in the thicker section you can have water damage and delaminating issues.  Many of the toppers out there had plywood in the thicker portion.  Leer uses a honeycomb design that could potentially trap water, but not rot or mold.
-Drilling at the outside gives the rack more stability and a wider bar area to use for mounting attachments.
-Weight distributes more evenly at the edge and transfers the weight down to the thick side walls of the topper.
 
I used enough marine goop where leaks should not be an issue, but easy to detect and fix if they do.
 
I had some pictures, but they were dark and poorly done.  I'll try to get decent ones a bit later.
 
Thanks for all the input.