New panels, old holes?

[foto4peter]

I've decided to use FRP (fiberglass reinforced panels) for the new interior skin BUT I do not have the old panels to use as templates.

I would like to reuse the holes that held the former skin unfortunately this is proving difficult as I cannot reach down behind the new panel, when held against the wall, and make a mark so I know where to drill a hole.

Any suggestions?

I'm going to go out now and try putting a bright light behind and see if this will provide a bit of light which I hope will illuminate the hole enough to see and mark it. (fingers crossed)

[perryg114]

There is no structural reason to use the old holes and finding them without the old panels to use as templates will be next to impossible. You do need to figure out where the ribs are so you know where to drill. I would use painters tape to mark the panels and then you know where to drill and you don't have to worry about ink staining the FRP board.

Perry

[newroswell]

What you need is a "hole finder".

Aircraft Tool Supply | STRAP DUPLICATOR | 72-12

Sheet metal Strap Duplicator tool demo - YouTube

[foto4peter]

the two answers I was hoping for, much appreciated!!

Now the big question is; "Am I patient enough to wait and have this hole finder delivered or just pop some new ones..?" I'm not typically known for my patience

[markdoane]

Are you using nylon drive rivets?

[foto4peter]

Originally Posted by markdoane

Are you using nylon drive rivets?

No... not familiar with these. I was planning on using aluminum rivets, what you typically get at big box stores.

[Melody Ranch]

With new aluminum selling at 35 dollars a 4 x 8 sheet...I would stay with aluminum.

[newroswell]

foto, the link I gave is for an inverted strap duplicator which looks like the pin comes in from behind the hole. That would probably work just fine. The one I have experience with has the pin going in the hidden hole in the same direction you are drilling.

Aircraft Tool Supply | 12" STRAP DUPLICATOR (#30) | 62-12

[markdoane]

Nylon drive rivets are what is normally used to apply FRP to metal studs. The color is a good match. I guess it depends on your application. If you use regular rivets I would use the large head belly pan rivets from VTS.

[perryg114]

You can get White painted pop rivets from mcmaster.com. If you hit an existing hole a little off center the rivet won't hold properly because the hole will be too big. Aluminum rivets are going to be stronger than plastic rivets. If there were rivets holes every 1/4" you would need to worry about not drilling more holes. Since the rivets are several inches apart the ribs are not being weakend by new holes.

If you can go to a larger rivet or at least one with a larger head you will be much better off.

Perry

[foto4peter]

Thanks for the input everyone!

I thought of using aluminum, which I find to be beautiful for interior but in the end didn't want to do the polishing and painting new aluminum would be a crime.

I really like this strap duplicator. My only concern is that 12" my not be long enough in some places so I'm going to try and fabricate one out of a couple yard sticks and see if this will work. If this doesn't work I'll either order one or make new holes.

I thought about getting the white top rivets but my better half has a specific decorating idea so I'll be painting anyway...

Thanks again!

On a side note concerning the painting of FRP... the FRP I purchased at HD is "dimpled/textured" and shinny on one side and smooth, flat and dull on the backside. I'm going to have the backside showing and curious to know if the backside needs the sanding preparation that people say the front side does? I assume yes but would rather ask than assume. cheers

[HiHoAgRV]

I wasn't too thrilled with the original spacing and wandering lines of the rivets so I redrilled using a 2" spacing on the up/down ribs and 7" on all of the horizontal lines.

http://www.airforums.com/forums/f109...ml#post1075682

[Minno]

Our concern with using FRP panels instead of the aluminum interior skins is that your fasteners will eventually enlarge the holes in the FRP as you travel due to trailer flex, and your panels will come unfastened and/or crack. When others have asked about putting wood or other material up instead of the aluminum interior skins, the general advice has always been to use the aluminum skins and then add your preferred panels over them. We used these panels to make a shower, so have worked with them. We glued them to plywood backing to form the shower. They do work well on curves but compound curves such as your front and rear endcaps will be a challenge.

Kay and Chris

[foto4peter]

HiHo, it's true the spacing and hole pattern on mine is zigzagging all over the place. I'm going to try and reuse as much of the holes as possible but feel I too will be making some new uniform lines.

K&C, you bring up a very good point. I didn't put much thought into what long term vibration could/would do to the FRP. Fortunately though (or not) our AS will not be moving much. I'm setting it up as an "in-law" type studio for myself when I visit family which will be more and more often as mom's husband is out of the VA hospital and needs 24/7 care.

Would applying "wet" rivets help absorb some of this vibration?

[markdoane]

I would be less concerned about vibration. Your failure mode will be the difference in thermal expansion between aluminum and FRP. I would use nylon drive rivets, and oversize the panel holes to allow for expansion and contraction. Unless it will be stored indoors.