Rivets for Fiberglass?

[DHS]

I am looking to mount seat bracket in a fiberglass boat and cannot get to backside to put washer on. Which one of these rivets would be best, or if you know of a better way let me know. (the fiberglass is about 1/16" thick)

http://cgi.ebay.com/ebaymotors/ws/e...0148582841&viewitem=&sspagename=STRK:MEWAX:IT


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290393640112&ssPageName=STRK:MEWAX:IT

 

[Designer]

I'm not a boat expert, but....Is there support material behind the fiberglass that you could screw into?

What is the thickness/material of the seat bracket? I don't see a 1/16th inch rivet joint lasting long in fiberglass with the weight of a person shifting around on it.

 

[DHS]

This is in a small skiff and the is nothing else supporting the fiberglass. My brother built me some aluminum mounts that wraps around the bench seat with a short 4" riser to bolt swivel to. The mount is probably 12" wide and goes down around both sides for about 8". I was thinking about using regular rivets.

 

[c_mccann]

I'd glass in a cleat on the front side with t-bolts in it, then screw into that. The rivets will crack the glass when pulled then will just be weak. Another recommendation is to bed it with 3M 5200 adhesive. Another way is to cut an access hole and access the backside with backing plates and mount a pi-hi (screw on PVC access cover) over the hole.
The last way I'd go is with rivets.

 

[DHS]

I may have to cut a hole but the bench seats I am attaching the seat to are also is safety floatation. So I would need to seal the hole up pretty good. What if I used rivets and 3M adhesive? I was planning on using a marine sealant anyways to seal around the holes.

 

[Designer]

Well, I think in that case you would want to do a combination of fastening and bonding. However, if you're going to bond it you'd better be sure you aren't going to try to remove the seat later.

I would think that one way to do it would be using a number of 1/8th inch rivets to hold the location and either epoxy or a JB Weld type of stuff on any flush surfaces to take the shear. But,wherever you apply the adhesive should be roughed up and cleaned first. But no matter what you do, if the fiberglass mounting surfaces flex alot, I would think that the rivet joints will wear out and the adhesive will pull off since the aluminum is alot stiffer than the thin fiberglass.

Maybe this helps you, but like I said, I have no familiarity with boat seats or how they are normally held on....good luck!


I like the access hole idea, that could work out really well

 

[DHS]

Thanks for the help. I have snapped the mounts of the bench seat and its pretty sturdy without rivets or anything. I will try to post pics latter.

 

[DHS]

Here are some pics of what I have. Sorry I didn't clean for the pic.