Fasteners in cured epoxy

[_Ryan_]

Does anyone have any experience with driving fasteners into cured epoxy. For my build there will be a couple places (roof fan, porch light mounting, brake lights, etc.) that will need to be secured with screws. Since my outer skin will be covered in epoxy I was wondering if there are any tricks or things to consider. I am specifically concerned about cracking the epoxy as well as potentially creating a place where moisture can enter.

Thanks,
Ryan

[doug hodder]

pre-drill the fastener hole and if it's not going to have some sort of a gasket or a butyl tape, take a toothpick and put a blob of epoxy into the hole prior to running the new screw in. Other opinions may differ, but that's what I do. Doug

[_Ryan_]

Thanks Doug!

When you apply the epoxy over the pilot holes should you allow it to fill the hole?

[doug hodder]

The only problem with that is when the fastener seats itself completely, if there is too much epoxy it's going to squish out somewhere, but a quick wipe takes care of that. I don't bother with anything on a roof vent as it has a gasket under it, no leaks on 4 of them so far. Doug

[_Ryan_]

Now you have me curious, do you use the provided foam gasket or throw it away and use butyl tape for the fantastic fan?

Also my question was referring the original epoxy barrier coat when I was asking about filling the pilot holes.

Thanks again!

[angib]

I was taught by a guy that put deck fittings on racing yachts (which is a pretty severe duty) that the obsessional way of sealing them was to intentionally put a countersink in the (yellow) deck material before screwing/bolting the (green) deck fitting to it. This gives a ring void around the screw (shown in red) into which the sealant can go and provide a long-lasting seal.

Bolting two flat surfaces together is pretty hard on sealants as there is only then a thin layer between the two surfaces.

obsessional-sealing.jpg (11 KiB) Viewed 345 times

[Woody333]

Hi Ryan,

Here is a link to an article on bonding fasteners and hardware using WEST System epoxy, although it applies to any good epoxy:

http://www.westsystem.com/ss/bonding-hardware/

The Gougeon Brothers developed the epoxy encapsulation method for boatbuilding many decades ago. The techniques are used in virtually every industry to bond almost anything, gain strength and eliminate wood rot. Their website http://www.westsystem.com/ss/ is a treasure trove of good information for anyone using epoxy.

Jamestown Distributors http://www.jamestowndistributors.com/userportal/main.do is a great source for epoxy, fiberglass cloth, fasteners, etc. They have a lot of good videos on techniques that translate well to Teardrops.

Hope this helps.......

Roger

[doug hodder]

Now you have me curious, do you use the provided foam gasket or throw it away and use butyl tape for the fantastic fan?

Also my question was referring the original epoxy barrier coat when I was asking about filling the pilot holes.

Thanks again!

I use the foam gasket, but not all hardware has a foam gasket...some can be bedded with the butyl tape. Doug

[Oldragbaggers]

Have never had any problem with fasteners in epoxy. You just have to take care to use the right size drill bit because that hole isn't going to give any like wood will. We usually put a little dollup of 5200 in the hole before driving our fasteners.

[_Ryan_]

Thanks everyone, that is exactly what I was looking for and more! I guess it is better to ask these questions beforehand than destroy a nice epoxy job.