Steel core or all aluminum blind rivets?

[Davidius]

Hello all, I'm new to the forum and to aluminum boats. I am freshening up an old 1648 my build is here, https://www.tinboats.net/forum/viewtopic.php?t=34965 I water tested my boat and found around 15 or so weepy rivets and went about bucking them. Several stopped weeping and some didn't. I've been reading on here for a few hours skimming and most people seem to recommend all aluminum blind rivets and I've read on other sites that you may not get a tight enough pull. They recommend steel core blind rivets for a tighter pull. All recommend a sealant and some recommend a backing washer. I'm all for the sealant and washers, I just need advise on the pin material. Any help or dirty jokes are appreciated, puns not so much. Thanks!

 

[PSG-1]

Do NOT use steel pin rivets. This sets up a condition known as "dielectric corrosion" because of 2 dis-similar metals in contact with an electrolyte (water) Use all aluminum rivets.

 

[surfman]

Ditto!

 

[rscottp]

2nd the ditto!

 

[bobberboy]

I believe the length of the rivet relative to the thickness of the material being riveted plays a role in how tightly the river grips. From the web sites I've seen, there is a recommended range of material thickness for rivets called a "grip range". There should be a chart or some kind of info on the box indicating the grip range of whatever you are looking at. Others have posted this web address but here it is again:

https://www.rivetsonline.com/

 

[onthewater102]

I think what they maybe referring to is the mandrel, the pin at the center of the rivet. The rivet body needs to be aluminum to avoid corrosion between dissimilar metals - but if the mandrel is steel you will get a tighter crimp on the rivet than if it had an aluminum mandrel.

But always take the belt & suspenders approach & goop some epoxy on the replacement rivet to be safe. 3M 5200 I've heard works, but according to 3M (https://multimedia.3m.com/mws/mediawebserver?mwsId=66666UF6EVsSyXTtMXfXnXfXEVtQEVs6EVs6EVs6E666666--) it only bonds to primed metals - which won't be the case with your repair. Over time it will eventually fail.

 

[Davidius]

Thank you all for the replies, I will order some all aluminum rivets and backing washers. I have some gluvit on order for going over my seams, would this be a better choice to dip the rivets in before setting them? Many thanks.