Rivet or Weld Holes?

[CO_4X4]

When I picked up my old boat the previous owner(s) had no concept of galvanic corrosion and managed to screw on un-galvanized and non-stainless screws in a few locations. I'm in the process of removing this garbage, most of which holds nothing at all anymore so who knows what it was put there for in the first place, and am wondering if it's worth taking to a shop to TIG weld the holes and blend them in like new or just add more aircraft rivets, for which I would need to acquire the proper equipment and properly sized rivets (and then also learn the proper way to use them). I suppose the easy route is to take them out and just put in SS screws to take their place but I'm trying to restore the boat, not have a screwed-to-death beater. Thoughts?

 

[MrGiggles]

Closed end pop rivet would work just fine.

 

[CO_4X4]

Thanks for the reply. The only reason I haven't considered pop rivets is that they don't really match the current rivet and, yes, I'm THAT person, haha.

 

[lckstckn2smknbrls]

Talk to some welders and get prices,

 

[airshot]

Welding can work if the welder knows what they are doing! The problem is...there is a seal/ gasket/ whatever between the overlap where the hull is riveted. The heat will/ can mess up that seal and cause more leaks.. Nothing wrong with welding a riveted hull if the weld doesn't mess the seam gaskets...and that is the difficult part. Nothing wrong with rivets, they have been holding boats and airplanes together for over a century.

 

[CO_4X4]

The heat will/ can mess up that seal and cause more leaks

Thank you, most of these aren't on a seam they were just drilled into the side, presumably for some sort of accessory like a rod holder or something like that, but I didn't realize there was a sealant between joints (but it makes a lot of sense) so I'll certainly be on the lookout for that! Maybe it wouldn't be that bad to get a rivet chisel for the air hammer and a bucking bar anyway so I can tighten old rivets that may have loosened over time. As of now I haven't found any leaks (filled the boat, no leaks), I've just had a heck of a time finding a convex bucking bar since my rivets are rounded on both sides.

The rivets aren't structural, just an aesthetic replacement for ugly screws that serve no purpose. They might not have been there originally but at least with rivets it looks like they were. These boats were made with recycled WWII planes so there are a few rivets around that serve zero purpose anyway.

 

[airshot]

If you have a machine shop in your area, they could easily make a bucking tool with the radius you need. I made mine for the heads and the inside of all my rivets are just flat. You need the radius tool when setting the heads or the edges can curl up and leak worse.

 

[jethro]

I'm just going to add something you and others should should know, stainless steel will still cause galvanic corrosion when in contact with aluminum.

 

[CO_4X4]

I'm just going to add something you and others should should know, stainless steel will still cause galvanic corrosion when in contact with aluminum.

Thanks for correcting me on that, I thought I had read that SS was ok to use on aluminum and after searching for why I thought this was the case I found that it is OK to an extent under some circumstances, the exception is "except in marine environments". Not that I had planned to use SS on my boat, it might have been a backup option if I couldn't find another way - now I won't!

 

[jethro]

I found out the hard way as the previous owner of my boat installed about 40 stainless steel snaps with SS screws for a custom cover that all corroded pretty badly. Salt water use makes this worse, which I'm sure you don't see much of in Denver, but still I'd avoid it.

 

[CO_4X4]

Salt water use makes this worse, which I'm sure you don't see much of in Denver, but still I'd avoid it.

Only when I make pasta

 

[DaleH]

FWIW acid rain is actually a pretty good electrolyte too … for precipitating galvanic corrosion!

Pure water is a poor one …

 

[Steph Boeker]

I'm just going to add something you and others should should know, stainless steel will still cause galvanic corrosion when in contact with aluminum.

Then why do all the teachers say to use a designated SS brush to clean aluminum ?? Sounds like they're promoting corrosion ?

 

[sonny1]

We are talking about prolong exposer with stainless and aluminum in salt water. First off there are different grades of stainless. Some grades have better corrosion properties. The bolts I took out on my 20 plus year old Lonestar show no signs of corrosion and the aluminum is fine. Pretty sure the boat has never seen salt water considering am sitting in Oklahoma. Plan on replacing with high grade stainless steel bolts and not worried about it. Odds are your not going to find proper grade stainless bolts in your local hardware store. Order from a place that specializes in nuts and bolts. May cost a little more but worth the money. If cleaning an area to be welded with a stainless steel brush would promote corrosion than the U.S. Navy is in trouble. Navsea certified tig welder. A lot of aircraft would be in trouble both civilian and military. Certified in that also.

 

[CO_4X4]

Thanks Sonny! Yea, I have a handful of stainless on this boat and it all seems to be fine currently. This boat has never seen salt water to my knowledge and won't under my watch, that big of water - even the Great Lakes - would seem dangerous in a low profile boat like this, or at least dangerous with me at the helm .

 

[Steph Boeker]

We are talking about prolong exposer with stainless and aluminum in salt water. First off there are different grades of stainless. Some grades have better corrosion properties. The bolts I took out on my 20 plus year old Lonestar show no signs of corrosion and the aluminum is fine. Pretty sure the boat has never seen salt water considering am sitting in Oklahoma. Plan on replacing with high grade stainless steel bolts and not worried about it. Odds are your not going to find proper grade stainless bolts in your local hardware store. Order from a place that specializes in nuts and bolts. May cost a little more but worth the money. If cleaning an area to be welded with a stainless steel brush would promote corrosion than the U.S. Navy is in trouble. Navsea certified tig welder. A lot of aircraft would be in trouble both civilian and military. Certified in that also.

 

[Steph Boeker]

We are talking about prolong exposer with stainless and aluminum in salt water. First off there are different grades of stainless. Some grades have better corrosion properties. The bolts I took out on my 20 plus year old Lonestar show no signs of corrosion and the aluminum is fine. Pretty sure the boat has never seen salt water considering am sitting in Oklahoma. Plan on replacing with high grade stainless steel bolts and not worried about it. Odds are your not going to find proper grade stainless bolts in your local hardware store. Order from a place that specializes in nuts and bolts. May cost a little more but worth the money. If cleaning an area to be welded with a stainless steel brush would promote corrosion than the U.S. Navy is in trouble. Navsea certified tig welder. A lot of aircraft would be in trouble both civilian and military. Certified in that also.

That's right sonny1, I remember you have been welding many plenty different applications for a career. I'm no skilled guru but when i started out, I worked for about 7-1/2 yrs in fasteners. Most of our business in the beginning was B-7 studs and 2-H nuts (alloy) for the refineries in S. Louisiana. I got teased when a keg of stainless fell over and the guys gave me a magnet to pick them up. That's when I found SS is not magnetic. At least not 18-8 or 304. Recently I read an article that informed me that there are SS's that are magnetic like in the 400's (410, 420, and 440).
When I got to San Diego and back into fasteners, I worked for 2 companies that supplied the navy which did work around and in salt water. Monel was the metal that was preferred but lot's of SS went to the navy as well. I guess I never learned about the details of the different uses (chemistry) and why (maybe pcs here & there) but I was proud of my fastener experience. Not many ppl can spit out the thread diameters & pitches of every coarse or fine mach. screw or bolt in regular use today. I know about different grades, types of materials, from nylon to nickel, and who might use them.
Thanks for the quick lesson and in the future I'll defer to you on the chemistry of a topic. It's always nice to "know a guy" !!

 

[thill]

Wire brush away any corrosion, drill the holes to 3/16" and use solid aluminum rivets, is what I strongly recommend. I never, ever have problems with this solution.

IF you are always in fresh water and decide to use stainless steel, make sure it's 316 grade stainless, not 304, 308 or some other lower grade. It does not react nearly as much as the lower grades, even to saltwater.