78 Starcraft home made welded canopy

[ts]

Re: 78 Starcraft home made welded canopy

I love the shinny state of the boat, but she leaks. This is a new bedliner kit (or at-least to me):redface: that is flexible and water tight. I'm going to wait until someone tests this on aluminum to see if it will stay on.

The common recommendation around here is to get a can of Gluvit and coat the seams and rivets on the inside of the hull. Everyone that has used it swears by it.

 

[ts]

Re: 78 Starcraft home made welded canopy

The fuel tank is aluminum, dont think it will be a problem, but I will be using the boat in salt water, maybe your right...Anyone?

Hey SC1, I've been thinking about leaving the bottom of my boat bare and doing a lot of reading on here about corrosion (even of aluminum).

Here's what I've read so far:

The guys that trailer their boats say that the bottom will be fine as long as you thoroughly rinse the hull AND trailer bunks with fresh water when you pull out at the end of the day. If you leave the boat in the salt water for more than a day you need to have the proper bottom paint on it to protect it. Secondly, even aluminum needs to be kept dried out when not in use or it will corrode. Lastly, make sure you are using the right type of sacrificial anodes for salt water (zinc for salt, magnesium for fresh).

...and if I've got any of this wrong, PLEASE, someone post a correction. I don't want to be spreading any bad info! :redface:

 

[Andy in NY]

Re: 78 Starcraft home made welded canopy

one major downside to using the truck bed liner on the OUTSIDE is it will cause drag and slow you right down... just as barnicles do on just about any salt water moored rig.

 

[elkhunter338]

Re: 78 Starcraft home made welded canopy

I would highly recommend gluvit around the rivits on the outside of the hull, paint the hull and you could probably use bedliner on the inside. I thought about bed liner for my boat but had already put the floor back in.
I would highly recommend the rust bullet or gluvit on the outside of your nice looking fuel tank. Salt water will corrode alum. especially if it is kept damp. I have been running my 21 foot cheiftain in the salt off the pacific ocean for 5 years and there are places where the salt will get into and stay, in those places with no paint the alum turns to white powder.
I run out of Newport and spend 2-3 weeks in the salt a year. I trailer the boat back home between trips.
Also bare alum screwed to wood starts to corrode, If I had to do it all over again I would make sure and paint or gluvit or rustbullet bare alum.
I really wish I would have gluvit or bedlinered below the floor but I found this web site only after most of my restore was completed.

 

[starcraftone]

Re: 78 Starcraft home made welded canopy

I would highly recommend gluvit around the rivits on the outside of the hull, paint the hull and you could probably use bedliner on the inside. I thought about bed liner for my boat but had already put the floor back in.
I would highly recommend the rust bullet or gluvit on the outside of your nice looking fuel tank. Salt water will corrode alum. especially if it is kept damp. I have been running my 21 foot cheiftain in the salt off the pacific ocean for 5 years and there are places where the salt will get into and stay, in those places with no paint the alum turns to white powder.
I run out of Newport and spend 2-3 weeks in the salt a year. I trailer the boat back home between trips.
Also bare alum screwed to wood starts to corrode, If I had to do it all over again I would make sure and paint or gluvit or rustbullet bare alum.
I really wish I would have gluvit or bedlinered below the floor but I found this web site only after most of my restore was completed.

The job of making a riveted hull water tight and last is impossible, when considering vibration, flexing, and the fact that the runners that strengthen the hull are impossible to get inside of unless you can shrink yourself to 1/8 of an inch. When two pieces of aluminum are laid together and then riveted, they are bound to leak at some point. I'm not criticizing the design, movement and flexibility are necessary under the conditions that boats and aircraft go under. Going around every rivet and every lap joint with a product that sets rigid will eventually fail (my opinion). Today's technology is Superior to that of the day of riveted boat design of the 70's. If the engineers get together and come up with a solution to once and for all, make a durable, polyurethane product that will stick to aluminum, under salt and fresh water conditions, that market would set a new trend for aluminum hulls all over the world. Maybe prep work is all that is needed to make current products work. The object is to spray on a product on the outside of a hull that will make it water tight for ever.

I ran across this in my research...
http://articles.jeepforum.com/U-Pol_...tuff_rocks!)

 

[moonfish]

Re: 78 Starcraft home made welded canopy

So every time you trailer the boat you have to walk it to a dock? You can't just step on the trailer and get in the boat at all?

 

[elkhunter338]

Re: 78 Starcraft home made welded canopy

That makes sense to seal it from the outside. I sealed 3 leaky rivits from the outside this fall with gluvit, bottom primer, paint. We will see home it works have not had the boat in h2o since.
One thing I learned with these rivited tin cans is do not use anything but carpet if you have a bunk trailer. I had the great idea of using a slick composit deck board on my bunks and this worked great for 4 years then I noticed the boards where starting to wear the rivits down, and when I launched it put alot of strain on the rivits and that is why I believe i have a couple leaking rivits. I now have carpet back on the bunks and I extended the tounge so I can float the boat on/off the trailer. With guides on the side this works very well.

What type of floor are you planning to install, wood, alum. other?

 

[Gnarly]

Re: 78 Starcraft home made welded canopy

Some interesting reading on this one ,

crevice corrosion occurs between aluminum sheet or other crevices with trapped salt water or even trapped freshwater with some mineral content where oxygen cant get to the surface of the metal , pretty common stuff here, see it alot on aircraft floats , water hulls and in other places depending on the alloy it can be fairly common. Zinc chromate and a good sealant on the faying surfaces ( not gluvit ) can go a long way in combating it especially when the rivets are installed and driven wet with sealant. (PR 1422 , Pro seal 870, both have chromate in them and remain flexible indefinetly ,used to seal wet aircraft wing fuel cells and water hulls in aviation)

50 series aluminum is pretty corrosion resistant(much better than 20 series aircraft aluminum) and can be left bare as within hours an aluminum oxide coating coats and protects the metal underneath, galvanic action and crevice type corrosion are the two main enemies facing the underlying metal. Salt water isnt acid , it just acts as a far more efficient electrolyte than fresh water.

It takes literally minutes to replace a rivet if you know what your doing and have access to both sides (solid), even less time if your using a blind rivet and both types installed and driven in the case of a solid wet are waterproof. They work primarily in shear not tension so make sure the application fits. 5052 waterproof blind rivets are certainly available and I'd recomend you replace them rather than gob on gluvit if you've got a leaker, if its leaking its most likely fretting as well which is another form of corrosion and a dead giveaway is rivet smoke ( aluminum oxide) around the affected rivet.

I dont mean to preach but it seems to work pretty damn good on all these beavers and otters flyin around here sitting in the salt year round landing and taking off in salt water day after day and the helicopters I work on hovering and manuevering in salt spray servicing ships and lighthouses.

Thats a pretty nifty cabin you've built there and It certainly looks dry and comfy, did add a fair bit of surface area to her though. Your gonna have to let us know how she fairs in a gale with a good swell and 3 or 4 feet of chop.