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Underskinning Materials....

Posted: Fri Jun 22, 2018 11:17 am
by andymul87
I am thinking about installing underskin but don't know what kind of material to get or where to get it. I can't seem to find it available anywhere....

1. What is the aluminum grade I should be looking for?
2. What thickness do I need?
3. Where might I start my search for material?
4. Do I need to think about anything else as I approach this project? (metal on metal rattling, specialty fasteners, etc.)

Thanks in advance!

Re: Underskinning Materials....

Posted: Sat Jun 23, 2018 4:16 am
by BADsDAD
I am preparing to start my Underskinning project this week. From my research, .063 5052 aluminum sheet seems to fit the bill.

I have a metalsupermarkets about 30 mins from me so I’ll likely get mine there. They have locations all over and sell to the public with no minimums like other metal yards who can’t be bothered by the diy guy. Downside is they aren’t the cheapest place around, but I only need a couple of 4x8 sheets.

For fasteners, I intend to try self tapping with the rubber washers from Lowes/HD. Hopefully they have stainless, if not, coated or galvanized will probably do since mine won’t see salt water. Some have not had luck with self tapping into the aluminum cross bracing and have used rivets, but I don’t want to have to drill them when I need access so I am going to try a small box first.

I also have to extend my fish finder transducer cable as it’s too short and is run diagonally under all my bracing and needs to be attached horizontally across the brace.

Re: Underskinning Materials....

Posted: Sat Jun 23, 2018 3:45 pm
by TDJ2591
There are lots of posts, including my own, on this forum about underskinning. Also, Google it for more links. I agree with the .063, 5052 aluminum. You can order SS screws and/or structural rivets on-line. Far more selections and sheaper on-line than in the local big box stores.

I used 3/16" Magnaloc aluminum structural rivets. For panels that I might want remove later I drilled and tapped for fine threaded SS screws and rubber washers. I'm not convinced that self-tapping screws get enough thread bite into the aluminum to not back out later. I'm of the "more is better" camp regarding the number of rivets or screws to use. I also ran nylon pull strings from under the console to each corner of the toon in case I wanted to pull wires later for accessories, speakers, etc.

I special ordered the aluminum from a local metals supplier

Re: Underskinning Materials....

Posted: Sat Jun 23, 2018 7:53 pm
by rbtnt
For a prior boat I was able to pickup some .063, 5052 aluminum from a local recycler at a reasonable price. I tried the self tapping ss screws and they would break off without pilot holes.

Re: Underskinning Materials....

Posted: Wed Jul 18, 2018 12:33 pm
by BobG
Just for grins, I took some corrugated galvanized steel roof panels, painted them with white epoxy paint, and screwed them up between my toons.
That was 2 years ago.
They're still doing fine.

Re: Underskinning Materials....

Posted: Sat Jul 18, 2020 7:26 am
by Bruenar
Looking at underskinning my boat. It seems like the general consensus in alot of posts is 5052 .063. Whats your thoughts on 3003 .040? Would it be too thin? on 16 1/2 centers.

The boat is a 22 foot Fisher Freedom with a 115Hp Mercury Optimax. The inside dimensions are 59 inches wide and 253 inches long. The logs are 26 inch big boys.

I can pick up 4X10 3003 .040 for 100.00 a sheet and by my calc it will take 3 sheets where as the 5052 is 5 x 10 at 200.00 per sheet. The floor is on 16 1/2 centers.

thanks

Re: Underskinning Materials....

Posted: Mon Jul 20, 2020 2:36 pm
by Liquid Asset
Nothing wrong with 3003. It was the go to alloy before 5052 came around. I used it to do most the stuff on my old boat. Lifting strakes, riser extension etc. The material you are looking at my be a but thin even with the 16" on center. I cut polyiso foam board to fit in between my cross members where the water sprayed really hard when I did the underskin on my old boat. I was worried about it getting pushed in. That could be an option.

Re: Underskinning Materials....

Posted: Wed Jul 22, 2020 5:06 am
by Bruenar
Thanks for the replys and information. I found some 5X10 dibond sheets at a good price. From what I understand its aluminum sheeting on both sides with a neoprene plastic core and its 1/8 thick. Weight wise its about the same as 5052. I am looking at that or spend the extra and go with 5052.