Should I use Fiberglass or PVC sheet to cover pontoons?

[bob kennelly]

I was actually going to go with a 6 inch gray schedule 40 that i picked up at HD and it didn't feel that heavy, but i feel that i really need an 8 inch pipe as it just looks like the right size and whether its the gray conduit/culvert or white plumbing, its says they're the same weight:
An 8-inch diameter, 10-foot long section of Schedule 40 gray PVC electrical conduit weighs approximately 53.9 to 59.5 pounds
An 8-inch Schedule 40 PVC pipe in a 10-foot length typically weighs between 53 and 56 pounds
A 10-foot length of 6-inch Schedule 40 PVC pipe typically weighs between 35 and 38 pounds
A 10-foot length of 4-inch Schedule 40 PVC pipe typically weighs approximately 20 to 22 pounds

so, i've decided a 2 prong approach to try and ligthten the weight of the 8 inch pipes i already have by drilling 1 inch holes in the upper 3rd of the pipes and covering the whole surface with a thin sheet of pvc sheet
and the 2nd approach to start from scratch, gluing together some foam board wtih plywood in between, shaping the foam and then covering with fiberglass, but won't be able to finish that until later

thanks for the suggestion

 

[bob kennelly]

And actually, I knew the pipes were supposed to weigh 59 lbs, but I think they're a lot heavier than that for some reason and they are definitely schedule 40, but they feel like the weight of a schedule 80 and so if drilling the holes doesn't help that much, I'm then going to scale down the length to 6, 5 and 4 as I think I can still use the 4 foot effectively

 

[bob kennelly]

but ultimately I'm looking forward to building those foam fiberglass pontoons

 

[ondarvr]

Drilling holes in PVC is a waist of time and money, skip it completely. You can buy inflatable pool noodles with 7" diameter and 5' long for under $10. This option gets you 90% of what you need for testing immediately and at a low cost. You could even wrap them in epoxy and glass as a more permanent solution if you want.

Or, skip all the reinventing the wheel mental gymnastics stuff and just buy inflatable tubes made for that exact purpose. They are easily purchased.

This isn't some unique idea you just came up with that requires a new age solution. It's a many centuries old craft design that has been optimized many times over the centuries with different materials already.

 

[bob kennelly]

let me check that again, so they actually make a pool noodle with a 7 inch diameter and 5 foot long and if so yes i could fiberglass over that, couldn't find that on walmart, going to check again, thanks again!

 

[bob kennelly]

and i could run an aluminum pole down the middle for extra strength

 

[bob kennelly]

the reason i originally wanted the 8 inch diameter was to be able to build a platform over the pontoon like the Expandacraft boats do and actually, the 6 inch pvc pipe is about the perfect weight and rigidness, but i just don't feel like it could float nearly as much weight as an 8 diameter tube, ie pic below

 

[ondarvr]

Walmart sells the smaller version 6" x 4'
Temu sells several versions. There are even low cost outrigger kits for canoes and kayaks, plus larger ones.

You could probably buy an old outrigger canoe or sailboat for cheap and canabalize those.

Or just skip all that and buy the complete craft you desire and go boating next week.

 

[bob kennelly]

well i was thinking about using the pontoons from a hobie cat 16, but those pontoons weigh even more apparently and right now i'm thinking about buying a raft, taking that apart as a plan d and i uploaded a picture of the Expandacraft example i have in mind, but the pic dissappeared. And yes after i exhaust all diy options, i'm probably just going to buy the Expandacraft kit, but that's up to $1700 now, but its starting to look well worth it for its portability. But i always have to find things out the hard way first and it looks like i'm well on my way to doing that, hahaha but actually i am seriously thinking about building this foam board fiberglass pontoon, but that's going to be a long term project for the winter time: Foam and Fiberglass Ama Construction https://amaconstruction.blogspot.com/2021/02/foamand-fiberglass-ama-construction.html

 

[gonzo]

This is getting more and more complicated and expensive. Get two canoes and make a catamaran. Tie them together at the cross members.

 

[bob kennelly]

hahaha, well i think since i've got these pipes i'm going to try something that sounds complicated but its really just more time and that is this time i'm going to drill 1" holes in 2/3rds of the pipe and then loosely wrap the pipe with saran wrap and then spray in some high density closed cell foam and then sand down the foam extrusions flush with the pipe and paint the whole pipe with an epoxy paint and according to google ai the closed cell foam for an 8 inch tube 7 feet long weighs only 7 lbs and is pretty strong:
google:
A column of closed-cell foam with an 8-inch diameter and 7-foot length would have a theoretical load-bearing capacity of approximately 1,250 to 2,350 pounds before the material itself begins to crush
A column of high-density closed-cell foam with a diameter of 8 inches and a length of 7 feet typically weighs between 4.9 lbs and 7.3 lbs for standard industrial applications.
Approx cost of high density closed cell foam for each 7 foot tube : $80 (4 tubes x $20)

 

[ondarvr]

What is hear is, I'm going to spend time and money on garbage that has no chance of being adequate, then I can pay to throw it away. And eventually I'll get the right thing and have fun.

Members here get this type of request periodically. It's a bit frustrating because the answer is quite simple, but the ears refuse to acknowledge it.

 

[gonzo]

A column of closed-cell foam with an 8-inch diameter and 7-foot length would have a theoretical load-bearing capacity of approximately 1,250 to 2,350 pounds before the material itself begins to crush

That would be foam of 47 PSI strength.

 

[gonzo]

according to google ai the closed cell foam for an 8 inch tube 7 feet long weighs only 7 lbs and is pretty strong

Artificial and smart are not necessarily the same.

 

[bob kennelly]

Well i get what you're saying and i think the best solution is to build that foam, plywood and fiberglass pontoon link below, but will have to start that later this year, so i think this pvc pontoon idea is still worth a shot as the total cost will be about $300 for both pontoons:

pvc tubes cost: 100
drill bits: 50
foam: 150
----------------
total: 300

and i just tested one of those step drill cone drill bits and was able to easily drill thru 1/2 pvc in about 15 seconds

future pontoon plan:
Foam and Fiberglass Ama Construction https://amaconstruction.blogspot.com/2021/02/foamand-fiberglass-ama-construction.html

thanks again!