Lets do a good post on floor repair?

[rbryant1492_mfb]

Being new to boat restoration I think I have had to learn the hard way how to do so much.

I think I like a lot of other people have learned that sometimes too much information is worse than to little. So times I have seen people ask questions and they are told do a search on the topic. The searh they do will give then 100's of each with a different way to do things.

What I would really like and would think would be really helpfull is to tell what to use and why to use it

Here is what I have found over the last weeks and months.

1) 3/4 inch ply makes a good solid floor and its cheap. Treated is very good too.

2) Boaters epoxy .. Which is Poly is not as strong as epoxy but 1/4 the cost of epoxy.
Regular Epoxy gives you the most strenght. Longest lasting product you can get.

3) Walmart has the best prices on spreaders and brushes and they are close to everybody.

Lets post ways to do floors and tell what and why you use it.

I did have to laugh when I was told that using boaters expoxy I might have to redo my floors in 20 years or so. HUmmmm lI kinda hope in 20 years i will have a new boat or somebody to fix it for me.

 

[tashasdaddy]

Re: Lets do a good post on floor repair?

i believe if you use 1/2 in exterior ply and turn it the right way across stringer, it gives as strong of a floor and the heavier 3/4 and never use pressure treated. there are so many different opinions on what works, and most do work, is why there is not a faq on this subject. some people aren't going to accept the cheap way out, even if it's just as good.

 

[Coors]

Re: Lets do a good post on floor repair?

This is like an oil thread..
no correct answer.

 

[lexkyboater]

Re: Lets do a good post on floor repair?

I toured the BassMaster/CrappieMaster/SeaStar boats manufacturing facility Sat in Bryantsville, Kentucky and the owner there showed me a plastic honeycomb looking sheet that they are using as the base floor for all their new boats. I called them and another person there said it's a raw material they buy and he didn't think it's available to the public. I may try to get back in touch with the owner as he was real helpful and very nice to me. This stuff was white in color and was used below the fiberglass non-skid insert on their Sea Star boats, and I think on the other boats too. They're not using any wood on the new boats these days, and the other thing that's a real bonus is that it's extremely light. It's made of polyethylene I believe he said. Anyone heard of anything like this we could use as a replacement? I've got to replace a floor in my 84 Cheetah bass boat sometime and would hate to go with wood if there's a better option.

 

[iwombat]

Re: Lets do a good post on floor repair?

Sounds like the same stuff they use in commercial aviation. Needs to be covered with something to provide some snowshoeing, and it's not UV resistant. Otherwise, great stuff and a good choice for the application.

 

[lexkyboater]

Re: Lets do a good post on floor repair?

I called Sea Star back (www.seastarmfg.com) and David there told me that the flooring they buy is Nida-Core H8PP structural honeycomb. It's made of out polypropylene, not polyethylene. Their site is http://www.nida-core.com/english/nidaprod_honey_h8pp.htm#below. I talked to Rod, I believe a midwest sales rep there, and he said they would sell to individuals on a piece by piece basis, but they're basically helping you out since they usually go through businesses in the composites field.

He said he'd recommend their H8PP fiberglass panel as a floor replacement, because it's already got a 17 oz woven mat applied to both sides, and would be more like a piece of plywood. They sell 13 mm or 1/2 inch as well as 20 mm or 7/8 inch. He estimated the fiberglass panel at $120, but is going to email me specific prices tonight, along with freight charges. Since it only comes via freight carrier, they have to deliver to a business.

Rod recommended that you put down a 1/2 inch bead of methacrylate adhesive (preferred) or 3M's 5200 urethane adhesive (second choice) to your stringers and then apply the panel to that. Around the edges, he recommended a 6 inch strip of woven mat, or at any butt joints. He said you could also lay another mat of glass over the entire panel for more strength. Spray contact adhesive on top of that after a light sanding for carpet.

He also said if you want to put seat pedestal bases, or other seat mounts, down over this, the boat manufacturers typically put something like a 16 x 16 inch 18 to 24 gauge piece of aluminum on the bottom side of the panel, and wet that in with resin. Then use sheet metal screws to anchor the base.

Looks like Nida-Core corp also makes Nida-Bond, a pourable transom compound similar to Seacast, and Sea Star is looking into that as an option too, but are making sure it holds up over time before putting it into production.

HTH, Steve

 

[erikgreen]

Re: Lets do a good post on floor repair?

The guys over at Bateau2 sell Nida-Core, the prices are impressive, and you won't save on weight, but you will not get rot:

http://boatbuildercentral.com/products.php?cat=30

Their message boards also have a number of discussions on using the foam core materials vs. plywood. They recommend marine ply for a lot of applications, and foam core for the others, because they designed most of the boats they work on and that's what their structural calculations call for. Boats that originally had plain ply are still ok to use regular ply, of course - it all depends on what the design wants in a given place for strength.

Foam is stronger than marine ply which is stronger than plain construction ply generally. Don't use treated anywhere because it will corrode metal fasteners... if you must avoid rot, then either keep the wood sealed in, or else use foam core.

Erik

 

[lexkyboater]

Re: Lets do a good post on floor repair?

Thanks for that link. Looks like the shipping is included in the price there too. I meant to say in my previous post that Nida-Core does have distributors, but Rod was on the road and couldn't tell me who those were. It would be nice to just pick it up and bring it home.

 

[chesiebaydecoys]

Re: Lets do a good post on floor repair?

I'll respond to the original questions based on my experience:

Use marine ply for floors. There's a reason they make the stuff and not just to charge you more. I've read that the glue used to make the marine ply is better. Yeah.. stay away from treated. Also, 1/2" marine ply is plenty thick and strenght for alot of starcraft floors. I have a '73 18' mariner i replaced the floor on last year. I was going to use 3/4" and was told to use 1/2" by those more experienced than myself. It worked out great and once you bathe it in expoxy / fiberglass, you're ready to rock and roll. very solid. also, 1/2" marine ply matches up well to the original hull setup on my 18 footer such as the rod holder brackets, 'dimple' that runs horizontally around the boat, etc. 3/4" would have been a waste and added nothing more than weight, cost, and problems lining the floor up to the gunwalls.

As for epoxy.. i had GREAT success w/ MAS epoxy sold at Boaters World. I wouldn't use anything else after using this system. very low fumes, very managable, very mixable, NO blushing that i ever noticed.

You didn't mention it but maybe someone in the future could use this info.. don't shove 20 old life preservers or 'open cell' foam in the bildge for flotation or sound deadening purposes.. yes.. i see all the time where people do this. it holds water and promotes rot.

lastly.. use 5200 marine adhesive in the screwholes in the floor and the interlux non-skid stuff works beautifully in the floor paint. but don't mix it w/ the paint. one coat of paint, sprinkle the non-skid on while still wet, 2nd coat of paint after the 1st coat (and non skid) dries, 3rd coat if you think it needs it. provides just the right amount of texture w/o it feeling like sandpaper.

good luck to all you future floor repairers!!!

 

[lexkyboater]

Re: Lets do a good post on floor repair?

An "expert" at Lowes - you know, one of those 22 year old kids - told me marine ply could be submerged while treated ply would fall apart in that environment. But, they also told me the marine ply is also over $100 a sheet and is special order only. I've also read not to use treated ply, but exterior A/C is better. Not sure of the difference - I'd think exterior is treated? Marine ply is better for lasting sol'n, but if you're on a budget and you glass the top and bottom might be okay for a long time, given no cracks. Also, I do know that boat manufacturers, back when they used wood floors, coated their ply in a wood sealer like Thompson's water seal.

 

[FastOrange]

Re: Lets do a good post on floor repair?

An "expert" at Lowes - you know, one of those 22 year old kids - told me marine ply could be submerged while treated ply would fall apart in that environment. But, they also told me the marine ply is also over $100 a sheet and is special order only. I've also read not to use treated ply, but exterior A/C is better. Not sure of the difference - I'd think exterior is treated? Marine ply is better for lasting sol'n, but if you're on a budget and you glass the top and bottom might be okay for a long time, given no cracks. Also, I do know that boat manufacturers, back when they used wood floors, coated their ply in a wood sealer like Thompson's water seal.

I agree, some sort of oil-based stain ,probably solid white (more heat resistant) would for sure give the ply wood a longer life

 

[chesiebaydecoys]

Re: Lets do a good post on floor repair?

I 'stole' this response from PAR on another forum.. hope you don't mind:

"Marine plywood differs from construction grades in significant ways. The veneer count is higher, which makes a more stable product, that is stronger and more reliably bent to conform to boat shapes. The quality of the panel construction is also much better, typically having same thickness veneers, few voids, defects, repairs and rot resistant species used throughout. This can't be said of construction grade plywood. You'll have to seal the plywood which ever grade you elect to use anyway, so it seems to me, like false economy to skimp on the planking, when in the end the marine grades will perform better and last longer. Generally, the planking is some of the finest material used in small boat construction."

ps.. Thomson Water Seal is useless junk for your house let alone a boat. Might as well save the $10 and just paint water on the plywood. As a very general rule.. if you can't find the product in a boat / marine store, you probably shouldn't be using it on a boat. (ie.. Interlux paints, MAS epoxy, tinned wire = great idea for boats.... pittsburgh paint, bondo, elmers glue and silly putty = probably not a good idea for boats). But hey.. if you want to save a couple bucks go for it... hope it works out well (or at least until you sell it).. worste case scenario.. you'll have more money in your pocket for when you have to redo it w/ the right materials.

 

[alloffroad]

Re: Lets do a good post on floor repair?

I had a thought. Once you clean out the old stringers and replace them, make sure they are glassed in. Then why not fill the cavity with spray in foam. I would keep out any water in the future and add bouency in the event of swamping. It is also very light so the weight added would be minimal.
Maybe this has already been done/posted but I haven't seen it.
Any comments?

 

[rebuilt]

Re: Lets do a good post on floor repair?

Alloffroad, you're idea is just what I was looking at doing. That is UNTIL some experienced hands steered me away from that. So I don't just parrot their ideas and experience, check out the thread in this forum with the words, "the last word on foam?". These senior builders covered it pretty well. It's less than 2 days old. KR