boat building materials.....

[Bondo]

Re: boat building materials.....

PT.... well... it resists glass. and it resists water... and about any other thing you can pour on it... but... it only resists it for so long. then the wood will give and start to rot. You can glass over it.. but it's more like a band aide on an open wound... instead of stiches. Glass will stick to PT if the wood is roughed up like crazy. But glass will not bond to PT, it will not penetrate PT enough to become one with it. Even with a great glass job, because boats flex under use, the glass will eventually start to peel away off of the wood.

get ready for the controversy. as you no i am not an advocate of pressure treated wood. there is something about stainless needing to be in an oxygen environment.

Ayuh,........ I'll Start,..............

Real World Here,.... Been Here,.. Done This,... Still got the Barge to Prove it......

Back in 98,+ 99,... I dropped a 4.3LX into my Starcraft 221 Islander.... The "Motor Swap" turned into a Total Refit,... As Usual.....

I built the New Transom out of the locally available P/T Plywood,....Reasonably Dry wood....
I cut the transom panels,+ glued'em up with Resorsenal glue,+ Clamped them together with a couple hundred Screws, which were removed after the glue set up....2" thick, 3 pieces... I then set it up,+ Soaked it in boiled lynseed oil for about a week on each side.... That all got bolted back into the hull with Many SSteel bolts,+ screws.....

The Cockpit Sole(No Floor, JB) was removed by drilling out the rivets,+ All the wood was replaced, which lead to the Bulkhead replacements(the Mahogany rotted out),...

The Deck, 1/2" P/T Plywood, was pop-riveted(3/16"Xlong) back into place, just the way it came from the lumberyard the day before, Wet....
I ran it a season just bare, then I painted it with Epoxy resin,+ sprinkled Sand over the wet resin,+ very light cloth I had,... After it set up,+ I vacuumed up the excess sand, I painted it with good old Rustolium battleship gray,...
It's a Great Fishing deck, but atad hard on bare feet, 'specially tender bootfeet like mine....

The Bulkheads I skeletonized with 1/2" aluminum conduit frames I welded up...
Some I left open,+ others I filled the void with 5/8" plywood I found laying around a jobsite, covered with upholstery vinyl of course....

The 10 year Update is,........
I repainted the deck a few years ago, trying to soften it underfoot,....

The Transom still Looks like the day I bolted it in,.... No Problems with the Wood, or Fasteners.....
Same with the deck,... The aluminum rivets are holding it together Way Better than any Screws....
The SSteel screws,+ bolts haven't been an Issue,... Even when I inadvertantly used the hull as a ground path,.... The metal disappeared at paint chipped areas, but the screws didn't present any problems......

My only Confession in this Refit is,............. I left the Foam in the hull........
It is the original 1974 Styrofoam,... Kinda like a foam cooler, only the little bitty 1/8" beads, are about 3/4" to an Inch BIG,.....It was laying there, caged in by the hull, stringers, bulkheads,+ deck(Great Drainage ),... Except for alittle oil staining, it looked,+ felt New......
Sooo,... I put it back in..........

(Edit,.... Just to add,... I did all this Pre-Internet/ iboats.com.....1st Big tinboat,+ merc. drive,.. Steep learning curve stuff)

 

[JustJason]

Re: boat building materials.....

--------------------------------------------------------------------------------

thanks so much for your detailed reply!

I was under the assumption that if dryed (dont know how long), fiberglass would stick to PT ply?

if fiberglass does not stick to it, why is it so widely recommended?

i think you said, if not glassed, PT will last 3-5 yrs, and if glassed, it will still only last 5-7yrs, seems like it would not really be worth glassing if it only lasts a couple more years...?

thanks so much for your time

might as well leave it here... it's oops's thread, but he can take what he wants to from here and have a locked FAQ created through the mods.

In my last note i said;

There is a mountain of information out there and try not to read into any 1 thing to much. There is no universal answer to anything.

That includes me... and the information i give you.
I'm not the know all of know it alls. I only know what i know, and what i've done. Everything i've done has worked out so far.... but i'm destined to goof one up eventually, everyone is.

I was under the assumption that if dryed (dont know how long), fiberglass would stick to PT ply?

Yep... it'll stick. But it won't bond. The difference is does the glass seep into the pores and fibers of the wood a few milimetsers.... or does it just sit on top? Glass will just sit on top.

If this is your own boat, your best off overbuilding it. When you look at manufacturers do... its not always the best way, but they do the most cost effective way to maintain mass production while meeting safety standards.

as far as what material you should use... that's up to you my friend. I've seen people lay down wood and rhino-line the whole thing. Makes for a heavy boat but it works.

again as far as how long things will last... it all depends how dry your boat stays both on and off the water.

 

[erikgreen]

Re: boat building materials.....

Well, here's my 2 cents worth.

I redid stringers and transom in my 1973 SRV-220 with PT ply. The transom was 2 layers of 3/4" with peanut butter glue in between and around the edges, covered with 3 layers of 8 oz cloth and tabbed in 3 more layers.

The stringers were doubled ply also, on edge, balanced on pink styrofoam strips, held in place by PB glue. I tabbed them in with 3x layers of 18 oz. roving and epoxy.

I never got the boat in the water, but after sitting outside for 8 months the stringers have started to warp, I suspect water intrusion due to poor adhesion of epoxy to the wet PT.

On epoxy: I've tried the stuff from West system, some generic stuff from ebay, and the stuff from US Composites. There's only a little difference between the various brands, and sometimes if you look they all get their resin or hardener from the same chemical companies. I use US Composites exclusively now, I may try out MAS in the future. The main differences I saw were in viscosity and pot life... the West system "fast" epoxy is much faster than the US Composites "fast" epoxy for instance.

Fillers: I like wood flour. It's cheap, hardens like rock yet remains a little flexible, and thickens epoxy well. I buy from Bateau.com, but Iboats has the MAS wood flour in quart jars for a good price.

I've also used milled 1/2" glass fibers for strength in places. They don't thicken a mix well and they make it hard to spread, yet it's still runny. You can mix in a powder filler of some sort to improve workability.

I've also tried cabosil/aerosil, which is silica that's been "fumed" or powdered. It thickens epoxy well, is very light, and makes a very smooth mix. However, it doesn't add strength, just volume. Epoxy with this stuff makes an ok fairing compound, but is harder to sand than microbubbles, and the dust should not be breathed.

Microbubbles from 3m make a nice fairing compound, similar to cake frosting. Again, don't breathe the bubbles. Interestingly, these bubbles plus a binder like epoxy are what's used to make syntactic foam, which is a floatation foam that won't compress even at extreme depth. They add little strength to a mixture, but probably more than cabosil. They are very easy to sand.

Wood: I've used Furniture grade, CD-X, PT, Marine, and dimensional wood. I like the marine ply, but it's not substantially different from the Furniture grade I use. It's also about four times the price. The furniture grade ply is very strong, being made of about 9-11 plys in the 3/4" version. It has no internal voids that I have discovered, and has a clear (knot free) veneer.

PT Ply works well if it's dry. I use a little of it in circumstances where the wood is going to get wet and I won't be able to pull it out immediately. Generally if wood in my boat gets wet it's coming out, even if it's supposed to resist rot.

CD-X ply is cheap, which is the only thing to recommend it. It has voids, comes apart easily, and generally should not be used for boats unless there's no other way. The voids collect moisture (which speeds rot), the wood itself is done in 3-4 plys so it's weaker than other types of ply, and the surface finish is much rougher than other types. But it's cheap, and if you've only got a few dollars it'll last a season, or longer if completely covered with resin.

I've used dimensional lumber for a few jobs. The upside of the stuff is that it's solid for putting screws into. I like to use well sealed/covered hardwoods as screw backing. I make sure to seal the screw holes too. Mostly I use this for non-structural work, since plywood is stronger and more uniform for most jobs. But it used to be used as the ONLY material for shipbuilding, and some of those vessels are still around, with new wood boats being built every day.

Glass:

I've bought the Bondo glass in home depot occasionally... it's the same quality as a lot of boat glass I've ordered online, just more expensive and folded up tightly. I've also bought bulk roving and biaxial by weight, a full roll of 8 oz glass on ebay as a "factory second", and biaxial "tape" from US Composites.

There are a couple different kinds of glass, and you can't really tell them apart by feel, so as far as I know I've only used E-glass, not the stronger S-glass.

The glass roll I bought on ebay was a great deal... I think I paid about $125 for a 100 yard (linear) roll. It's silane coated and I use it with epoxy. It's listed as a factory second, IE has defects, but I frankly don't see any. It may have had some runs in the glass, but I make bigger ones just cutting it anyway.

The bulk roving and biaxial from ebay was a fantastic deal. There's a guy in michigan who gets scrap glass from a fiberglass manufacturer (boats or something else) that's good quality, and he cherry picks it and boxes it by weight for sale. I paid $40 for a 55 pound box of biaxial, most of which is 2 foot by 3 foot sections. Buying the same glass new I would pay probably $200 new.

I have no complaints except the price on the US Composites glass.

Fabric types:

Cloth - the plain woven glass - well documented, classic, and well known. Usually the cheapest glass you can get.

Woven roving - looks like big cloth. Also pretty cheap usually, with poly resin mat must be used for adhesion.

Biaxial - not woven, but fibers laid together and stitched. Much easier than cloth to bend around corners if you use the fiber orientation to your advantage. Contains three orientations of fiber rather than the 2 of cloth, so is a bit stronger in most applications. Usually it comes as "1708" or "1208" cloth, which is the biaxial in 12 or 17 oz weight stitched to 8 oz mat for use with poly resin. Still works well with epoxy, and builds up glass thickness quickly.


Polyurethane glue - 3m 5200 or PL polyurethane or Liquid nails.

3m 5200 is the standard marine sealant. It's been around for more than a few years. Very, very strong, but not terribly cheap. Sells at Home depot for about $10 a tube.

PL and liquid nails are very similar to 5200, yet are not used much for boatbuilding and repair (yet). Underrated in my opinion, these glues are as strong as 5200, are waterproof, and remain a bit flexible when cured.



That's my brain dump for today

Erik

 

[oops!]

Re: boat building materials.....

first of all........

LETS HAVE A BIG ROUND OF APPLAUSE FOR
BOND-O

thats the longest post ive seen him do in a while.....it must have taken a long time ....one finger hunt and pecking the keyboard...!!!!

thank you
cheers
bud !

jason and erik.....awesome.....

this is great stuff...if we can keep the personal squabbles ( like poly vs epoxy and ply vs MDF ) outta this...we can keep this thread from getting locked up and we will have a real library for future iboaters

cheers guys
oops

 

[erikgreen]

Re: boat building materials.....

Hey oops... I suggested in another thread that we need an iboats wiki... maybe once this is collected we could put it all in one, so it can be easily added on to?

I dunno if Iboats would support that, it's just a thought.

Erik

 

[oops!]

Re: boat building materials.....

that would be ultimate......as a new miracle product could come on line at any time.....

just think...insta-spray foam, glass, stringers, and transom all in one for 2 bucks a gallon....and no grinding nessary.....

cheers
erik.......thanks for the hard work

 

[jcsercsa]

Re: boat building materials.....

that would be ultimate......as a new miracle product could come on line at any time.....

just think...insta-spray foam, glass, stringers, and transom all in one for 2 bucks a gallon....and no grinding nessary.....

cheers
erik.......thanks for the hard work

OOOOOHHH man I want some just spent the last 7 hours grinding !!!! I will take a case !!!!!! John

 

[Coors]

Re: boat building materials.....

I'm still in shock... Bondo has foam in a boat.

 

[Robj]

Re: boat building materials.....

What a great idea, unfortunately it will be more like a book and a thick one! One thing I have noticed are the naysayers on the use of PT ply. So far I am a fan of it, and none of the research that I have done suggests that there are any problems with resin sticking to it. Just make sure you DRY it out before you use it. Regardless of what type of wood you use, if it is wet, it will cause problems. That is why Erik's stringers are warping, the water from the wet wood has nowhere to go.

Looking forward to reading this new post. But for now, just keep working on your project, tommorrow is the first day of spring and the Bikini's will be out on Okanagan lake in a couple of months! Still hoping to get up there to give you a hand, and drink your Coronas.

Have a great day,

Rob.

 

[oops!]

Re: boat building materials.....

What a great idea, unfortunately it will be more like a book and a thick one! One thing I have noticed are the naysayers on the use of PT ply. So far I am a fan of it, and none of the research that I have done suggests that there are any problems with resin sticking to it. Just make sure you DRY it out before you use it. Regardless of what type of wood you use, if it is wet, it will cause problems. That is why Erik's stringers are warping, the water from the wet wood has nowhere to go.

Looking forward to reading this new post. But for now, just keep working on your project, tommorrow is the first day of spring and the Bikini's will be out on Okanagan lake in a couple of months! Still hoping to get up there to give you a hand, and drink your Coronas.

Have a great day,

Rob.

wuz hopin youd drop by for this one rob.
ill get a 24..
cheers
oops

 

[Bondo]

Re: boat building materials.....

that would be ultimate......as a new miracle product could come on line at any time.....

just think...insta-spray foam, glass, stringers, and transom all in one for 2 bucks a gallon....and no grinding nessary.....

cheers
erik.......thanks for the hard work

I'm still in shock... Bondo has foam in a boat.

Ayuh,....

With statements like That,....
Oops,... I think I've discovered Where all those disappearing Beers have been going.......

And,...... Coors,......
That's Why I'm not running for President.........
With a Dirty Little Secret like That,..... I wouldn't stand a Chance.......

 

[BillP]

Re: boat building materials.....

hmmm
Mahogony... Fir... for construction
cypress... teak... for trim

Pressure treated..... hmmmmm
I have used it... and will use it
However.... Mohogony is my choice... it's always been cost/availability thats been the compromise.
Searay and others use foam for their stringers.

Glass... be it epoxy or poly or vinyl... will not bond to PT. You can get it to stick if you rough up the wood with 36 grit... but it will not bond.
But... even in the bilge area... unglassed PT will last a long long time. Keep in mind that PT come's a million different ways... and the stuff you buy at depot is not the same PT that you can get from a true lumber yard that is treated for marine use.

Stainless.... hmmmm.
For trim its fine
For construction.... boat hulls flex under use. Having very little iron stainless isn't very tensile. The heads can pop off under stress... takes less than you think.

I'm a big fan of brass. Very malleable... it will stretch, and not snap. There's a little care when using brass. You can't just grab the screwgun (aka dewalt 18V) and start hammering them down. They will strip out. You need to use oversize, extra coarse screws... predrill, and cut reliefs for the heads for it to perform well.

For glass... Epoxy and poly work equally as well for the homebuilder. And you don't really need epoxy unless your constructing something hi performance and the weight/strength ratio is a major consideration. Personally i'd stay away from vinylester as a homebuilder... its a PITA to work with.

I'd like to hear more about the newer synthetics/plastics that people are using in for home construction. Stuff like trex and vinyl trim. I'd be curious if anybody as any experience with those type of materials.

`tip of the hat to ya~

WOW!

Surf the APA web site and read the pdf file on their pt test...it's maybe 10 yrs old now. Then surf Greenwood products web site (the people who make the most used marine pt ply in the boating industry). Write them for a list of boat mfgs who use their pt. The company names rank from the low end to high end snob brands. Been going on for 20 something yrs with success. No bonding issues with poly resin. Who's data debunks those sources?

Both polyester and epoxy "bond" to pt. No ifs ands or buts about it. The data is well documented in the APA testing...which shows no difference in bonding between standard ply and standard pt ply. Both resins pull wood off before their bondings break. Current pt processes use water as the carrier and when dried leave no hostile materials to cause bonding issues.

Also, PT processes are not a waterproofing. They are made to inhibit rot spores from sprouting and to detour insects from eating the wood. Also, "official" marine pt ply has LESS chemical concentration than store bought home depot pt ply. When encapsulated in glass there is no leaching and zero need for heavy concentrations. It's light duty service.

The reason for using epoxy instead of polyester? It's a structural gap filler and has superior secondary bonding compared to polyester. The superior bonding helps make up for human error or in places where it's impossible to prep (such as between the weave on heavy woven roven where stringers and bulkheads are attached). You can't sand down between the weave and that effectively leaves 50% of the bonding surface unsanded. The alternative is to sand the entire layer of glass down untill level.

BRASS...Using brass dates back to the 40's & 50's and novice homebuilt rowcraft...when copper and bronze was actually what the boat building industry used. It's completely outdated and unacceptable compared to other materials. It dezincs naturally and quickly (even when encapsulated), is major brittle and weak compared to other materials...Bronze, SS, monel or galvanized is stronger and longer lasting. When using SS the standard is to upsize the fastener to make up the difference in strength. If heads popped off SS somebody greatly undersized them.


bp

 

[ondarvr]

Re: boat building materials.....

Bp

Good to see you added this, my experiance is the same, I have GreenwoodXL PT in my aluminum jet boat that I put in 6 year ago, full contact on aluminum, held in place with SS bolts and there is no corrosion and it was used in my F/G 19' CC. Many of my customers use Greenwood XL PT to increase the quality of construction.

 

[oops!]

Re: boat building materials.....

Ayuh,....

With statements like That,....
Oops,... I think I've discovered Where all those disappearing Beers have been going.......

And,...... Coors,......
That's Why I'm not running for President.........
With a Dirty Little Secret like That,..... I wouldn't stand a Chance......

if i ever get to meet you bond-o... can ya help me make some dissappear?

and....why not run for president.....

no one would tell fo the "dirty little secret".....we all have skelitons in the closet....or ping pong balls in the bilge....

.we could use the no-bull approach to politics....!!.....you could also abolish the "foam law".....

 

[redfury]

Re: boat building materials.....

As far as stainless goes, yes, it likes an oxygen rich environment...it's what makes it stainless. The stainless part of stainless steel is the base metal oxidation when exposed to oxygen compared to the rust you get from steel exposed to air. It's all oxidation...

This is a great thread, I've bookmarked it for future reference.

The biggest question I've had for a long time in regards to foam is the 18lb stuff...it's hard as a rock, can be drilled into, etc. Wouldn't that poured into my cut out stringers and then completely glassed in be 1. easier than trying to cut wood to the contour of the bottom, and 2. be just as resistant to water absorption as any wood you would encapsulate in fiberglass?

 

[Bondo]

Re: boat building materials.....

if i ever get to meet you bond-o... can ya help me make some dissappear?

Ayuh,.....

I've been sober for over 10 years, goin' on 11,......
But,......
If, or When that particular Day arrives,.....

Ayuh,..... I'll toss down a couple with ya.............

 

[beerfilter]

Re: boat building materials.....

This is an excellent idea , IMO .
I think there should be an entire set of "FAQ's" set as stickies for all those commonly asked questions .

This particular thread topic is mainly geared toward glass hulls , although the techniques and materials for deck and transom repairs are easily applicable to us tinny owners , as well .

Not to hijack this thread , but , I think there should be a sticky for rivet repair / replacement , as well . This topic comes up daily , it seems .

 

[Bondo]

Re: boat building materials.....

This particular thread topic is mainly geared toward glass hulls , although the techniques and materials for deck and transom repairs are easily applicable to us tinny owners , as well .

Ayuh,.....
My post, #21 Is about a Tin Barge.......

Not to hijack this thread , but , I think there should be a sticky for rivet repair / replacement , as well .

Ayuh,.....

I guess this is a Great Place to mention that all ya gotta do is Google up "Closed-end Pop-Rivets"........

That's what is used for replacing Rivets when you Can't access the backside.....
Ayuh,.... They're Water-Proof.....

 

[BillP]

Re: boat building materials.....

As far as stainless goes, yes, it likes an oxygen rich environment...it's what makes it stainless. The stainless part of stainless steel is the base metal oxidation when exposed to oxygen compared to the rust you get from steel exposed to air. It's all oxidation...

This is a great thread, I've bookmarked it for future reference.

The biggest question I've had for a long time in regards to foam is the 18lb stuff...it's hard as a rock, can be drilled into, etc. Wouldn't that poured into my cut out stringers and then completely glassed in be 1. easier than trying to cut wood to the contour of the bottom, and 2. be just as resistant to water absorption as any wood you would encapsulate in fiberglass?

The deal with SS needing oxygen often seems to be taken technically out of an engineering handbook without using applied engineering in context. In reality, 316 SS (passivated) fasteners embedded in wood boat parts and glassed over look brand new when pulled out 25yrs later. This is so common that any fright of using them is 99.99% unfounded. Few are ever compromised and the ones found with crevis corrosion are likely the cheaper 302/304 variety that were never passivated in the first place.

Yes foam is as resistant as wood if you seal it well.


bp

 

[redfury]

Re: boat building materials.....

Oh, don't get me wrong, I agree completely. SS just needs to be exposed to oxygen long enough to form the oxidation that makes it stainless. Once that oxidation has formed over the metal, it's not going anywhere unless the oxidation is removed ( never got into that part of Stainless when I worked in a electroplating shop )