money saving tip?

[thehermit]

Many posts talk about how important it is to saturate all plywood decking with resin prior to instalation. <br />So my question is this: If you plan on using 5200 to adhere the decking to deck framing could you use poly resin to undercoat this plywood decking to save money instead of using epoxy? What about a good paint?<br />I will be using Epoxy on the topside and to tie into the the hull sides too. After going through 2.5 gals on the transom build I am scatching my head on how to save without too much compromising.

 

[b.gagnon]

Re: money saving tip?

I could be wrong but I think floors tend to rot from the inside out, so treating the underside with at least poly resin would be very important.

 

[Chris1956]

Re: money saving tip?

Hermit, Epoxy's is stronger and stickier than polyester resin. The bottom of your plywood floor does not require these advantages, so poly is fine. Most boats are all poly (newer boats are vinlyester). I would use SS screws to attach the floor to the framing, and I would paint the underside of the floor with poly resin, lay a couple of saturated cloth strips over the framing and screw the floor down. The cloth strips help "glue" or bond the floor to the framing. Remember, epoxy will always stick to hardened polyester resin, but poly doesn't stick to epoxy without sanding and wiping it with acetone.<br /><br />Also, since your floor is new plywood, you can use polyester resin and cloth on that as well! Save the epoxy for the areas where new and old materials meet and strength is needed(transom to hull, stringers to hull...). You don't need it on the floor to hull joint, since this does not have to be too strong, and the insides of the hull tend to be clean, dy and sound, thereby allowing a good bond with the poly.

 

[ThomWV]

Re: money saving tip?

Laminate a chunk of plywood with polyester resin and set it aside for a year. Come back and see if you can peel off the polyester without too much difficulty by hand. You almost always can. Use epoxy.<br /><br />Thom

 

[thehermit]

Re: money saving tip?

Thom,<br />what about an epoxy paint....the west system is puttin me in the poor house

 

[Rmac]

Re: money saving tip?

Try www.uscomposites.com for your epoxy,, they are pretty cheap compared to west systems, and their shipping is pretty reasonable too,, good luck<br /><br /><br />Richard

 

[ThomWV]

Re: money saving tip?

I get mine from Raka. A gallon and a half (a gallon of resin and a quart each of fast and slow set hardner) runs me $75 delivered. Might have gone up a little bit since my last one, but not much. You can seal an acre of plywood with a gallon and a half of epoxy.

 

[crab bait]

Re: money saving tip?

anyone who knows me,, know how much i'm an epoxy fan.. but not of epoxy paint.. <br /><br />it fades quick in sun.. wax don't help with sun or fade..<br /><br />all it is ,is hard.. an takes a good 'keying' good..<br /><br />do not confuse epoxy glue with epoxy paint..

 

[Bco128]

Re: money saving tip?

Hermit<br /><br />I dont know if you have a boaters world near you but they have a gallon of epoxy with a price comparable to poly.it was about $15 for a gallon.here anyway.unable to think of the brand at this moment but will check it out and report back asap so you can get back to workin on das boot.

 

[thehermit]

Re: money saving tip?

Bco....I cleared the shelves at the local (or not so local) Boaters world of WS epoxy. It was on sale for 50 bucks for the resin! I think in total I got 3 of shelf and ordered 4 more @ the sale price the last day of the sale. I am a big fan of epoxy!! I was only considering using the poly (resin coat only) to coat the underside of the 1/2 marine plywood deck. Also I have a self bailing deck so there are spruce 1x3 going from gunnel to gunnel that I was going to coat with poly. I realize a real money saver would be to not coat them at all. But I though some of the "boatyard resin" for 20 bucks may be a good treatment.

 

[JasonB]

Re: money saving tip?

I put 6-7 gallons of the boatyard resin in my old tri-hull last year. It is solid as a rock. I used it for the stringers, transom, and as a wood protectant. Will it last as long as epoxy.. maybe not, but the original poly the boat was built with was still strong after 30 years of abuse.

 

[crab bait]

Re: money saving tip?

don't be cheap.. don't skimp.. an extra 30 /60 bucs in epoxy cost..in the realm of life,,is nuthin'..<br /><br />polyester resin is not a glue an truley does not bond well with wood.. <br /><br />also,, it does nothing to stop rot.. it lets rot spores pass right on thru like a sive..

 

[BillP]

Re: money saving tip?

If you use poly resin to coat without cloth be sure to thin it with styrene and do several coats. Poly is brittle without glass and that is the main problem when using it as a sealer. I did it that way on homemade plywood (ac exterior) hatch covers and it was still fine 4 years later when I sold the boat. The boat was kept in the water in Florida and exposed to the worst elements.<br /><br />Rot spores are in wood naturally and dormant until the right moisture and heat make them active. They don't come though the resin and start rot. It seems most rot found under glass can be traced to poor workmanship and a breached glass job. I have never found bad wood under a good poly glass job.<br /><br />I bought generic 2:1 epoxy from Florida Fiberglass last year. The 3 gal pkg was $33 gal and a 10 gal pkg was $26 gal. This cheap stuff works fine for these stringer/floor/transom projects. WS is way too expensive and overkill.

 

[crab bait]

Re: money saving tip?

the proper term is water moleclues.. it lets water moleclues pass right on thru..which activate the rot spores..

 

[BillP]

Re: money saving tip?

It takes years of wicking for moisture to make it through the lamination. It is mostly, if not exclusively, seen on boats that spend 100% of their time in warm water...and not seen on 99.99% of those that do stay in the water except for exterior hull blisters. <br /><br />Wicking problems on trailer boats and interior stringers glasswork is virtually a non issue in the practical world. Stringers spend very little time submerged and don't see the moisture. Pinholes from dry laminations or shoddy work generally let the water in and rot starts from there. <br /><br />Anyone who has built fiberglass fuel tanks knows how difficult it is to get the lamination "pin hole proof". It shows under pressure quickly and the pin holes can be glassed over. It's a time consuming ordeal...thus bulky laminations/vac bagging and or coating with gelcote takes care of the issue. In the old days nobody coated the interior of a glass hull (under the floor)with gelcoat, now all of them do it. It isn't done just for cosmetics.

 

[thehermit]

Re: money saving tip?

BillP, Well maybee I will try a thinned poly on the underside of the deck and the deck beams. I guess I never checked the internet for prices on cheap epoxy before investing in the west. I am thinking of naming the boat the SS West System! The score is transom and stringers in (replaced one and patched others)5 gallons of epoxy used and 4 more coming at that sale price I mentioned. I guess after that I will look up some of the generic....do you think generec epoxy will stick to west system??? (usual prep work) The goal for this boat was to build a 10 year boat. It is already 30 years old and was hand laid up right here in town. I am doing my best on the restore but hey Bill I am guessing I have some pin holes!<br />Hermit

 

[BillP]

Re: money saving tip?

I'm sure there are exceptions but I doubt there is any problem applying one brand of epoxy over another. <br /><br />I wouldn't worry about the pinholes. Stringers don't see pressure like fuel tanks. A final fill (as in fill the weave of the cloth) coat at the end will help seal them too.

 

[thehermit]

Re: money saving tip?

I read a boat building artilce this morning about a guy who put formica on the bottom of his plywood decking so it would not absorb moisture! I dont know if this is a money saver or not but thought it was a new approach.<br />hermit