Polyester resin or epoxy resin

[wildvortex]

I will be restoring the deck and stringers on my bayliner. 1:1 epoxy is expensive and I am wondering if polyester resin will do just about as well when encapsilating the plywood prior to install since this is mainly to combat rot potential

 

[BWT]

Re: Polyester resin or epoxy resin

Poly resin by itself doesn't really do much; best thing to do is to coat the wood with poly, let it tack up slightly and lay some glass (csm) over top with more resin. At that point you can then set it in place and glass it in. Personally I would use laminating resin (the kind that stays tacky) rather than finishing resin (the kind that has wax added). Main difference between the two is no sanding between layup's if you use laminating resin. The last coat of poly and glass can be used with finishing resin, however I find it easier just to use gelcoat for sealing the resin to allow a full cure. If you look up Woodonglass I believe in his signature is a step by step on how to do this.

Hope this helps~

~BWT

 

[Woodonglass]

Re: Polyester resin or epoxy resin

Here's my drawing on how I recommend using Poly and mat to do your deck.

www.USComposites.com is a good source for your supplies.

(Click the Pic to Enlarge)

 

[oops!]

Re: Polyester resin or epoxy resin

to answer your question directly.....

i would not use epoxy on a polyseter boat.....for many reasons.....some here will swear by the product........give me poly any day at half the cost, a fraction of the time, 10x more options.....varying temps......and far stronger than you will ever need.....

imho....poly is just a bigger bang for your buck

 

[wildvortex]

Re: Polyester resin or epoxy resin

I agree totally oops but like you said many have recommended it. Seems like I will go with poly. BWT and woodonglass, I have seen and have a copy of woods layup and did plan on going that way. I was and am still planning on coating all sides of the ply with resin. Is the matting really needed on the underside though? I know that there will be some expansion of the wood. would ity be too much for the resin if matting is not used? Simply want to do the best job at the least cost. There have already been a bunch of surprises with this boat. Guess that is why they say your happiest days as a boat owner is the day you buy it and the day you sell it. I still disagree but there are alot that do agree with that statement. anyone know an inexpensive place to get fiberglass matting?

 

[BWT]

Re: Polyester resin or epoxy resin

Is the matting really needed on the underside though? I know that there will be some expansion of the wood. would ity be too much for the resin if matting is not used? Simply want to do the best job at the least cost. There have already been a bunch of surprises with this boat. Guess that is why they say your happiest days as a boat owner is the day you buy it and the day you sell it. I still disagree but there are alot that do agree with that statement. anyone know an inexpensive place to get fiberglass matting?

It personally believe that the wood needs to be completely wrapped with resin and glass otherwise there is the risk of moisture getting underneath an edge of the glass which will result in lifting/delam. It doesn't cost much more in materials or time so I figure better safe than sorry. I get my materials from an outfit called Express Composites (www.expresscomposites.com) but have also used www.uscomposites.com for my 2part foam. Either way I think these are going to be the best price (maybe check shipping to your area). Otherwise try a google search to see if there is someone more local. The resin and MEK-p ships hazardous so closer will be cheaper..

Hope this helps!

~BWT

 

[oops!]

Re: Polyester resin or epoxy resin

too add to what BWT just said....

resin coat ing wood......does nothing. ....resin is very brittle.....the thickness of layer you would put on the underside of your deck would crumple in your hand worse than peanut brittle. just by adding the csm to the underside of the deck you will increase the water resistance 10 fold......this simple step of adding glass (if you are resin coating...you are half way to glassing any how) will make your boat last another 20 years.

i don not order my fiberglass supplies on line.....i just go the the local fiberglass supply shop[.
if you look.....there will be a supplier in your town/city.....or at least not far away.

if you cant find one.....call a local boat repair place and ask where they get thier resin and glass from....or call composites one. they will tell you where a retailer is in your area.

 

[Yacht Dr.]

Re: Polyester resin or epoxy resin

too add to what BWT just said....

resin coat ing wood......does nothing. ....resin is very brittle.....the thickness of layer you would put on the underside of your deck would crumple in your hand worse than peanut brittle. just by adding the csm to the underside of the deck you will increase the water resistance 10 fold......this simple step of adding glass (if you are resin coating...you are half way to glassing any how) will make your boat last another 20 years.

I dont think just resin coating the underside was what BWT was suggesting ..

Personally I would resin coat your ply ( whatever wood you choose ) until it stops drinking the resin ( less expensive wood will require more resin ) then apply the 1.5 oz mat bottom side and 1.5 oz top with a layer of 1708.

i don not order my fiberglass supplies on line.....i just go the the local fiberglass supply shop .. if you look.....there will be a supplier in your town/city.....or at least not far away.

Be Very careful of buying from your locals ..

if you cant find one.....call a local boat repair place and ask where they get thier resin and glass from....or call composites one. they will tell you where a retailer is in your area.

Yea.. um..that same thing happened to me today whey I met and helped out a Local Iboater .. sent him to my local supplier for resin and glass..

Thing is .. I pay 2.50/yd of 1.5 oz mat .. and basically 9.00/yd for 1708 .. so I suggested he will probably pay a bit more because I buy by the ROLL or 80 and 100 yards..

He called me up when he got his total and said MY "local" supplier wanted to charge him something like 11/yd for cut BY THE YARD CSM .. and 14.00/yd for 1708 !!!

It was resolved in the long run after a few phone calls and after said Iboats member called him on his "over charge" of glass.

Be warned .. look up your cost of ONLine cost and Confront your Local seller .. you will get a better price or tell them to get lost !! .. Then order online if needed.

Hopes this helps some out there.. I KNOW it helped my new fount Iboat friend today ..saved him 200 buckish ..

YD.

 

[oops!]

Re: Polyester resin or epoxy resin

yeah....BWT was not suggesting to resin coat alone.....i was adding further why not to do it.

as far as the locals....if i ever caught my dealers doing that....it would not be polite.....if i sent them business.....i expect the person to be treated fairly...glad you got it all straightend out. every time i have ordered for an iboater....i get them to put it under my account so they pay my price. and then just payy cash....i also do the order or tell the owner they are coming. but i live in a smaller market than you i think.

btw....couple of threads in general about cracked glass and hull hooks to look in on.
have a look at the one with cracked glass.....i could be wrong....but it looks like serious stress fracture going thru to the glass

 

[sasto]

Re: Polyester resin or epoxy resin

i'd save the poly for the pros..If she were mine, Wild? i would go with epoxy.

Depends on your usage and achievement too.

 

[wildvortex]

Re: Polyester resin or epoxy resin

ok, so total encapsilation it will be. could anyone give me a rough estimate of how many yards at 50 inces wide I will need to do this? it will be a 94 bayliner capri 1800 18 foot and will be redoing deck as well as stringers. would like to get a little more for any incidentals

 

[gasch]

Re: Polyester resin or epoxy resin

I read somewhere on the net that if a person thins out the poly resign with acetone the entire mixture will soak into the wood better. I found 2 link that speaks to this
http://books.google.ca/books?id=HUbcp6IvPDYC&pg=PA45&lpg=PA45&dq=thinning+polyester+resin+with+acetone&source=bl&ots=DNpcnYQdgs&sig=44gUv9QXv3dQ4uYvdlLMKz90iSk&hl=en&ei=b_lTToOKNYHOhAfVypysBg&sa=X&oi=book_result&ct=result&resnum=5&ved=0CDsQ6AEwBDge#v=onepage&q=thinning%20polyester%20resin%20with%20acetone&f=false
http://www.ehow.com/how_6329199_thin-polyester-resin-acetone.html
I have not tried this and have no idea if it works or not.

 

[wildvortex]

Re: Polyester resin or epoxy resin

I kow that the resins can be thinned but am very sceptical about the thinning not having any effect on the strength and durability of doing so. I have some resin here and may try it both ways on scrap plywood just to get an idea. Reading the latest posts from OOPS and YACHT DR. you can almost tell from the comments about suppliers that they are more than likely not common DIYers but rather do this kind of stuff commercially or atleast very often. If they did not mention thinning as a possibility than I really don't think it should be done.

 

[Cadwelder]

Re: Polyester resin or epoxy resin

I Reading the latest posts from OOPS and YACHT DR. you can almost tell from the comments about suppliers that they are more than likely not common DIYers but rather do this kind of stuff commercially or atleast very often. If they did not mention thinning as a possibility than I really don't think it should be done.

Correct on both counts Oops ,YD and BWT are pro's not do-it yourselfers and they know what they are talking about. And yes also don't thin the resin with anything.

We are very fortunate to have guys like this on board with us here.

 

[Yacht Dr.]

Re: Polyester resin or epoxy resin

The debate on to thin or not to thin has been discussed here on Iboats a few time that I can recall.

Just IMHO .. It depends on how thick your resin is from the get go..some resins from some suppliers are THICK ( almost too thick to do anything more than make putty out of ).

I would thin out with acetone "too thick" resin ( 10% there about ) to precoat ply.

I normally dont have to do this anymore because I have a Good Local supplier with Good laminating resin ( I dont even bother buying general purpose resin ).

Its basically a resin to resin and wood to wood thingy ..

I would rather have thinned resin penetrating a bit more into the first ply than have thick glob resin just sit there and cure on the first time. Basically if you coat your ply and it stopped drinking resin on the first coat .. then the resin is too thick and should be thinned out a bit.

Its the same ( again IMO ) with Varnishes .. If you have raw exotic wood ( Teak .. Mohog .. etc ) your varnish is going to be thinned out on the first few passes. We would use Marine varnish with a reduction of 10% Mineral Spirits AND another 10% Gum Terps for the first coat .. then 5 % on both reduction .. then the proceeding coats with just Varnish.

Back to the poly thinning .. yes the thinned resin will lose properties .. but ( IMO ) will gain you better penetration on your BASE Glass Lam. That is the key to proper glass to wood adhesion is your FIRST coat .. period ! if your first coat fails then the 1/2" of buildup glass failed with it.. its all in the First mat bond..

Hope this helps ..

YD.

 

[BWT]

Re: Polyester resin or epoxy resin

Yup, pretty much what he said If the bonding coat(s) fail the whole layup is pooched. Thinned or not the goal is to saturate and seal the ply so it does not suck the resin out of the glass. If you're starting with thick snot it's not going to do much other than make neat amber drink coasters in the bottom of the mix cup. So sometimes IMO it needs to be thinned, but like YD said the good laminating stuff doesn't...

 

[wildvortex]

Re: Polyester resin or epoxy resin

I am ordering us composites 435 layup resin. any experiance with this stuff? http://www.uscomposites.com/polyesters.html

 

[NSBCraig]

Re: Polyester resin or epoxy resin

No to thinning and if you use 1708 on the top then there is no need to use csm also as it's part of the 1708

 

[Cadwelder]

Re: Polyester resin or epoxy resin

The pro's have spoken. Personally I've never thinned resins, but haven't had the "real thick" problem either. I can see it for the first coat (to precoat the wood it aiding penatration), but even there I don't thin it. I've spread many, many gallons of polyester resins, but no where near what Yacht Dr , BWT and Oops have. .02

 

[Outback Jack]

Re: Polyester resin or epoxy resin

No to thinning and if you use 1708 on the top then there is no need to use csm also as it's part of the 1708

Myself I never worked with 1708 before as I did fiberglass back in the early 80's, everything was chop gun, csm or roving . But when I seen 1708 first thing I felt was there was not enough mat on that to start a good base bond. I started with csm then go to 1708. I coated my plywood with a csm about 10 minutes after wetting the plywood and seeing if it was drinking up much. Like the guys have said your first bond is what you rely on afterwards.