Polyester Resin choices

[rickryder]

Hi All!

It is getting near the time for me to concider the type of poly to buy for layup on the deck and stringers. I have been looking at US Compsites site and can't decide what resin is best to go with.... 404 Tooling Polyester Resin-Isophthalic,700 Vinyl Ester Resin,435 Standard Polyester Layup Resin,B-440 Premium Polyester Layup Resin... So many choices
Thanks for any help!

 

[oops!]

Re: Polyester Resin choices

ok....lets tool at this from a logical point of view first.

the tooling resin is for making molds.....so that is out.

700 ve resin is very good...it is stronger than poly and it is used in boat building lots....this is a viable choice....not as good as epoxy...but stronger than poly. it will cost more than standard resin by 1/3

435 standard layup resin....the cheapest solution that will work well in your boat. no issues.

b. 440....preimum.....dont really know about this resin......more than likely just a few additives that will give it a longer shelf life than the regular resin....will it be better for your boat?....i doubt it.

now......having said that.......what do the boat manufacturers use?.........the cheapest carp they can get.....really..(in most cases).....
uasually there is a layer of good resin right next to the gellcoat but the rest is the lowest cost resin they can get.

we all forget here that fiberglass with cheap poly resin can be as strong as steel if used correctly. so even the worst decking resins are far stronger than the boat will need.
you still have to use the appropriate number of laminations for the required task, and follow the manufacturers specs on the proper mixing and catylisation rates......but in large....a standard cheap poly will be just fine.

just to further impress upon you the actual stregnth of the stuff........i mix up a special peanut butter (gype)....(oops super dooper peanut butter ver 5.2 ((pat pend))...lol )
in a 1/4 inch sandwich......this stuff is so tough it cannot be broken by a 20 year old with a sledge hammer. ....i let some go off in a cup the guys took it out to the back alley and beat the heck outta that thing for about 20 mins with a sledge.......they hardly dented it......even the thinner areas stood up to the pounding.

so.....even cheap poly fiberglass resin is super strong !

 

[dccordell]

Re: Polyester Resin choices

From USComposites, I used the even cheaper EB General Purpose Polyester resin... I've never used any other kind of resin, so I can't talk about the differences, but it seemed to work well in my stringer/deck replacement. I asked about the EB resin back before I got it and nobody really have anything bad to say about it, so that's what I used. It is around $20 cheaper per 5gallon bucket, so it's not really a big price difference, but that's $40 to put towards something else (I used 10 gallons).

One thing I did notice about that resin is they recommend a mix ratio of 1% which was WAY too low to get it to kick for me. I ended up using around 2.5% most of the time. Outside temps were cooler, so that may be why.
Hope that helps..

 

[dccordell]

Re: Polyester Resin choices

...this stuff is so tough it cannot be broken by a 20 year old with a sledge hammer. ....i let some go off in a cup the guys took it out to the back alley and beat the heck outta that thing for about 20 mins with a sledge.......they hardly dented it......even the thinner areas stood up to the pounding.

Just to add, I noticed this with my "peanut butter" mix, too. That stuff is super tough! Mixed with cabo and glass bubbles and 1/4" strand. Doubt it will be going anywhere anytime soon...

 

[oops!]

Re: Polyester Resin choices

one percent wont get you anything....that is literally a drop in a bucket.

mekp rates are between 1.7 -2.5......no more ....no less.

here in canada....i pay 108 for 5 gals. my good bud robj said he could get it out of vancouver at about 80 bux a 5.

the states will be a little less i would think......i mean you guys only pay 2 bux a gallon for gas....why should resin be any different?????

shop around....even the cheapest stuff will work......

by the way....the bondo stuff at wallmart is expencive....but that is due to its long shelf life.....

 

[dccordell]

Re: Polyester Resin choices

Looks like we are losing our $2/gal gas for $3/gal gas or more...

I would think even paying more than that for the resin locally would be cheaper because freight on that stuff is high! Hazardous shipping fees.. $$

I wonder why USComposites recommends such low mekp ratios? Maybe that is in a perfect temperature controlled shop? I don't know.. sure made my first batch a gooey mess!

Check it out...

 

[rickryder]

Re: Polyester Resin choices

Great info guys! Oops do you recommend going to the higher percentage of Mepk in the cold weather to help it kick? I have the boat all tarped in and was thinking of using a few sets of 500w halogen lamps under the hull to warm it up and some above to help the stringers warm up. I know glassing can be done in the cold with the correct prep and fool the resin by keeping the substrate 70 degrees or so.

I will be wearing all of the proper safety gear... gloves,safety glasses,respirator etc. Plus venting the boat during lay up then closing it up and heating it while it cures.


On another note Oops I would like to return the artic cold blast that came down from Canada! It's -10 here in NJ......you can have it back

 

[Yacht Dr.]

Re: Polyester Resin choices

Rick..the MEKP does not dictate what % you use with X resin..only the resin does that..( so forget about that lable on the MEKP bottle ).

Low VOC resins are approx 2% at working temps..cold weather might require more MEKP..

At extream temps..I would not even bother working with resins/gels .. Its just not worth the time man.

Wait till you have better working conditions IMO..

YD.

 

[Yacht Dr.]

Re: Polyester Resin choices

BTW...there is more then One type of MEKP...just like epoxy there is slow and fast .

I like to use whats called in this area High point 90 MEKP for smaller repairs/builds .

YD.

 

[rickryder]

Re: Polyester Resin choices

YD I agree with you 100 percent on the cold weather and the resin..... I sure won't be out there in 0 weather.... I'll wait till were above freezing.... I hope for some 40+ days

When you say small repairs I would guess some patching or minor jobs.... I will be working on about 30' of stringers and bulks and I don't want the resin to kick too fast or I'll be throwing it away in the bucket... What type of MEKP would you or Oops recommend for the project at hand? I'll be wrapping the stringers with 1708 biax....30' x2 sides and about 12" tall to give you an idea my yardage of cloth.

 

[Yacht Dr.]

Re: Polyester Resin choices

Thats still considered to me a small job..

I would use HP90.

Wet out your glass on a large piece of cardboard and then place them in..

One trick I will give you is before you wet out your glass..tape the sides and cris-cross tape your piece of fiberglass with 1" masking tape ( I use 2040 3m masking tape ) lay the glass in place then remove the tape and roll out every 2 layers ).

This will help with the Streach that comes into play with 1708 while laying up ( You will find it hard to roll out One layer of glass..you need at least 2 layers before you start to bubble roll or your wasteing time ).

YD.

 

[oops!]

Re: Polyester Resin choices

Great info guys! Oops do you recommend going to the higher percentage of Mepk in the cold weather to help it kick? I have the boat all tarped in and was thinking of using a few sets of 500w halogen lamps under the hull to warm it up and some above to help the stringers warm up. I know glassing can be done in the cold with the correct prep and fool the resin by keeping the substrate 70 degrees or so.

I will be wearing all of the proper safety gear... gloves,safety glasses,respirator etc. Plus venting the boat during lay up then closing it up and heating it while it cures.


On another note Oops I would like to return the artic cold blast that came down from Canada! It's -10 here in NJ......you can have it back

lol....sorry about the cold.....thats from EASTERN CANADA....we....out here in the west, get out weather from hawaii....so right now...in canada....under clear blue skies.with birds singing its +7 here, thats just under 50 degrees


when ever i glass......cold or hot....i try to keep the ratio around 2%.....i will go a little hotter in colder temps ...but not much, i try to adjust my working conditions temp....then fine tune the resin.....that way i know im allways in manufacturers specs.
(it is very inportant to stay within the manufacturers specs of the cat/resin....they make it....they test it.....they know where the product will work best)

if you are really cold.....you can go as high as 2.5 or 2.6 ( but at 2.6 its allmost impossible to get a correct measurement. there is allways mekp left on the side of the shot glass (measureing cup)

rick bud....understand.....poly resins and mekp have been used at 3% all the way up to 5% and higher......did the stuff get hard?...yep....did it bond well....yep ......but what happens is that the resin kinda cooks during cure....that makes it very brittle.....that issue makes it weaker than the manufacturers tested it to be.....and considered it a fail.
....well in our boats...a fail is not an option or people could drown.

i would not worry about glassing in colder temps at all if you are regulating your enviornment. but then again i am used to it.

the stuff we have here for summer time is called a DDM,,,,60 or 90... i use that stuff when we are over 90 deg out side....lol....thats also when i keep the resin in the shop fridge!

 

[rickryder]

Re: Polyester Resin choices

Thanks again guys! I will be waiting for some fair weather before starting this. I want to do it correct the first time around and safety for anyone thats aboard the boat if first! It is great to have people that can lead you in the right direction and provide great advice!