An editorial on Polyester Resin

[sdunt]

The B440 lay-up resin is the product on the left that we ordered 2 gallons of from US composites. Our estimates were running at right at 2 gallons of resin plus or minus a little for the project. The US composites resin is layup resin and it not waxed, so if we use it for a final coat we need to add wax to the resin when we mix in the MKEP, and we had done that for small batches with no problems..

We did the entire floor install, made putties, did the taping as well as the transom lamination and install with this resin. We also put down the 1st layer of 7 oz glass clothe over the entire floor with this resin. B440 is very easy to work with. It has a nice wet out and consistent SLOW setting. We installed the 1st layer of cloth on the floor as 2 - 50 inch wide panels that ran across the floor and had a seam running across the boat right behind the driver’s seat.

We had 0 – ZERO problems wetting out and laying the 1st layer of glass. No bubbles, no wrinkles. The wood grain showed through the cloth and resin beautifully. We still had time after the entire layer was done to do some minor tweaking of the clothe before it totally setup.

So, the plan was that we were to finish off the floor with a 2nd layer of the same cloth running from the back of the boat up to the front of the boat. Because this was to be our final layer we needed a finishing resin, a waxed resin, or we needed to add wax to the USC resin.

Well we didn’t have enough of the USC resin left to do the entire job and we had some things to finish on the transom, so lets hold on to the remaining resin and do get ourselves some finishing resin.

Wholla, product 2 on the right in the photo is purchased (we are purposely NOT naming the product because we are so PISSED about the quality of the product, and we don’t want to get in a lawsuit)

This resin is a waxed finishing resin and all indications are that you catalyze and use it exactly like the previous USC resin. WRONG !!!.. Absolutely, totally DEAD WRONG.

We mixed the 1st pint batch of this resin at 1% MKEP like all of the other batches of USC resin that we had mixed. First off the wet out was problematic and we needed allot more time to work the resin into the cloth, this resin was NOTICABLY thicker than the USC resin and it didn’t wet out as easily. 2nd about ½ of our 1st batch of resin setup in the pot before we could use it, like in under 10 minutes.. Keep in mind that we had USC resin catalyzed at the exact same rate that took 30 minutes to jell. (We are operating in early June, at maybe 65 to 70 degree temperatures)

So we start mixing batches at ¾% MKEP and finally wound up thinning the resin 10% with styrene and mixing at ½% MKEP and it STILL setup in the pot.

We went from one layer of cloth that looked nearly perfect to a ‘finish’ layer of cloth that looked like a 10 year old had laid it. Obviously we are not the least bit happy about this situation. We were working towards that being our final layer of cloth on the floor and not having to go back and glass it again.

Now we get to grind down the ENTIRE floor, get more cloth and more, USC resin this time, and cover the entire floor with a 3rd layer of glass.

So, my recommendations:

1. Buy your resins from a resin supplier, like USC, not from the auto parts store.


2. Always do jell time tests on resins before you use them.
3. Always do jell time tests on resins before you use them.
4. Always do jell time tests on resins before you use them.

 

[neat]

Re: An editorial on Polyester Resin

I second that.
Same company, different package, bought in Home Depot.
Here at 110' in AZ working time with that crap is about 60 seconds!!! And yes, no matter what you do it looks like crap.

 

[JasonJ]

Re: An editorial on Polyester Resin

I was in a similar situation when I did my floor/transom/stringers. I needed another gallon of poly and did not want to drive for over an hour to the boat builder I got my bulk resin from. I bought a gallon of the above branded poly, but I had the oposite happen. It wetted out fine, the final result was fine, but it took a week to cure vs the few hours of the other resin. I was working in 60 degree weather by the time I was using this resin, and night time temps were lower but that had not been a factor in the other resin. It eventually cured and I didn't worry about it.

The one thing I keep seeing on this forum is how people are doing separate layups or layers with poly. When I went to the boat builder/repair place to get my resin, I spent half a day there talking with the guys and watching how they did their work. They mixed for a slow kick, and would lay the multiple layers wetting each layer out, all before the resin would kick. They moved pretty fast while doing it, and the end result was a single layup consisting of multiple layers of cloth and mat in a single field of resin. They specifically told me that laying up a layer, letting it cure, and then laying up another layer was not the best way to use poly. Too many secondary bonds. I agree with that, and I did my project in the same way, and it turned out fine. I suppose a person could get away with multiple layers of cured resin with epoxy, but when I use epoxy I use it the same way as poly. To each is own I suppose, but considering a hull is layed up in the manner I described, I see no reason to not do structure the same way.

 

[neat]

Re: An editorial on Polyester Resin

This is what I read on FiberGlassics:
http://www.fiberglassics.com/fiberfacts/


The thicker the new glass layer, the more heat will be generated. Don't lay up more than 4 layers at a time. Too much heat will cook the resin and spoil the job.

...

Work 2 layers at a time for larger areas. More in small areas. More layers will actually cure faster than fewer layers. The curing process is an exothermic reaction (i.e., gives off heat), so the more material, the more heat, the faster the cure. But be careful that on hot days and working many layers you don't cook the resin

...

Next, start building in the repair with your schedule of materials. Do not work more than 4 layers at a time, or the exothermic reaction may create too much heat and cook the resin.

 

[andy6374]

Re: An editorial on Polyester Resin

Agreed. The same thing can be said for different manufacturers glass. Some mat isn't even worth using, just throw it away.

 

[Kevin70]

Re: An editorial on Polyester Resin

That's good to know. I was about to buy some scrap pieces off of ebay.

 

[Mark42]

Re: An editorial on Polyester Resin

Hey! That looks better than some of my finest fiberglass work! LOL!

I have used that brand before, I think it is best left for fixing fiberglass patio furniture....

 

[SS MAYFLOAT]

Re: An editorial on Polyester Resin

I've used a lot of the bondo brand stuff. I didn't have any problems with it. For the right mix, I used half of the catalyst of what they recommended. When the temps got higher, I reduced my catalyst. Still gave me about a 15 minuets of pot life. From past experience, I always lay up multiple layers to get the best bond. Sanding between coats is a pain.

The glass I got off ebay worked good for me. I bought the mill ends or drops and the stuff worked well for me. Keep in mind the fresher the glass, the better it is to work with.

Every product has its own personality and quirks. Its the ability of the user to make the adjustments neccessary to compensate for the differences.

Sometimes changing brands is not good idea as well. Compatability maybe different and make more of a mess wasting time and money spent.

Good post and sorry to hear about your problem.

 

[ondarvr]

Re: An editorial on Polyester Resin

There are only a few companies that make resin, none of the places you can buy resin retail makes their own, they get it in larger quantities from somebody else and repackage it.
When they change resin suppliers the product can be very different and can change from region to region. Resin also has a shelf life, 90 to 120 days is normal, so check and see if the resin can looks old and dusty, if it does, don't buy it. As resin ages it changes, it can get thicker, thinner, slower or faster, so even the same product can be a little different from can to can.

Resin can be very thick, very thin, have a fast gel time or slow, this does not mean it is good or bad, each type is formulated for different applications. I never use the thicker no sag or no drip type products, they can be harder to work with, but not always.

I rarely (almost never) apply one layer at a time, it's not because of secondary bonding though, it's because most of the time it's harder to get the glass to lay down and a waste of time to do one layer and wait for it to get hard. Unless you use waxed resin, or are working in the sun, secondary bonding is not as big of an issue as most people think. If you are going to let it sit for more than a day or so it's a good idea to sand it though. The reason for the concern on secondary bonding is due to the first formulas of DCPD resins, DCPD resins cure very fast on the surface even without wax and the industry was not ready for this change. Over the counter resins normally have no DCPD in them because it has a very short shelf life. If you buy resin from a boat shop it will have a very good chance of being a DCPD ORTHO blend though, so secondary bonding "might" be an issue, but you still have a day or so to put on another layer without problems.

Testing the gel time is a very good idea, most good boat shops check each batch of resin they get, they don't want any surprises.

 

[BillP]

Re: An editorial on Polyester Resin

Unless it was a bad batch of Bondx, your problems could have been avoided by reducing the hardener. Polyester has a very wide range of acceptable measures for hardener and you have to use that to your benefit. Always test a sample of the product first. Measure temp, humidity, kick time, resin and hardener...record it for future glass jobs. Then adjust hardener to match what you need for glassing time. Record the same everytime you glass and your kick/work time problems will go away.

Another thought...Any blanket statement saying not to lay up mulitple layers due to heat only shows a serious lack of knowledge in glassing. It is more about how to catalyze than how many layers not to do at one time. It is almost impossible to ruin 2-3 layers of any boat cloth by laying all 3 up at the same time. 3/4" boat hulls are done in one lamination without a problem. I used to layup 25 layers of 10oz cloth to make surfboard fins without a problem...and this layup generated much heat and needed way less hardener. Live and learn but don't blame the product.

 

[Kevin70]

Re: An editorial on Polyester Resin

Preach on, Brotha' Bill.

 

[ondarvr]

Re: An editorial on Polyester Resin

Another thing to look at on gel time is that all resins are tested at 77F, as the temp goes up the gel time is shortened. Every 15* increase in temp will cut the gel time about in half, so if the gel time is 15 minutes at 77* it would be 7.5 minutes 92*. This goes the other way too, so at 62* it would be 30 minutes, this is not exact but will be close for most resins. One problem is that you don't know what the gel time is on most retail resin, you have to trust the guy that ordered it from the resin manufacturer to decide on a gel time that will work for you, and he has no idea of exactly what you are going to use if for.

These tests are done in a 100gram (close to 4 oz) amount, this is less than you would normally mix if you were glassing more than just a very small repair. The more you mix at one time the faster it will gel, so if you mix a quart it will gel faster than the 100gr test, if you mix a gallon it will be faster yet.

The safe range for catalyst is from about 3/4% to 2.5 or 3%, but does change a little with each resin. There are also other types of catalyst you can use to modify the gel and cure, but these are not easy to get retail and you would need to buy at least a gallon if you did find it.