Polyester Resin and Temp ?

Well my boat is finally reaching the end of it's restore !
I am getting the engine aligned this week and all I have left to do is glass the topside of the deck !

Anyone know what temp range will poly resin cure ?
I live in Canada and my daily highs are about 9 celcius

Can it be done or should I wait till spring ?

Thank you

Re: Polyester Resin and Temp ?

That temp is a bit cold, however, what will happen if you hold off 'till spring? Will the work surface be subject to rain, snow sleet? If so, you need to seal it with resin now. if you are indoors, can you get some heaters? Can you make a tent over the work and heat it? I was applying resin to the floor of my boat. I put a sleeping bag over the boat's canvass cover and stuck a heater under it to warm the work area, warmed the resin, mixed it with plenty of catalyst, and painted it on. I reinstalled the canvass and the sleeping bag, and it took some time to cure, but t was successful.

Poly resin is very flamable, so be very careful with heaters and flame. Heat guns and hair dryers may be used with caution to warm the resin's surface. Cured resin is not too flamable.

Re: Polyester Resin and Temp ?

Thank you

Will it cure eventually if I let it go or should I heat it for sure ?
I was thinking of putting in a electric heater ?

Thank you

Re: Polyester Resin and Temp ?

Most of the curing takes place in the first few hours and it's best if it cures as much as possible during that time period. If the cure is delayed because of cool temps it may not reach full strength even after being heated at a later time, not that it will terrible, just not as good as it could be. If you're putting on a thin layer, then you need to heat the area to around 15C or so, 21 is even better so it will cure well. If you're putting on a thicker laminate the resin will generate heat on it's own and will cure better, but you should still keep it warm if possible. Heat lamps work well, just keep them back away from the laminate, you just want the surface warm not hot.

Re: Polyester Resin and Temp ?

If you don't have heat another way to help it kick is to do a final resin only "hot coat" over it. Mix about 10x the normal catalyst and apply a coat of resin over the job immediately after glassing. It will generate xtra heat to help kick the whole laminate. Be careful for fires in the pot. Just for reference, I use 40cc catalyst per pint at 85F & 95% humidity for worst cases (100s of times without problems).

bp

Re: Polyester Resin and Temp ?

Thank you for all the replies !!

Re: Polyester Resin and Temp ?

wow 10x catalyst?

I'd get that out of the pot pronto.

Re: Polyester Resin and Temp ?

as you can see......poly resin is a really neat product to work with......

lots of ways to do it......

the best way ive found.....is to fool the resin into thinking its where it should be used at.........

keep the resin and your tools warm......75 deg........heat the substraight.....use the lights.....warm not hot......

mix the resin where its warm small amounts......run it to the boat....and paint it on under the lights.......it will think its in regular temps....and react the way it should.

Re: Polyester Resin and Temp ?

BillP said:

If you don't have heat another way to help it kick is to do a final resin only "hot coat" over it. Mix about 10x the normal catalyst and apply a coat of resin over the job immediately after glassing. It will generate xtra heat to help kick the whole laminate. Be careful for fires in the pot. Just for reference, I use 40cc catalyst per pint at 85F & 95% humidity for worst cases (100s of times without problems).

bp

Click to expand...

NOT!

Re: Polyester Resin and Temp ?

ondarvr said:

NOT!

Click to expand...

This coating is only to generate heat and make the resin kick. It's
WAY better than having a rubbery glass job. It salvages glass jobs that would otherwise be too soft to even pull out of a mold in one piece. It provides high build on surfaces for sanding. It reduces drainage on vertical or horzontal surfaces and prevents dry/weak glass jobs on foam by not letting the resin have enough time to suck from the fabric into the foam...etc, etc, etc. Real world, everyday.

I'm still waiting (a yr or two now?) for published lab data to show strength vs weakness with high catalyst values. Phone calls to chemist friends of a resin salesman are hearsay and don't hack it...certified lab tests showing stength breakdowns do...where are they on hot coating to kick an undercatalyzed glass job?

When and if there are no bonified tests (nowhere to be found) then empiracle data (everywhere on the planet) is there to prove hot coating works beyond a doubt. It's been done for decades in the FRP industry and 10-20 yrs later products show no problems. But NO, it doesn't jive with the published spec sheets which are printed on the severe safe side to CYA mfgs. Resin reps and chemists only see a small part of the applied engineering of their products in use (or should I say understand what is really being done with their products beyond spec sheets?). Most probably have no clue what a hot coat is and see only what their customers want them to see.

Do the hot coat and don't worry.

bp

Re: Polyester Resin and Temp ?

Bill

When I gave you the phone #s for the people (chemists) to talk with and offered the information for you to download, you wouldn't do either one, so please don't complain about the lack of supporting data. Hot coating with over catalyzed resin is a mostly abandoned practice that was done by less informed workers in shops with little actual knowledge or training.

Coating a laminate with resin or gel coat can do good things, the problem is when it's over catalyzed you've degraded the physical properties, many times to the point of creating quality issues and a much shorter life span for whatever it is you're working on.

Re: Polyester Resin and Temp ?

ondarvr said:

Bill

When I gave you the phone #s for the people (chemists) to talk with and offered the information for you to download, you wouldn't do either one, so please don't complain about the lack of supporting data. Hot coating with over catalyzed resin is a mostly abandoned practice that was done by less informed workers in shops with little actual knowledge or training.

Coating a laminate with resin or gel coat can do good things, the problem is when it's over catalyzed you've degraded the physical properties, many times to the point of creating quality issues and a much shorter life span for whatever it is you're working on.

Click to expand...

History? Abandoned only where mfg process control takes its place. But it is still being used where ultra fast kick time IS the control. There are uninformed workers in all facets of the frp industry...from shop workers to resin reps. If I had to rely only on one for knowing what does and doesn't work it would be highly skilled shop worker.

You are still providing generic statements that have no DETAILED engineering or test data to back them up. Downloads? You provided NO testing data showing high ratios of catalyst and physical properties (hardness, brittleness, etc) degraded by it. If I missed that one post it here. The chemist phone # you gave...no 800 numbers...I'm not spending my nickle on something any chemical sales rep should graciously provide to anyone who asks. So far, everything posted about over catalyzinhg has been generic (in %) or opinion (ref your statements above). My opinion is based on yrs of doing various hot coats and as posted already the degrading doesn't show. Your opinion is based on?

I still don't understand why the info is such a deep dark secret that hasn't been posted yet. If your company has these tests just post the data. If not then qualify your opinion based on fact based empiracle info. While posting that one, go ahead and post a cure rate graph like I mentioned on another thread. I know they exist because I've used them. Uninformed people can use the data.

bp

Re: Polyester Resin and Temp ?

The cure rate graphs you mentioned are generic also, each resin and type of catalyst will give different results, so these are just vague estimates unless you're using the exact resin and catalyst specified and most don't even list the resin.

The rule of thumb on gel times is each 15 or so degrees below 77F will about double the gel time, each 15* or so above will cut it in half. This is for a 100 gram mass in a small container, different amounts of resin in different shaped containers will yield different results. The age of both the resin and catalyst will affect the gel time also, so when you add in all the variables the graphs are just a general guide line.

The other issue when estimating cure times is the actual gel time of the exact batch of resin being used. A resin may list a gel time of 20 minutes, so 20 minutes would normally be the center of the range for this product, the range may be 2 to 3 minutes either side of that 20 minutes though. This means the gel time on one batch might be 17 minutes and the next one might be 23 minutes, so there could be a 6 minute difference between the two to start with. If you lower the temp by 15* you just doubled that 6 minute difference to 12. This means at 62* the gel time on one batch could be as short as 34 minutes and the next one might be as long as 46. Remember this is for the exact same product.

As far as the amount of catalyst for resin, the recommended amount is 1.2% at 77*F.
For each degree lower than 77 add .07% to a maximum of 2.4%. For each degree above 77F reduce it by .07% down to .9%

For gel coat, start at 1.8%, with 1.2% being the minimum and 3% being the maximum.


All of this has been discussed before, so if you have a graph then just post it.

I would also like to see the graph, or any other information from a supplier you have that says 10X the recommended max of 2.4% catalyst is advised.

Re: Polyester Resin and Temp ?

ondarvr said:

The other issue when estimating cure times is the actual gel time of the exact batch of resin being used. A resin may list a gel time of 20 minutes, so 20 minutes would normally be the center of the range for this product, the range may be 2 to 3 minutes either side of that 20 minutes though. This means the gel time on one batch might be 17 minutes and the next one might be 23 minutes, so there could be a 6 minute difference between the two to start with. If you lower the temp by 15* you just doubled that 6 minute difference to 12. This means at 62* the gel time on one batch could be as short as 34 minutes and the next one might be as long as 46. Remember this is for the exact same product.

Click to expand...

actually...... i have found the above statment to be totally true......

bill, ive tryed to duplicate what youve said about humid factors and such and nailing down gell times.....

what i found is there is a "window" not an exact.......i was very exact in my mixing...and mixed the resin/cat as best i could with a power mixer.
same day......same temp....1/2 hour laying time difference in the two samples..... so the humid was the same.....

but i never could nail down an exact time.....it was allways a 5 or 7 minit window.......i even used different a cat one time....(not ddm 30)


i do know of guys that hot coat. but for just too many reasons i dont like to do it...but sometimes in glassing.....you do what you can........ i just heat everything with lights.....and the product thinks it is in the correct temp range......even the glass itself........i did my bow gas tank area.......(a large area)......i was curing like it was 75 deg.....actual temp in the shop was so cold i could see my breath.....approx 5deg celcius

cheers
oops

Re: Polyester Resin and Temp ?

99% of the info about glassing here is "generic" so it's funny to see a post critical about cure charts being generic. They are way less generic than someone saying "too much hardner is bad" but they can't say HOW bad.

Anyway people who know about cure charts know they aren't generic...they are specific for the resin and hardener. I haven't seen one in yrs and don't have one to post. We came by them from our resin reps, who by the way, were alway forthcoming with detailed (not generic) tech data. They were professional and always backed comments and suggestions with credible engineering data. Too bad none of them post here.

Concerning kick times...I've posted how to do it several times. It isn't hype or BS. Its easy, but if you aren't able to dial it in you haven't done enough glassing to have a reliable history log to go by. Anyone who says it isn't real only knows enough to be dangerous. 10 minute "windows" are what novices and factory workers use. Pro glassers dial in kick times to the minute or less WHEN NEEDED. It isn't practiced on boat hulls and big parts...which are the easiest and lowest tech frp work on the planet. However, boat factories DO adjust kick times. It's usually practiced on small sensitive parts where cosmetics or other factors dictate it. In the surfboard industry it's done to keep the foam from sucking the resin out of the glass and making a pin bubble in every weave...same for any foam application where weight is a factor that eliminates coating the foam first. It isn't BS and any pro glasser in the surf industry will vouch this as accurate. These guys don't have ruined glass job like others. Just like hot coating to make a high build sanding surface, it isn't "abandoned" or done by those who don't know better. It's proven by 50yrs constant use in the industry NOT to cause problems...from the smallest shop to the largest. There is no debating it either.

Oh, and dardude don't read into my post as saying a mfg says to use 10x. I didn't say that...what I said (without knowing temp, humidity and exact use) is to start at 10x to kick an undercatalyzed batch...that be ME saying to do it. You said use a heat gun and I'll put big money a hot coat works better in this case...everytime. What I also said is I used 40cc to a pint of resin...many 100s of times. Also, your blurb on kick times is basic and meant to prove that resin kicking depends on temp and catalyst? How amazing. It's obvious you have never kept a log to dial in kick times whether in or out of catalyst specs. Do you need an explaination on how to do one? Do you even know why kilns are used for glass production? Where are the charts showing catalyst damage over the recommended spec? Huh? Still waiting...2yrs? Why?

I'm done and going back to Pluto.

bp

Re: Polyester Resin and Temp ?

You say these exact charts exist, but you can't produce one, interesting.

Actually like I said, there are charts, but they?re not exact, even for a specific resin, there are just too many variables that you have no control over.

We do QC testing with the same brand and type of catalyst the customer uses in their plant so it will simulate production a little better. To get even closer than normal we?ll have the customer ship catalyst from the batch they?re using and QC their product with it, this get?s it closer. As both products age their reactivity changes and gel times tend to be lengthened, so even if you made a chart using the exact batch of resin and the exact batch of catalyst, it may not be accurate in a month or so and sometimes even less depending on the product. If you change the brand of catalyst, even if it?s supposed to be an exact duplicate, you?ll get different results.

The other variable is the QC equipment and the person doing the testing, each piece of equipment will give a slightly different result and the operator can influence the test also. So even if you test the exact same products on the same day, by using different equipment and a different operator you?ll get different results.

The surfboard segment of the industry is one of the smallest there is and while there are a few resins formulated for it, little money is spent on it unless the same resin can be used in another much larger market.

Just because you didn?t see the negative effects of your less than desirable methods during your limited exposure to the FRP industry, doesn?t mean how you did it was correct. Or maybe you did see them, but didn?t have enough experience to recognize them for what they were.

Re: Polyester Resin and Temp ?

I can see the general idea of over catalysing for purposes of capturing a slow batch thermally, I wouldn't want to make a habit of it,
I'll always use the heat gun first simply because its cheaper !,
and since this is just a hobby, labor cost isn't a factor.

for very accurate time regimens I'd look at the very high grade epoxie$.
The local company here (Emmerson and Cummings) makes resins for nasa, by comparison the resins I use are junk but they work. Gel times are all over the place with my cheapo poly so I just take the "use or lose it" approach.

What about adding extra wax to a fixit batch, the resin I get is sold with the catalyst and wax packed seperately, no need to buy 2 different types of resin.

Re: Polyester Resin and Temp ?

Jonesg

I'm glad you had something to say. I forgot to say that there is very little heat generated by a hot coat when it's brushed in a thin film over the surface of a cool laminate. The difference in mass between the two means that "if" there was any heat from the hot coat it would be dissipated into the laminate and air with little or no noticeable change in temp of the substrate. Plus there is no penetration into the laminate, so even if you cure the thin layer that came in contact with the over catalyzed resin, it would have no effect on what's underneath the surface. It will create a great deal of heat if left to cure in the container though, melted buckets and foul smoke will fill the room rapidly sometimes.

A hot coat product can be made by adding the right amount of cobalt and DMA, then using the correct amount of catalyst (not over catalyzed), this can give a gel time as short as 3 minutes, that?s barely enough time to stir it. This type of product will create a much better surface to sand on. Just adding more catalyst doesn?t always speed the cure of resin or gel coat.

One of the big problems with polyesters is that they are so user friendly they can be abused severely and still appear to build a good part, then after a period time the part begins to fail and the resin get?s blamed. With epoxy it?s understood that it needs to be used in a specific way for it to work at all, so people are more careful with it.

Re: Polyester Resin and Temp ?

"there is very little heat generated by a hot coat when it's brush in a thin film over the surface of a cool laminate. "

yeh that thought crossed my mind.
I suspect I've avoided these slow gelling problems because I always run out of catalyst before a gallon is empty.

Re: Polyester Resin and Temp ?

Dardude, expand your "exposure" where the rubber meets the road. This stuff isn't learned reading product specs handed down from the sales dept. In relation to you saying I have limited exposure to frp...that exposure tells me (without a doubt) you have zero exposure to hot coats...never done one or been around the industry where its standard operating procedure. If so, you would have a different opinion of what they are about and know product life is in no way degraded when used appropriately. Besides that, there is no engineering data (which I have asked for many, many times) to back up your self alleged vast knowledge on frp.

Also, those experienced with hot coats know they do more than produce just heat to kick undercatalyzed batches. They also know hot coats will kick an undercatalyzed batch following a heat gun that does nothing. Those who have exposure also know hot coats penetrate deeper than the surface coat into underlying layers (within limits). I suppose its chemical linking. Regardless, it can repeated over and over with the same results...heat doesn't work...hot coat does. Hot coats for undercatalyzed batches are a last resort when nothing else works...exposure proves it. Then there are hot coats to build sanding surfaces...exposure proves it.

bp