Question on polyester resin and working temps.

[JasonJ]

Okay, I am stuck, but I have a few master plans. Its North Idaho, its cold. The question is, on a day that is 40 or 50 degrees, can I mix and apply the polyester resin, then tarp the hull firmly with a ceramic space heater to raise the temp and keep it warm, will it cure properly? Will mixing and applying at a cold temp and them immediatly raising the temp effect the curing process negatively? I know that epoxy can be used down to like 35 degrees or something, and that the colder temps just slow the curing process. Can polyester work similarly, or do I have to wait until the 60 degree minimum recommended by my shop? <br /><br />I am working out of my carport attached to my house. My other option is to close off the half-wall and the front of the carport (it is closed off at the rear with a full wall and a wall on the side that is 3.5 feet high). I could use tarps to close it off, and would need a heater that does not produce flame to warm the space, but I think it would be more difficult to maintain the temp for the full 24 hour cure time.<br /><br />Last option is to wait until April or May, but who wants to wait that long? I personally feel that my mix/apply/cover with tarp and heater idea would work, just due to the small space with good heat. I could tarp it, put the heater in, and see how warm it gets, and how quickly. Any insight is appreciated....

 

[Bondo]

Re: Question on polyester resin and working temps.

Plan A, should work just fine.... you can also bump-up the hardener abit, in polyester... In epoxy this is a no-no... poly can be jacked, without problems... a salamander can be used to pre-heat your hull, then glass it, tarp it, then maintain the heat a couple hours with the ceramic heater.... pre-heating will make things "flow" alittle better.....

 

[JasonJ]

Re: Question on polyester resin and working temps.

Thanks Bondo. Now to wait for a decent day....

 

[wezie]

Re: Question on polyester resin and working temps.

Bondo is most likely right.<br />If this is a major project, you could do both.<br />That would give you a warmer working surface on which to apply the resin.<br />Then cover and warm the whole thing.<br />Suggest you try a test panel under whichever circumstances you choose. See if you like the results.<br />Good Luck!

 

[plywoody]

Re: Question on polyester resin and working temps.

Polyester resin will achieve its maximum hardness when used at 70 deg F. Anything you can do to approximate this will enhance the finished product. While a bit more catalyst will aid in the reaction time (It is, after all, an exothermic reation and will help generate more heat)<br />While using it at something less than that may produce satisfactory results, it will not be as hard a finished product as it is designed to be.

 

[Hawkeye1]

Re: Question on polyester resin and working temps.

To carry on farther it is the catalist that evaportats out of the resin b4 it has a chance to set up it its too cold. The cold boat will act as a giant heat sink and when a layer of glass hits it it will lower that resin temp pretty quick b4 it starts heating up to cure. Your best bet is to control the whole enviroment for a period of time while doing this work or wait till warm weather gets here.

 

[JasonJ]

Re: Question on polyester resin and working temps.

I want the end result to be as solid as possible. If I have to wait until it warms up, I am cool with that. Farting around with tarps and all that won't cut it, I don't think it could stay warm enough consistantly enough. My shop said 60 degrees was about as low as I wanted to go. If its a 45 or 50 degree day and it is sunny, I can roll the boat into the sun to preheat it, or I could set up the heater under the tarp a day or so prior, and preheat the hull like was said. In the end, I can't get on the water until May, so I'll stress then. On a side note, I had to get that nasty smelling resin out of my house. I got it in a five gallon jug and three 1 gallon milk jugs. I thought the cold could hurt it, but I have doubts. Its in my tool closet in the carport, I'll heat the closet for a day prior to using it or set it in the sun to warm it up, but that smell in my house won't cut it, not if I have to wait another month.

 

[Bondo]

Re: Question on polyester resin and working temps.

I Hate to rain on your parade, But polyester doesn't like to be frozen.... I'm not sure, but you maybe having a problem with the plastic jugs.. I've Always bought poly in Metal Cans.... Poly is Very Unfriendly to Many Plastics....

 

[JasonJ]

Re: Question on polyester resin and working temps.

Thanx Bondo, I have been very concerned about keeping the resin in a cold place, and you are the first to give me a good answer to my concern. I went out, bought three new clean 1 gallon metal paint cans, transfered the resin, and it is all back inside, no smell. Thankfully the ouside temps have been between 40 to 50, and the storage closet is always a little more warm, so it never was exposed to the supre freezing temps. The boat shop I got the stuff from doesn't sell the resin as a business, so I was forced to recieve the 5 gallon plastic bucket they recieve it in, plus the three milk jugs. I knew the jugs were a bad thing, I guess I was hoping to use it sooner than I am. Its all good now....

 

[Bondo]

Re: Question on polyester resin and working temps.

OK, JJ,<br />I was abit concerned about the milk jugs... When I saw this thread back up near the top, I figured you'd be saying that your resin was running out of the cabinet, all over the floor....LOL....

 

[bidlimit]

Re: Question on polyester resin and working temps.

I am in the process of putting a floor in my '70 MFG but I had to stop due to cold weather. My last lay-up was performed in 50 degree weather in November (hadn't snapped cold yet). The resin would not set up, and I made it hot to boot. Anyway, I had to drag out the old infared heater to make the resin set. As a result, the boat is now sitting under a tarp in the back waiting patinetly for spring to come. Good thing I did cover her as she would have been under 2.5 feet of snow. (and I live in NJ )

 

[BillP]

Re: Question on polyester resin and working temps.

You can actually spritz hardener on the surface (after you have already laminated)and it will kick the lamination. I have done it many times with a chopper gun and it shows no problems. Using red hardener make this easier to judge. Try a sample to get the technique down. <br /><br />I also hit small jobs with a heat gun right after laminating and that works too. You really want to get the "kicking" process off immediately so the resin cures properly. Don't wait to see if it is going to kick, just do the heat right after you have glassed. Polyester has to kick within a certain "window" or it doesn't reach the max hardness. It feels hard but the tensile strength is compromised. Just don't over heat with the gun.<br /><br />When doing glass work log the temp, humidity and amount of hardener...then log the results, as in how long it took to kick. Do this everytime for trends and you will get a history for future glass work. Knowing how long it takes resin to kick is everything and this is how to find it.

 

[DDJ]

Re: Question on polyester resin and working temps.

JasonJ,<br />Been lurking here for awhile. Saw your Skanky project and different posts. You have balls dude.<br />I thought I could offer my .02 cents. From what I've seen on your pic's it shouldn't be that hard to enclose your car port with plastic. <br /><br />I have worked construction in winter in IA with a plastic barrier. They heat better than you think.<br />With the temps you're talking about it won't take that much extra heat. Although it's a trade off for time for extra expence. It sounds to me like you want to keep moving.<br /><br />In my oppion just enclose the whole space and turn on the heat. Preheat everything and keep going. It won't be that expensive and you'll get the job you're looking for.<br /><br />Keep the pic's coming. I'm betting you're being followed more than you know. GOOD LUCK.

 

[JasonJ]

Re: Question on polyester resin and working temps.

Thanx New Guy. I have basicaly been waiting for better working temps, and gathering more materials. Temps have been getting in the 50s, but it has been really rainy and humid. I have my transom wood cut and ready to glass in. Pretty soon the temps will climb a bit more. I am not in a huge hurry, as long as I am on the water by end of May I am happy. All our snow is gone, so that is a motivator......

 

[Kenbo]

Re: Question on polyester resin and working temps.

Jason,<br />when it starts getting warm out, you may run into the problem where the resin cures too fast. One trick we used to use is to refridgerate the resin. Probably nothing to worry about in May but if you have delays and can't finish until later in the summer it might be helpful. I've been watching for progress too and I'm rootin' for you! Good luck!!

 

[Kenbo]

Re: Question on polyester resin and working temps.

Just one more tidbit, If you are glassing in an enclosed space, an automotive paint type respirator with the proper cartridge would be a good idea. The fumes will make you loopy!

 

[plywoody]

Re: Question on polyester resin and working temps.

Polyester resin works best at 70 deg F, with the recommended amount of catalyst, and out of the direct sunlight. I too am a little surprised your milk jugs worked, but had they not, you would have known right away. They would have melted away pretty much immediately.<br />Also be careful there is no rust in your metal containers, as any oxide (like iron oxide) can act as a catalyst.<br /><br />But it is important that the temp be as close to that optimum as possible for best results. It is a somewhat complex reaction as the smell you smell from the resin is styreme monomer, which acts as a cross-linking agent to the polyester molecule, which is a long chain like molecule. The polyester moledule has little strength across, and requires the styrene to develop its strength. For best hardness results, the styrene needs to react at the same time as the polyester. Plus or minus a few degrees is no big deal, but the more you vary from this (like refrigerating the resin, for example) the more likely the results you get will not be what you were hoping for. The more catalyst that is used, the more quickly the reaction happens and the more heat is generated, also leading to varied results of the finished product.<br /><br />Good luck.

 

[SS MAYFLOAT]

Re: Question on polyester resin and working temps.

Hi Jason, Just a side tip here. On your final layer of resin, spray a good coat of Pledge Furniture wax on the surface. This will keep the air off the surface of your resin and allow it to cure properly without a tacky surface after curing.<br /><br />I agree with Plywoody on working it at the recommended temp. Makes a world of difference when your structure is put under stress.<br /><br />Good Luck....SS

 

[Kenbo]

Re: Question on polyester resin and working temps.

With my apologies, I guess Plywoody and I will have to disagree a little on this one. I would say that polyester resin cures at a wide range of temperatures, depending on the amount of catalyst used. Provided the ratio of catalyst to resin is within the range recommended by the manufacturer, full strength is developed as a function of time and temperature. Literature that I have seen specifies a full strength cure time as a number of days based on a controlled 70 degree temperature. I do not interpret that to mean that the resin will not cure to full strength if the temperature is not maintained at a controlled 70 degrees. After working for several years in the fiberglass boatbuilding business, building anything from a 14 foot skiff to a 52 foot Transpac ocean racer, I would say that we very rarely had what I would consider optimal climate conditions. Successful polyester resin/fiberglass lamination also requires proper wetout and rolling to remove air bubbles to achieve the best results. If refrigerating the resin, (as long as you remain within within manufacturers recommended temperature range), on a hot 85 degree summer day will extend the pot life of the resin long enough to ensure the layup is properly wet out and rolled to allow a successful result, I say go for it. I would agree with Plywoody that you should stay out of the direct sunlight when doing your layup.<br />If you are looking for another source of technical info as well as boatbuilding supplies, check out www.legnosboat.com . This outfit is the source I use in the local area and he has a wide selection of laminating tools and supplies.<br />With respect to spraying Pledge, I haven't heard of this before, but some types resin do contain a wax additive. If this type of resin is used, you must sand the cured surface before doing additional lamination or gelcoat to ensure a good bond. Good luck!