Resins at low temperatures

[makobuilders]

How much are "standard" fiberglass layups (polyester or vinylester resins) affected by low winter temperatures where water is easily 30-32F and air below 0F? Do they become brittle against impact or are able to still function properly without special design allowances?

 

[ondarvr]

There is an effect, but it typically show's itself at lower temps than these, although cycling the temperature up and down can cause cracking without other stresses being introduced.

The temperatures and conditions that may cause issues can vary depending on the exact products used (gel coat and resin), plus the construction methods.

 

[TeddyDiver]

None what so ever if there's no blisters. Around here gf sleds are used in temperatures down to -40C.

BR Teddy

 

[makobuilders]

I suppose if a guy from Norway doesn't know about cold temperatures, then nobody does!

Thanks

 

[ondarvr]

Methods and products used to build stuff in cold locations are slightly different, not that you would really notice though, because the products are available and used everywhere.

I did a great deal of research on this due to boats and RVs being built in the southern states in the US and being shipped directly to Northern parts of Canada, some builders had no issues, and others had huge problems.

Boats built, or items repaired in the North didn't have problems, but some that were imported shortly after being built in the south did. If a boat sat at a dealer in the south for 6 months to a year, then shipped north it didn't tend to have issues.

We also did thermal shock testing to see what products or methods worked best, the panels would go from about -30 to well above 100F several times per day. Some products cracked and failed rather soon, others held up much better.

As Northern parts of Canada became more affluent due to mining and oil, more fiberglass toys were sent that direction, the RVs came first, then high end ski boats, both items had issues for years while trying to figure out to best prevent thermal cracking.

Ski boats that sat outside over the winter tended to crack on the sunny side of the hull, the side against the garage, or that didn't see the sun tended to not crack. The surface on the sunny side would go from -20 to +80 (even hotter if it was dark color) every day all winter.

Also relatively thin laminates with a core were far more likely to crack than a thin laminate with no core, this was very obvious on RVs.

 

[TeddyDiver]

Crap is crap where ever it happens to be. If something fails up here it fails in south much sooner. Cold climate slows down aging in plastics and less UV..

 

[ondarvr]

Not talking UV, strictly thermal shock.

I worked for Neste during the first investigation, our Corp. headquarters were in Finland, and I can tell you the formulas and expectations from the fabricators and end users of the products are different in Europe than in North America. If a product (resin or gel coat) was developed in Europe it had to be modified to be used in North America. Some of our best formula's came from Finland, and they are still in use now, but they had to change them slightly for use in North America.

This has a great deal to do with how these products are used in production, when you're building 20 boats per day, 5 days per week, the resin and gel coat need to be able to be applied and processed quickly. The other difference that's common to both of this type of boat and RV was a very good distortion free surface profile, this was one of the main objectives in the resin and gel coat choice, plus the laminate schedule was designed for this too. In moderate too very warm climates, where these boats had most commonly been sold, this choice of products worked very well, when the temperature swings increased, especially on the low end of the scale, cracking occurred sometimes.

The products built were very high end ski boats, the customers valued a distortion free surface with a very high gloss, they also had very detailed in-mold gel coat designs and patterns, so the products used to build the boats were not general purpose products, nor were the methods standard.

Boats and RVs made with more typical general purpose resins, gel coats and fabrics didn't exhibit thermal cracking to the same degree, if at all.

So if you go back to my original, much shorter first answer, it says about the same thing, just with far less detail.

Metal boats are affected in the same way, but most people don't think it's an issue unless they've looked into it for a particular reason.


PS. Neste was an oil and energy company owned by the Finnish government, they made and sold resin and gel coat globally. The resin and gel coat division of Neste was purchased by Ashland Chemical around 2001.

My next investigation into the thermal cracking issue was around 2009 or 10, with a different resin and gel coat company. Canada's economy was in better shape than the US, so boat builders started looking at new markets, they sent boats made in their normal way to Northern parts of Canada, where again, they saw much wider temperature swings that were much lower. The thermal cracking issue reappeared with the new builders that hadn't sold into this market before.