farmer boy 7:10pm, 19 June 2013
A long time ago - (18 months) I bought some epoxy plus hardener and I remember posting that it was taking an age to harden.... I have recently used it again and it has the same problem - the correct ratio is 2 to 1 and I have just experimented with a 1 to 1 mix and it still has not hardened after 4 days!
Am I missing something or do I have a bad batch - or does it go off after a while?
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NormanKlipspringer 5 years ago
I have always found that so long as the temperature is ok it is hard after 12hours but can take 5 days to go off completely.
Skykomish1 5 years ago
that's the price you pay for buying those blue tablets on the internet Norman...lol
Seriously though I have never had an issue with West System and their ratio of resin to hardener is a lot higher.
I do find however that cheap epoxy glue bought from pound stores takes forever to go off whereas known brands like Araldite tend to be more reliable and harden quite readily which would suggest that perhaps there is a difference in quality and that not all Epoxy is the same.......
Super Snoopy 050 5 years ago
I bought some from Reactive Resins about the same time as Farmer Boy. Whilst the "hardener" has turned a bit brown and stinks of ammonia, it all still works when used in the correct ratio. Putting more "hardener" into the epoxy is asking for grief. I've also used ten year old West System to good effect.
farmer boy 5 years ago
hmmm.... yes.... my hardener has also turned a bit brown. Am I correct in thinking that the more hardener you add, the quicker it sets or is it critical to get the correct ratio ie 2 parts epoxy to 1 part hardener by weight. I have just been out to check my "test" batch of 1 to 1 and it is still soft after a week.... I feel some more viagra jokes coming on.....
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NormanKlipspringer Posted 5 years ago. Edited by NormanKlipspringer (admin) 5 years ago
I have used MAS epoxy and they say that changing the ratio can alter dramatically the cure time and even lead to no cure. I would stick to the manufacturers recommendation when using epoxy resin. It is not like using polyester which is a lot more forgiving.
Skykomish1 5 years ago
I know that all the articles that I have read about using Epoxy glue emphasise the importance of correct measurement and temperature control. As I understand it it is temperature that effects cure rate and needs to be as constant as it is practical to achieve. I agree with Norman that it would be better to stick rigidly (no pun intended) to the manufacturers recommendations and maybe contact them with regard to curing issues.
pjbharrison 5 years ago
Hi John
I've used West epoxy systems in the past and found them very good but expensive compared to other marine epoxy resins. The have 4 different hardeners. www.westsystem.com/ss/hardener-selection-guide/
I found that the West epoxy cures fully overnight even in temperatures as low as 10 deg C. Working times can be quite short in warm temperatures.

For building a new rudder for Helm's Deep I chose a cheaper epoxy resin from www.as-ireland.com/. The hardener supplied is described as a "fast" hardener.
The woven roving they supplied is very good and much more supple and easier to form than chopped strand mat. It gives a better looking finish too. www.as-ireland.com/index.php?main_page=index&cPath=66...

I found the resin slow to cure even though the temperatures in my garage were quite warm during the build period. It took a few days to fully cure before it could be sanded. The addition of fillers seemed to slow the cure even further. I used an electronic scales to weight the components and used the manufactures recommended proportions. I don't think I would like to use this resin over the winter in a cold garage.
The final finish of the resin is comparable to the West system and seems just as durable and strong. It just cures slower.

I'll post photos of the rudder build in the next few days.
rothwell_neil 5 years ago
You can normally get different cure rate hardners. The resin stays the same but the cure time is controlled by the activity of the hardner. There is an old school that reckon you get better cross linking with slow cure which is why they always claim you should use 24 hour araldite rather than 5 minute. Me I find 1 hour to be good for impatient people like me and also just enough working time.

The answer is that the hardner has gorn orff, keep it in the fridge if you want it to last (wife won't let me obviously). It should work at 2:1 if that was the original spec. Adding more should speed things up but will also result in likely weaker epoxy. Trouble is it is often hard to find hardner without resin. You can mix and match assume that resin is resin and then use the hardner at the ratio specified so west hardner usually works with reactive resin etc. Most people add too much just in case so we all end up with resin and no hardner. Temperature does make a difference as warmer is faster, thermodynamics and all that.

Different reactive hardners for different results
www.reactiveresins.com/Epoxy-Hardeners 1.html

See if you can get separate resin on t'interweb other wise buy some more!
Freebird 1011 5 years ago
I have used many different epoxy resins but not the Reactive brand I don't know what it costs but generally speaking I have found you get what you pay for. The most common fault particularly in cold damp conditions is failure / slow to cure with the 'budget' epoxy. It is expensive stuff and I prefer to use a good brand such as West or System 3 .
farmer boy 5 years ago
Just been out to have a look at my "test" batch and it is still soft after a week so I guess I am doing something wrong! I remember it being VERY slow to set when I first bought it so maybe budget brands are a bit risky!
Super Snoopy 050 5 years ago
Have you spoken to Reactive Resins? They are members of the Achilles Flickr Group.
rothwell_neil 5 years ago
I have always been a big fan of reactive resins and have a had a big tub of West go crystalline on me so happens to all of them. Keep them cool!
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