West System Epoxy help

[Franziska]

They also do an ultra slow "tropical" hardener, just in case.
Tall high mixing cup is not good.

When you use the flat mixing pan make sure you stir well.

[jefjo]

Originally Posted by aclmck

When using west system or most other epoxies only mix what you can use or require in a few minutes
NEVER change the mix ratio only ever try using differing hardness (part b) get everything ready and mix quickly then always spread out your mix on a board or a piece of glass and trowel it out quickly over the largest area you can this keeps the exotherm as slow as possible given the hardner and the temp while you are working
If you feel it's going off too quickly use smaller batches but always mix the correct batch ratios, the 8..1 you said you used might not work it may set but may not have other exothermed (cooked) correctly if you used this on anything structural I would remove it

Just experiment a bit and you will understand that any big volumes will heat up quickly (exotherm) so much so that it will start a fire in large volumes
With the powders or fillers some are glues and set very hard making it so hard sanding is difficult some powders are made for topping off and are easy to sand on slopes I use both types and normally use glue to fill holes then top with the softer top coat,if left too long these coats need sanding between them also lookup the material (looks a bit like silk) peel ply it is used to lay on the epoxy coats then peeled off leaving a smooth and easier surface to sand ATL have this info on their site.

I was just going to say this...

[Flyingriki]

Read what the moderator sent you!
This will answer both questions: https://www.westsystem.com/instructi...product-guide/

[Cadence]

Originally Posted by Island Time O25

Are you using too fast catalyst? Also what is the ambient temp? Epoxy will heat up much faster if the temps are much over 70F/20C. How much epoxy are you mixing? Too much will produce significantly higher temps and faster cure times. Counter intuitive but that's epoxy for you.

I haven't used West in a while as I found it to be too unforgiving if the mixing ratio is off. I use industry sold stuff which I buy from a local carbon mast manufacturer. He says his stuff is so much more forgiving about the mixing ration that it could be mixed at anywhere from 3:1 to 3:2, by weight not volume. Plus it is about 1/2 the price of West.

That sounds like System Three. I've had excellent luck with it and saved a bunch over the West System.

[glcalahan]

I have just started looking for an alternative to West system because of the cost. Who is the manufacturer of this product you foun? Simplier and less costly is especially important when there is a learning curve and product/cost losses!

[rbrentp]

What everybody said plus a BIG vote for icewater. I am in Houston and is often 35c when glassing. Everything is in icewater before and after mix. Triples work time. If you can put up a sun shade that helps too.

You don't truly appreciate the "peanut butter" level of thickening till you replace rotten balsa core in a deck from below. It will stay in place and quick setting there is a blessing.

[Siberian Sea]

Always mix in a pot that is wide and shallow not a pot that is narrow and deep. For some reason the epoxy will not generate as much heat in the wide shallow container and will give a much longer working period before it sets up. This is also true with polyester resins.

[roverhi]

Mixing and using in direct sun light decreases the working time significantly. Lay up very early in the morning or very late in the afternoon if you cannot shade the work area. Work under an awning in the daytime if your stuck out in the sunshine. Usually never mix more than four pumps of resin and even less if I can't slap it on quickly. Mixing in a largish diameter container also helps.

The 209 slow hardener is definitely a plus when working at higher temperatures. Have had the opposite problem of taking too long to kick in temp's around 70 degrees with the resin draining out of the glass on a steep surface. Ended up with the 209 hardener in an emergency when that's all I could find in the area.

[Terra Nova]

Originally Posted by Dave_S

...I used some of my creative licence and altered the mix down to 8-1...

An exceedingly foolish thing to do. NEVER alter mixing ratio. Mix at 5:1 ONLY!

Mix in batches small enough that you can use it before it heats up.

In hot weather, use slow or extra slow hardener. Keep epoxy containers cool and out of direct sunlight.

[Island Time O25]

Originally Posted by Cadence

That sounds like System Three. I've had excellent luck with it and saved a bunch over the West System.

Cadence, I don't remember the name but should have it written down somewhere. The guy who sells me this stuff (practically at his cost, may be 10-20% over) has been building sailboats since the 70s (Newport 30). And for the past 30+ years doing carbon masts and rigging. He has no polyester at his shop.

I was not advocating changing ratios etc but just stating what he told me i.e. that his stuff is much more forgiving of amateurs' mixing mistakes. West is not so much.

As far as the containers - my boat building buddy (not that carbon guy) with 45+ years of experience both in polyester and epoxy tells me that the shallow 8oz plastic supermarket containers (the kind you get olives in at the salad bar) are almost ideal for small jobs. More perfect would be the ones which are as shallow and have sloping sides and fully flat bottom but those supermarket ones will do.

Never had an issue with non-West heating up as I do not fill the container more than 1/3 of the volume, usually 1/4, i.e. 2-2.5oz at a time. With West I did have a heat up issue once but that was 10+ years ago, during one of my first epoxy jobs. I mistakenly used small high side containers (small empty jello jars). Learned since then. ))

Also his advice is to scrape all over the container as well as one can since one would be surprised how unscraped epoxy on the sides of the container can throw the ratio way off. I did a bunch of jobs with him acting as his understudy and this was a great experience. Would recommend to anyone who contemplates future epoxy work on their own boats to volunteer on such jobs.

This boat building friend used to work for that carbon plant guy for 3-4 years and it was awesome just to watch them work or discuss all things epoxy. There were like 80+ years of experience between the two of them.

[crazyoldboatguy]

Originally Posted by Steve Bean

To avoid the runaway exothermic reaction, use a wide shallow metal pan and place the pan on a container of ice water. In fact I think I remember seeing such a setup for sale. As mentioned above, ambient temperature can be a factor. WEST has information available about use of its products.

[Mike Banks]

I have not read any of the other posts--but never alter the mix,. This is not like polyester resin--it HAS to be mixed in the correct proportions.

Now--there are two reasons your resin is curing too quickly--maybe three.

Firstly--do not mix large amounts--and use SLOW hardener not fast hardener unless you need a very fast cure in one small area. Mix fast resin mixes for small jobs only and in small amounts, because it DOES go off very quickly indeed and generates an exotherm which also further accelerates the rate of cure--so it can get out of control very quickly and even catch fire if the amount mixed is large..

Mix epoxy resin it at the recommended temperature. The colder the temperature--the slower it will cure. If it becomes too viscous at cooler temperatures--one can add the proper thinner--which also helps slow it down a bit--but if you thin a resin mix it will soak in better but you will need multiple coats--probably a good thing.

My recommendation is to get a slower hardener and mix smaller amounts--using a new container for each batch (or one that has been cleaned out after the resin fully cured)

[Terra Nova]

Originally Posted by Mike Banks

...one can add the proper thinner--which also helps slow it down a bit--but if you thin a resin mix it will soak in better...

NEVER thin WEST epoxy.

[Geitz]

Are you using the West System mini pumps? If so, you mix equal pumps (strokes) of resin and catalyst.

https://www.westsystem.com/the-105-s...00-mini-pumps/

[Thumbs Up]

Lots of advice here but sorry Dave, You will have to redo it. You are going to have a gummy mess that you will have to remove somehow and start over. Never alter the mix ratio with epoxy!