epoxy resin help

[jim1950]

anyone tried Alumilite clear resin fast setting from House of resin, if so is it any good for turning? or can you recommend one in the UK
Just had a go with some deep pour EH125 from Swindon Composite but having trouble getting it to set been told my them it needs temp. around 30deg to set but had it at 23/28 degs in temp control cabinet for 7 days and still not set.
Thanks for any help
JIM

 

[alex robinson]

You appear to be comparing 2 very different products. One is a deep pour casting resin, the other a viscous coating epoxy. What are you trying to achieve?

Deep pour resins are very slow, but after a week it should have set, even if it is not fully hard. Are you sure you got the mixture right? Ratios are different depending on if you are measuring by volume or weight.

 

[jim1950]

You appear to be comparing 2 very different products. One is a deep pour casting resin, the other a viscous coating epoxy. What are you trying to achieve?

Deep pour resins are very slow, but after a week it should have set, even if it is not fully hard. Are you sure you got the mixture right? Ratios are different depending on if you are measuring by volume or weight.

the deep pour was for two jobs one deep (yet to do) the other was only 6/8mm deep but would not set, very carefully mixture ratios done by weight and always with a fresh mixing cup, never had a problem with the mix before. But I only normally crack and shake fill.
The resin was very cold when delivered and had gone very thick placed the resin in hot water before mixing.
Really just looking for a resin you can turn, hardens in a normal time at room temp, only doing the deep pour for a friend

 

[Linus]

I've just used some EH50 (now called EH125) on a deep pour and no problems at all despite being a bit old. 3 days in pressure pot and temp between 15 to 20 C. Swindon composite reckon 20C is good for a cure according to their blurb. You say you heated the resin before mixing but did you allow the temp to drop back to room temp before mixing? I am told that non-setting is normally wrong ratio mix or incomplete mixing.

 

[jim1950]

I've just used some EH50 (now called EH125) on a deep pour and no problems at all despite being a bit old. 3 days in pressure pot and temp between 15 to 20 C. Swindon composite reckon 20C is good for a cure according to their blurb. You say you heated the resin before mixing but did you allow the temp to drop back to room temp before mixing? I am told that non-setting is normally wrong ratio mix or incomplete mixing.

Had an email for Swindon saying higher temp would be better, I was very carefully with the mix and a label on the resin said to heat it if thick and tried 3 small lots since over the space of 4 weeks all have not set

 

[Sachakins]

Had an email for Swindon saying higher temp would be better, I was very carefully with the mix and a label on the resin said to heat it if thick and tried 3 small lots since over the space of 4 weeks all have not set

I'd get back on to supplier and explain this to them. It may be a bad batch?

 

[David Lloyd]

I used some epoxy resin to reinforce the base of a bakelite camera body that I was making a lamp with, so there was only a small amount of resin no thicker than 5mm. My workshop was very cold so I used a fan heater on the bench while pouring the resin. Then I turned the heater off and left it to set. Two days later it was a sticky semi set mess, I realised that the cold had stopped the setting process and took the camera into the house and warmed it up - hoping it would harden. It didn't, the cold obviously stopped the reaction and nothing could restart it.
My only solution was to scrape the resin out, and at the bottom of the 5mm pour it was still as liquid as when poured.

 

[alex robinson]

Had an email for Swindon saying higher temp would be better, I was very carefully with the mix and a label on the resin said to heat it if thick and tried 3 small lots since over the space of 4 weeks all have not set

It is very odd. I have had a problem with a very small batch and assumed it was that it was a ratio problem, but if it is multiple ones it does sound as if you may have a bad batch.

If you just want a different product that is reliable, I have found the glasscast range brilliant. Glasscast 50 is a very clear deep pour, 3 the much stickier surfacing version. I have not tried 10, but I think it is the same base as 50, but with a faster hardener. Their culr pigments are pretty good. I have also used and been happy with Epideco procast max as it is very runny so is good / bad at getting through small cracks (depending on what you want!)

 

[jim1950]

It is very odd. I have had a problem with a very small batch and assumed it was that it was a ratio problem, but if it is multiple ones it does sound as if you may have a bad batch.

If you just want a different product that is reliable, I have found the glasscast range brilliant. Glasscast 50 is a very clear deep pour, 3 the much stickier surfacing version. I have not tried 10, but I think it is the same base as 50, but with a faster hardener. Their culr pigments are pretty good. I have also used and been happy with Epideco procast max as it is very runny so is good / bad at getting through small cracks (depending on what you want!)

thanks for that will try it

 

[illumaphonium]

Hi,
I've done a huge amount of resin casting with epoxies over the years and later with urethanes.

Epoxies are slow and ENTIRELY dependent on temperature. The reaction is exothermic - i.e. energy is released during the reaction and so the mixture will become hot. This heat then speeds up the reaction. So if you have a deep pot of epoxy mixed up it can actually start to boil on its own! I've had this happen and it's pretty scary. Conversely if the mixed epoxy is very thin - perhaps 2 or 3mm then it may not generate enough heat to set.

Epoxies like to be at around 25 Celcius. Below 15 and they may not set at all. Above 50 and they may spiral out of control and start smoking.
If you can MAINTAIN a constant temp between 30 - 40 then you should be able to get a 'slow' eopxy (with a listed cure time of 24hour) to set within an hour ot two. Just be careful that it doesnt get too hot. Infra red lamps are pretty good at this job but make sure the spread of heat is even across the workpiece.

Once the energy in the reaction has dipped below the point where the energy released is sufficient to 'fuel' the reaction, then the reaction will stop. If you then apply heat then you can get the mixture to react further - this has the effect of lengthening the polymer chains and so increases the strength and mechanical properties of the cured resin - i.e. it is worth the effort. This process is known as 'post-cure'. As a rough guide if you may need to keep the cured resin at around 30 C for a week, or at 80 C for an hour it will achieve its full strength, hardness and ability to be polished to a good shine. This is an advanced process and I would just get to know the resin first, but the above info on post-cure times will shed some light on the benefits of keeping epoxies at a good temp.

I've not had good results with glass cast - I found it difficult to be bubble free and had an uneven surface.
I have had good results with Tarbender from Bentley Advanced Materials - benam.co.uk but this is only for thin layers.
I've just bought a batch or Pro-set laminating resin from Wessex resin and adhesives for a current piece of work but not used it yet.

Epoxies are hard to de-gas with a vacuum tank as they are so thick, but as you get them hotter they become more fluid. On a thin layer you can (carefully) use a hot air gun on a low heat setting to remove surface bubbles.

Just one more thing about epoxies is that they will go yellow over time. There is nothing you can do about this. There are additives that may lessen this affect but you will never stop it completely.


...one more thing relating to turning the finished resin - if it gets hot in the process then it will soften and you'll never get a shine on it.

Hope that is helpful.....