Use of epoxy for levelling

[njhussey]

I did consider making a single bush with a hole for the tapping size drill at one end and a hole for the tap at the other end...

But then there's not as much of the bush in contact so the chance of wobble is greater?

[reefy86]

cheers guys, im going to look for a decent pillar drill as i want this project to be perfect :) any decent ones to recommend ?

cheers

ash

[AndyUK]

Hi All,

Sorry to resurrect a four year old thread, but I'm trying to do a post-mortem of why my epoxy pour went so wrong.

I was using West 105 with the 209 extra slow, mixing 3.5 parts by weight 105 to 1 part 209 - in my book thats 350g to 100g.

The air temperature was about 21 degrees when I poured, which the manufacturer states: Pot life at 72°F (22°C): 40 to 50 minutes - we didn't get anything like that. The full description of what happened is in my build thread (here), but short story is we mixed 1.3L into one pot in 6 stages, stirring for a minute at each stage.

We then thought lets leave it for 10mins for the bubbles to rise, but we didn't realise the temperature of the mixture was rapidly increasing. By 8 mins into the wait, the whole thing was burning hot and we started to pour as the plastic container was melting. That kinda ties in with the manufacturers Pot life at 95°F (35°C): 15 to 20 minutes.

How do I get it to wait 72hours? Mine was rock hard within minutes, you guys are still leaving fingerprints after days! Was it just those few minutes waiting that screwed me, or should I mix a small amount, pour, then mix more and pour over?

[routercnc]

I've only done this a few times (3 in fact, 1st time was not so good, 2nd and 3rd went OK !) and used exactly that epoxy mix. I think what has happened in your case is if a lot of mixture is altogether in one pot then the heat from the parts of the mix in the middle cannot escape so it heats up. This promotes rapid onset of the curing of the rest of the mixture which releases more heat in a runaway reaction. I'm sure they mention somewhere not to mix large quantities in compact containers.

I think you will get ~72 hours when it is all spread out in your moats, so in my view it needs to be mixed and poured straight away. I didn't see much escaping of bubbles after the stirring when I did it as it is such as dense mix, so I don't think waiting helps (is my limited experience).

I only mixed about half that amount in a relatively wide plastic jug, alternating between 105 and 209 and think I only stirred at the end, slowly to avoid incorporating more bubbles. Then I did what others had suggested (Clive?) - the "2 jugs" method.

The fresh mixed is carefully poured into a second jug, which seems to promote some of the bubbles to be released, possibly because in the thin stream that pours from one jug to the other they are forced to the surface.
This second jug has a ~5mm hole towards the bottom of one side covered with tape and once all the mix has been transferred across you hold the jug over the machine, release the tape, and this will pour out into the moat. Again this seems to prevent too many bubbles getting into the moat.

Leave a small amount in the jug as this will be very aerated.

Here was my second attempt on the X axis:
https://www.youtube.com/watch?v=FDrcpnVUcEE

And using this method on the Y axis:
https://www.youtube.com/watch?v=aw0pM_uV1kw