Here we go again . . . MK4

[driftspin]

I think it was Clive who mentioned pouring into another container with a hole in the bottom. It crossed my mind but I had decided on the water bath to decrease viscosity and was concerned that water may get in and ruin the mix.
Sylavski had also posted lots on epoxy as well as Neal plus many others.
Thing is I'm not ignoring what others have written and it all goes in, and you have a plan, but you need to do it for real yourself to appreciate all the subtle aspects.
As for the tropical hardener I was using the 206 not the 205 hardener as this takes longer to set. I actually emailed West systems about what I wanted to do and was advised to use the 206. Thing is that a skin forms after 30 mins or so anyway and any bubbles will then be trapped so I don't think the long set time helps on the bubbles side. Good for self levelling though.
West said laying in one session was best rather than layers but I got the impression from the overall reply that they had not used it for 5mm beds for CNC rails. It is usually for boat repairs etc.

Whilst I wait for supplies to arrive plus some other parts I am rethinking my approach. Looked into vacuum pumps to degas but this is £200 for a small kit. I think next time I will :

Mix gently
Then place in water bath to help bubbles escape
Pop any remaining bubbles
Slowly poor but start in the 2 channels as bubbles come out first (and these are waste area)
Make sure surface is all wetted and coax with cocktail stick into all areas on first layer
Then maybe leave to just skin over (so still tacky) and repeat or may just go in one long session?
Pop any bubbles with cocktail stick or gently blow

Intuitively feels like this should be gently poured and touched as little as possible ( I think any prodding and touching will show on the finished surface)

Also thinking even with a perfect pour the last tiny deviations (once cured) will need shimming or epoxy putty to get the last 0.05 or so dialled in?

Hi guys,


I must say by the sound of it West is harder with the bubble issue then the resin i used.


I did not use west systems resin, 209 was unavailable in NL.... had to look for a alternative but found a usable resin else where. 5hr of pot life so plenty of levelling time. Get the slow hardner


I weighed out (kitchen type 1gram scale) and mixed the resin+/- 1kg at a time in a 1.5 liter kitchen type container with a bend wire on the batterydrill.

The whole mix turned greyish from air getting trapped in the fluid. This worried me at first.


After mixing i left it to de-bubble for at least 30min or so, some bubbles at the surface of the container remained and where wiped away with a paint brush.

Then poured only in the bridge channel, in between the x rails. no bubbles remained after flowing out evenly.


Hope this helps.

Grtz Bert.



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[Zeeflyboy]

Pain that it didn't quite go as planned...

I have no experience with pouring epoxy for rails, but from having done other things where bubbles can be a pain I definitely suggest thinking about putting the epoxy in a container you can seal and plug into a vac pump or even just shop vac for 30 mins to de-aerate... if you can vibrate it at the same time (I sometimes use an old orbital sander stuck onto the container) it speeds up the process.

Once poured, is vibrating the frame an option? Can help bring bubbles to the surface.

Better luck for round 2!

[routercnc]

Thank you for all those great and useful replies. I seem to remember reading on the West site (?) maximum of 6 pumps from each tin before mixing which meant about 150ml. I needed 4 of these mixes to fill the channel so I needed to mix then pour then mix then pour etc.
This means it all needs to be choreographed. If I could mix it all in one go and then stir with the drill and bent wire method that could have done advantages.
Shop vacuum and some vibration sounds interesting.

Maybe now I have a bit spare I can experiment with a method which combines all the good ideas above and still flows out before it starts to cure. Away from workshop until weekend do plenty of thinking time. Thanks again really appreciate it.

I'll try to capture whatever works in the next video to help the next guy out !

[mekanik]

Am i reading this correctly total epoxy required 600ml ? had a look @ my measuring jug and 150ml is a really insignificant amount. the larger the quantity the bigger the exothermic reaction but i would have thought with the slow setting hardener exotherm would be reduced. i would drop West an email and see if you could do the 600ml in one mix, will make life a lot easier.
Good luck on your next attempt.
Regards
Mike

[Chaz]

This is why, for Thor, I did not go Epoxy. I ended up with DWH Diamant, different approach.

[mekanik]

Hi Chaz
did you detail the procedure in you build log, i do remember reading it but didn't notice a detailed description, would be interested in the process.
Mike

[Chaz]

Hi Chaz
did you detail the procedure in you build log, i do remember reading it but didn't notice a detailed description, would be interested in the process.
Mike

Hi, might be some in my Thor thread, not sure. Can explain it again if needed.