epoxy question

[Clive S]

I am not sure about epoxy leveling the bed before or after making the legs.

I would bold the legs to the floor, spirit level the bed , and then pour the epoxy on bed and x axis and 1 side of the gantry y axis. flip the gantry pour the other side.

I am not sure you are understanding the correct purpose of the epoxy. You have to epoxy both rails at the same time so that they end up on the same plain.

What do you mean by this:- then pour the epoxy on bed?

[driftspin]

Hi Clive... the bed...x axis.. is uh... the shape in the picture...

Yes i will poor the both x axis beams at the same time.. and one side off the gantry...

let it cure. flip the gantry and pour the other side..

ill post the design in a minute..

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[driftspin]

Attachment 21861


Ok this is the design...

The bed and raised X Axis is 1 solid welded up part (heavy, easy over 100Kg with no legs attached)
Did any of you put concrete in box section?
Heavy is good :-)

Legs and diagonals (50x50X4) are welded together, leg assembly will be a bolt on to the bed.
Should be plenty stiff.


I know a raised gantry is less rigid.
There will be reenforcing braces inside the raised box section of the gantry to
counter flexing forces in the Y directions, one disadvantage of a raised gantry...


The welding heat warped the boxsection a bit.
For what i can messure now, overall horizontal accuracy = +/- 1.5 mm (2Mtr Spirit level)
No flat surface to be found on any side of the box sections, no really, none of them....



Ok so the epoxy will be poured on all horizontal linear rail and bearingblock mounting surfaces (X and Y).
The aim is a +/- 60 mm wide epoxy mounting surface, for rail and bearingblocks
(80*120*4 box section has round corners 60 mm is about the max flat surface to be poured on)
2.5 liters epoxy will be more than enough.
Aiming for 5mm+ thickness.


I will mount a temporary leveling bridge (or maybe 2, More? X boxsection 1850mm long ) for the epoxy to flow between the 2 X rail mounting surfaces.
So now the X rail mounting surfaces will end up in the same horizontal plane.


The gantry will be poured simultanious, but upside down first (bearingblock X, and bottom Y rail, mounting surfaces)
I will also mount a temporary leveling bridge for the epoxy to flow between the X linearbearing mounting surfaces


After curing, the gantry will be flipped in normal position and placed in its natural position but no linear rail mounted.


Since gantry bottom X/Y surfaces are now in the same parallel horizontal plane,
it can be placed on the level X-rail mounting surface,
the top Y rail surface can now be poured in the same parallel horizontal plain.


I hope this discription is kinda readable...


Sorry for the English, i am not a native speaker...

[driftspin]

Capillary action.

So did you guys experience capillary action on the channel walls off the poured on areas?

I have done a quick test to see what the epoxy is like.. viscosity wise its really ok on a hot day 25+ C like today.

A gust of wind made ripples in the surface @ 45 min.

@ 4 hours .. the fluid will still flow and close gaps when disturbed.

For my quick test i de-greased some flat metal and worked it partially with the angle grinder to get scaling of... I want to know difference in strenght...
I made some wobbly channel using adhesive glue/kit..

Now on all edges there is capillary action visible... about 5 to 8 mm wide.. in corners it is more.
so a square of 40mm X 40mm gives about 25x25 mm usable flat surface.

Any opinions?



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[JoeHarris]

Capillary action.

So did you guys experience capillary action on the channel walls off the poured on areas?

I have done a quick test to see what the epoxy is like.. viscosity wise its really ok on a hot day 25+ C like today.

A gust of wind made ripples in the surface @ 45 min.

@ 4 hours .. the fluid will still flow and close gaps when disturbed.

For my quick test i de-greased some flat metal and worked it partially with the angle grinder to get scaling of... I want to know difference in strenght...
I made some wobbly channel using adhesive glue/kit..

Now on all edges there is capillary action visible... about 5 to 8 mm wide.. in corners it is more.
so a square of 40mm X 40mm gives about 25x25 mm usable flat surface.

Any opinions?



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In a word yes! You can file it down but better to make it wider than you need in the first place.

[driftspin]

In a word yes! You can file it down but better to make it wider than you need in the first place.

Ok guys...

Results of the test pour are:

- Surface is orange skin like.
so no mirror finish.

- Plexiglas like properties.

- Simple seperation from scaled steel surface.

- Simple seperation from grinded steel surface.

So ... I need to be carefull when removing unwanted material.


Did any of you prime the steel with a coating to prevent easy seperation?






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[Clive S]

- Simple seperation from scaled steel surface.
- Simple seperation from grinded steel surface.
So ... I need to be carefull when removing unwanted material.
Did any of you prime the steel with a coating to prevent easy seperation?

Did you make sure that the surfaces were clean and free of any oil deposits. I have used the West system with no issues and the epoxy bonds well to the steel.

[JoeHarris]

Did you make sure that the surfaces were clean and free of any oil deposits. I have used the West system with no issues and the epoxy bonds well to the steel.

I also used West System, ground back the surface a little and it was fine. Make sure you have the ratio correct and mix mix mix!

[driftspin]

Did you make sure that the surfaces were clean and free of any oil deposits. I have used the West system with no issues and the epoxy bonds well to the steel.

well made sure... degreased with brake cleaner.. wipedown and brake cleaner 2 times before grinding...

maybe use paint thinner or amonia or something else...



the test was done with 20gr resin + 8 gr hardner.... bigger volume will give me better resolution (1gr precision scale )

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[JoeHarris]

well made sure... degreased with brake cleaner.. wipedown and brake cleaner 2 times before grinding...

maybe use paint thinner or amonia or something else...



the test was done with 20gr resin + 8 gr hardner.... bigger volume will give me better resolution (1gr precision scale )

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To be honest I never tried it with such small quants just went straight for the big pour! But it worked fine.
http://www.mycncuk.com/threads/4513-...9752#post79752