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Neil,
The heat I tried with the hair dryer was not enough to affect the foam, I kept it moving, but the thing is in my case it did not help with the bubbles. Maybe heat with less force would work ? it's just that with the draught excluder method there is not much room to create a tidal swell in the epoxy,
Hair dryer and heat gun are different beasts though...hair dryer will never get hot enough to melt the foam. Heat gun would if you hovered in one place too long I'd wager...
It's a compromise with the foam of enough heat to expand the air bubbles to pop them and not too much heat to melt the foam :)
Dragging the tooth pick worked for me and it physically moved the epoxy about thus aiding the self leveling process.
You can't beat low tech...I can't wait to start playing with the epoxy next week!
It's done !
This is before showing the moat in place. Clive S recommended 10mm epoxy each side of the linear rail so with my rail being about 20mm wide the epoxy bed has to be 40mm wide. Because my support beam is 50x50x3 box section it only left 5mm spare each side which meant the draught excluded would have been on the radius of the box section, that's why I clamped strips of wood each side so as to fully support the draught excluder. You can see I've coated the joints and any gaps with sealer.
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The gear used and the environmental conditions at the start. I used an old ice cream tub and a sawn off milk carton, the epoxy was mixed in the milk carton then poured into the ice cream tub with a thin stream as suggested previously. I'm not sure this did much but at least there was no mess created. The ice cream tub had a 7mm hole on one side, right at the bottom, with a piece of tape across and this proved to be perfect for pouring. Humidity is quite low because I always have a dehumidifier in there.
The calculated volume of my moat to give 5mm depth of epoxy was about 605300 mm^3 and it worked out that 500g of epoxy plus 250g of hardener was just right.
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This is after the pour, you can see the meniscus. There were no leaks and there was never any risk of it overflowing the moat. The epoxyducts were about 10mm wide and I'm thinking they could have been wider, definitely no smaller, the reason being that with this viscosity it needs a decent channel to flow down otherwise I would not be confident that the whole surfaces were at the same level.
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Eddy That looks nice re the moat I did find that my moat could have been a little wider although I did have two of them. I am sorry that I forgot to mention that before but you have plenty of width now in the centre even you don't get rid of the meniscus. :thumsup: ..Clive
I think the meniscus extends about 5mm across the width so with that each side it leaves a 30mm flat section in the middle, as you say that will be plenty for rail mounting. A file will soon sort out the meniscus removal later.
I forgot to mention that I had an epoxyduct at each end, plus, and it might be going extreme, I gave the epoxyduct pieces of wood a coating of sanding sealer thinking that the bare wood might soak up some of the epoxy, unlikely though it might be.
Attachment 11493
Also in the excitement I forgot to put Vaseline on the sides of the draught excluder but not to worry it just means a bit of sandpapering later.
Looking good Eddie, I've ordered the draught excluder so will be finishing off the frame to the point where I decide whether to paint it first or epoxy and then paint. I quite fancy getting it powder coated...
I had those thoughts myself but decided to epoxy onto bare metal. I had put metal primer on the box section beam but before putting the moat on I sandpapered it off the top. My intention is to fit the linear rail and paint over everything up to that.
Also sod's law, my glasses fell to bits as I was getting set to pour, the frame had broken letting a lense drop to the floor, had to quickly superglue it all back together.
I know this is somewhat less than scientific but I just had a play with the sample epoxy pour I did 3 days ago, a scriber barely scratched the surface and a centre punch made no more of a mark in it than it did in the steel box section. Overall I'd say that stuff was rock hard.