casting resin/river table

[Royce Meritt]

I am in the process of making a new fly tying desk. May plan is to make the top look like a trout stream. For the top, I have 2 slabs of natural edge walnut mounted to a 1/2 plywood substrate. This gives me my "stream bed". My plan is to "line" the bottom of the "stream" with pea-sized rock for the "stream bottom" and place a few larger stones here and there as "boulders" in the stream. Maybe a stick or 2 to look like "sunken logs" and some sort of "artificial vegetation" as well. This will then be filled with clear casting resin

The attached pictures may give you a rough idea of what I'm talking about.stream 2.jpgstream 1.jpg

The space for the "stream channel" is approximately 1.5" deep by 41" long and probably averages about 6" wide. Keeping in mind that part of this space will be taken up by the stones, is there a way to calculate how much casting resin I will need?

Also, what would be the best type and/or brand of clear casting resin to use?

Thanks.

Royce

[Jim Becker]

I'm not going to help with the calculation, but a gentleman on a CNC forum I participate in frequently displays projects that have objects embedded in amazingly clear resin. When I asked what resin he was using, he responded:

West System 105 with super clear hardener 207. It’s as clear as glass. (Guess that’s why that hardener is 2x as expensive) haha

[Steve Demuth]

You could get pretty elaborate and precise in your calculations, but it's not worth effort. You're talking about buying gallons of epoxy here, not pints.

So, try to firm up the 6" wide average by measuring 10 evenly spaced widths and averaging. Measure the length and depth. The volume in cubic inches is then the product of those three measurements. There are roughly 29 cubic inches per pint of mixed product.

So, using your original guesses: 41" X 1.5" X 6" = 369 cubic inches. Divide by 29, that's just under 13 pints. With West System 105 and 207 hardener (3 parts resin to 1 hardener), you'd need 5 quarts resin and a quart and 2/3 hardener, and that'd be cutting it very very close. You're outside the margin of error in your width average + wastage, so you'd really want 6 qts and 2 qts, respectively.

Which is about $400 worth of epoxy.

Edit: Realized I didn't account for the stones, which I suppose was your point. My apologies. I would account for them by putting what you need in the stream, then measuring their volume by putting them in a bucket and either figuring 50% free space from what they fill, or if you really care to get closer, filling the bucket with water to a known volume, measuring how much you put in the bucket. The volume of stones is then easily computed. Again, it makes no sense trying to get too precise, because you're going to be buying the epoxy in gallons and quarts anyway.

[Bill Space]

What I would do is take some plastic sheet, say from a large garbage bag, and place it in the “Stream channel”. It will not fit perfectly but that doesn’t matter really, as whatever voids here are will mimic the stones or other things you plan to place there.

Pour measured amounts of water onto the void until it is full. You will now have a good idea of the amount of epoxy you will need. Since the voids resulting from poor fit of the plastic sheet will likely be less than the volumn of rocks, etc, you plan to put in there, the water measurement will likely give some excess epoxy.

Given the the cost of the epoxy and hardner, you will then be in a position to evaluate if the cost of the project is worth it to you.

Bill

[Chuck Nickerson]

Wonderful concept! When I think of something like this I hurt myself patting my own back.

[Brad Shipton]

Smooth on Is another option: https://www.youtube.com/watch?v=wWkldrESy3Q&t=8s

[david blakelock]

Check out www.blackforestwood.com. I follow them on Instagram. They do amazing epoxy tops and I believe they sell the epoxy. They have many videos on Instagram which are probably accessible on the web. I have no affiliation with them, just follow them on Instagram. If you are on Instagram look up blackforestco

Hope I didn't violate any T&C's for posting a website. If I did I apologize and will delete it. Don't have a dog in the hunt here, just passing on some information

[mike falconer]

Any other options on a good epoxy? I to have been wanting to build a river table, I was looking at a tinted epoxy with a light blue/turquoise color.

[Andreas Sohre]

I have done a similar project using West System (207/105). Some time ago, I had used a very cheap epoxy system and had that didn't turn out so well. The West System is as close to fool-proof as possible from what I can tell (i.e. using the pumps to measure the mix properly and following their instructions). I did not worry about air bubbles in the final result so I did nothing to prevent them and there were virtually none when I was done. I would highly recommend it but it gets very expensive. Limiting the volume needed will make a huge difference in price. On the other hand, there is a lot that can go wrong so to me it's worth the extra cost to ensure a successful outcome.
Btw, it's very easy to add color. Drop(s) of dye as needed and stirred in (the dye needs to be compatible).