Homemade float box

[markr]

I was recently thinking about making a homemade float box using an animal trough float, is this a good idea? Will it hold up to the heat? I have seen other float boxes made this way and when I asked questions I was told this was for cold sap only. My concern is that after I shut down for the day would the hot sap leach back in the box and melt the plastic mechanism inside the float? Or can you purchase a float with a metal float inside? I have no problem drilling my pan to attach another smaller pan with the float in it, has anyone else tried this?

[wmick]

I made one this year.... I was going to weld the traditional stainless box type float but I ran out of time and just used a plastic cattle waterer float ball....
However I did buy a couple valves from McMaster Carr -that have fluoroelastomer seals capable of 450 deg F. From my experience this year, I would not have needed the special (hot) seal.. Float box never got that hot... but better safe than sorry I guess.
16347
It worked pretty good... I think the flat rectangular float will be more precise, though, when I get to making it.

My biggest mistake, was using too small of a line from the float box to the flue pan.. I connected the two with a chunk of 1/2" hose... and the hose barbs were probably only 3/8" ID. I came very close to boiling dry at one point, because the (almost non-existent) head pressure from the float box did not push the sap to the pan, as quick as I was boiling it off... I will improve with larger stainless fittings for next year.

[mol1jb]

Good point wmick with the outlet size from float box to sap pan. I have heard guys wanting 3/4 to 1 inch outlet sizes.

[DJ87]

I used a cattle trough float for two years and it worked great. This year I upgraded to a stainless steel ball
float valve I got off eBay . Brand was aquamedia.