it gets cold up here in wisconsin...so cold that if i turn on the big exhaust fan, it removes all semblance of heat from the shop in about 2 minutes flat.
i decided to make a smaller exhaust system and remove the big one altogether. it works much better, much quieter. centered it over my machine and the fumes rise right into it, but it can be raised or lowered with the chains that hang it.
this was accomplished by mounting a broan bathroom exhaust fan inside a steel garbage can. drilled two holes to hold the chains to hang it...made the cover for the old fan cavity in the window(insulated behind it). ran the flex tube to it and got back to work pouring.
very pleased with the efficiency of it, and much quieter to boot.