If you do, “boil your own,” as I need to do, this Practical Sailor article discusses best solutions to use. This is a lot gentler on your HE that an acid dip by a radiator shop, even if you find one. Many years ago, I had mine boiled and they “found cracks,” which I don’t think existed before I took it to them, and they charged me for re-soldering. I think they caused the cracks themselves with strong acid dip and overly aggressive pressure testing. Christian’s blog is real good, but doesn’t discuss diy boil out, but you can do it in a bucket.
Be careful with acids and if diluting,
always add acid into water, not the other way around. These are mostly pretty weak or mild acids, btw. It may be good if you can find a stiff bristle bottle brush to run through the interior pipes after soaking, too. Harbor freight. Has useful, cheap brass brushes, though I don’t know about one for inside the pipes.
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