Water tight bulk head fitting on concave surface

[DarrenSL]

I have an SS Brew Bucket which I really like. The only downside is it has a crappy one piece tap that cannot be cleaned inside (when I dismantle my 3 piece taps it always surprises me how much wort finds its way behind the ball!). I have had a few bad batches that I'm putting down to the tap so am planning to replace with a 1/2'' 3 piece. The problem is, the brew bucket is quite small and the surface of the cone at the bottom is quite curved.

Anyone have any idea's how I can get a good leak proof seal?

Thanks :)

 

[peebee]

It can be a right pain fitting flat pipe fitting to curved vessels. I was faced with a similar situation but much bigger vessels (70 and 100L) with bigger hole (48mm, 1-1/2" BSP). And not complicated by "cones" (all parallel sided vessels). "Bigger" in this case means "easier" - the surfaces to be mated are nearer to flat.

I dealt with it by getting really farty: Gently rubbing a rigid fibre washer against wet+dry paper slapped on the vessel side until it has near-enough the right shape. Took an age. I expect it will take even longer with a cone surface (limits the rubbing to a much smaller area). Doing it properly will require an appropriate "boss" to be welded on, which will probably be impractical (and expensive). Fashioning your own washers might take an age, but probably not as time consuming as coming up with an alternative solution (with no guarantee you find one).

An alternative to fashioning hard fibre washers is to try fairly thick squishy washers (silicone) without modifying (can't modify!), but they can't work if the profile is too varied.

 

[Dutto]

After being heated to cherry red and then quenched in cold water, copper becomes very malleable. (Which is why hammering a copper bowl out of a flat copper sheet, is the first job they give you at Metalwork in school.)

If you can find a sheet of 2mm thick copper it is possible to:

• Cut out 2 washers to the correct size with a hand-held jig saw.
• Heat them to cherry red and quench them.
• Tap them into the correct curve. (Keep an eye on which is "inside" and which is "outside".)
• Heat and quench them again.
• Fit them inside and outside of the vessel on the tap's spigot.
• Hold the tap in place as you tighten up the nut on the tap spigot.
• The copper washers (and/or the sides of the vessel) will then deform to form a seal.

They will only work on a limited curvature - the flatter the better!