Carbon Fittings OK

Short version: I would like to buy Carbon Steel fittings for keggle. Is that OK or do I need to get stainless?

Longer Version:
I bought some keggles on Craigslist and they have 3/8" NPT instead of the standard 1/2" NPT. I bought a stainless steel bushing to convert the 3/8" to 1/4" NPT and was planning to get a 1/4" NPT thermometer, but it seems those are hard to come by especially with 4" stem length.

Now, I am thinking I need a Reducing Adapter instead in order to get up to 1/2" NPT. Called a reducing adapter, but it is the male side that is smaller so for me it is an "expanding adapter". Unfortunately they are pretty expensive. Carbon Steel is half the price of stainless


$12 Carbon Steel: http://www.drillspot.com/products/349122/Parker_8-6_RA-S_Reducing_Adapter
$24 Stainless Steel: http://www.drillspot.com/products/352789/Parker_8-6_RA-SS_Reducing_Adapter

Thx for the help

Carbon steel WILL rust, I would use stainless. You might be better off using a nipple and reducing bell adapter, a far more common set of fittings might be cheaper.

Why not just cut out the 3/8 welded fitting and use a weld less 1/2 fitting

Thanks so much for the very speedy replies.

LordUlrich: I appreciate that. Will spend the extra dough rather than get rust in my beer. As far as the more standard parts: that makes it stick way out of the keggle which creates more opp to bash the thermometer when moving (I don't brew in the same place I store my equipment). Guy I bought it from had reduced it down to the width of the therm stem, then welded some metal onto it and put a little nut (not sure what actual name is) that screwed into the final piece.

JRems: that sounds like the best way to go to end up with the simplest setup, but I don't have welding skills to cut out the existing fittings and I am just getting into kegging so have way too many beer projects underway right now
- in progress: portable 5 gallon igloo kegerator for 3 gallon corny. Need to install shank/faucet, cut hole for Co2 hose, and bore out lid so it fits on top.
- in planning: keezer collar because 5 gallon cornies are just barely too tall with lines attached for the Danby 10.2. Fits with the connectors, but not when you add the lines.