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View Full Version : Epoxy baked moly coat for pistons



MTECHMARINE
06-10-2010, 06:39 PM
I went for it and bought a quart of epoxy moly coat for pistons.:) The company provides the same stuff to Chrysler for V8 pistons, etc.

Coated a pair of Wiseco 56CID OMC Looper pistons, 2 for my C service Speeditwin resto and the 4 Wisecos for my Classic sandcast Quincy D MOD. They came out GREAT. :eek: :D

The speeditwin pistons were pretty nasty looking after being in hurricane IVAN flood and this stuff really spiffed them up.

So out of a quart I've used about a quarter inch. It has to be kept in a freezer and is good for about 4 months. I have the MSDS if you want to read it. So if you have some pistons you want coated call me at 850-623-1197 and we can set up something. I'll work cheap ($10.00 per? U pay shipping - -) if you send me CLEAN parts. Most of the work is in masking. I will post some pictures tomorrow of the ones I did. BILL

MTECHMARINE
06-11-2010, 02:26 PM
Here's the promised pictures. Hope you enjoy them. I'll post more C service pics and an SR50 as well under antiques.:)

Bill Van Steenwyk
06-11-2010, 02:45 PM
Don't know how you are spraying them as far as technique, but some years ago when Harry ZAK was doing molycoating of pistons, he used an old 33/45/78 RPM record player turntable and placed the pistons on it and then let them rotate while spraying with an "air brush" type gun and then baked in a small electric oven. Don't remember the temperature he used. The method provided a very even coating on the piston and made a very professional looking job, as is yours.

As you have mentioned, prep of the finished part to be coated is key. He used a glass bead blaster to clean the pistons completely, masking them first before blasting so as to protect the ring grooves. He then used MEK to clean them further, and handled them with rubber gloves after cleaning so as to not transfer oil from his hand skin to the piston before spraying with the moly. The rubber glove trick came after the moly flaked off some of the first pistons he coated when he did not take that precaution. After that he never had a problem with the moly staying on as long as after cleaning/prepping, he wore rubber gloves and baked them in the oven. He had also tried some without the bake treatment and they also were not satisfactory.

I became a great believer in moly coating of pistons after I ran a complete heat of four laps with a "D" Konig after the water line from the lower unit to the power head came off while milling for the start. It was apparent from the bank that I was not "watering" out the relief tubes but facing forward I could not see it. The engine ran four laps full throttle without sticking. It got so hot the aluminum in the block turned brown but the engine continued to run until I came back to the pits after the heat was over. That made me a believer in moly coated pistons.

When I asked him what speed he used on the turntable he came up with a little "Polish" humor by saying that for the smaller classes of slower speeds, he used a slower speed on the turntable. For the faster classes like C/D/F Hydro as they were called at the time, he put it on 78 RPM. I think he was pulling my leg, but with Harry you never knew for sure.

MTECHMARINE
06-12-2010, 08:53 AM
Looper and Speeditwin pistons were glass bead blasted, the 4 "D" pistons were just trued by Doug Kay so I just cleaned them (and the others too) with MEK B4 I sprayed them. Just used small gun, it was easy to get an even coat. They are then baked at 250 for 1/2 hour, then 400 for another half hour.

David Mason
06-14-2010, 10:50 AM
Those look great. Eric Vanover has been spraying his own pistons for some time now, it is not expensive and easy to do with some simple crude tools.

I love the record turn table method. I think Eric use an old drill and made a jig to hold the piston and rotated it when he sprayed them, and baked them in a toster oven. Bake this in your wife's oven and you may end up having an oven all to yourself. :D

Bill Van Steenwyk
06-14-2010, 02:18 PM
I made the mistake in the early 70's of prepping for paint/cleaning a set of ZAK pipes in my wife's new oven we had just bought that had the self cleaning feature. I figured if it would remove baked on grease/spatters etc. that it would certainly remove baked on castor oil from the interior of the pipes while removing the paint from the exterior. It did a really nice job, the only problem being the smell left in the kitchen and other areas of the house for the next month or so of burning castor.I thought it smelled great as did some other boat racing friends, but not everyone was as enthused about it, including Eileen.

That was almost as good of a move as buying her a vacuum cleaner for our first Christmas together after we were married. You would think after two previous wives I would have learned something about women and how they feel about "personal" gifts at Christmas and other special occasions. WRONG!!

We have now been married 37 years and I am a little smarter than I once was as far as men/women relationships are concerned. Not much, but some.

She did appreciate the new sporting clays 12 GA I bought her a couple of years ago. She has kicked my butt several times with it too. Maybe she has mellowed a little also, or we both have learned a little over time.

David Mason
06-15-2010, 09:41 AM
I made the mistake in the early 70's of prepping for paint/cleaning a set of ZAK pipes in my wife's new oven we had just bought that had the self cleaning feature. I figured if it would remove baked on grease/spatters etc. that it would certainly remove baked on castor oil from the interior of the pipes while removing the paint from the exterior. It did a really nice job, the only problem being the smell left in the kitchen and other areas of the house for the next month or so of burning castor.I thought it smelled great as did some other boat racing friends, but not everyone was as enthused about it, including Eileen.

That was almost as good of a move as buying her a vacuum cleaner for our first Christmas together after we were married. You would think after two previous wives I would have learned something about women and how they feel about "personal" gifts at Christmas and other special occasions. WRONG!!

We have now been married 37 years and I am a little smarter than I once was as far as men/women relationships are concerned. Not much, but some.

She did appreciate the new sporting clays 12 GA I bought her a couple of years ago. She has kicked my butt several times with it too. Maybe she has mellowed a little also, or we both have learned a little over time.

Bill,

That is funny. You know what they say, third times a charm.... and the sweeper.... ya, you should have known better !!! Even if it is one of those fancy high dollar ones... ;)

A nice Sporting Clay gun is a much finer choice. I just use my Beretta for both Skeet and Sporting clays.