Corrosion Prevention Technique Questions

[Al Peffley]

I have some US-made grade 8 black oxide bolts that I am using to fasten my motor mount plates to the transom that are beginning to surface rust while my hydro is in my race trailer during fall-winter storage. I have been looking at LPS Labs MIL-C-16173D Grade 3/2 products for coating the bolts each winter (LPS-2 or LPS-3 surface lubricant). What corrosion inhibitor products do you folks prefer to use?

I cannot run a ceramic heater in my trailer where it is stored for the winter because there is no electricity available at my outdoor storage site. I have placed a Dries the Air plastic container with crystal spheres in the trailer each fall. What do you use to keep the humidity level down in your race trailer?

Al

[G Stillwill]

I try not to use the black bolts just for that reason I use the grade 8 gold color ones that dont rust.

[Al Peffley]

Gold-color Plated Bolt Source?

Sounds like a good idea to me, George. Where can I buy grade 8, 1/2 in.-13 (or another thread size) Allen-head cap bolts that are 3 1/2 inches long with a gold-colored plating on them? I don't think MSC sells them, so I am always looking for another specialty fastener source.

[Bill Huson]

Stainless bolts? Yes, SS is not as strong as steel but you could jump a size or two. For coating I like LPS spray cosmoline.

[G Stillwill]

Al I will have to look and see if the place where I get special bolts from has allen head ones. The hex head I get over in town at Tractor Supply they have every size in those there.

[mercguy]

why not use stainless bolts??? I mount 250+ hp (600+lbs) outboards all the time with 4 stainless bolts.......as almost all outboards are mounted. If you are worried about galling the threads from time to time when loosening them for adjustivity, just put some antiseize on the threads....fine thread is preferred.........

black carbon steel is strong, but will easily rust, as you have found......plus will deteriorate the transom wood faster than a stainless bolt..

[Dave M]

Strong Enough

I have used everyday bolts (local hardwatre store) that are i think simply nickle plated ? I mounted a new transom into my SEH (850CCH) but cutting out the old, leaving about 1 inch or maybe 2 to bolt to in 4 spots. Cut a sort of U shape. 3 or 4 years ago I used these bolts becasue they were what I had at the race site. I never changed them out. The rig survived a barrell roll one time with no damage. The next crash happened last season with those same bolts and the boat was destroyed. The transom board stayed in tact. The cockpit sides were removed by the crash, and a good portion of the bottom. I could still hang a 3 holer on it in the condition it is right now, and it would hold. If that heavy pig of a motor that tourques more than just about any outboard kneeler class out there in any division does not break those cheap 50 cent bolts... you do the math. A 120 or 250 or 350CCH is not going to need a stronger bolt.

[Al Peffley]

Deterioration of Wood?

I am interested in the deterioration of the wood comment. Would a corrosion protection lubricant help reduce wood deterioration? I have experienced some elongation of the holes in wood transoms, but never in a wood boat transom motor plate on a hull used only in a fresh water operating environment. These bolts I am talking about will be constantly loosened and tightened to adjust the motor height and remove the complete motor with tower (or "stork", if you prefer) for servicing. Thank you for your comments and lube info.

[Bill Huson]

Hole deterioration: Holes should be primed (coated) with WEST resin. I heat up the wood with a hair dryer to enhance resin soak up, then slobber resin in there with a pipe cleaner. For high stress holes: I no longer mess with race boats but an example of a high stress hole in my builds is the "Jesus" pin hole in a sailboard centerboard. For holes like that I over drill (upsize about 1/8" D.), do the hair dryer resin prime bit, then fill the hole with WEST (w/slow hardener) mixed to a putty with WEST 404 high density filler. When cured, redrill hole to correct size. Throw some graphite powder in with the 404 mix and you get a slippery epoxy bearing surface. The 404 goo and redrill trick can also be used to repair holes that have been chewed up and elongated.

[G Stillwill]

Al find some stainless steel tubing with the id of the bolts you are using cut bushing and epoxy them in the transom that way the bolts are in the tubing and wont wear the wood

[Dave M]

Bingo

Hole deterioration: Holes should be primed (coated) with WEST resin. I heat up the wood with a hair dryer to enhance resin soak up, then slobber resin in there with a pipe cleaner. For high stress holes: I no longer mess with race boats but an example of a high stress hole in my builds is the "Jesus" pin hole in a sailboard centerboard. For holes like that I over drill (upsize about 1/8" D.), do the hair dryer resin prime bit, then fill the hole with WEST (w/slow hardener) mixed to a putty with WEST 404 high density filler. When cured, redrill hole to correct size. Throw some graphite powder in with the 404 mix and you get a slippery epoxy bearing surface. The 404 goo and redrill trick can also be used to repair holes that have been chewed up and elongated.

That is the best method to try and prevent elongated holes. Not perfect for transom bolts, but it is the best method to ensure it is sealed.

Georges method is also a close second in my opinion. I have done both.

Here is a tip, if you put in a stainless tube such as George suggests, get it slightly longer than you need, and flare one end. When you are putting the bolts in, this flare will prevent you from gouging the wood finsih and prmoting rot. That is the best way to do cork holes too.

[Al Peffley]

Good Thoughts on Treating the Transom Holes

Great advice, guys. A person never stops learning if he/she seeks new ideas and proven techniques for installing new/updated hardware. I will wait until spring to treat the holes (weather here is very wet and below 50 degrees now in the trailer), but I will leave a note to myself on the transom to remember to apply West Systems in the holes and re-drill them. The Yamato motor I used previously on the hull was clamp-mounted and I used several layers of West Systems epoxy under the clamp surfaces to protect the transom wood. The added sleeve material also sounds interesting - I'll have to think on that idea a little more. I am sure that there might be other sleeve options to the inserted stainless steel tubing application when considering the type of bolts I am using for the mounts. The holes also need to be a snug as possible to reduce water seepage problems into the inside of the hull if a bolt loosens up from the 125cc motor vibration under way in rough water conditions.