Marine Tex

[STARFLIGHT85]

CAN MARINE TEX BE USED TO PATCH DAMAGE TO A CAVITATION PLATE,OR IS WELDING THE ONLY ANSWER. IVE BEEN GIVEN SOME REALLY WILD PRICES TO PATCH A SMALL CHUNK OUT OF MY PLATE. WHATS REASONABLE IF THE "TEX" IS NOT THE ANSWER.

[Gordie Miller]

can you post a GOOD close-up photo? That would help people to answer more accurately.

[Raceman]

I can't imagine why you'd get wild prices on Mig or Tig welding a piece that you could imagine fixing with Marine Tex. Most outboard repair shops have old gearcases laying around with skeg damage and it's a good source of repair chunks for stuff like cavitation plates.

[STARFLIGHT85]

I WAS TOLD I WOULD HAVE TO TAKE MY LOWER UNIT OFF BECAUSE WELDING COULD DAMAGE THE ELECTRONICS, COULDN'T I JUST DISCON. THE BATTERY? THAT IS PART OF THE PRICING. ALSO THEY SUGGEST CHANGING SEALS ETC BECAUSE HEAT COULD DAMAGE THEM ETC. ANY ADVICE WOULD BE MUCHO APPRECIATED. THNKS. E. STARK

[capnzee]

Its winter time, so you got time. Forget the marine-tex. Marine tex is good, but for a different application. Just get yourself a DREMEL tool with a few cutting discs and cut the broken part of the cavitation plate out. Pick up an old broken unit from a marine "junk-yard" and cut a "like" peice out of the cav-plate. Fit it into the cav-plate on the unit you are trying to save and clamp it. Take it to a welder and have him "spot-weld" it every couple of inches, giving it a little time to cool between each weld. Then the welder can come back and fill between the welds keeping a close "eye" on the heat build-up. Now, you may be able to fill between the welds with marine-tex, disc sand the repair, fill in the sanding marks with a more marine tex, sand until smooth and paint. This should not take you more than a few hours of work and should take the welder less than 30 minutes if you have done the preparation. If you are unable to do this kind of work, then curse your father for never teaching you, yourself for never being interested enough to learn and be prepared to PAY. Three hours of this kind of labor will probably cost you from $150 to$250.00. If you do the "grunt" work, the welder should cost you less than $50.00. I am not an expert and am not trying to be a "smart guy", but some how, you either learn to do a few practical things for yourself or you "pay the piper"! It is never too late to learn---You experts out there, am I far off the track? capnzee

[Raceman]

I'm not gonna say that welding with the gearcase on is safe, because I don't know for sure. Especially if the motor's not an EFI, I doubt there's a danger to the electronics, but I don't know for sure. In any case, removal and re installation of the gearcase isn't rocket science and dozens of people here can talk you through it. I've posted specific instructions on Mercs multiple times in the past. Gearcase removal is also a good excuse to replace the waterpump if it hasn't been done recently. I replace mine annually and it would get expensive if you're paying somebody.

[chris_lacey]

Bodyshop guys weld on EFI cars everyday. Should be safe if done properly.

[Hooty]

Just connect the ground to the cav plate close to where the weld is.

c/6
Hooty

[Gerben]

Hi,

Haven't seen the exact damage, but you might consider mounting a hydrofoil/whaletail (bob's, allison, etc.) and mask the damage that way.
Ofcourse this only works with slight damage to your cav. plate.

The hydrofoil could also help on holeshot.

Gerben

[capnzee]

Regarding the whales tail: seems to work good for the whales and thats about all! Might be ok on an inflatable, but never seems to work on anything that could be considered "high performance". May work as a "mask" to hide your damage, but I would have too much pride in my outfit to cover it in this manner. There is an old adage, if it's worth fix'n, it's worth fix'n right or something like that. capnzee

[Raceman]

Whale tales are also ugly as hell.

[O/B Dude]

Lets cut to the chase.....you got a photo nof this damage???????

[jlittle]

This article might help or is the damage extensive? I have some whale tail mounting holes that I might try this on...

http://www.diy-boat.com/Pages/Archives/links/2001_3/power/power.html

[capnzee]

I think this thread has about run out! capnzee

[chris_lacey]

Capnzee, sorry I disagree. Can quote quantitative if you'd like. Whale tails really help hole shot (ask any drag racer) and if they don't drag on plane don't hurt top speed much. Of course, every set up varies. Some after prop set up's may hurt top speed, some what.

[capnzee]

Hi Chris, I bow to a senior member! capnzee

[chris_lacey]

Capn'. sorry aint really any "guru" . Some "whale tail" type hydrofoils that are installed after the prop can hurt top speed. No contest. Most "performance" type of foils, like the Allison units, do not affect top speed.
Although, in medium applications, You can use a comercially available "tail" for good results. My V-King with a V4 OMC had a terrible hole shot. Ran 62 once on top. Added a "Stingray" after plane. Hole shot inproved 500% and still ran 62. Your results may vary.