common problem with outboard brackets !!

[jawz12]

dadmarine.com


Jawz, I know this is an old thread, I don't like powdercoat either. I'm thinking about having my aluminum bracket done with line-x. What do you think about that?

why ???

personally,i use a different approach...if you're serious,drop me a line and i'll explain the process i use...
609-214-7556

[captcl]

Jimmy, thanks for all the info about brackets! You just convinced me to leave the solid transom of my Mako22 alone!
i am thinking about a cowl over the outboard though. Ever done one? thanks again for the info!

[nautiduck]

Ive seen tubular stainless used for brackets and was wondering why they arent used more often instead of the aluminum or fiberglass,it seems it would be more durable and structurally stronger. Is it because of the floatation issues? I imagine enclosed stainless would be prohibitively heavy but if the boat were designed for a bracket wouldnt the stainless be better?

[getusummm]

Jawz, I know you reccomendthe fiberglass brackets, but I found a very good price on bare aluminum brackets. I am thinking of sandblasting, zinc cromate primer, 2 coats of epoxy barrier coat, followed by a urethane top coat. The boat stays on a trailer. Any thoughts?
Thanks,
Patrick

[jawz12]

Jawz, I know you reccomendthe fiberglass brackets, but I found a very good price on bare aluminum brackets. I am thinking of sandblasting, zinc cromate primer, 2 coats of epoxy barrier coat, followed by a urethane top coat. The boat stays on a trailer. Any thoughts?
Thanks,
Patrick

i wouldn't use zinc chromate as a primer...you need to chemically etch prime the surface...zinc chromate is a paint...first ecth prime the surface,then epoxy coat the surface with interprotect,just like i described...just follow what i posted,it will stick real well...

[wasabikid]

"trilux 33 problem solved- 9 yrs no problems yet! started w/new bracket- old bracket -sand -etch- trilux 33"

this is a common problem with the aluminum outboard brackets.the powder coating will get scratched or nicked from every day use,these surface defects will fill with water.the salt water will evaporate,the salt is left behind.this salt build up will wick moisture,actually prying the powder coat off the aluminum,leaving behind the bare aluminum.this bare aluminum will corrode.if the bracket has been painted with a copper based antifoulant paint,the problem is worse,it will cause a galvanic corrosion,due to the dissimilar metals-the aluminum will sacrifice itself to protect the copper-what you have done is create a battery !!!
if the powder coat has been damaged it needs to be repaired NOW !!! the way i reccomend to do this is by sand blasting the bracket,followed by "etch priming" the bare aluminum surface,followed by epoxy coating the surface,then finally painting the surface using a 2 part paint....
these brackets have water drains,these drains need to be pulled at the end of the season.water will collect into the bracket,due to condensation,etc...
there should only be a very small amount.if when removing the drains a large amount of water is present,you have a problem,and it needs to be repaired NOW !!! the problem will not get better it will get worse.water can and will enter the bracket from the inspection ports,as well as the edges where the bracket seats against the hull. these areas deserve close inspection !!
the bottom paint should never be against the aluminum surface,there should be a 1" gap between the bracket and the surrounding copper based bottom paint.the bolts securing the bracket to the transom should be seperated from the aluminum surface by using a plastic or nylon bushing washer.
check out the posted pics and you will see the end result.....
as you can see the bracket was pretty well filled with water-not a good thing !! the problem with the water is the weight and it's leverage-we've all used a pipe to turn something,to gain leverage,the water in the extended bracket acts as leverage.it can cause the scuppers to allow water to enter the boat,and eventually sink the boat-due to the boat sitting lower in the water...
if you've never removed the drains in your bracket-i highly reccomend you do so....
the bracket was sand blasted in a few spots,to determine the extent of the damage-the result of those spots being blasted are in the next post....[/QUOTE]