How the heck do I get antifoul to stick to the prop?

E

ex-Gladys

Well-Known Member
Joined
29 Aug 2003
Messages
5,252
Location
Colchester, Essex
Visit site
First chance to see Gladys after lift out today and... Aaaaarrrrgggghhhh all the bleeding antifoul has gone. Since I've fitted the Autoprop (2013) I've spent £150 on Propspeed (silicone one) which fell off and was resorted free of charge for 2014 and fell off again. I then cleaned all the remnants off and used Primocon and brush on Trilux, which lost all but about 25%. This season I used a lurnishing disc to strip the prop, cleaned it off before application with Seajet recommended thinners, and applied Triple pack, following the instructions to the letter. To be fair, most of the primer is still there, but all the AF has gone. A neighbour in the yard has used the same and his (non Autoprop) was and is perfect.


Any observations willingly received...
 
Spray Trilux works on my Flexofold. Or do the same as Vyv Cox did on his Autoprop. Bite the bullet and do the full Velox treatment.
 
Primocon. For wood, metal and GRP. Also works a base coat for Unknown antifouling. You must use an international antifouling as other may come off over time. But it will more than likely take more than a year for this to happen! I've done it with blames/hemple on top it worked fine until I scrubbed the hole then it flaked off!!! A cheap sort of shelf shedding!!!
 
mikenfi said:
Primocon. For wood, metal and GRP. Also works a base coat for Unknown antifouling. You must use an international antifouling as other may come off over time. But it will more than likely take more than a year for this to happen! I've done it with blames/hemple on top it worked fine until I scrubbed the hole then it flaked off!!! A cheap sort of shelf shedding!!!
Click to expand...

May or may not work. conventional antifouling on props is generally the least effective as the action of motoring erodes the paint very quickly. Getting anything to stick to bronze is a challenge.
 
We have reasonable results with Primocon, but needs a spotlessly clean prop roughed up and just a single thin layer of Primocon. Next again a couple of thin layers of antifoul paint, Uno in our case. This year having bought a spare prop I tried a layer of epoxy as the primer. Hopeless it all fell off. Back to Primocon next year.

However, the spare prop give me the opportunity to prepare a prop at home and fit mid season on the scrubbing grid.

Pete
 
A propeller made by brass related alloy must have a zinc anode not to corrode. A bronze propeller (NiBrAl alloy) does not need the zinc.
When the zinc anode starts its galvanic process, an intense exchange of Ions will occur between the zinc and the propeller. This exchange tends to creep under the paint and make it fall off.
Short conclusion: Buy NiBrAl propellers like Flexofold and others and throw the zink away. (See also the thread about copper plating propellers).
 
For last eight years I just wire brush the prop and paint 2 new coats of Trilux 33 (no Primocon), easily lasts a season on West Coast of Scotland. If using Primocon I suspect it needs to be abraded to allow the Trilux to grip. When I lifted out in Mar I watched the Yard Operators jet wash the hull and where I had applied antifoul (Cruiser Uno) directly over Primocon it just washed off.
 
Thanks for all the pointers. I think the issue is a bit more generic, since my previous fixed prop everything stayed on it, it's just the Autoprop nothing seems to adhere... On the basis so far, Trilux over Primocon did the best, and as that what my shaft has, I may revert to that...
 
On my Autoprop I have had the same original coat of Hammerite Special Metals primer for the past four or five years. I abrade the Velox back to the primer and recoat. My P-bracket is treated the same way. Previous attempts without this primer were unsuccessful. The four coats of Velox, as per instructions, are too much and the coating chips in use. Two coats work well for me.
 
Any particular reason to use the Hammerite Special metals primer rather than the Velox primer? The instructions I have looked at for Velox state 2 coats only, on top of 1 coat of their primer.

I am not sure what A/F - if any - is on the props on our new acquisition, but am looking for the best suggetsion to keep motor boat props clear of fouling.
 
Leighb said:
Any particular reason to use the Hammerite Special metals primer rather than the Velox primer? The instructions I have looked at for Velox state 2 coats only, on top of 1 coat of their primer.

I am not sure what A/F - if any - is on the props on our new acquisition, but am looking for the best suggetsion to keep motor boat props clear of fouling.
Click to expand...

I used Hammerite because I had a new tin of it and have found it to be excellent stuff. I have not used their own primer.

It sounds like Velox have acted upon feedback, my tin, bought five or six years ago, definitely says four coats but application at this rate chipped badly.
 
We have Volvo props, Abrade with an 80#, don't touch the prop with your fingers (leaves grease), wash with water. Apply primer - we have had fair success with the Velox primer, in the absence of non water based Hammerite.

Be harsh if you, or the previous owner may, have had Prop Speed/Gold on your props - leave any vestige of silicone and nothing will stick, ever. Grind with 80# and grind again.

Against advice I have touched our prop abraded with an 80# disc on a angle grinder - it is very rough, you can feel it catching your skin. But grind where you touch and then wash with water.

Jonathan
 
+1 for the hammerite special metals primer. I use the velox primer two years ago and it didn't stick too well to the prop despite by best attempts to prepare it (Darglow Featherstream, mix of stainless and bronze). I used hammerite special metals primer this year and, on last inspection in the water, the antifoul seems well attached to the primer (and prop!)
 
For the last few years I have used Hempel Prop-primer spray under Trilux with very good results on a bronze prop. Much better results than the Trilux on its own.
 
You must log in or register to reply here.

Share this page

Top