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Putting a shine on a dull alloy boat

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Post Options Post Options   Likes (0) Likes(0)   Quote bricker Quote  Post ReplyReply Direct Link To This Post Topic: Putting a shine on a dull alloy boat
    Posted: 19 Aug 2018 at 8:06am
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Just wondered if there's a good way to rejuvenate a Marco 4.9m? The surface finish has dulled over time - are there any simple ways to tidy it up??
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Post Options Post Options   Likes (0) Likes(0)   Quote CrayZfish Quote  Post ReplyReply Direct Link To This Post Posted: 19 Aug 2018 at 8:27am
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Its aluminiums way of protecting itself with an oxide layer which is very hard and durable. If you remove this it will reoxidise unless you seal with something equally durable
Why choose either diving or fishing when you can do both. Besides crayfish tail is very good bait!!
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 19 Aug 2018 at 9:23am
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Titanium
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Yep the same is for zinc galv.
 Aluminium oxide and zinc oxide are very hard chemicals, and attach very well to their base aluminium and zinc metals underneath. Not only that, the molecules of the oxides are a little bigger squeeze together forming an impenetrable skin..

Polishing will remove the protective oxide layer, repeatedly eventually removes the galv.. thu on an alloy boat ...
 put it this way will take a long time and quite a few polishing wheels to wear thru the solid hull.

We polished a lot of old school V8 valley covers, manfols , carbs, trans and wheels over the yrs.. some so bad they where solid white oxide.
 When polishing or cutting, machining different metals require different cutting fluids.. aluminum is kero.
We us  white stainless steel polishing rouge..

 Also aluminum is a little different to polish than most other metals.. other metals is more fine 'sanding' of rough layer...
 Aluminum one gets heat into it, as you move along slow building and keeping heat.. quite hot to the hand, keeping  the top layer of molecules melt into the tiny pits and scratches...
 But id there is deep corrosion, pits scratches...start with a sander .. or if real bad a file
 When sand (or file) .. and this goes right thru to poolishing stage.. watch real close.. nearly take out the pit/ scractch. Do not scratch the bottom of the pit, not quite.
 Then move to a finer wet and dry paper.. then finer, by this stage you will be at 400 or 600 grit... When have a very faint pt/ scratch left.. then buffer, rouge to finish taking it out and the scratches from the sand papers.

Once polished, cleaned down with kero, can choose to clear coat or quaity  car polish  depending on end use..
3 or 4 layers  a day apart of polish is good for wheels, manifolds etc..  2 pot clear coats  for trans carbs etc  and boat..

 Now thats a hell of a lot of real dirty , messy , time consuming work...
Seriously consider a wrap...
 but check out the surface prep for wrap...never done it ,therefore never found out about it, so dont know.

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Post Options Post Options   Likes (0) Likes(0)   Quote pjc Quote  Post ReplyReply Direct Link To This Post Posted: 19 Aug 2018 at 12:30pm
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Titanium
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I am one for leaving ali alone,the self protecting oxide is doing its job.Have a look at painted alloy.Eventually starts to bubble due to a stone etc the water finds its way and starts eating the alloy,may do the same with wrap over the years
Sex at 58.Lucky I live at 56
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 19 Aug 2018 at 3:28pm
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Titanium
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Im also very strongly of that philosophy..
 A good wash down, after every trip, using a quaity detergent, and a rinse with a polymer added.. designed for purpose , from new goes a long way.
 Its called maintance, regular maintance.
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Post Options Post Options   Likes (0) Likes(0)   Quote Tagit Quote  Post ReplyReply Direct Link To This Post Posted: 19 Aug 2018 at 3:36pm
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There are aluminium cleaning 'acids' available that will bring back the shine without having to sand any more than the worst areas. Trouble is that it then needs a protective coating to slow down the oxidation. You can just use a normal car wax etc and with the occasional recoat you can probably go a couple of years before using the acid again. I have done it on a couple of alloy boats and with a bit of elbow grease plus the acid wash you can normally get quite a decent result.
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Post Options Post Options   Likes (1) Likes(1)   Quote bricker Quote  Post ReplyReply Direct Link To This Post Posted: 19 Aug 2018 at 5:39pm
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Thanks folks.....I rather think I'll leave as is. I thought there may just be a miracle cure to put some life into it but it's very much "in the eye of the beholder" and I'm pretty sure the fish won't worry one way or the other!! 

Appreciate the sound advice, as always!!!
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 19 Aug 2018 at 6:18pm
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Titanium
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The acids.. we used to use strong solns of citric acid.. a good spoonful in a cup warm water... and soack up for an afternnoon.. dont let dry out
 mentioned in old posts..
Reading labels (out of interest) on the products Tagit refers to are a mixture of weak acids including citric and phosphoric.
 I was hesitent to mention the acids.. as used on carbs, trans box etc but never on a boat...and not my boat..and knowing alloys come in a lot different formulas, could not recommend doing so..
 In saying that.. if was my boat I would try a little in a cnr somewhere have a play.

While at it check out what is in rust kill.. the stuff without epozy additives.. and also gelcoat cleaner...
 That brown 'stain ' on the hull of a glass boat.. maybe also and alloy boat..
 Rust killer.. couple caps in a bowl of water, a rag and simply wipe on and leave.. no need to rinse

BIG WARNING here
 these acids DO NOT let drip onto the galv of your trailer.. eats the crap out of the thin layer of zinc...
 So wet the rag, wring well out and wipe.. I dont bother with gloves.. the acids are to weak.. like coke or lemon juice
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Post Options Post Options   Likes (0) Likes(0)   Quote KikBac Quote  Post ReplyReply Direct Link To This Post Posted: 19 Aug 2018 at 6:36pm
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The boat in the photo is 17 years old and has spent it's entire life living outdoors. Topside is virgin aluminuim. I treated the topsides (as well as cockpit, transom and swim step) with Ali-brite (available from Super Cheap) Product is basically hyrochloric acid. I diluted 10:1 and applied with a sponge. leave 2 minutes and rinse off. I had to apply 3 x coats to get the result I wanted. I will probably have to re-apply every 3 years or so to keep looking Bright. As others have said make sure to rinse the galv trailer often and REALLY well.
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Post Options Post Options   Likes (2) Likes(2)   Quote puff Quote  Post ReplyReply Direct Link To This Post Posted: 19 Aug 2018 at 6:54pm
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best way to fix is buy a fibreglass boat..😀😀😂�£
Who said alloy boats are less maintenance...
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 20 Aug 2018 at 8:54am
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Titanium
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Realy?
 Im a fan of glass, inthe approiate conditions.
But again for long term condition/ appearance glass also needs ruotine maintace and protection from eliments/ sun espec the upper deck / cabin..
 And down side glass.. if not well maintained and going to cut polish.. that cuts back the gelcoat.. do that a few times and the gelcoat starts to get thin
 An alloy boat is solid alloy

 
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Post Options Post Options   Likes (0) Likes(0)   Quote MikeAqua Quote  Post ReplyReply Direct Link To This Post Posted: 20 Aug 2018 at 9:05am
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Originally posted by puff puff wrote:

best way to fix is buy a fibreglass boat..😀😀😂�£
Who said alloy boats are less maintenance...


Me, several times

We own an alloy boat built and painted (properly) in 1987 and 90% of the paint is still in really good shape. 

There is localised paint loss in the areas you would expect like the leading edges of the bow.







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Post Options Post Options   Likes (0) Likes(0)   Quote puff Quote  Post ReplyReply Direct Link To This Post Posted: 20 Aug 2018 at 11:37am
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Was being cheeky...
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