PDA

View Full Version : Preparing Aluminum Boat for painting



thylacene
28-07-2009, 09:58 PM
I was wondering what sage advice is out there in respect of treating corrosion and preparing aluminum boats for paint?

Recently purchased a secondhand Quintrex 540 that had been less than well looked after cosmetically. As such, there are a few scratches on the sides, and being stored in a rack, there is some corrosion on the top of the gunwhales, especially where upholstery fittings have been screwed on with stainless steel self tappers causing what looks like electrolysis, with bubble forming in the paint. Might just be the humidity when it was originally painted.

Before anyone decides to turn this into a Quintrex bagging exercise, I read ALL of the posts on this board and a hell of a lot of others elsewhere and spoke with owners of other boats. The choice was made with eyes wide open, and within the bounds of our budget.

Anyway, to the point. The Minister for War and Finance has approved research into a complete colour change, following on from the decision to replace the Bimini because it is too low. First step is to decide what I can do myself, and then what I am prepared to do myself, to be able to get quotes for the work I choose not to undertake.

So finally to the questions. What can be done to treat the electrolysis/corrosion around the fittings to minimise re-occurrence once painted? My initial thoughts are relatively fine wet and dry sanding followed by a liberal application of the buffer wheel.

Also, what thoughts on etch primers? Can anyone tell me what type of paint Quintrex use? Enamel, acrylic or 2 Pack? and what type of paint is best for marine use?

If it all comes together we should end with with a flash looking Flattie Fetcha ;^)

Cheers

Taz

Noelm
29-07-2009, 08:48 AM
the first part is you have to remove all the old paint, this can be done with hard work and the correct type of paint strippers, or it can be done by "sand" blasting by someone who knows what they are doing, it needs to be done by a pro who has done it lots before, the metal is very thin and the heat generated can distort it, or at worst, eat right through it, next comes the actual paint, best advice is to go to a paint specialist and ask questions, there will be a dozen brands and probably all are OK, but I tend to use the one brand of etch primer, undercoats and topcoats, and follow the instructions carefully.

Noelm
29-07-2009, 08:49 AM
OH and call Quintrex if you want to use what they do, although there has been some discussion about their paint quality, but you would have read that already.

jighead
29-07-2009, 05:47 PM
G" day Thylacene
I suggest you remove the old paint either by machine sanding or soda blasting
I recently painted mine [ ex spraypainter ] when you have it stripped wash the hull with a mixture of metho and water [50/50] and apply a 2pak anti corrosive etch primer over this apply a 2pak primer which you can sand or apply your colour over wet on wet and use a 2pak polyeurathane top coat this will give your hull the best protection and be aware that the products used above are toxic and should not sprayed without good ventilation and and breathing mask with vapour cartridges
Cheers Mal :)

thylacene
29-07-2009, 06:30 PM
OH and call Quintrex if you want to use what they do, although there has been some discussion about their paint quality, but you would have read that already.

Yep, that would be why we're looking to paint it. It isn't that bad, but the odd bubble or two makes me think it will only get worse.

Figure I am up for the prep work but will leave the application of paint to a pro with a booth and masks. The only time it gets hot enough for 2 pak to go off in Canberra is when the winds are coming in from Dubbo with all that lovely reddish dust ;^(

Cheers

Taz

lethal098
29-07-2009, 07:36 PM
definately look at soda blasting, just had my boat resprayed and made life so simple, i had stripped half of it myself and what a massive task, painting needs to definately be 2pak or dont bother, most of the corrosion that has formed will need to be filled. cost to paint and soda blast $2500. cheers Lee

murf
29-07-2009, 08:25 PM
aluminium boat plus paint = galvanic corrosion no matter how hard you try to prevent it

I would never paint one (I have a painted one now) unless it was just the sides for looks but not covering any dissimilar alloys like welds/extrusions bollards etc

I have friends that spend more time cleaning and looking after their boats than fishing from them and after a couple of years they are still all corroded up, one little chip and its a mess

sorry for the downer post :(

cheers Murf

BaitThrower
29-07-2009, 08:53 PM
You know, I painted the sides of my old second hand ally boat not long ago... it had old paint and who knows what on it... All I did was sand off any flaking paint, then hit the sides with a bit of metho/water mix to degrease and clean up surface, then a bit of sugar soap for very light abrasion... Then I got a can of Hempels Multi-Coat (primer and topcoat in one)... Whacked on 2 coats using a brush! I was fully expecting it to come off after the first couple of trips out (as i was planning to do it properly for next season), but 6 months later with weekly trips and the stuff is sticking like you know what! Only chipping is on the sides where the anchor chain gets dragged over the edge, as you might expect... But the paint looks great, clean and you can't even see the brush strokes. Very happy with result, so you may not need to go the whole hog, unless you want perfection and a 20 year lasting paint job investing lot sof money in the process :)

Reefmaster
30-07-2009, 10:49 AM
Mate here's the link to my boat build and all the steps and products I used to paint it. Hope it helps and good luck because I would never do another one again lol

http://www.ausfish.com.au/vforum/showthread.php?t=124086&page=8&highlight=alodine

Cheers
Greg

murf
30-07-2009, 11:41 AM
Mate here's the link to my boat build and all the steps and products I used to paint it. Hope it helps and good luck because I would never do another one again lol

http://www.ausfish.com.au/vforum/showthread.php?t=124086&page=8&highlight=alodine

Cheers
Greg

best paint job I have seen on plate boat :)

watch that sinker :o :(

is that a bird? keep it away, arrrr NOOOOO haha :P :)

cheers Murf

andkat
30-07-2009, 06:13 PM
I have Nyalic on my Surtees, look on the net for Nyalic.
I have been quite impressed so far, I have a touch up spray pac, seems to work a treat when I get a small scratch I just use it to touch up with.
Some will disagree, but I find it easy to keep the tub clean.:)