My Rust Bucket is Rusting

[lorenzo b]

Help! I've got this large steel La. shrimp boat that I reconfigured into a trawler and it's rusting faster than I can paint. We did a lot of welding on it and some of the buckshot rusts through the paint. Also my silencer on top on my dry exhaust just burns whatever paint I put on it. When I got the boat some of it had this really thick rubbery paint that looked like it was working well, but the paints I got from commercial marine supply places just aren't holding up.

I'm not real fussy, this boat looks just like what it is, but I'm 66 and I'll be damned if I spend the last few years of my life chipping paint.

What's the meanest toughest stuff out there?

[Vasco]

Steel rusts. Chip and paint is the only solution. If you paint over or put rubber paint over it'll just rust underneath and get worse. A guy I know put pick-up bed rubber compound (rhino paint?) on his deck but the rusting just kept on. Unless steel is perfectly clean and coated immediately it'll rust.

Also your boat makes a helluva racket! I tried to pass you on the ICW last Sunday and hailed you on the vhf half a dozen times. No response, did you finally hear my horn when I gave you two whistles? I don't think your dry stack silencer is working or was it something else making that racket.

[idpnd]

Try Nigel Warren - Metal Corrosion in Boats for reference, apparently surface preparation and the initial primer are the most important bits, i.e. to make peace with the material, sandblasting is pretty much obligatory, followed by a 2K epoxy primer.

[conachair]

Ameron sealer is the best I´ve found for a holding coat, takes about 24h to kick so it soaks deep.
http://ppgamercoatus.ppgpmc.com/prod...mary.cfm?id=14
they do a high build epoxy as well, amerlock 2 or something like that, goes off quick so you can get a few coats on in a day.
very good downloadable book on the subject here.. http://www.lulu.com/product/paperbac...-guide/4735595
Well worth $12.

[DaveC]

Maybe you can hire a bunch of high school or college kids to do it over the summer?

Free burgers, cokes, and a little bit of money and it could be sanded and painted in no time.

Trying to handle that kind of work on a 63' trawler by one "mature" person is quite a task. It might be better to have many young, energetic hands working at the same time at it.

Good luck with it...

[idpnd]

Originally Posted by conachair

Ameron sealer is the best I´ve found for a holding coat, takes about 24h to kick so it soaks deep.

I enjoyed that ebook, he's raving about ameron sealer. This is meant to be applied to manually treated rusty surfaces? I'm a bit sceptical about miracle solutions

Do you know where this can be obtained in the UK/EU?

[idpnd]

Btw you can take a good look at the book for free on the preview

[SabreKai]

If you have a large shrimp boat, I'd say you have space to carry a compressor and a small sandblasting setup. When ever you do some paint work, sand blast the area and immediately coat with the paint of your choice. Personally I go with an epoxy based paint. Right now it happens to be interprotec 2000 which I gather isn't too popular amoungst our forum members, but it works for me.

I have a small sandblaster with a hopper on top of the hand grip, and for small areas its the shiznitz. I picked it up a an automotive jobber for next to zip, along with spare nozzles. So far its working just great, but to do the job proper you need a beefy compressor. Mine is a tad small so I can only blast for about 3 minutes at 90psi before the compressor kicks in again. But it does get the area clean for painting and seems to prevent rust through. Part of the secret is to do the blasting on a day with low humidity as well. The lower the better. Or use a heat gun to remove whatever minute bit of moisture may be on the surface after blasting.

Sabre

[lorenzo b]

A little sand blaster sounds like a great idea, thanks

Vasco You sure know how to hurt a guys feelings.
No, I didn't hear your horn. I usually like to listen Led Zepelin on my headphones when I'm cooking up a batch.

[boden36]

Lorenzo, you could spend the rest of your life fiddling around, or bite the bullet and have the boat properly abrasive blasted and coated and never have to worry again. Regards, Richard.

[SabreKai]

Boden36 has a good point. If you have major rust then perhaps the best bet is to have the entire boat blasted and repainted. It will cost you some money but it will get it done. As for day to day maintenance I will swear by my small set up. For scrapes n dings it works great.

Sabre

[lorenzo b]

I had the bottom blasted two years ago and that worked fine except for the subsequent scrapes and abrasions, but what a mess. To blast the superstructure I would have to completely strip the boat and move off it for awhile. Even a small sand blaster could make a mess, I would imagine. I do have a large 240v compressor and needle and chipping guns so maybe I'll try that and see if i can stand the noise. If I do it while underway I might not notice it.

[chala]

Lorenzo use tarp, exhaust fan, do a small section at the time, brush the abrasive away and paint brush the first coat without delay after blasting. Nothing is as good than blasting and beat needles gun you may find some information in this thread also Steel Boat Maintenance.

Originally Posted by chala

Question 2
Pic 1. Cheap blasting pistol with spare nozzle, the nozzle does not last long. Cost around $30, and the abrasive material, (garnets, reusable many time)
Pic 2. More expensive blaster, aluminum body, 5mm professional nozzle, last for ever for small cleaning job, 70 to 100 dollars, air valve extra.
Pic 3. Protective gear, if you need to wear glasses, you can fit welder glasses inside this hood, modify the shade with replaceable plastic lens. The blasted garnets go everywhere, eyes, ears, nose, protect accordingly by wearing extra protective goggles, if you already have clean fingers, wear thick rubber gloves.
Pic 4. A 2 ½ hp compressor will do the job of Pic 5. This one did cost $80. Two of them in parallel will let you clean fittings more easily and 3 even better, keep between 80 to 120 psi. When blasting fittings, doing it in a small tent ($40) this will let you recover most of the garnets.
Pics 5. repair to the keel, mask area using ordinary masking tape. A 3 seconds blast (120 psi) cleaned the steel, the tie coat and feathered the 4 layers of Jotomastic 87. Then rebuild the paint layers, tie coat and antifouling.

Question 3
See CF thread Zincs and hot marinas.