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NorthwichTrader

Boat Painting - Sand Between Each Coat?

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Thanks, gents! I did paint a reasonable panel today smile.png...my biggest problem is a vertical row of six rivets every 18 inches along the side panels, it really keeps you on your toes, especially this weather!

My plan is 3 coats, but I was just wondering what the options were for any 'inconsistencies' in the last and dying hours of the final third coat?

If I shaved a tiny bleed under a rivet, I'd still need to lightly sand and T-Cut that spot, presumably...I'm taking it that this can OCCASIONALLY get you through, without leaving a nasty shiny flat spot in the panel?

 

I don't envy you your working with rivets. You are particularly keen to have a good finish, and why not. You are going to have to pay attention to the amount of paint you're putting on above the rivets and try to avoid wiping paint onto the rivets as you're finishing around them. Keep taking the excess off your brush. If it is a real problem, paint the rivets as a separate job, and with a very small brush, after the main work is done. I still don't fancy the cutting back solution.

 

Cutting back sounds more of a pain than painting the rivets separately. Good luck.

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Is there a reason why more boaters don't use spray guns? I've seen a lot of very nice finishes on boats but it still doesn't compare to car paintwork. Do boat paints not spray well?

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Is there a reason why more boaters don't use spray guns? I've seen a lot of very nice finishes on boats but it still doesn't compare to car paintwork. Do boat paints not spray well?

 

Brush painting or spraying. Boat paints do spray, only, don't do it anywhere near another boat and protect the environment. The overspray from oil based paints is very sticky, unlike cellulose.

 

I see very few canalside painters using vacuums attached to their prepping equipment.

 

But, I think the casual painter is not used to spraying such large areas and orange peel and an uneven application is a risk.

 

Lots of boats are sprayed these days at boatyards., it isn't uncommon. Having brush painted boats and cellulose sprayed vehicles, as long as both techniques produce a good finish, I've no preference. Well, may be slightly favour the brush.

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You could get as good a finish as on a car, but you would need to be a highly skilled sprayer to do so. and apply the paint to a perfectly prepared surface, which would be difficult to achieve on a boat due to such large panels. Much of spray application is down to using the correct viscosity for the paint you're using as well as skill in application. Also car refinishing is usually undertaken in strict controlled environment and painted in a temperature and air flow controlled spray booths, and in some cases paint is actually baked on to the car.

 

If you really wanted to achieve as much I would triple the cost of a quality boat paint at minimum, 15 to 20k

 

If you use car paint product though it probably wouldn't last long on a boat as car paint tends to be quite hard and brittle and expansion & contraction occurring on a boat would have paint cracking all over the place in time. So you would need to get a car finish from boat paint usually oil based, again possible but more difficult and more time consuming.

 

I sprayed most of our boat top sides and roof, it makes application much smoother, far quicker and generally easier. I spray painted my boat roof on my own with 5 good solid coats of paint in 5 hours, This would have taken days with roller & Brush.

 

Masking of course is required but takes no longer on average than time spent cutting in or removing paint where you overlap.

 

Our Green side panels though were brush finished in Gloss but spray painted in primers and undercoats. I haven't spray painted to get a shiny finish though, I've done it for ease of application and to ensure good coverage. The paint was applied thickly using a larger spray nonzil so the finish is deliberately mottled to reduce shine especially on the roof.

 

Personally I see little point in trying to get such perfect finishes unless you want a show boat. General cruising and wear & tear will have shiny paintwork looking pretty awful pretty quickly. I prefer to concentrate on the protection the paint is giving to the steel rather than it's finish, I think brush finishing is much easier to touch up on the canal, and looks more inkeeping anyway IMO

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Personally I see little point in trying to get such perfect finishes unless you want a show boat. General cruising and wear & tear will have shiny paintwork looking pretty awful pretty quickly. I prefer to concentrate on the protection the paint is giving to the steel rather than it's finish, I think brush finishing is much easier to touch up on the canal, and looks more inkeeping anyway IMO

 

When I first started painting narrowboats, the business owner used to try and overide my wish to be a craftsman by saying the effort wasn't worth it (insult). The customer always wanted a good finish. The customer pays the bills and the business owner didn't count. I did eventually walk off the site and threw my overalls on the fire.

 

Personally, as painter, the finish is what four or five weeks of work had been leading up to. So. I have to slightly disagree on the importance of the finish. smile.png

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I know we've spoken a bit about sanding topcoats on this thread, but can I ask...

 

What do you do to take off the fine particles that stop the topcoat having that brilliant-smooth finish it had at prep stage?

 

I know in the past, if I'd sprayed a panel on a car, that a very fine grade of wet and dry would nicely de-nib and, followed by T-Cut, would transform an uninspiring spray job! So, would a topcoat tweak with a fine grade be beneficial?

 

If it would, what grade would easily 'wipe-out' with T-Cut? 1200? 1500?

 

What would YOU do?

 

Many thank, as always,

 

Stuart

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Sometimes a bit of orange peel or brush strokes is an advantage. If you polish up to a mirror finish it'll show up any imperfactions in the steelwork.

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I know we've spoken a bit about sanding topcoats on this thread, but can I ask...

 

What do you do to take off the fine particles that stop the topcoat having that brilliant-smooth finish it had at prep stage?

 

I know in the past, if I'd sprayed a panel on a car, that a very fine grade of wet and dry would nicely de-nib and, followed by T-Cut, would transform an uninspiring spray job! So, would a topcoat tweak with a fine grade be beneficial?

 

If it would, what grade would easily 'wipe-out' with T-Cut? 1200? 1500?

 

What would YOU do?

 

Many thank, as always,

 

Stuart

 

I already covered this in post 23.

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I already covered this in post 23.

What made me re-ask the question was a now different set of circumstances, and also a small gap in my knowledge re the paste you spoke of that bridged 1000 sanding to Tcut?

Ideally, I think I'd now be looking at the lightest touch of paper, at a grade that would easily cut back with T-Cut, which made me wonder whether 1000 might be too course, in light of the intermediate stage you mentioned?

Sometimes a bit of orange peel or brush strokes is an advantage. If you polish up to a mirror finish it'll show up any imperfactions in the steelwork.

A really valid point, many thanks!

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What made me re-ask the question was a now different set of circumstances, and also a small gap in my knowledge re the paste you spoke of that bridged 1000 sanding to Tcut?

Ideally, I think I'd now be looking at the lightest touch of paper, at a grade that would easily cut back with T-Cut, which made me wonder whether 1000 might be too course, in light of the intermediate stage you mentioned?

A really valid point, many thanks!

 

If you want to do this properly then rubbing compound should be used especially on paint that will be softer than that of general car paints, 1200 grit is the finest we ever used in the paint shop for pre polishing prep on cellulose paints, other paints as fine as 1500 grit and that would only involve very light wet & dry rubbing down on very slight imperfections on newly sprayed panels fresh out of the spray booth. You could miss out the cutting compound proceedure if you like and spend 5 times longer polishing with T cut. there are steps and procedures in this type of work for a reason, cutting compound is one of those steps and exists for exactly that reason.

 

I would use this stuff

http://www.ebay.co.uk/itm/Freepost-Farecla-G3-Rubbing-Compound-Regular-Cutting-Paste-1kg-Tub-Car-Polishing-/181046806494

 

If you want it any shinier then there's a G10 fine finisher, seems this stuff avoids the use of T-cut which is a real pain to use anyway, especially when hot. I would invest in a polishing machine also, saves hours of elbow grease and ensures more even polishing. I have one hardly used I did some polishing with I'l be selling off soon if you're interested, only a cheap basic model, but does the job well.

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If you want to do this properly then rubbing compound should be used especially on paint that will be softer than that of general car paints, 1200 grit is the finest we ever used in the paint shop for pre polishing prep on cellulose paints, other paints as fine as 1500 grit and that would only involve very light wet & dry rubbing down on very slight imperfections on newly sprayed panels fresh out of the spray booth. You could miss out the cutting compound proceedure if you like and spend 5 times longer polishing with T cut. there are steps and procedures in this type of work for a reason, cutting compound is one of those steps and exists for exactly that reason.

 

I would use this stuff

http://www.ebay.co.uk/itm/Freepost-Farecla-G3-Rubbing-Compound-Regular-Cutting-Paste-1kg-Tub-Car-Polishing-/181046806494

 

If you want it any shinier then there's a G10 fine finisher, seems this stuff avoids the use of T-cut which is a real pain to use anyway, especially when hot. I would invest in a polishing machine also, saves hours of elbow grease and ensures more even polishing. I have one hardly used I did some polishing with I'l be selling off soon if you're interested, only a cheap basic model, but does the job well.

Hey, Julynian, thanks again for your knowledge in this field! At the boatyard, it's become a standard wind that I'm a ludite, even for hand sanding...I'd hate to disappoint in the last hours for an electronic finish!

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Rather than starting a new topic I'll just resurrect this thread.

 

I'm repainting my roof section by section. Most of the old paint (International Interdeck) is sound and I'm taking any rust spots or patches back to metal with a wire wheel and patch-priming with Bonda Primer before overcoating those patches with 2 coats of Hempel Undercoat-Primer and then 2 topcoats over the whole lot.

 

I think the idea of using the Bonda Primer first is that firstly it's has zinc in it and is meant to prevent rust coming back and secondly it really sticks well to bare steel, so if the topcoats and undercoat do get chipped the Bonda primer is likely to stay on and the steel won't rust, meaning the chip or scratch is much easier to repair.

 

Today after prepping a section I realised I didn't have any cellulose thinners to spirit wipe over the patches before priming (Bonda Primer is an alkyd resin based primer so cellulose thinnners are used, not white spirit). Anyway, I couldn't be bothered to go out and try to find cellulose thinners and decided to prime with the Hempel Undercoat-Primer instead.

 

Will skipping the Bonda Primer coat really make any difference?

Edited by blackrose

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Rather than starting a new topic I'll just resurrect this thread.

 

I'm repainting my roof section by section. Most of the old paint (International Interdeck) is sound and I'm taking any rust spots or patches back to metal with a wire wheel and patch-priming with Bonda Primer before overcoating those patches with 2 coats of Hempel Undercoat-Primer and then 2 topcoats over the whole lot.

 

I think the idea of using the Bonda Primer first is that firstly it's has zinc in it and is meant to prevent rust coming back and secondly it really sticks well to bare steel, so if the topcoats and undercoat do get chipped the Bonda primer is likely to stay on and the steel won't rust, meaning the chip or scratch is much easier to repair.

 

Today after prepping a section I realised I didn't have any cellulose thinners to spirit wipe over the patches before priming (Bonda Primer is an alkyd resin based primer so cellulose thinnners are used, not white spirit). Anyway, I couldn't be bothered to go out and try to find cellulose thinners and decided to prime with the Hempel Undercoat-Primer instead.

 

Will skipping the Bonda Primer coat really make any difference?

 

Personally I wouldn't be using cellulose thinners as a degreaser on old or new paintwork, that's if you mean standard cellulose thinners. It will lift and soften many paints even some 2 packs.

 

There are several different types of cellulose thinner and a substance made using cellulose as a base that can be used as a de-greaser. If de-greasing isn't advisable with spirit, then buy in 5 litres of proper panel wipe from auto paint supplier. This can be used on any surface without effect other than thoroughly de-greasing. It can also be uses for loads of other different things like removing sticky substances sealers etc, a bit like turps but evaporates quickly and leaves no oily residues.

 

Having said all that, sugar soap takes a lot of beating and for large areas cheap and easy LOL

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Yello,

 

I have a very experienced boat refinisher and friend moored next to me at the moment ...... if you have a two pack primer already laid onto shiny steel, then are you using epoxy paints to complement the primer ? It is a chemical bond thing !

 

I'm just stripping my 50 x 10 barge to bare steel to allow the use of epoxy fillers and primers. Then comes the epoxy gloss !! Unfortunately my barge was purchased with coats of red oxide primer on. #:o( They all have to come off to get the epoxy to adhere.

 

Happy days Malc.

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I'll double check when I'm down at the yard on Friday but, as far as I know, I've done nothing to my 2-pack primer except key it and apply regular coach paint undercoats and enamels?

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Yello,

 

After your boat builder has applied expensive epoxy 2 pack primer to bright shiny steel ....... your applying cheap nasty enamels !! Epoxy sticks to bright steel like sh*t to a blanket. Then you can apply any epoxy filler as required, then 3 coats of epoxy primer which goes off like iron. It forms a chemical bond ..... epoxy on epoxy. That's the whole point. Then you can use an epoxy gloss ..... which also goes off like iron. Any paint job is only as good as the first coat's adhesion to the sustrate .... the whole idea of 2 pack paints is the continuing adhesive properties of the entire paint layers. Each layer chemically bonds itself the the last. Putting oil based paints over epoxy primer is ...... errrr ..... cheap and a waste of paint in the longer term.

 

Maybe I've missed the point ....... but I don't think so.

 

Cheers Malc.

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Fair enough! I don't know how much your full epoxy system is going to cost you, but I'll be able to repaint my tired colours, every three years if neccesary, for around £300, and that was a huge factor in our choice of paint...and that's a 70ft boat too!

Another point for me was to stay traditional, I'm not sure that our boat would've looked 'right' sprayed!

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