Minor body repair prior to painting...

[robtheplod]

Hi All

 

With Summer coming I'll be sorting out the outside of the boat and painting. There are a few spots where its rusty/been rusty when the surface is uneven and if i prep/paint over it, it will be very noticeable - no big holes, just rough!   I'm looking to find the best light/thin filler i can use to take a way the slight rough area.... I have P38 and P40 from ages ago and wondered if these would be ok to use or if the team would recommend something more suitable?  thanks as ever!!!!!

rob

[Tony Brooks]

I just Googled "car body stopper" which is a very fine form of filler. You can get one or two pack products. By all means try the two fillers you have, but you might find that when you sand them, and they get really thin, they tear away from the steel. I am sure a boat painter will be along soon.

 

Be aware that stoppers and fillers are porous, as is most/all single pack paint, so if you get water sitting on the filled section for long enough the filler is likely to absorb some water so rust ensures.

[Mike Hurley]

For a nice smooth filler Plastic Padding used to be nice if still available, P38 is a bit coarse.

[blackrose]

20 hours ago, Tony Brooks said:

 

Be aware that [automotive] stoppers and fillers are porous, as is most/all single pack paint, so if you get water sitting on the filled section for long enough the filler is likely to absorb some water so rust ensures.

 

Corrected that for you.

 

The porosity of car body filler is exactly why it's not suitable for marine use. If you want to do it properly you need a marine grade filler. I've used International Watertite before and it's completely different from Plastic Padding, P38, etc, and is not porous. It's also more expensive of course, but you get what you pay for.

 

Buy Boat Fillers (marinesuperstore.com)

[truckcab79]

Covered up the car fillers will be fine.  As said, they are porous so can’t be left exposed.  
 

in terms of brand Upol easy-1 is decent, and sensibly priced. Evercoat Rage Gold

is better.   
 

fibreglass fillers are waterproof of course but may not be fine enough for you as a finished surface. 
 

You want dolphin glaze for really fine finishing but a bit overkill to be honest. 

 

More important is your prep If the rusty spots before applying anything. 

[Tony Brooks]

29 minutes ago, blackrose said:

 

Corrected that for you.

 

The porosity of car body filler is exactly why it's not suitable for marine use. If you want to do it properly you need a marine grade filler. I've used International Watertite before and it's completely different from Plastic Padding, P38, etc, and is not porous. It's also more expensive of course, but you get what you pay for.

 

Buy Boat Fillers (marinesuperstore.com)

 

I tried one of the so-called marine fillers once and it was extremely difficult to sand down - as one would expect from a product with more resin and less powder in it. Therefore, I doubt it would suit the OP's job. It was also far more difficult to apply. I think it was the Plastic Padding one. I never had any problems with automotive fillers on vertical or near vertical surfaces on the boat, but if the area suffered any paint damage I touched it up at once.

[MrsM]

8 minutes ago, truckcab79 said:

 

in terms of brand Upol easy-1 is decent, and sensibly priced. Evercoat Rage Gold

is better.   
 

I use this quite a lot in house restoration work. Very nice to work and sands easily. 

[robtheplod]

thats everyone for taking the time to reply. I shall investigate all...... assuming i can survive this, looking at the safety info on some of these!

 

  

Danger

• Causes damage to organs through prolonged or repeated exposure.

• Causes damage to organs.

• Causes serious eye irritation.

• Causes skin irritation.

• Flammable liquid and vapour.

• May be fatal if swallowed and enters airways.

• May cause allergy or asthma symptoms or breathing difficulties if inhaled.

• May cause an allergic skin reaction.

• May cause cancer.

• Suspected of causing genetic defects.

• Suspected of damaging fertility or the unborn child.

[BilgePump]

Have used the Osculati gelcoat filler before. About £13 for 200g small bean can size tin. Can be sanded quite fine and painted but as noted above don't put on too much or it will take ages to sand back flat.

[truckcab79]

45 minutes ago, MrsM said:

I use this quite a lot in house restoration work. Very nice to work and sands easily. 

Amazing stuff. Use it for all sorts. In fact as we speak I’ve just mixed some up to repair the minor imperfections in the plastering on the latest bathroom project before I paint. 👍

[Ronaldo47]

I used to use Plastic Padding Type Soft for car body repairs and general filling jobs, but I haven't been able to buy it for some years. I now use Ronson High Performance Wood Filler,  a polystyrene-type filler that looks, smells, and behaves much the same as Plastic Padding Type Soft, apart from the colour. 

Edited April 15 by Ronaldo47
typos

[ditchcrawler]

Do the cabin sides of a Narrowboat get any wetter than a car that is not kept in a garage?

[blackrose]

5 hours ago, Tony Brooks said:

 

I tried one of the so-called marine fillers once and it was extremely difficult to sand down - as one would expect from a product with more resin and less powder in it. 

 

I think that's the idea, it's much tougher than car body filler. For cabin sides car body filler is ok I suppose but I've seen it applied on the top plank of a narrow boat (the area above the top rubbing strake and gunwale), and it just got scraped off as soon as anything touched it.

 

2 hours ago, ditchcrawler said:

Do the cabin sides of a Narrowboat get any wetter than a car that is not kept in a garage?

 

No, but the paint of a car is generally professionally applied and will keep any filler beneath better protected than a DIY paint job that most narrow boat owners do, which ends up scratched and flaking after a few years. If the paint applied over marine filler gets scratched and flakes it doesn't really matter.

 

The marine filler is also much tougher and in normal use cars don't tend to get bashed around in quite the same was as canal boats have the potential to be. It just depends on what you want to put on your boat. Personally I'd use the proper stuff, but I'm not trying to save money when I buy stuff for the boat.

Edited April 15 by blackrose

[Canal321]

On 14/04/2024 at 12:10, robtheplod said:

Hi All

 

With Summer coming I'll be sorting out the outside of the boat and painting. There are a few spots where its rusty/been rusty when the surface is uneven and if i prep/paint over it, it will be very noticeable - no big holes, just rough!   I'm looking to find the best light/thin filler i can use to take a way the slight rough area.... I have P38 and P40 from ages ago and wondered if these would be ok to use or if the team would recommend something more suitable?  thanks as ever!!!!!

rob

I like 'Big boy bodyfiller' from Toolstation. Goes on nice and is easy to sand. Get it in the 600ml tub and it's good value.