Jotun Jotamastic 87 and orange peel

[Marky_Lad]

Morning all,

I’m looking for a bit of advice with regard to an orange peel finish. I’ve primed by narrowboat with Jotun Jotamastic 87, this was rolled on due to time constraints and the fact that laying off with a brush really didn’t appear to provide a better finish. The boat has had three coats of primer which has left an orange peel texture. The plan is for 3 coats of undercoat, followed by 3 coats of topcoat. I plan to spray this using an airless paint sprayer. As the Jotun is an epoxy based paint it’s difficult to flat with sanding discs, these clog pretty quickly and this clogging is then spread to the surrounding area, might this be that it hasn’t dried enough in two days to cure properly?

Having no experience in painting a boat I’m unsure as to how best to proceed. Will 6 coats of sprayed paint leave a smoother finish or will it amplify the orange peel. Should I attempt to flat the primer before the undercoat, or flat it after the undercoat. I’m expecting some texture in the final coat but would like this to be reduced as much as possible. Any advice would be greatly received.

Mark

 

[julianf]

I don't know the jotum product, but lechler will sand fine, so long as it's nicely cured.

Too soon and it will ball etc, but when hard it sands. Not as easily as high build etc but it's entirely possible.

I'm not certain I see what you're wanting to do assing 3 coats of non epoxy over epoxy with an airless sprayer. Id suggest this would not really benefit anything.

 

[Marky_Lad]

I don't know the jotum product, but lechler will sand fine, so long as it's nicely cured.

Too soon and it will ball etc, but when hard it sands. Not as easily as high build etc but it's entirely possible.

I'm not certain I see what you're wanting to do assing 3 coats of non epoxy over epoxy with an airless sprayer. Id suggest this would not really benefit anything.

Thanks @julianf! I suspect I did try to sand the epoxy too soon after application. The epoxy is just the primer not the final finish, the other coats are just providing the finish (i.e. final colour and design, hope that makes sense.

 

[Pigeon_Droppings2]

Might not have fully cured...with some epoxy products you have to be mindful of the temp range in which they will cure...if it's too cold overnight it can cause issues.

 

[MetalMonkey]

It will take more than a couple of days to cure, especially if its a thick layer.

 

[Marky_Lad]

Definitely sounds like I haven't left it long enough. I certainly don't mind putting the effort in to sand it, might just need a little more patience! That certainly accounts for the clogging of the sanding discs.

 

[ajlelectronics]

Definitely sounds like I haven't left it long enough. I certainly don't mind putting the effort in to sans it, might just need a little more patience! That certainly accounts for the clogging of the sanding discs.

The clogging is called "Pilling" and is indeed an indication that it hasn't fully cured. Lechler 29107 automotive epoxy wants 48 hours really and Jotun has a thicker film depth so I would expect it would be wanting a bit longer. You will find it hard going, so it might be a good idea to start fairly coarse.

 

[Marky_Lad]

The clogging is called "Pilling" and is indeed an indication that it hasn't fully cured. Lechler 29107 automotive epoxy wants 48 hours really and Jotun has a thicker film depth so I would expect it would be wanting a bit longer. You will find it hard going, so it might be a good idea to start fairly coarse.

Thanks @ajlelectronics, I'll give it a go. Given I've been painting outside I won't get to finish off the final coats until the weather improves. I've a varied of discs so might start at 80 and go up or down as necessary, given the later painting to take place what grit should I finish with?

 

[ajlelectronics]

given the later painting to take place what grit should I finish with?

It depends on the final coats and the quality you are looking for. Anything from 320 dry to 800 dry, the upper end only really needed for metallics. Solid 2k sprayed conventionally I would go to 500 dry with Mirka Abranet discs on a D/A. You may get away with 400. Let us know what you are going to spray it with and we can be more helpful.

80 might be OTT even to start with. See what it does with 180 and decide from there.

 

[ajlelectronics]

Morning all,

I’m looking for a bit of advice with regard to an orange peel finish. I’ve primed by narrowboat with Jotun Jotamastic 87, this was rolled on due to time constraints and the fact that laying off with a brush really didn’t appear to provide a better finish.

If you do another, consider an automotive epoxy, sprayed on.

The boat has had three coats of primer which has left an orange peel texture. The plan is for 3 coats of undercoat, followed by 3 coats of topcoat. I plan to spray this using an airless paint sprayer.

Oh dear! I would advise against airless sprayers unless you want an "industrial" finish, in which case the epoxy finish won't really matter and it can just be keyed. Most paints will require a far smaller nozzle and a reasonable air supply. If you can't get a decent compressor on site, I would look for a brushing top coat designed for marine use.

Having no experience in painting a boat I’m unsure as to how best to proceed. Will 6 coats of sprayed paint leave a smoother finish or will it amplify the orange peel.

It will not amplify it but the gloss will show up how bad it is.

Should I attempt to flat the primer before the undercoat, or flat it after the undercoat. I’m expecting some texture in the final coat but would like this to be reduced as much as possible. Any advice would be greatly received.

You MUST at least key the primer if you are outside the overcoat window. Check the data sheet for that, but it will not be more than a few days. If you take it down through the grades you could have a nice smooth finish.

You will also need to flat the undercoat although I would be going direct to colour. The use of any other medium will reduce the benefits of the epoxy coating to that of whatever you use. In your shoes I may take the Jotun down to 320 dry and then spray Lechler 29107 over the top, tinted to a similar colour to the colour coats. That will make chips less obvious, although you need to take care not to miss areas with the final colour.

 

[badabec]

I used Jotun on my Citroen DS several months ago.
Easy to sand with Abranet discs on a DA. No clogging, a bit dusty, even with a vacuum attached.

 

[Marky_Lad]

If you do another, consider an automotive epoxy, sprayed on.



Oh dear! I would advise against airless sprayers unless you want an "industrial" finish, in which case the epoxy finish won't really matter and it can just be keyed. Most paints will require a far smaller nozzle and a reasonable air supply. If you can't get a decent compressor on site, I would look for a brushing top coat designed for marine use.





It will not amplify it but the gloss will show up how bad it is.



You MUST at least key the primer if you are outside the overcoat window. Check the data sheet for that, but it will not be more than a few days. If you take it down through the grades you could have a nice smooth finish.

You will also need to flat the undercoat although I would be going direct to colour. The use of any other medium will reduce the benefits of the epoxy coating to that of whatever you use. In your shoes I may take the Jotun down to 320 dry and then spray Lechler 29107 over the top, tinted to a similar colour to the colour coats. That will make chips less obvious, although you need to take care not to miss areas with the final colour.

Thanks @ajlelectronics , I was looking at a traditional narrowboat coach enamel, something like the Craftmaster offering although I was a little unsure as to how good a finish could be achieved as a result of using an airless paint sprayer. I think your 'industrial' comment possibly speaks volumes. Are you suggesting that with the epoxy primer (with the final coat tinted to that similar of the boat, I go straight to the topcoat? Excuse my ignorance but if the airless paint sprayer gave an industrial finish, could this not be flatted down to look good?

@badabec, that's just what I wanted to hear!

 

[ajlelectronics]

Thanks @ajlelectronics , I was looking at a traditional narrowboat coach enamel, something like the Craftmaster offering although I was a little unsure as to how good a finish could be achieved as a result of using an airless paint sprayer.

I have no experience of it, so check its data sheet. You may find that it is meant for brushing and capable of a nice finish.

I think your 'industrial' comment possibly speaks volumes.

I wouldn't use a domestic type even for fence paint, far better a budget gun and modest compressor in my view

Are you suggesting that with the epoxy primer (with the final coat tinted to that similar of the boat, I go straight to the topcoat?

Yes, there is no reason to apply anything other than more epoxy primer before the colour coats.

Excuse my ignorance but if the airless paint sprayer gave an industrial finish, could this not be flatted down to look good?

It would be far too much work and your enamel may be a synthetic which is not really repairable like that.
My advice is to forget the airless sprayer, they are unsuited to your job.

@badabec, that's just what I wanted to hear!

There you are, so let it cure and have at it.

 

[steveo3002]

think you need to slow down and have a proper think

the jotun will be like rubbing down a stone once its cured , and yeah you put 3 coats on but will sand 2 1/2 off getting it smooth

sounds like youre hoping to paint over bad prep in the hopes it will flat and polish afterwards , a good finish comes from the correct prep

 

[Marky_Lad]

@steveo3002, what would be the correct prep? I stripped the paint so it was bare metal, application by roller gave a significantly better finish than by brush, I presume it could have been professionally sprayed to give it a smoother finish. I'd be interested to know what you'd do at this stage?

 

[ajlelectronics]

@steveo3002, what would be the correct prep? I stripped the paint so it was bare metal, application by roller gave a significantly better finish than by brush, I presume it could have been professionally sprayed to give it a smoother finish. I'd be interested to know what you'd do at this stage?

Bare metal was ideal, hopefully abraded to the level suggested by the data sheet. For Lechler it would be 120-180 dry. Jotun (according to the manufacturer) is intended for a commercial airless sprayer, rather than conventional spraying. But it is on there so see how it flats. As Steve says, you might take a lot off to get it flat so if you break through, spray 29107 or Mipa / Kapci etc equivalent AUTOMOTIVE two part epoxy primer.

Final flat is as per the colour coat's data sheet, my guess would be 400 dry.


Let's see what others say in response now.

 

[Marky_Lad]

@ajlelectronics, you mention spraying it on, what type of spraying are you suggesting as the boat is on the canal, not in a dry dock.

 

[steveo3002]

i dont know what to suggest , rollering on 3 rough coats of jotun wasnt the best idea

id wait for it to cure , sand it back smooth by which time most of it will be gone and see then , ideally wants a smooth coat of primer spraying on with a proper gun /compressor

 

[ajlelectronics]

@ajlelectronics, you mention spraying it on, what type of spraying are you suggesting as the boat is on the canal, not in a dry dock.

Hire a 100 litre 3HP belt drive compressor and buy or hire a middling quality gun. It will run from your power bollard and you can do a decent job with it.

 

[ajlelectronics]

i dont know what to suggest , rollering on 3 rough coats of jotun wasnt the best idea

id wait for it to cure , sand it back smooth by which time most of it will be gone and see then , ideally wants a smooth coat of primer spraying on with a proper gun /compressor

Agreed, as I pointed out earlier. Flat back the Jotun and lay a couple of coats of an automotive epoxy.