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Two painting questions: silicone and rain.


Starcoaster

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Ok, I have two questions about boat painting.

 

1. I have had to use silicone to externally seal around the edges of some of my windows. I just sort of assumed I would paint around/over it when the time came, even if the paint didn't actually adhere to the silicone itself, and didn't leave totally clean lines. But I feel like I've read here somewhere that someone got in a hell of a mess like this, and that painting on the silicone not only didn't work, but that going over the silicone did something detrimental to the rest of the paint in the kettle/ on the brush that was used on it. Am I going mad, or is this something I need to be aware of? What happens?

 

2. Rain. I understand that the idea is that you do not paint unless it is totally dry and with a good weather forecast for some days ahead. But what happens if you get it wrong, and it rains after you've painted? The paint I am using says touch dry in three hours and proper dry to put a second coat on in sixteen hours. (I know there is merit in leaving it longer between coats also.)

So how long after painting should I consider it 'safe' if it happens to rain? Three hours? Sixteen? Some other figure? Also, what does the rain do if it hits paint that's recently been applied? (Ie, within a few hours of application).

Will any problems be clear right away and I can just re-do the affected area, or is it all likely to look just fine on the surface but then bubble or lift or something in fairly short order?

 

 

I get that there are like 20 potential alternate suggestions to direct answers that could be made here (like remove the windows when you paint and remove the silicone, or paint under shelter to avoid rain, etc), I do appreciate that.

But I would really appreciate it if anyone who has first hand experience of either issue or knows from a basis of fact what the actual likely results are for the queries as stated could give their thoughts.

 

Many thanks as always!

Edited by Starcoaster
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Ok, I have two questions about boat painting.

 

1. I have had to use silicone to externally seal around the edges of some of my windows. I just sort of assumed I would paint around/over it when the time came, even if the paint didn't actually adhere to the silicone itself, and didn't leave totally clean lines. But I feel like I've read here somewhere that someone got in a hell of a mess like this, and that painting on the silicone not only didn't work, but that going over the silicone did something detrimental to the rest of the paint in the kettle/ on the brush that was used on it. Am I going mad, or is this something I need to be aware of? What happens?

 

2. Rain. I understand that the idea is that you do not paint unless it is totally dry and with a good weather forecast for some days ahead. But what happens if you get it wrong, and it rains after you've painted? The paint I am using says touch dry in three hours and proper dry to put a second coat on in sixteen hours. (I know there is merit in leaving it longer between coats also.)

So how long after painting should I consider it 'safe' if it happens to rain? Three hours? Sixteen? Some other figure? Also, what does the rain do if it hits paint that's recently been applied? (Ie, within a few hours of application).

Will any problems be clear right away and I can just re-do the affected area, or is it all likely to look just fine on the surface but then bubble or lift or something in fairly short order?

 

 

I get that there are like 20 potential alternate suggestions to direct answers that could be made here (like remove the windows when you paint and remove the silicone, or paint under shelter to avoid rain, etc), I do appreciate that.

But I would really appreciate it if anyone who has first hand experience of either issue or knows from a basis of fact what the actual likely results are for the queries as stated could give their thoughts.

 

Many thanks as always!

I'd trim off any excess silicon with a sharp razor blade or modelling craft knife then T-cut the area very vigorously then wipe with white spirit clothe.

Your paint should be safe after about 6 hrs from rain but if very heavy or hail it will probably pock mark it. Even at this time of year I would stop painting no later than about 3pm for if a dew falls it will bloom the paint and it will have no gloss and be dull and flat, this mainly of course applies to the last finishing gloss top coats.

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Excellent, thanks Biz that's just what I was looking for.

I've already started tidying the edges of the silicon with a blade where it doesn't need to be, will T-cut remove any invisible bits that I may have smeared when putting it on, that may affect the paint?

Edited by Starcoaster
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Excellent, thanks Biz that's just what I was looking for.

I've already started tidying the edges of the silicon with a blade where it doesn't need to be, will T-cut remove any invisible bits that I may have smeared when putting it on, that may affect the paint?

If you feel around the area with your fingers you should feel any stray silicon, rub it with your finger and it should rough up and peel off.

After T-cutting and wiping off don't forget to to prepare the surfaces before priming ect with a sander, wet or dry or whatever.

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We had some painting done this week, professionally; dodging the showers. The only bit that got affected by the rain was a small stretch that was heavily rained on after about an hour; the other areas were about 3 hours old when they got rained on, and they seem to have been just fine.

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Excellent, thanks Biz that's just what I was looking for.

I've already started tidying the edges of the silicon with a blade where it doesn't need to be, will T-cut remove any invisible bits that I may have smeared when putting it on, that may affect the paint?

 

I wouldn't expect anyone to go to the lengths a boat painter would to remove and avoid silicon, but if it's around it will contaminate the paint, your brush, and will create fisheyes where ever it is found.

 

If the silicon is cut back to a margin, you will still have to avoid touching the margin; it's as much a problem as that. When you feel as much has been done as you can, vacuum the area. If you can get your hands on a surface wipe, finish with that. White spirits is slow to evaporate, suface wipe is almost instantaneously evaporated. Decorators suppliers or a motor factors will probably stock the stuff. The surface wipes I've used should be applied with rubber gloves. It will generally rot latex gloves in a few minutes. Wear eye protection, and in enclosed areas, wear a decent VOC mask. Volatile Organic Compounds.

 

Don't use paint straight from the tin. Mix an amount in another container. This is to avoid contaminating good paint. Do not put any used paint back into any paint still remaining in the original tin the paint was supplied. If your used paint has picked up any silicon there's no point in wrecking the fresh stuff in the tin. Put the used stuf in jam jars or something. This should be a general practice, anyway.

 

Silicon will get in you brush and it will be spread around as you paint.

 

Moisture is a fine thing and surface wipe should be used immediately before painting. Conditions haven't been good, of late, to paint in the open. Just do your best and keep your fingers crossed. Don't paint before the sun has had time to clear the morning cold air, and don't paint too near to dusk. Keep an eye on the forcast and just wait if there's bad weather in store. If the job can wait, leave it till warmer periods.

Edited by Higgs
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Just an aside to the problem of silicon, I would never use silicon but would use adhesive such as Sticks Like Sh*t or some such, usually white in colour can be applied even to damp surfaces and more importantly can be over painted.

 

Phil

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Hi star,

 

When we got our nb we had little choice (and funds left!) To complete a "proper job" on the painting and fixing leaky window thing, we applied silicone sealer to various areas, let it 100% dry, painted over with red oxide and then with the colour of our choice, the paint went on well and is still there a year later, when I used to repair alloy wheels the wet silicone tyre dressing would always give the paint an orange peel effect and would have to be thouroughly cleaned with spirits, In my own experience if the silicone is completely dry and cleaned with spirits the paint has taken very well, try a little test area.

 

If it rains on wet paint, it leaves craters as I found out the hard way and had to start again! And if an oil based paint is nearly dry (just past tacky) it runs off with no ill effect.

 

This is from our own experience, I hope this helps and good luck!

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Interestingly, I got a cheap brush and tipped some paint into a disposable container to paint over some silicone 'just to see.' I did this yesterday and it went on fine, and has stayed on (so far!) without pulling back or doing anything odd or different to how it behaved on non siliconed areas!

I will see if anything has changed in a week and report back!

 

In case anyone is interested, I painted onto (and been so far on) three different products: Captain Tolleys (where the paint went on like silk and looked and felt even better than it did on plain prepared surfaces) MarineFlex, and a generic silicone sealant that says it is 'marine suitable.'

Edited by Starcoaster
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If there is a threat of rain or dew, something that can be done is cover the most recently done paintwork with a new or clean thin polythene dust sheet once it's just about touch dry.

 

The polythene may stick to the paint a little but should peel off OK without affecting the gloss finish as it's too light to mark it, and it'll protect the paintwork from 'bloom' (matt spots or areas) caused by water getting on it before it's dry enough.

 

cheers, Pete.

~smpt~

Edited by smileypete
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Cheers! I think Marine Flex is very similar to Sikaflex, so that maybe why it's holding it in some places? Although the paint seems to be sticking the same to all of it.

I've not had any problems with it doing anything odd to the paint, or created 'fish eyes' as mentioned earlier so far.

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The paint will probably shed from the silicone over time.

 

If you use Polyurethane sealant (eg Sikaflex) instead of silicone, it will hold paint much better.

 

Tim

Can you tell me the exact type of Sikaflex you've used, as there are many different ones for various tasks?

Or is it called "Sikaflex Polyurethane Sealant" on the tube

Thanks

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Can you tell me the exact type of Sikaflex you've used, as there are many different ones for various tasks?

Or is it called "Sikaflex Polyurethane Sealant" on the tube

Thanks

 

Sikaflex 221.

As said, Marineflex is similar.

 

I don't recommend them for actually fitting windows, as they are also fairly strong adhesives and you might regret it if the window has to be removed.

The OP was talking of 'sealing externally'.

 

Tim

Edited by Timleech
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Cheers! I think Marine Flex is very similar to Sikaflex, so that maybe why it's holding it in some places? Although the paint seems to be sticking the same to all of it.

I've not had any problems with it doing anything odd to the paint, or created 'fish eyes' as mentioned earlier so far.

 

It might be that what you have on is a silicon lookalike and not silicon. Silicon and oil based paints are definitely not pals.

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I've found Stixall to be a brilliant all rounder, since discovering it I've never needed any other type sealer or adhesive, there simply isn't anything sealing or stickery it can't tackle and as yet it's not failed anywhere on the boat or anywhere else.

 

It can be painted over no problem and now comes in 5 colours and at a reasonable price.

 

http://www.tool-net.co.uk/p-345611/everbuild-stixall.html?gclid=CM286pC0pbcCFZMftAodw0UAkg

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I've found Stixall to be a brilliant all rounder, since discovering it I've never needed any other type sealer or adhesive, there simply isn't anything sealing or stickery it can't tackle and as yet it's not failed anywhere on the boat or anywhere else.

 

It can be painted over no problem and now comes in 5 colours and at a reasonable price.

 

http://www.tool-net.co.uk/p-345611/everbuild-stixall.html?gclid=CM286pC0pbcCFZMftAodw0UAkg

I think Starcoaster wants know to about painting over sealants not about using sealants over paint Julynian. smile.png

Edited by bizzard
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