Pic of the Day

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Mike Bull
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Re: Pic of the Day

Post by Mike Bull » Wed Feb 14, 2018 8:55 am

No, that'll be me. :roll:

Still, we must be doing ok if that's all anyone can find fault with! :lol:

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mtskull
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Re: Pic of the Day

Post by mtskull » Thu Feb 15, 2018 8:34 am

Fantastic progress, as always.

A handful of questions re. the intakes:

If every join and rivet needs to show, isn't it self defeating to use high build primer in that area? Wouldn't a light coat of thin grey primer be sufficient to give a uniform base colour before painting?

It has been stated elsewhere that when the intakes were repaired in 1966, they were painted directly on to the metal with no primer or undercoat whatsoever. Now, as anybody who has ever tried to paint aluminium knows, it is a very devil of a job getting paint to stick to it, so how on earth did the paint stay on even for 5 minutes, never mind 30-odd years underwater?

Many years ago I used to paint vehicles for a living and was occasionally called upon to paint aluminium alloy panels. What we used back then was a "wash primer", applied in an ultra-thin and almost transparent coat that left just the slightest yellowish tint to the metal. Subsequent coats of paint would stick to this extremely well but if you managed to peel some off, the wash primer wouldn't be noticable as a layer. Is it possible that something like this was used in 1966 and has escaped detection?
Obstacles are those frightful things you see when you take your eyes off your goals.

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Richie
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Re: Pic of the Day

Post by Richie » Thu Feb 15, 2018 10:11 pm

We use high build because we have high build.

High build is applied then blocked back until Mike is satisfied we have the panel looking as close to the 67 Guise as is possible.

The high build is laid onto the powder coated panel which is thoroughly keyed before hand.

Once all and sundry are in agreement, the blue paint is applied.

They painted the base colour onto bare metal, all be it I thought there was an etch primer used on that panel back in the day, as you say a very thin wash.

It was done in a hurry remember.

There are a number of hurdles etc to address, but it is agreed that a similar finish to the 67 guise can be obtained using the methods adopted by the team... if it isn’t what we are wanting after we have tried, it will be rectified before the boat hits Coniston water.


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Mike Bull
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Re: Pic of the Day

Post by Mike Bull » Fri Feb 16, 2018 12:13 am

There's a new theory regarding the intakes paint, too - see the 'Bluebird blue' thread at the top of the forum.

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Renegadenemo
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Re: Pic of the Day

Post by Renegadenemo » Fri Feb 16, 2018 1:08 am

Good questions and the answer is that we're rolling many cheats into one with the intakes.

The 66 version imploded and had to be rebuilt so it was paint-stripped, strengthened with much added material and epoxy glue then painted with a very thin coat of cellulose paint atop a chromate wash-coat to etch the aluminium.
Now look at the pic's of the boat with this repaired structure returned to service and it's a totally different shade of blue - except it isn't. That is, unless someone popped to the bottom of the lake in the 34 years it was down there and repainted it the right colour. So what is going on?

After a huge, and I mean huge, amount of research, arguing, analysing the colour properly with gadgets and procuring the colour in all sorts of paint from that which you'd use on your bedroom ceiling to ordinary coach enamel we finally arrived at the conclusion (finally pointed to by a forum for those who 'detail' their cars (clean them stupidly because they mustn't have a life)) that the only difference between the darker coloured intakes, post-repair, and the lighter appearing remainder of the craft is the degree of polish.

The physics says that the reason we see blue intakes at all is because the paint absorbs all the red, green, yellow and everything else and only reflects blue so that's what you see. But polish it to death and it will reflect an amount of blue too so what you get is a darker blue. In theory, keep going with the polish and you'll get black because all the blue will bounce off too.

Now apply that to our boat - the 34 years under water simply took the shine off - voila!

So - in the interests of looking after our work until the end of time we applied the chromate wash-coat and then a polyester powder coat inside and out before fitting the panel so that'll look after it's longevity - but it was bright green and that might show through any top coat so we put a single coat of high-build over it. One coat won't lose the rivet lines but it gave us enough to flat it back through 180 grit to 320, then 500 and finally 1000 so the substrate would take a coat of blue that will polish, glaze and wax so that light will simply tumble into it never to be seen again.
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mtskull
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Re: Pic of the Day

Post by mtskull » Fri Feb 16, 2018 10:29 am

Thanks gents; questions well and truly answered!
Obstacles are those frightful things you see when you take your eyes off your goals.

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