Heat Transfer - POR-15

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Polybus
Posts: 37
Joined: Sat Oct 21, 2017 3:42 am
Location: Port Douglas

Heat Transfer - POR-15

Post by Polybus »

I've currently got a few Seagulls stripped down and giving their water galleries a really good scrub and flush out.

A couple of them are quite badly rusted - but not gone yet.

I am (carefully) sand-blasting them to get them as clean as possible and I'm looking at ways to extend their life-spans as long as possible.

Is anyone familiar with POR-15 (or the very similar Bill Hirsh Miracle Paint) Rust Prevention Pains.

I have had fantastic success with them on other applications but was wondering if anyone here has used them on Seagulls.

I am considering painting them with Rust-Killer type treatment, then coating them with POR-15 or Miracle Paint.

I am considering paining the inside of the water galleries with this stuff - from past experience, it will stop it rusting for many, many years. I would of course be careful not to allow it to gum up any of the holes through which the cooling water travels.

So the question is this:

Does anyone have any idea if these type of products will affect the heat transfer from the cast iron barrel/water galleries, to the cooling water?

With just cast iron - the heat will easily move from the hot cast iron, to the cool water.

But will a layer of POR-15 (or Miracle Paint) between the Cast Iron and the Water prevent or slow this heat transfer from occurring, causing the engine to run hot?

If it does slow the heat transfer, will it be significant enough to worry about?

Am I worrying about nothing??

Any other suggestions about how to "rust proof" as far as possible, the interior walls of these water galleries?

Just another thought - how about those Fuel Tank Sealers that are designed to seal and prevent rust inside fuel tanks?

Cheers
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Oyster 49
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Location: Derbyshire, UK

Re: Heat Transfer - POR-15

Post by Oyster 49 »

POR15 is also used in classic bike and car petrol tank lining, but requires 100% careful preparation, which involves 100% rust removal and 100% dry.

I would not put it anywhere near the inside of a seagull block, as it will lift and very quickly clog your waterways.

Best thing to do is to clean the waterways and remove any loose rust, run in fresh water often, and as a preservative. Let it run dry for just enough time for the block to warm up before storage.
Polybus
Posts: 37
Joined: Sat Oct 21, 2017 3:42 am
Location: Port Douglas

Re: Heat Transfer - POR-15

Post by Polybus »

Yes - I've used POR-15 many times before, but never on Seagulls.

And Yes - it does need careful preparation - in other words, it should be done properly - which I have no issue with. Careful cleaning with Marine Prep, followed by a thorough drying, then primed with Metal-Ready, more drying and then the POR-15. I have used it properly on all my other projects and I have never, ever had it peel, or even looking like it might peel, and some of those projects are over 25 years old now.

The only "peeling" I have ever seen is me peeling more and more wads of cash out of my wallet - My God that stuff can be expensive - but its good.

BUT!!!

I have never used it for prolonged use in Salt Water. (POR-15 has been tested for "Salt Water Spray" - but the test doesn't seem that rigorous hence the results are unconvincing for my intended application.)

I have never used it on surfaces that need to conduct heat as part of a cooling system.

I am beginning to lean away from using POR-15 - at the moment - for me anyway - it is "the great unknown".

I might stick the the old tried and true methods that Seagull Owners have been using since day one - ie: Always give them a good flush out after use, heat them up to let them dry properly, and store them well.

I suspect some of mine have not been taken care of that well - hence the rust damage already present.

Or maybe, in the interests of science - I will do just one of them (the very worst one) with POR-15 and see how it fares over the years. It will I suppose be a very subjective test as I will have no control engine to compare it with, but it will tell me if the POR will flake with prolonged Salt Water exposure.

Probably won't tell me anything meaningful for about 5 years or more though........

I guess I could also try some pseudo science type heat test as well- run it before the POR and monitor the block temperature - thencoat with the POR and try to replicate the test conditions (yeah - right) - and run it again, monitoring the temp and see if there is any noticeable difference. A lot of trouble for a very inaccurate test - but hey - I'm a bit weird like that! And lets face it - I like any reason to get the Seagulls out on the water. :mrgreen:

I am starting to side with Oyster 49: I think I will leave them as they are (except for the one possible test engine), always flush them with clean, fresh water, and one last thing - after they dry, give them another flush but with water containing soluble oil, which should leave a nice oily residue to protect the waterways after the water has evaporated - because some of these things go quite a long time between uses.

Thanks Oyster - your thoughts have helped me decide on a direction - and it wasn't the one I originally planned. So thanks again. :P
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Charles uk
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Location: Maidenhead Berks UK

Re: Heat Transfer - POR-15

Post by Charles uk »

Let's carry this subject further can anyone with a "cracked" Silver Century cylinder, post pictures of the damage, so the areas most prone to salt water damage can be established.

How much heat do we need to get rid of via water cooling, from a Silver Century running at peak revs.

Does anyone have a dead Silver Century cylinder that can be dissected so all the water gallery's nooks & crannies can be noted, so it can be seen if blasting would work as a rust removal method?
Make it idiot proof and someone will make a better idiot.
Horsley-Anarak
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Location: Surrey

Re: Heat Transfer - POR-15

Post by Horsley-Anarak »

here is a rusty one
rusty block.jpg
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andrew
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Re: Heat Transfer - POR-15

Post by andrew »

This one was my fault, I ran it in salt water about 10 years ago then stuck it in a damp garden shed without flushing. Found it in this condition last year.
234C8555-7111-43F9-8C66-095DDF7E9ADA.jpeg
0A7A37F9-E080-43AE-A470-0EF16335C773.jpeg
B937014B-0B3C-4E51-A5FF-B0F6A943E4CD.jpeg
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Sandro Picchio
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Location: Lago Maggiore (Northern Italy)

Re: Heat Transfer - POR-15

Post by Sandro Picchio »

Did it crack because of frozing in the shed or just because of the push of the swelling rust?

Sandro
andrew
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Re: Heat Transfer - POR-15

Post by andrew »

Only rust swelling! Doesn’t freeze here fortunately.
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