Stabilising Dob Rot?

[barees63]

Hi Dobbers,

I have one of the rusty GSO dobs, it has now got to the point where it is starting to alarm/bug me.. rust spots are appearing all over, apparently anywhere I handle the OTA it starts rusting.. I read the older thread about rusty dobs but thought I'd ask again.. what is the best way to a) stop the existing rust and b) prevent future rusting - without dissassembling the whole thing and having it re-finished by a painter. Can anyone recommend a good "rust stop" product that I could apply to the existing spots and a good product to coat the OTA to seal it or otherwise prevent rust from occuring in future?

Thanks!
Bruce

[mick pinner]

you can only treat the rust you can see and not stop the rust that will be under the paint waiting to break out. try to get a product called Dioxidine from an auto paint outlet, brush it on the rust and wait till it goes black, generally around 12 hours, then sand it of and use a good self etching metal primer. the reason these scopes are rusting is that there is no etch primer on the steel and the paint is porous so the moisture sits between the steel and the top coat and forms rust.

[mick pinner]

p.s being a spraypainter for 30 years l can tell you there is nothing you can apply to untreated steel that will stop it from rusting, l've heard of people applying Mr Sheen and other things to seal it but it will not work.

[slice of heaven]

Mines nearly 12mths old and not a speck of rust.
I coated mine with Inox twice. It's similar to CRC and such, but a much better product. I use it on all my fishing gear to stop corrosion and for lubrication.
Or maybe I was lucky to get a good tube :shrug:

[barees63]

Thanks Mick, a bit depressing.. I suppose my options are to ignore it and hope it doesn't go any further than surface rust or spot treat it every few months (just as ugly looking as the rust I suppose) or disassemble the scope and have the tube taken back, primed and repainted properly. I wish they'd used aluminium, I'm almost tempted to look into the cost of having a replacement aluminium tube fabricated but I'd have to wonder if the other components are good enough to justify it.



It would be interesting (to me anyway) to have a poll of GSO owners regarding rust, maybe there was just a bad batch..?

[barees63]

I can get stuff here called "servisol" which is supposed to be like Inox, "Penetrator+Surface protector".. but according to what Mick has said it seems this would be pointless for my OTA?

[slice of heaven]

Probably better for prevention than cure.
I'd stick with Micks reply, it's his field.
A poll would be nice to see the response.

[Hammerman]

I don't know if this product is available in your part of the planet, but I'll mention it anyway, just in case.

I moved into a new house (new for me) 8 years ago. In the back yard was a swimming pool, surrounded by a wooden deck, with a cast iron decorative railing all the way around the deck. The railing was covered with surface rust. My brother works in a local paint store and he mentioned a product made by 3M called a rust restorer. They had another brand made by Rustoleum which was supposed to be just as good.

What I had to do was use sandpaper on the iron to get the loose rust off, but only the loose rust. Then I applied 2 coats of the rust reformer, then a single coat of primer that was made for metal and exterior rated, and a coat of black glossy paint made for metal and exterior rated.

This railing has been outside in the rain and snow for 8 years, sometimes the bottom half is covered in snow for 3 months. It is just starting to show the slightest signs of rust after all this time outside. If you were to use this on your dob, which I'm sure you will not leave outside in the snow and rain, it will probably last for many years.

Hope this helps!

[ving]

had mine for a while now, no signs of rust at all :)

[barees63]

Thanks Gary, (and thanks for nothing Ving! :P ) I think I'm going to try and ignore it for a while then eventually take the disassembled OTA to a painter to get it re-finished (and then I'll flock it as well).. for now I've coated the worst areas with CRC in a lame attempt to slow it down a bit, kind of a bummer considering I've had the scope only 3 months and it is stored next to a de-humidifier (ie always dries very quickly when I bring it in).. Antares in the USA have the right idea, although they're still GSO scopes they have seamless aluminium OTAs.

[netwolf]

Mick, out of curiosity are you able to supply a replacement tube for the GSO Dobs? I recall in another thread you mentioned you maybe able to, if i am not mistaken. I am wondering if it would be possible to reduct the weight of my OTA by replacing the tube with something a little lighter and rust proff (if such a thing exsits).

Regards

[mick pinner]

l can roll aluminium tubes up to 1500mm long and pretty much any diameter.