Rust spots on GS OTA

[iceman]

Hi guys.

Does anyone else's silver GS dob OTA suffer from spot/surface rust?

Mine has bits of surface rust on it, from leaving it outside, getting dew on it etc.. My wife gives me hell about it, tells me that "I bet noone else's has rust on it.. you don't look after it" etc.

So, tell me - does yours?

Any way I can get it off?

[davidpretorius]

simple:

Galmet Ironize Rust converter

It converts the rust to a chemically neutral state, ie the iron stops reacting to form rust in that area. you can then paint over the top of it.

I sell it and I have lots of sample bottles, so I can airbag it to you, or your local hardware should have a 125ml bottle.

Tip a small amount out into a throw away container (washed milk cap). Then put cap back on the solution and put away, you don't want the remaining stuff in the bottle to be contaminated.

From there, the milky white liquid will turn browny black as it reacts with the rust. Once dry, either get a silver texta or small spray can from a hardware and colour it in.

The problem with rust is that if you don't neutralize it and just paint over it, rust will still grow under the paint.

Stuff will last a few years.

Let me know anyway Numero Uno!

[vindictive666]

yes mike

mine had since i first got it the the rust seems to follow is where someone seems to have leaned on the ota when it wasnt quite dry :(


i posted on this site about the problem and was advised to use mr sheen so thats whats iam using :) :)

[[1ponders]]

I know nightshift had a patch on his new 12" when it come out of the box. Nothing serious but still.....disappointing.

[Starkler]

Mine has rust on it also. The rust started appearing just a few short months after i got it. Its just surface rust, so I figure I have another 30 years before rust eats a hole in the ota :lol:

Even worse, I held a bit of paper to the tube with sticky tape and when removing it, the paint came with it :( .

[gaa_ian]

I have the black OTA, and it doesn't seem to have any rust problems, surface prep may have been different for that batch ? Mine is 3 Y.O.
A good tip for holding paper on your OTA is to use those little flexible fridge magnets.
Thus avoiding the sticky tape/paint peeling problem.

[Starkler]

I think theres a lot to be said for giving the ota a coat of mr sheen, wax or something to seal the surface.

[xrekcor]

Hmmmm... I feel really bad, my OTA has rust spots on it, in it, on almost every bolt
and screw open to the air on the mount. It's nearly two years old, and yes the mount
can stay out in the yard (covered of course) for anywhere up to 3-4 weeks. The OTA
doesn't usually stay out, but that's because it's been blown over when the wind has
picked up and I've gone and hit the sack. Otherwise it would stay out too. However
everything else is in pretty good condition includding Primary and secondary mirrors.
Personally it doesn't worry me have a lil bit of rust on there, shows it's used or loved.

Edit to include However if it was worth a few thousand it might
be a different story :P


regards,CS

[jjjnettie]

The rust converter is a great idea, followed by a very fine sanding, primer then repaint.
Mr Sheen or similar sounds a good idea too, but I'd be scared of residues getting on my EPs.

A decent cover for your scope is essential if leaving out overnight.
Concider an old sleeping bag, $5 at the op shop, buy the widest one you can, it will keep the heaviest dew off, and goes on and off easy because of the zipper. I guess you could zip 2 sleeping bags together for larger scopes.
A folded sleeping bag on a hard viewing chair, is very comfy.

Giving your scope a proper wipe down before storing will help stop rust starting.
I'm stating the obvious I know, but after a long night, it seems easier to just throw the cover on, and leave the sun to dry the scope out in the morning.

[ballaratdragons]

I suggested about 8 months ago about spraying OTA's with Mr. Sheen. It does sound like 1 or 2 people were listening.

Make sure you use the Mr. Sheen with the wax in it!!!! It doesn't leave any reside.

Cover up what you don't want overspray on and give the whole OTA a good heavy coat, and polish it in with a cloth (just like you would using Mr. Sheen on furniture).

When completely dry (approx 5 minutes) repeat the procedure again. When dry repeat for a 3rd time. The 3 coats gives the wax a chance to build up!

I did this in the first week I got my GS dob and it has been out in some horrific frosts and it dews up practically every time I use it and I don't have one tiny spot of rust anywhere on it.

If you use Davo's rust inhibitor (whether you re-paint the repair or not) it is well worth Mr. Sheening the whole OTA and any metal parts you have on mounts, finderscopes, brackets etc.

I have a special cream which is a metal preserver for salt-water power boats which they stopped making in the 60's and it is un-available now, but I didn't use it on the OTA coz Mr. Sheen does a good job and I want this cream to last me as long as possible coz I can't replace it any more. I have used it on some parts of my new EQ mount though.

Prevention is better than a cure!!

Sing-a-long:

Oh Mr. Sheen
Oh Mr. Sheen
Clean, wax and polish as you dust with Mr. Sheen
from the table to the chair
and OTA's everywhere
clean, wax and polish as you dust with Mr. Sheen

[acropolite]

Mike, years ago I used extra cut car polish to remove light rust from motorcycle forks; worked a treat. It will take the paint back a little as well, but may be worth a try. If that works it may be worth trying a wax type auto polish to seal the surface.

[mick pinner]

having read the posts on Mr Sheen, nice little fella but will not stop your tube from rusting, people think that rust starts by direct metal to air contact, not true, even the final coat of paint on your OTA is pourous and will absorb moisture.
whether your tube is protected against rust all comes down to the preparation and primer used underneath, the rust you see is the result of many months or years of oxidisation and there will generally be surface rust under the paint in other areas waiting to erupt later on, you can treat the rust with a converter of some sort and ideally Deoxidine but you cannot seal the surface with sprays or waxes because they themselves are pourous also if the tube has been badly prepared it will rust on the inside eventually anyway.

[ballaratdragons]

Thanks Mick. (trust a spray-painter to know LOL)

And here I was thinking my scope wasn't rusting coz of Mr. Sheen. I must be up for the award for False Advertising :lol:

Birds aluminium tube must be the answer (or a cardboard tube like Meade)

[mick pinner]

hi Ken, l can see your logic but the idea is not to stop moisture from getting to the OTA, the only thing that protects against rust is an acid etch primer and without that protection any ferrous metal WILL rust in time.

[ballaratdragons]

Mick, would the best answer be to strip the OTA back to bare metal, acid etch prime, and then repaint?

[mick pinner]

it really is the only way Ken, big job but for long term protection a neccessity.

[ballaratdragons]

But it sounds like it's worth it Mick going by the amount of GS OTA's that are showing signs of rust.

Sounds like a great project to get done during those cloudy below zero winter months.

[mick pinner]

l'll do a small tutorial recommending some good products if anyone is interested.

[ballaratdragons]

Yes please Mick. I will get my 12" done as it has to last me a long time.

[avandonk]

Angle grinder!

Bert

[avandonk]

Sorry could not help myself.

Bert

[Starkler]

Would anyone really go to the trouble of stripping back the paint and doing special treatments? I think the ota should well outlast the base .

[davidpretorius]

to be honest, no

a few minor conversions of rust and paint that area should be about the extent of it.

[ballaratdragons]

I am going to. Seeing as my 12" will probably have to last me the rest of my life I want to make sure it's always in good nick. I don't mind doing it, especially in the lousy viewing months.

[acropolite]

I can see a market for Mick's non rusting custom painted replacement dob tubes.

[Starkler]

Replacement dob tubes?
Make mine aluminium :)

[davidpretorius]

yes, aluminium is the best!

[xrekcor]

If you ever come across someone manufacturing aluminium tubing big enough.
let me know as I'm keen at looking into that. Not really because the rust
issue but my OTA fell over in the wind one day and bent the OTA tubing,
now it a real pain to rotate in the rings :(

regards,CS

[davidpretorius]

i have mentioned to Mick Pinner i think, if not i shall.

birds is great, aluminium and also a rotating section for where the focusser is!!

very nifty!

[barees63]

FWIW, I can add my GSO 10" to the ranks of rusty dobs, Mine is basically new, stored in a room with a dehumidifier but already has rust appearing in various places.. I not too upset yet, just thought I'd add a datapoint. (btw, I see the new Antares scopes, which are GSO in US I believe, have aluminium tubes).