Greenhouse Restoration

[habanerocat]

I came across this in a news article recently. It's the glasshouse in historic Donaghmore House in Co. Donegal Ireland. The house burned down last week. I presume the greenhouse is still okish. It's made from wroth iron. A nice little project for somebody with time on their hands.

DG0045_7.jpg (146.11 KiB) Viewed 4160 times

[habanerocat]

Anyway, the point of this thread was Greenhouse Restoration.

I've an old greenhouse I salvaged a number of years ago. I'd be embarrassed to say how many at this stage. A tree fell on it during a storm. Lots of problems with it, the main one being rust. I've made several attempts to get it erected over the years. I'm ready to try again.

The greenhouse is mainly made out of aluminium but the longest sections are strengthened with mild steel. Some of the steel parts are very bad in parts. Other parts haven't rusted at all, which makes me think that they must be different grades of steel. I've tried Hammerite and the like on the steel but because it's bolted to the aluminium the paint just won't tale and form a seal. A year later it has all peeled of again. Removing all the steel just isn't an option either. It's not that bad in places anyway. I've also tried that very expensive galvanizing spray.

Is there anything out there that I could use to seal the aluminium and steel supports as a unit?
Here is a sample of what I'm up against.

I'd be interested in any tip or tricks. Suppliers of universal spare parts. Paints, seals. Anything really....

[agavedave]

A couple of options

sandblast and powder coat
sandblast and galvanise.

The latter would be my preferred option because when steel is in electrical contact with aluminium, the steel will come off the worst.

Firms that do galvanising are usually found on industrial estates galvanising components for security fencing or similar products.

Regards
Dave

[DaveW]

One of the problems with Victorian iron greenhouses, since they were not galvanised is rust, since corrosion builds up in thickness and cracks the glass. It used to be a perpetual problem with the early house steel windows before they started galvanising them, corrosion and cracked glass.

As Dave says sand or grit blasting is really the only successful way to remove all the corrosion.

[habanerocat]

Yea, ye are right. Best solutions.

I looked at getting them sand blasted a number of years ago but the sections are over 13 foot long. So transport and the work it self, even back then when I had a few bod was excessively expensive. I actually did some work in a galvanizing plant and was advised that dipping aluminium wasn't an option as it would ruin the aluminium and ruin their pit. So for a number of reasons I think my solution must be home based.

I actually bought a "home use" sandblaster. It was next to useless. So my options are running low, which is another reason this project has dragged on and on.

I'm currently looking at Rust-Oleum Universal All Surface Paint and Universal Special Metals Primer. Anybody any experience of these on aluminium and rusty steel?

[BryanW]

It's been a while since I've done any metal restoration work but I 'think' Zinc based coatings are up to the job, you could also hire a decent sized output of CFM compressor and sand blast the lot in the open, you'd need a fair amount of dry sand though.
As Agavedave said aluminium is a begger when in contact with certain metals.

[Jim_Mercer]

The latter would be my preferred option because when steel is in electrical contact with aluminium, the steel will come off the worst.

I think it is the other way round as Aluminium is more anodic and the aluminium in the pictures does seem to have more corrosion than I would expect given the state of my own greenhouses https://en.wikipedia.org/wiki/Galvanic_corrosion

[habanerocat]

It's been a while since I've done any metal restoration work but I 'think' Zinc based coatings are up to the job, you could also hire a decent sized output of CFM compressor and sand blast the lot in the open, you'd need a fair amount of dry sand though.
As Agavedave said aluminium is a begger when in contact with certain metals.

What exactly is a zinc based coating? Thanks.....

[Jim_Mercer]

What exactly is a zinc based coating?

Zinc = Galvanised

[Tony R]

Or get rid of all the steel strengthening bars and replace with new aluminium, eg https://www.aluminiumwarehouse.co.uk/1- ... m-flat-bar