Thread: acid dip or sand blast or both?

Clear coat would look good.
Andrew

Another probably more practical alternative for a job like this, including low cost and that you can do it yourself is one that many members of this forum are aware of. ie Molasses solution for cleaning rusty steel and cast iron.. Can buy in 20 kg drums at a stockfeed place. To dilute it, I find best start with mixing something like equal volumes of molasses and hot water before diluting it further. A wide range of further dilutions will work. Whatever is appropriate depends on things like amount of rust. Maybe if your engine block can be submersed in a container of 100 litres capacity start with eg 5 litres of molasses in solution.


It works slowly in cold weather and much better when warm. After maybe a couple of days, fine bubbles come up from rusty areas and they form froth which may keep increasing and drying. It turns rust to black gunk which can be scrubbed off when wet far more readily than brown rust. Areas of light rust may be quickly removed but longer and repeated treatment is usually needed to get it all when thicker. Also grease and paint on top of rust needs to be removed. With something like your engine block, maybe needs removing from solution, scrubbing with clean water and possibly detergent and replacing at 3 day intervals until regarded as clean. If there are some thick flakes of rust, they usually become easier to scrape off after soaking in molasses before turning black and soluble right through.


Remember that molasses attacks zinc and removes galvanising, so do not use a galvanised container unless not worried about inside galvanising being removed. It also dissolves aluminium. Something I have seen reported on aulro - recall by Lotz-a- Landies is using molasses solution to remove aluminium alloy pistons seized in a cast iron block - most likely from severe overheating. End result just cast iron piston rings still in bores.


Further points worth remembering is that after a while it develops a sickly sweet stink that becomes less noticeable after a while. Good idea to wear rubber gloves when washing parts as seems to take more than one wash to remove smell from hands. After final clean, best to keep parts very dry, or oil or paint soon after. Otherwise prone to quickly go brown with fresh rust.


As the solution gets older and has removed more rust, as well as becoming more smelly it may stop working. Up to a point can get it going again by adding more molasses rather than replacing with new solution.


Most likely others will make further comments here based on their own experiences using molasses.

Mole Asses is good stuff.
It wont work on the painted steel on the block.
Imagine the poor buggar that cuts all the mole asses out,tedious job
Andrew

If it's full of gunky old oil residue you might need to dip it, but I would suggest sand blasting as it will give you a nice even finish for what you want to do.

Cheers, Murray

I'd be starting with a steam cleaner and then a sand blast.. Really depends on the finish you want.. Are you planning to paint it all over, or just the externals, whilst trying to retain the sheen of the bores, head face etc? Certainly a good steam clean first, and find some of that acidic cleaner to help whilst steam cleaning. If you do it on a warm sunny day and have the steam cleaner cranked, the residual heat left in the block will do most of the drying for you.. You should also be able to find 4 metric rubber stoppers that screw into the old sump holes, giving you floor friendly feet! Ho are you proposing to hold the glass top to the block?

Originally Posted by Sitec

I'd be starting with a steam cleaner and then a sand blast.. Really depends on the finish you want.. Are you planning to paint it all over, or just the externals, whilst trying to retain the sheen of the bores, head face etc? Certainly a good steam clean first, and find some of that acidic cleaner to help whilst steam cleaning. If you do it on a warm sunny day and have the steam cleaner cranked, the residual heat left in the block will do most of the drying for you.. You should also be able to find 4 metric rubber stoppers that screw into the old sump holes, giving you floor friendly feet! Ho are you proposing to hold the glass top to the block?

all good questions and im not really sure what i want to do.
i'll either do rubber stoppers for the glass or i'll use the pistons, attach to the head and have the pistons hold the glass

I've used molasses, phosphoric acid, rust strippers etc but found electrolysis the quickest and simplest. Get a 240/12 volt converter, big wheelie bin and some washing soda. Strips rust and paint, cheap to operate and the solution last for ages. You need to operate outdoors as it produces hydrogen which might go BOOM in a confined area. Sandblasting I use on projects where I want paint to really stick.

For this project I would use electrolysis after thoroughly degreasing and when the block is totally cleaned then get it sandblasted to bring up a clean grey metal finish then clear lacquer. Might cost a bit more but the effort would be worth it. After all if it is going to be a coffee table you would like to be looking at the table you would rather have, not the table you would rather pay for.

Originally Posted by stealth

I've used molasses, phosphoric acid, rust strippers etc but found electrolysis the quickest and simplest. Get a 240/12 volt converter, big wheelie bin and some washing soda. Strips rust and paint, cheap to operate and the solution last for ages. You need to operate outdoors as it produces hydrogen which might go BOOM in a confined area. Sandblasting I use on projects where I want paint to really stick.

For this project I would use electrolysis after thoroughly degreasing and when the block is totally cleaned then get it sandblasted to bring up a clean grey metal finish then clear lacquer. Might cost a bit more but the effort would be worth it. After all if it is going to be a coffee table you would like to be looking at the table you would rather have, not the table you would rather pay for.

I'm a big fan of phosphoric, especially being able to buy 20l of 83% for $65. Way faster than molasses.

I have a 240 / 12V convertor and am interested in the details of the electrolytic method. Can you elaborate please?

cheers, DL