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How to clean rust and old paint from inaccessible spots

petak

petak

Enthusiast
Messages
1,903
Location
Vodice, Croatia
Hi to all!

I an in middle of a problem here!

I had a plan to clean all suspension part to the bear metal and take them to hot-dip galvanizing and to powder coating.

But front suspension lower arm is hollow, and it is unreachable with drill or grinder.
Not sure if even sand blasting could reach inside.
Here are some photos to give you closer idea of my problem.

Hole below ball join on lower arm that goes all the way to the bushing on other end of lower arm. Torsion strut goes in here.

P1060612.jpg

Rear end of front lower arm
P1060613.jpg

From one end to the other there is some 35-40cm (do not know right dimension)

Does anyone here know how to clean inside front lower arm to the bear metal?
So that it will be prepared for hot-dip galvanizing!

Thank you for reading
 
Various restoration companies offer an acid dip to remove rust, etc. and then a further wash and dip with a special coating.
 
Barnfind: Yes know about that dip process that you are talking about but unfortunately i am some 2000km away from London, and shipping will be to much cost to send it. I was thinking about method that you are suggesting.

Azazello & PaS83: Electrolysis will remove rust but not so sure about old paint.
Will certainly try

Thank you!

H!
 
Caustic soda (sodium hydroxide) will remove the paint for sure!

I have used oxalic acid as rust remover too, works fine for small spots on chromed bumper etc.
Dont know if it will work with that much rust as in your suspension parts.
 
Tx PaS83!

I have tried to find out little bit more about sodium hydroxide, and noticed that is very toxic.

Can you give me some guidance for usage and not to end up in hospital.

Did you use it for paint removal?

What ratio do you use?
 
petak said:
Tx PaS83!

I have tried to find out little bit more about sodium hydroxide, and noticed that is very toxic.

Can you give me some guidance for usage and not to end up in hospital.

Did you use it for paint removal?

What ratio do you use?
Click to expand...

I've used it mostly to remove paint from old furniture, but it does not matter what is painted as long as it is not aluminum...

I use a mixture with wallpaper adhesive to bring the solution to remain on the surface, with a ratio of 200-300 grams
of sodium hydroxide mixed to 1 litre adhesive.

I always work outside, use thick rubber gloves and ALWAYS protective eyewear.

Then just put the mixture on with an old paint brush, let it work for 15-30 minutes, give it a good scrub with the brush.
If there still is some paint sticking to the surface let it work a bit longer and then just rinse with clean water.

And yes, it is a strong chemical that will give chemical burns in contact with skin, so be careful!!
 
Little back info on this matter.

I have used sodium hydroxide and water.
4 soup spoons for 15 liters (cca 4 galons) of water.
and 12V batery charger.

after 12 hours (over night) it was so clean that i could not beleive it.
But some paint and rust still was on parts.
In some tricky corners.
First i washed part with hot water, then left to dry and clean with steel brush by hand.

Then i put it in bath for another 12 hours and after that was only left to put it in hot zink bath.

I will never again use drill and steel brush for taking old paint down.

Thank you
 
Ive done it before as well - it works a charm - also you can use washing powder to make the water conduct (Alot nicer on the skin :))

http://mad-web.org/Pages/Data/Random/Rust_Removal/

I am interested in what you are doing regarding the zinc bath as my fear is always that paint will be removed inside a closed space and then it will go rusty inside.

(Otherwise I would do this to the whole chassis)

Regards,
Andrew
 
I was surprised how fast and good this method cleans metal parts from rust and paint.

Regarding zinc bath my plan is to put all front and rear axle part (and all other metal parts around car) in hot zinc bath and then paint it with plastic paint - powdercoating.

I have learned that powdercoating is good method for protecting and "painting" metal but have one big disadvantage. If plastic layer is chipped off than rust grows rapidly underneath the "paint".
So, to avoid this disadvantage i am going to cover metal parts with zinc.
This way if paint is chipped, metal part will be protected from rust.

Also it is important to make difference between galvanizing and hot zinc bath!
Hot zinc bath is much better method for protection but it can be done only on thick metal sheets.
Galvanizing can be done both on thick and thin metal plates

That is reason why i did not put chassis in hot zinc bath.
Galvanizing could be possible on chassis

I have talked about chassis and hot zinc bath with a person who is working with hot zinc.
They can dip chassis in hot zinc but can not guarantee how will look after come out. Big chances are it would be a whole twisted. And they rather would not do it.
It could be done but technological process should look little bit different. First, chassis need to be heated slowly to temperature close to temp oh hot zinc. Then dip chassis in bath, and afterwards slowly cool to room temp.

Galvanizing on other hand is done with electricity and it is cold method and would not damage chassis.
 
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