Rust scale removal methods before paint?

[Sammy]

They make a small hand held sand blaster called the speed blaster it holds about a quart of sand it would be perfect for that.You will need an air compressor the small unit costs about $30.00 and works very well it is perfect for cleaning small parts like that.You can find one at Autobodystore.com or any auto body suppliers.Ive had one for about 3 years still works great.Mike

Don't want to hi jack the thread but how much CFM or how big of a tank do you need for one of those small hand held blasters? Would an 8 gallon tank do it?
Thanks in advance

[H80N]

TurboDSM
in case you need it... that hitch number goes to a Subaru Forester..
here is a link to the mounting instructions...

http://www.etrailer.com/instructions.aspx?pn=36240

hope this helps
Heiti

[TurboDSM]

in case you need it... that hitch number goes to a Subaru Forester..

Thanks, the guy I bought it from pulled it from a Forester. It's going on an Impreza though. Already mocked it up and it should fit no problem (my 97 Impreza and his 2000 Forester have the same basic chassis). So I have a class III hitch going on an application that normally would only have a class I hitch. Not that I'm going to be pulling anything that requires class III.

I've made some good progress in removing the rust and paint. No pics of the progress yet, I'll try to get some up soon.

I stopped by Harbor Freight and picked up a wire wheel and cup, also picked up one of these for grins:


WOW, I'm impressed! That thing pulls paint off like wiping dust off with a rag. Well, maybe not quite that easily but I like it compared to other things I've used. It does OK with the rust, but was worth it to strip the paint without damaging the metal.

It's time for a a bit more brushing, chemical on the rust spots and then primer/paint.

[TurboDSM]

Any one ever use rust remover acid called "OSPHO"?

It doesn't require a water rinse like some of the other rust converting chemicals. Water is the last thing I want to put on bare metal before paint.

If I use an acid like this, I don't think it would be wise to use an etching primer. From my understanding an etching primer is like a primer and acid combo. I think an epoxy primer will be better.

Here's the process I'm thinking now:
Manually remove as much rust/paint as possible (almost done)
wipe down with some type of wax and grease cleaner (not acetone or thinner)
Apply rust chemical (OSPHO?)
use scotch bright pad to remove chemical leftovers
wipe with tack cloth
apply epoxy primer
block sand and wipe with tack cloth
apply topcoat (paint)

Sound OK?

[H80N]

OSPHO
is really a phosphoric acid conversion coating... and does not really remove much rust.. just leaves a phosphate layer on it... it is good stuff for what it was intended but I would not use it on the heavy stuff.. here is a link to their site...

http://www.ospho.com/directions.htm


hope this helps
Heiti

[crawdaddy]

Don't want to hi jack the thread but how much CFM or how big of a tank do you need for one of those small hand held blasters? Would an 8 gallon tank do it?
Thanks in advance

8 gallons would be a little light but it also depends on the CFM of the compressor if you have a high output pump it might work or you could do small areas then wait for it to fill. Its only 30 or 40 bucks might be worth it to check it out.Mike

[crawdaddy]

Any one ever use rust remover acid called "OSPHO"?

It doesn't require a water rinse like some of the other rust converting chemicals. Water is the last thing I want to put on bare metal before paint.

If I use an acid like this, I don't think it would be wise to use an etching primer. From my understanding an etching primer is like a primer and acid combo. I think an epoxy primer will be better.

Here's the process I'm thinking now:
Manually remove as much rust/paint as possible (almost done)
wipe down with some type of wax and grease cleaner (not acetone or thinner)
Apply rust chemical (OSPHO?)
use scotch bright pad to remove chemical leftovers
wipe with tack cloth
apply epoxy primer
block sand and wipe with tack cloth
apply topcoat (paint)

Sound OK?

If you plan on using automotive epoxy make sure its compatible with acid treatments or it will delaminate down the road.Phosphoric acid isnt going to do much to heavy rust.Im suprised no one here has mentioned Muratic acid it removes rust very quickly and the metal will look brand new in no time flat.You just need to use it safely and keep any waste away from children or pets.Mike

[TurboDSM]

OSPHO
is really a phosphoric acid conversion coating... and does not really remove much rust.. just leaves a phosphate layer on it... it is good stuff for what it was intended but I would not use it on the heavy stuff..

Thanks Heiti. Heavy stuff, like heavy rust? Looks like I need something that can keep the cavities under control.

[H80N]

TurboDSM
I think what you may be looking for is a tannic acid type conversion coating like por15 and many others... one that converts the brown rust to an inactive BLACK magnetite... and seals the surface with a water based latex primer..that you can paint over with enamel once set up.. and dried.. here is a link to one of those products... there are a zillion of them with about the same recipe..

http://www.corroseal.com/technical/productdata.aspx

the tractor collector community swears by that class of stuff and it works..
hope this helps
Heiti

[TurboDSM]

If you plan on using automotive epoxy make sure its compatible with acid treatments or it will delaminate down the road.Phosphoric acid isnt going to do much to heavy rust.Im suprised no one here has mentioned Muratic acid it removes rust very quickly and the metal will look brand new in no time flat.You just need to use it safely and keep any waste away from children or pets.Mike

Thanks Mike, something to keep an eye out for as far as epoxy primer. Muriatic (Hydrochloric) acid...not sure I want to venture there. I would be better off grinding the rust out.