Spraying bilt hamber hydrate-80

[bigegg]

I just ordered a 5l drum of hydrate80 to lather the underside of my land cruiser.

Tech sheet says it "can be sprayed".

Which is likely to be best:
Kitchen cleaner type Trigger spray bottle
Manual pump "weedkiller" spray
HVLP "fence sprayer"
Gravity fed spray gun (what size nozzle/PSI)
"Bottle" type spray gun. (Again nozzle size/PSI)

I am also considering spraying it into the chassis box sections. Is that a good idea?

 

[Blobber]

Got to be honest that wouldn't be my choice of product for that purpose, surfaces need to be clean, grease free and roughed up for it to stick
I used it on the wing sections I had chemically dipped and it was OK but there are some odd looking spots coming through in places which will need investigating, Im not going to use any more...

 

[bigegg]

Got to be honest that wouldn't be my choice of product for that purpose, surfaces need to be clean, grease free and roughed up for it to stick
I used it on the wing sections I had chemically dipped and it was OK but there are some odd looking spots coming through in places which will need investigating, Im not going to use any more...

The underside has been cleaned, degreased, and wire-brushed to remove as much /everything/ as possible.

My thoughts were to spray three or four applications of the hydrate-80, then a blast over with grey zinc phosphate primer.

That will give some protection until I can get it sandblasted properly next year.

Unless it still looks clean enough that I can just touch it up.
At the very least, it will identify the worst bits.


Anyway, back to my question:

What sort of sprayer?

I'm worried that if I use my decent spray gun, it'll clog up with the hydrate, and be uncleanable

 

[Craig-SM]

It’s a thin product so you could use a pump up garden pressure sprayer for even coverage. The initial coat is just a mist coating for the next two thin coats to adhere to.
I used it this weekend but brushed on and covered with zinc spray.

 

[marlinspike]

If you can access under the car I'd first do any remaining signs of rust with a brush so you can work it into every bit of pitting. It's a rust treatment and encapsulator but you do need to work it in a bit, I've found.

 

[Roger440]

Not a fan of this stuff. Unless the surface is really quite rough, you can peel it off.

And with a job like this, you cant stop it going on to the non rusty bits.

 

[bigegg]

Update:

Disposable Kitchen cleaner type trigger spray bottle clogs almost instantly.

5l "pump up" spray bottle (from 'the Range") does work.
Not well:
not enough pressure to atomise properly cause quite a lot of wastage.
I estimated 2-3L of product to completely do the bottom of my LC, including box sections. I used nearer 4L for two coats.

After the second coat had about 30minutes to dry, I used the same spray bottle filled with water and finely misted the entire area to wet out and spread the heavy "puddles" then went over it with a soft brush to get any bits I missed.



I know the drives not going to rust any time soon. I reckon there's about £20 there.

Most of it is from the misting/brushing tbf

 

[Danez]

I've used a fair bit of hydrate 80 and i always without fail pour too much out and, not wanting to waste any, desperately go about trying to find random rust spots to lather this stuff on.
Thankfully I've never had an issue with finding enough rust on my projects

 

[steveo3002]

since this only reacts with rusty metal , does the 2nd coat do anything at all

 

[bigegg]

since this only reacts with rusty metal , does the 2nd coat do anything at all

Dunno.
But it says apply two coats, so that's what I did.

 

[steveo3002]

Dunno.
But it says apply two coats, so that's what I did.

fair enough....give it a scratch once its cured and see if its still red rust underneath

 

[TEO]

Is the hydrate 80 a rust converter? I could Google but having read the thread I'm here already

 

[steveo3002]

^yeah turns rust black so must be fixed right ?

 

[Roger440]

Is the hydrate 80 a rust converter? I could Google but having read the thread I'm here already

Not in my world. Its an encapsulator.

 

[bigegg]

Not in my world. Its an encapsulator.

It's both, apparently.

It converts the red rust to a dark brown/black coloured form - I'm guessing iron phosphate? Iron oxalate? Iron citrate? Maybe all three and others?

And then it forms a clear film over the top - almost like a waterproof PVA glue, judging by what's stuck in my hair(!)