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MG Midget and Sprite Technical - Hydrate 80

Hydrate 80, the Bilt Hamber rust converter product.
Anyone have experience of overpainting this stuff? My question is how it performs where it may be lapped over paint adjoining a treated rust area. Does it need to be stripped back off such paintwork before applying a 2K epoxy resin primer?
Quite awkward to do this around all the intricate paint edges though I could use a stripping disc to remove the paint back to bright steel. What's to do?
GuyW

Guy,
I have used it and rate it (as I do all of their products I’ve used) can’t you just wipe off any excess / runs with a rag if it’s anywhere it can be seen ?

Mine was mainly on old parts cleaned up etc and just painted straight on.

They are a fairly small UK company and you can phone straight through to get tech help from guys that know their products !

R.
richard b

I didn't wipe off the excess where it extended over paintwork and it has dried on pretty hard. It's not wiping off with panel wipe or thinners. I guess the proper thing is to strip it all off back to bare metal but apart from the extra work I am a bit loathe to strip sound paint which is still doing a good job of rust protection.

Yes Richard, I've used other products of theirs and have been very impressed. I may try ringing them.
GuyW

Could you cut into the paintwork say with T cut or something slightly more abrasive?
Jeremy MkIII

Yes Jeremy, I think something like that is the way to go. I will try a few light passes over with my sander with 280 grit paper. That will remove excess dried on Hydrate 80 and key the paint surface for the epoxy primer. I just need to be careful not to break through the converted Hydrated 80 surfaces. That system relies on an unbroken covering.
GuyW

Hi Guy,

My default was to wire wheel as much of the rust as I could, back to bare metal. I found the wire wheel on a drill the best in all my years restoring my rust bucket!

Then I’d apply a coat of rust converter. Then when dry have another go with the wire wheel to check if any rust remained. Then apply rust converter again, sand a little and over paint when dry with epoxy primer.

I can appreciate your challenge with matching the edges with the good remaining paint. But I would assume that with having removed some rust you should still have room for a thin coat of filler to blend it all in before colour coat.

I’d give two thumbs up for Bilt Hamber products as well. It’s really thin to apply.

Good luck



James Paul

James, that's as I have been using the Hydrate 80. Wire brush or flap wheel then 2 coats. Its going over a variety of steel from bright new repairs to mostly clean but pitted where its nigh in impossible to mechanically remove the rust. I also use it as a protective coat on bare steel as sion as its welded in place as it chemically bonds to the metal and prevents flash rusting.

I guess top and bottom of my question about it is whether splashes, runs and smears of the stuff onto sound paintwork would be a problem to the bond of a subsequent epoxy primer coat.
GuyW

I really don’t think it will be an issue with bonding as you have described as they say it can be painted over, just it might show a tiny bit through as slightly raised unless you sand it down flat.

Depends on how flat the good paint is as to whether it will stand out.
James Paul

Hadn't thought of it that way! But stands to reason, if paint bonds to it, then it bonds to paint!
I think I just need to lightly key the surfaces and paint over with the epoxy primer.
GuyW

I have seen rust converter being used on Wheeler Dealers. It was painted over rust with a brush that was fitted to the cap of the bottle and it left a rough surface. I wondered how this could be smoothed down. Do these converters kill any rust or do they encapsulate it? If its the former you would be able sand off the treated steel. If it is the latter sanding would reveal more rust.

Jan T
J Targosz

Jan, I think these rust converters are very variable formulations. I've used some in the past which seem to just skin over the surface and if left the rust just comes straight through within a matter of days. Others only convert rust and don't bond to clean steel so you have to leave a rust coating on the steel anyway which seems counterproductive!

This Hydrate 80 seems a much more permanent solution to me. It bonds to both the rust and fresh steel surfaces so is good for pitted areas and for dealing with micro-rust which normally starts within minutes af mechanically cleaning steel.
GuyW

HI Guy,

That's exactly what I was referring to. A greyish liquid is painted onto the metal and it forms a black crust over the rusty parts. If you want to get a smmoth finish you need to sand down the crusts and this then exposes the rusty again. I have allways found Jenolite to be effective. It returns rusty items back to clean steel but you do need to grind off thick patches of rust first. I wonder if it is still available though, maybe it has gone the same way as the original Nitromors paint stripper.

Jan T
J Targosz

This thread was discussed between 28/10/2022 and 31/10/2022

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