What next after blasting?

[Rivertest]

I'm about to have my MG Midget tub blasted, the guy uses Soda.
What I need to know is what are the next steps to attain a good corrosion resistant shell. Obviously I've done a bit of reading but just wanted to run things by you to see if we're in agreement.

BTW. I'm not looking for the ultimate in corrosion resistance, as the car is not gonna be used in the winter and will only go out in the rain if it gets caught out, but it has to be better than the Zeibart it had originally..!!!!

The blasting shop will apply a coat of zinc primer, Red Bonda, following the strip. I will be inspecting before they do this.

Back at home I then intend to finish some chassis repairs, I've done most of the major stuff, sill replacement etc.

Then, seal seams with polyurethane.

Underneath will then be primed, then a coat of stone chip, then topcoat and finally waxoil throughout. I'm using cellulose BTW.

Have I missed anything?

Thanks in advance for your help.

 

[malcolm]

Sounds good to me. When I blasted my Renault chassis I primed it with Bilt Hamber zinc paint that contains 90% or more zinc. Very heavy stuff. That is said to have a galvanising action, and indeed where I have scraped paint off and left for a year the metal is still clean.

Downside is it scrapes off reasonably easilly and requires a blasted surface to have half a chance. I don't know if the soda blasted surface would be rough enough. Also not great if you have further welding to do.

The process and paints you describe are exactly what I did with my MGA in the early 1990s, and they are still working very well. Cellulose on top of stonechip has been very effective, and I've not had to repaint underneath despite a lot of miles. My old Renault on the other hand was undersealed, and that's been blasted off in places in only 30,000 miles.

The only thing I'm not happy with is the wayoyl which didn't get into the seams in the bottom of the sills, and they are starting to rust. The sills need to be very hot to get it to flow. For my new project I'll be considering one of the wax injections where a lighter oil is sprayed first to protect the seams. I think Dynatrol do something like that.

 

[Rivertest]

Yeah funny you should say that about Waxoyl, I've had the car since 1980 and treated it in 82, it's a 72 vintage. I've noticed that even though the bottom of the drivers sill has about half inch of Waxoyl in the bottom the floor to inner sill seam has blown. It certainly wasn't like it in 82, and its not been used since 86. Stored in a dry barn. Although having said that its not in bad shape rust wise, so the Waxoyl must have had some affect.

I will look into into Dynatrol though.

What Stone chip brand did you use?

RT

 

[bigbadbugga]

Have a look at the epoxy mastic 121 for the chassis, it requires little prep and is supposedly very good.

The dinitrol products are also available from the link below

http://www.rust.co.uk/epoxy-mastic.cfm

http://www.rust.co.uk/dinitrol-products.cfm

 

[jaykay]

what you need is a wand to get inside of the sills.
the waxoyl wand is like a tube with a flat head nail inserted.that fire the waxoyl sideways.i'm sure you could rig something along those lines.
what you could do is close the end of a tube,then drill it across section.
4 holes at right angles should do the job.

 

[steveo3002]

i recon the bondaprimer would suit if its dry use only

other options are the expoxy mastic 121 system , which ought to be harder /tougher as its 2 pack

 

[eil]

All the repairs that I have done to date under my rover I have just painted with the bondaprimer, why is it needed to prime with a primer again before stonechip instead of just the bondaprimer ?. as I understand its pretty good stuff.

 

[steveo3002]

you can stonechip straight onto the bonda...

the only time you might want another primer is for the body...high build filler primers would be used to smooth and straighten any repairs etc

 

[eil]

Ah gotcha, I had underneath in mind.

 

[brightspark]

what you need is a wand to get inside of the sills.
the waxoyl wand is like a tube with a flat head nail inserted.that fire the waxoyl sideways.i'm sure you could rig something along those lines.
what you could do is close the end of a tube,then drill it across section.
4 holes at right angles should do the job.

u could thin the waxoil down with turps then then spray it in with the tube no trouble getting into small places

 

[Rivertest]

Yeah, should have made that a bit clearer in the original post, bonda and stone chip on the chassis and wheel arches etc, bondaprime, filler prime and topcoat on the topsides.

RT

 

[series2]

One trick I have found works well with waxoyl, thin 10% with white spirit spray in as usual using wand inside box sections, then warm up the seams with a heat gun. You will see the Waxoyl seeping out of the seams. Then Waxoyl again, just for good measure!

You only need to get the metal upto about 30degC, so can be done safely after painting. worked well on my TR7, still doing well after 10 years.