Undersealing the R

hey guys,

i have never done this myself before and i am after some advice. i want to underseal my car, not sure how to go about it, or what is the best stuff to use? any advice would be most appreciated

tetrosyl is good comes in a big gallon tin

Dont bother with wax oil it just dries out and looks like its done nothing within a month.

I prefer using stone gaurd on the underside then a coat of gloss over it seals everything nicely.
cant stand waxoyl or underseal

ok that sounds great, obviously need to clean the surface first? or can i spray on direct?

grinder to get back to metal, then wirebrush on a drill, then clean with thinners, the cold zinc primer or grey metal primer and then your choice of undersealer

I used a wire brush wheel on a grinder to get the big areas done  then wire brush on a corded drill for the fidley bits and assortment of hand wire brushes ....i did  it over a few evenings  starting with a wheel arch per night then underside of the boot  then sills and floor pans  .... my advice would be take your time dont rush  clean and be thorough doing it in sections rather than just trying to do the whole lot in one go ...

Makes life a lot easier if you have a mate who has a lift in his garage. Or you could try a small local garage and ask if you could pay to use there lift and do it yourself. You'll be surprised how many will be nice and friendly about it, but if you must do it at home please spend abit of money on some good axel stands I see so many folks doing jobs using a trolley jack with there legs stuck under the car

Thanks for the advice guys, i have all yhe equipment, i have a workshop,with lots of space. Also have a friend with a lift. I have just never done this before. I was interested to see how you guys have done it so i had a heads up.

I used hammerite

Any particular hammerite??

You get two choices smooth or hammer finish .... only thing with hammerite it ideally takes two coats .... especially with bare metal it goes abit patchy with first coat ...still a good contender though imo .... dont buy the sprayer with hamerite as its crap and doesnt work ...

Yeah the spray is shit! Clogs the nozzle!
Not sure which I used but I think it was just the usual under seal can.

It went on quite thick if I remember right tho.
Only one coat.

Make sure you use a phosphoric acid on the metal especially along the seams, this actively eats the rust rather than just converts what it touches.
You'll find the acid will get into the seems properly as it's like water and the capillary action will pull it in.

And whatever you do, do not just paint over the old underseal....every car i have restored has had a lot of surface rust under what looks like good underseal, it MUST be removed back to bare metal otherwise you are just adding a couple of years at best to the life of the car and making the repairs MUCH MUCH more difficult when the rust makes it back through your nice shiny paint or underseal that you think is helping......

I restore gtir's for a living so know what I'm talking about from personal experience....

How many gtirs have you restored? That's a big claim

Would love to see pics of the restorations you have done!

Stu wrote:How many gtirs have you restored? That's a big claim

Would love to see pics of the restorations you have done!

theres a throead on the oc with him ripping a pulsar to bits and rewelding everything, good write up

yep scotts done a fair few restorations now
top work too

I wanna see! I don't use the oc now.

im sure scott wont mind putting up a thread with regard to some of the resto projects hes done, think hes doing billy's car at the moment

Yeah I'm happy to post up pics, when I suss out how.....I'm better with the welder than computers! Hahaha  

I started helping my father restore classic cars when I was about 6 and learned from him (he has a double-distinction city + guilds in panel beating and used to work on 60's F1 cars and classic racecars including building race engines for Sir Stirling Moss amongst others)
I am now 39 so thats a few years experience now...

Last year I carried out 3 bareshell restorations on gtir's and have 3 more booked in for this year so far and a full resto on a Nismo March Super Turbo and a 2 dr mk1 Escort.

My restorations are back to bare metal, acid treatment, zinc primer then underseal...I have learnt over the years that without dipping a shell to remove corrosion this is the only sensible way to stop the rot.

I'm not trying to tell anyone that their way is wrong...just what I've found to work best for me..

Impressive!
I had no idea we had someone so talented in restoration amongst us!

I look forward to the pics!

Haha wouldna go so far as talented! I'm still learning all the time...
I enjoy what I do and get a great sense of satisfaction from saving cars especially gtir's.

It's extremely hard work and the pay really is crap for the effort that goes into saving them....but I love gtir's and hope that accepting less money to save more cars now will pay off long term and keep me working on them for the rest of my career...

warpspeed wrote:Make sure you use a phosphoric acid on the metal especially along the seams, this actively eats the rust rather than just converts what it touches.
You'll find the acid will get into the seems properly as it's like water and the capillary action will pull it in.

And whatever you do, do not just paint over the old underseal....every car i have restored has had a lot of surface rust under what looks like good underseal, it MUST be removed back to bare metal otherwise you are just adding a couple of years at best to the life of the car and making the repairs MUCH MUCH more difficult when the rust makes it back through your nice shiny paint or underseal that you think is helping......

I restore gtir's for a living so know what I'm talking about from personal experience....

With regards to the phosphoric acid, which brand is best to use, and also which concentration?, thanks.

Scale-x at 45% concentration is about the best value for money.
1 ltr is about £18 and that should just be enough for 1 car, I buy 5 ltres at a time for just under £25 so the 1 ltr is false economy..

Higher concentration will keep attacking the rust for too long after application so if you van get a higher concentration you'll need to dilute it to around 50% or less..

And you MUST use a decent breathing mask as the fumes are bad, good quality Gerson ones can be bought for under £25 on ebay and should be used for grinding etc anyway...