Attacking Rust Inside Drawbars

Submitted: Saturday, Sep 28, 2013 at 13:35
ThreadID: 104509 Views:5699 Replies:3 FollowUps:6
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Just wondering if anyone has a good self help method of attacking rust on the inside of a drawbar. Outside is simple enough, treat with rust converter & then paint with a "rust preventative" paint. At the moment is only surface rust (thank goodness), just want to stop it going further. Thought of the usual fish oil etc which may stop it spreading, but looking at trying to eradicate /convert.

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Reply By: The Bantam - Saturday, Sep 28, 2013 at 14:39

Saturday, Sep 28, 2013 at 14:39
The truth of the matter is rust converters work very poorly.

In fact in a lot of cases they actually promote corrosion.

Rust conveters the way most people think they work are nothing but a dream.

There is no substitute for mechaincal removal to bright metal followed by a good metal primer.

I have had a lot of sucess heating chasis members on boat trailers with a gas torch.
It causes the rust to dry out, it the either pops off, falls off or can easily be brushed/ scraped off.

Inside a chassis member is always a problem.

Its not like you can get in there and scrub the stuff.

I have used a length of flat bar bent and sharpened at the end as a scraper..its marginaly effective.

banging the chasis member with a hammer will both knock some of the flake off and tell you if the member is getting a little thin.

a pressure cleaner is marginally effective...but ya wetting the surface so its only a primary choice if you are following with another heating.

Now this "rust" are we talking about a light film or is there flake?

If its nothing more than a bit of light stuff.....get in as far as you can with whatever you can to scrub/ scrape as much as you can off.

get this area as dry as you can....park it in the sun, stuff a heat gun up there...dry rust seals up better.

then get in as far as you can with a good etching metal primer any way you can.
let it dry and then go over with a coat of good paint.
I prefeer " galmet duragal" this is not a cold gal it is a metal rich silver grey top of my favorite things that comes in a tin.
let that dry then

get some heavy lanolin spray in there...I have found it best to cut the lanolin about 30% with white spirit ( that is not metho) and spray it in.

I have a patented device constructed from a good quality trigger bottle, and length of micro irrigation hose and threded joiner and a 360deg sprayer.

drill and thred the joiner into the nozzle of the trigger bottle and attack a few meters of micro irrigation and the sprayer on the end.

That will get ya lanolin meters up a chassis rail and a good 360 deg coverage.

park somehwre it does not matter while the suprlus stops running out.

thinning the lanolin will make it spray better, bet into cracks and the solvent will evaporate leaving an even film.

done this on a few boat trailers and it works very well.

Not caution with the flamable liquids.

AnswerID: 518861

Follow Up By: Hairy (NT) - Sunday, Sep 29, 2013 at 12:36

Sunday, Sep 29, 2013 at 12:36
Unless you know what your doing, I wouldn't recommend heating chassis members with a gas torch?
FollowupID: 798840

Follow Up By: The Bantam - Sunday, Sep 29, 2013 at 21:21

Sunday, Sep 29, 2013 at 21:21
You don't actually have to heat the metal very much at all.

Remember pretty well all trailer chasis are made of mild steel, so it not like you will draw the temper or weaken the metal in any way, even if you get it red hot.

Besides, you would have to have a pretty big gas torch to get such a large lump of metal very hot.

Ever tried to get a piece of 50 x 75mm RHS red takes quite a bit of heat and a bit of time.

We are not trying to melt anything we are trying to dry the rust out, and that takes only a little more than needed to burn paint.

I will generally use an oxy torch with a medium sized welding blow pipe, but I have tried it with a butane torch and it works reasonably well.

Anybody who has sufficient knowelegde to safely operate a oxy set should have some basic undestanding of metal and welding.

In the case of a butane torch, ya not likely to do any damage to steel with that now are you.

FollowupID: 798873

Follow Up By: Hairy (NT) - Tuesday, Oct 01, 2013 at 09:59

Tuesday, Oct 01, 2013 at 09:59
I could see over heating chassis members causing numerous problems if done the wrong way?
Each to there own I suppose.

FollowupID: 798944

Follow Up By: The Bantam - Wednesday, Oct 02, 2013 at 21:55

Wednesday, Oct 02, 2013 at 21:55
Mate I can see crossing the road causing all sorts of problems if it is done the wrong way.

FollowupID: 799077

Reply By: Ron N - Saturday, Sep 28, 2013 at 15:03

Saturday, Sep 28, 2013 at 15:03
Kevmac - I use Phoenix Paints Metalfix metal primer. This stuff is dear as sin, but it works like nothing you've ever seen.
I think the stuff was $47 a litre the last time I looked - but I got lucky and picked up a heap at auction several years ago, for about $5 a litre!

Phoenix Paints Metalfix is a water-based primer that converts rust to a solid coating that resists all further corrosion and it will resist high temperatures and some modest abrasion as well. I believe the paint contains phosphoric acid for rust conversion.
This primer sets solidly and quickly and can be painted over with any oil or water-based paint with no problems.

Get a look at the blokes rusty old 'Cruiser traytop on the Phoenix Paints website, that he painted with Metalfix 10 yrs before!
It's a coastal 'Cruiser used for fishing and boat launching, and it doesn't have a skerrick of rust in it any more!

I use the stuff for painting chassis' and forklifts and I've never had a single problem with it in the 14 yrs I've used it.
It locks firmly onto the rusted metal and never lifts, and no further corrosion can ever get a foothold with it.
It can be brushed or sprayed on (I brush it on), and you can dilute it with a little water to get it to penetrate difficult-to-paint surfaces.
You just wire brush off any flakey or loose rust and whack it on. The stuff keeps for yonks, you can still use it after 10 years, provided you keep the lid on securely.
AnswerID: 518862

Follow Up By: The Bantam - Sunday, Sep 29, 2013 at 21:35

Sunday, Sep 29, 2013 at 21:35
There are several of these top shelf " dirty metal primers" around POR50 is another, but as you say they are very expensive.

They rely on sealing and bonding to the rust rather than doing much in the way of "converting"

FollowupID: 798875

Reply By: Member - Wamuranman - Sunday, Sep 29, 2013 at 14:00

Sunday, Sep 29, 2013 at 14:00
My chassis rails are galvanised so its not a problem and they also have black caps on each end (to keep moisture and dirt out I guess).
But I have thought about this on older trailers.
Would it be possible to secure a cap on one end of the chassis rails and park van on the steepest slope you can with the capped end at lowest point, and fill chasis rails with something like sump oil or diesel. Let it sit for a few days and then drain out and seal ends with caps to avoid getting dust or water in. Would cost next to nothing.
Just a thought.
AnswerID: 518898

Follow Up By: The Bantam - Sunday, Sep 29, 2013 at 21:30

Sunday, Sep 29, 2013 at 21:30
what we are talking about here is a caravan, the probelm should be way less than we see in boat trailers.

In general boat trailers they make sure the chasis remains open so it can be cleaned and will dry out.

In other than boat trailers it is considered wise to prevent mud and dirt accumulating...any good design should account for that

people have tried all sort of hair brained schemes and a wide variety of things to prevent rust.

sump oil and diesel just don't cut it....lanolin does.
Sump oil and diesel are both messy, fish oil stinks

Lanolin smells a bit sheepy for a couple of days but the smell disipates quite quickly.
The lanolin dries out to a reasonably clean waxy film.

FollowupID: 798874

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