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| Body work: rust and body filling https://www.ausmini.com/forums/viewtopic.php?f=2&t=53542 |
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| Author: | miniac11 [ Sun May 24, 2009 12:34 pm ] |
| Post subject: | Body work: rust and body filling |
Hi guys, I'm looking for some advice in regards to body work, and specifically fixing both rust and dents. The front fender of my mini had cracking body filler on the front wing and underneath that rust had developed. After getting rid of most of the rust, I've treated it with Exit Rust (http://www.liquideng.com.au/exitrust.html). I was told to immediately protect the converted surface, so I have done so with either Epoxy etch primer or Cold Galv (a zinc based weld thru primer). However, now I have a dilemma in that I now need to body fill the surface to shape it back to normal. The dents have been hit out as much as possible back to normal. My problem is whether I should sand the surface back to metal or just body fill over the etch primer/cold galv paint. My main concern here is whether the rust will return should I sand back the epoxy primer/cold galv and the rust converted metal. I have seen some information regarding putting body filler over epoxy primer, some recommend it for added protection, others believe it is unecessary (see: http://www.chevelles.com/forums/show....php?p=1748793). Does anyone have any experience with body work who is able to clear this up? I am particularly concerned with having to sand back to the metal and having the body filler crack back up again in a few months due to rust! |
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| Author: | mini maxx [ Sun May 24, 2009 12:43 pm ] |
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Hi Buddy, The best thing to do with rust is cut it out and weld in a patch panel, Ive found over the years that rust will allways come back if it is just treated etc. Well thats my opinion any way, there are a lot ov very knowledgable people on this forum so i am sure you will get the advice you need. Welcome to ausmini dude 
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| Author: | bimborocks [ Sun May 24, 2009 2:51 pm ] |
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I agree the only way to really get rid of rust is to get back to bare metal. you can do this by either sanding/grinding/sandbalsting the rusted area or just cut and replace. You also need a fairly course surface for the bondo/body filler to key/grip onto so the same thing doesn't happen again so if it where me i would be sanding it back before filling |
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| Author: | Morris 1100 [ Sun May 24, 2009 6:13 pm ] |
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Minis don't have fenders. 
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| Author: | bigtimmyp [ Sun May 24, 2009 7:31 pm ] |
| Post subject: | |
IMO, if there is rust holes bigger than i 5 cent coin, cut and weld a patch in, if they are smaller than that id make sure both sides of the panel are completely free of rust (using a wire wheel, sander ect...) and just bog over the top, making sure u have roughed up the surface with at least 40grit b4 you apply bog. Remember bog absorbs water and will rust underneath if left open to moisture. so apply paint/primer asap afterward wouldn't recommend bogging over the top of old bog/paint as there is likely to be more rust underneath if the old bog has cracked even slightly... it is recommended to apply bog to bare metal also... not primer, and make sure you sand back the areas that you have rust treated as bog wont adhear to the converter, hahaha, to sum it up, bog on rough clean bare metal and seal it asap and you should be fine 
this is just my personal opinion not saying its right but hope it helps 
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| Author: | drmini in aust [ Sun May 24, 2009 7:37 pm ] |
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I never bog over holes. I had Valiants for years, it doesn't work... 
If I can't fill the (small) hole with MIG alone I cut the hole back to good metal and butt weld a patch in. |
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| Author: | bigtimmyp [ Sun May 24, 2009 7:44 pm ] |
| Post subject: | |
yep thats the go dr. i dont have access to a welder usually... and i cant weld, and tight budget 
i dont bog anything seriously bad tho. |
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| Author: | Blokeinamoke [ Sun May 24, 2009 7:58 pm ] |
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bigtimmyp wrote: yep thats the go dr.
i dont have access to a welder usually... and i cant weld, and tight budget i dont bog anything seriously bad tho. Everybody cant weld until they learn to. Welders are reasonably cheap to rent. The money you spend on welding a patch in now will be a lot less than price to fix it if the rust gets away from you. As for being on tight budget - who isnt Lots of people on here weld for others - a case of beer and can be done |
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| Author: | Wombat [ Sun May 24, 2009 8:53 pm ] |
| Post subject: | |
Been reading up on using a MIG to fill small holes - the recommendation is to use a copper backing ( can use brass or aluminium but copper is best) - the weld doesn't stick to the copper and leaves a smooth surface. Anyway going to give it a shot with the copper 'ingot' I just picked up - measures 2" x 1/4" by nearly 12" Let you know how it comes out. |
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| Author: | drmini in aust [ Sun May 24, 2009 9:14 pm ] |
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Wombat wrote: Been reading up on using a MIG to fill small holes - the recommendation is to use a copper backing ( can use brass or aluminium but copper is best) - the weld doesn't stick to the copper and leaves a smooth surface. Anyway going to give it a shot with the copper 'ingot' I just picked up - measures 2" x 1/4" by nearly 12" Let you know how it comes out.
Ah Grasshopper.... there are ways to fill holes with MIG, no backing required... 
Technique son, technique...
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| Author: | mini maxx [ Sun May 24, 2009 10:38 pm ] |
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Yup, its all in the way you hold yer tongue whilst welding
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| Author: | david rosenthal [ Mon May 25, 2009 12:53 am ] |
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remove any rust. If there are small dimples of rust the treat with phosphoric acid and then wire brush clean. I either fill the dimples with bronze weld or tin the area and fill with solder. The only bog i use is the fiberglass reinforced type. It sticks well and will not crack like talc/resin type. The glass stuff is harder to sand but at least it's waterproof. Does not cost much more than std bog. |
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| Author: | miniac11 [ Mon May 25, 2009 5:52 pm ] |
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david rosenthal wrote: remove any rust. If there are small dimples of rust the treat with phosphoric acid and then wire brush clean. I either fill the dimples with bronze weld or tin the area and fill with solder.
The only bog i use is the fiberglass reinforced type. It sticks well and will not crack like talc/resin type. The glass stuff is harder to sand but at least it's waterproof. Does not cost much more than std bog. Yeah, this is the problem. Basically I have removed the rust with wire brush on the grinder, but the metal is pitted. And the dents and irregularity of the metal makes it very difficult to fully remove the rust; thus the use of the convertor. I'm also paranoid rust will return after all my hard work! I'm very wary of phosphoric acid, I've used it before and didn't like the results. My local paint shop recommended Exit Rust over phosphoric acid for the same use. |
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| Author: | Bubbacluby [ Mon May 25, 2009 6:31 pm ] |
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You can get de-ox gel. Its distributed by the same people as POR-15. Its great stuff put on, cover in glad wrap, come back 24hrs and hose off ... shiny metal its Brilliant stuff. Thats what i used for the heavy pitted surface rust on my car. Only attacks the rust and is hosable to get off Expensive though at about $50 a litre |
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| Author: | wild_willy [ Mon May 25, 2009 7:25 pm ] |
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Morris 1100 wrote: Minis don't have fenders.
Hear! Hear! Nor do they have "hoods" or "roll-ups"!!!!! |
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