cheap rust hole filler?

[punkrawker]

So I was hanging out with some buddies of mine the other night, shooting the shat when I asked them if they have ever tried to fix rust holes along the bottom body pannels by cutting out the rust and welding in fresh metal.....they both said it was a gigantic pain in the neck and said what they have done on the past is clean the area spotless via water pressure and take a can of expanding foam. Fill the hole, let it go past the body, let it cure shave to fit along body line and spray over with a nice thick coat of rocker guard. Seems like it would work, just currious if anyone else has done something like this. They said this works at bottom of body pannels, doors as long as the hole isnt so big that you can drop a bag of potatoes through. Any thoughts comments? Will try to post a drawing to better explain what I am talking about sometime this weekend

[Big-Bird]

as long as the inner panel is dry before you start this would work....although it won't hold up against stones and will chip quickly even with the rock guard.

arust hole is usually a bigger problem than the hole itself as the surrounding metal is usually compromised and may affect the structural strength.

Lots of folks have posted videos using expanding foam to make bumpers, fender flares, rocker skirts but many of them have applied a bondo skin to increase damage resistance. This will also prevent paint from attacking the foam and stones chipping away at your 'fix'

[punkrawker]

im not disagreeing by any stretch, does seem like it would work for the short term but why go through all that hasel just to make it an annual maintence issue. personally, I would use the foam for insulation AFTER the hole was welded but lacking access to a welder and also having zero welding experience kinda dampens that train of thought. lacking the funds to pay an over priced body shop is also out of the question. feel free to laugh if the next question is dumb, what about cleaning the inside of the body panel and using carbon fiber sheets to cover the hole from the inside and put a thin layer of bondo on the outside going over the carbon fiber sheet and spreading it past the work area, let it cure and add rocker guard after. my understanding is, body shop is very pricey, using foam and rocker guard is cheap A$$, the carbon fiber sheet idea seems like a happy medium between the two as far as cost goes and seems like it would last a bit longer than foam n rocker guard.....giving you more time to pay for a welder/body shop...does this make sense or am I out to lunch?

[TieMyShoe]

don;t do it..... using expanding foam is probably the worst possible way you can fix rust.

1. its not an automotive body work product.. sure you can use it but thats not what its meant for.
2. it will actually speed up the rust. foam holds moisture against the metal speeding up the rust process.
3. you will have to cover it in bondo, bondo and foam have zero strength to them.
4. its just plain lazy....

the correct way to fix it is to cut out the rust hole and weld in a new piece of metal. Yes its a pain.. but its the right way to do it. If you absolutely cannot weld in metal then fiber glass is your next option. cut out the rust, grind back the paint until the are is clean and rust free. Spray down the back side phosphoric acid and prime. Now lay down down your fiberglass over the hole. take you time make its is decently thick. sand smooth, skim bondo over the top and smooth again. Prime, Respray.

More work yes... will it last.. well it will last a hell of a lot longer then spray foam will, and it won't speed up the rust if you do it right.

[punkrawker]

sh1t you are very right about the moisture in the expanding foam, pretty much defeating the whole purpose of this exercise. I was thinking carbon fiber over fiberglass because of the obvious strength carbon fiber vs fiberglass, I am aware of the cost difference between the two but in the same breath I have never had an issue for forking out more dough for a better overall product because well you get what you pay for at the end of the day.

Because we are on the topic of DIY, if you wanted to make the interior of the van warmer and stop as much noise as possible from transferring outside to inside, what products would you suggest? sprayfoam keeps popping up and I have to agree with the points you made, so it got me thinking...what if you sprayed down the backside of the panels with por15 / rockerguard, let it cure and then use spray foam. my understanding is that the por15 / rockerguard would stop moisture from penetrating the metal and in theory would stop the moisture from the spray foam penetrating the metal.

if it makes a difference as to why I am doing this (other than because I am nuts) I want a better insulated van for camping and in theory......an insulated van might shorten the time you have the AC cranked in summer and heat in winter

[TieMyShoe]

if fiberglass is good enough to the take the pounding of waves on the ocean, rocks hitting a kayak, and hold a plane int he air. It'll work fine on your deli ;)

also note that carbon fibre can react to some metals and cause more damage.

As for sound deadening you can use rock guard but it doesn't really help much. the best thing to use is Dynamat, however the stuff isn't cheap.. and its bloody heavy! A cheaper alternative foam lined foil duct insulation. not as effective but its cheap... honestly the main sound transfer in a delica is wind getting into the very much exposed door seals, and theres little you can do about that. the area around the engine bay is already very insulated.

Heat transfer is the same deal. the deli is a big fish bowl, most of your heat loss and gain is through the glass.

[punkrawker]

didn't know that about carbon fiber, could have been a very costly hard lesson learned so that's why i'm researching around finding out what works and what doesn't. like probably the rest of us on here im doing the work myself, not a mechanic but enjoy working on something you can still work on unlike everything new out there now and don't have 20k burning a hole in my pocket to do what I want to it....hence forums like this.

once the starter gets delt with and a few other things when they arrive in the mail, looks like im going to get familiar with the ins and outs of fiberglass

[almac]

IMO, if you really love your van, don't go cheap.
get someone to do the heavy work, like the welding, and do the rest yourself.
if you go cheap, you will regret it when the rust reappears under your cheap repairs.
it will cost more, but IMO, it will be worth it.

[punkrawker]

sadly, it looks like fiberglass it is. trying to find ANYONE to do the job is the same as using napa for parts....."uh.......we dont deal with jap stuff because they are too different" mentality......so i rekon i will be getting good at fiberglas before long now hahahaha, thank god for youtube