Hot Rod Forum banner

groovy new (to me) all-metal "bondo" experiment: warning:long read

4K views 5 replies 3 participants last post by  bullheimer 
#1 ·
when the body shop installed a new drivers side lower door hinge in my door they cut out a kinda rusted panel of the cab right in behind it (towards the front of the truck). it directly faces the front tire so it sees alot of water. unless i fixed it water would splash on the hinge onto the door and drip onto my running board (which i have drilled drip holes thru). you'ld have to be a magician to put sheet metal there, make a paper mache' mold to copy then bend it and it's kinda curved, like holdinig water in both hands. i am trying this fiberglass mesh i got from the plasterer that is used for "eifs" exterior insulation finish system. its like 1/4" squares and not too stiff, very bendable but not wishy washy and cuts easily w/scissors. they have thicker stuff that is sorta hard to bend. i didn't use that (panzer grade) but the other (medium grade). they are both way stiffer than any fiberglass mesh i've seen, and glass would just drip right out of these holes. since all-metal is spozed to be water proof (ive seen some 5 years old on a rusty vehicle that hasnt even started to fall apart) i decided to torture test this stuff and build a (hinge cover)if you will for my cab. mixing a tiny bit at a time i attached the bottom of the mesh onto the metal that i ground to bare metal, and let dry, then the top and sides. then i gradualy coated the whole peice a little at a time till it was solid. the whole thing could have been fiberglass but i've seen poor adhesion with fiberglass and metal-at least when i do it. anybody think this will hold up for long? i was planning on spraying rubberized undercoating over it but am tempted not to just to torture test it. it looks totally perfect, except for being silver. i have an extremely rusted out 65 pick up that i would like to see towed away that if i get stuck with having to keep, i want to try this technique on a lot larger scale, such as re-building the lower fender quarters, bottom of doors, etc etc. any thoughts or experiences?
 
See less See more
#2 ·
I would have no problems using your home-made hinge pocket (neat trick!) but I would definitely screw or pop-rivit it in place. However, I would keep the technique for use in that type of hiden structral part but not for the body pannel repair/replacemet you describe. Your problems will come in the joint between the steel and plastic pannels. There is no way to make it seemless, even if it didn't eventually de-bond, due to thermal expansion differences between the two materials. Further, the mesh/bondo structure is far too weak for large structures. Fiberglass mat and cloth are many times more dense and strong than the mesh in your part and the fiberglass iso-resin is much stronger than bondo. There is no good substitute for metal replacement patches in the original or a complete fiberglass replacement pannel.
 
#3 ·
If we are talking about a tri 5, I think I know the area you are talking about at the bottom front of the cab. When I did my '57 in '93, I used the fiberglass mat and the green fibrglass filler over the mat. I covered it in rubberized undercoating, and to this day it has not come loose or cracked. Still looks good as new.

chris
 
#4 ·
whattabout the expansion differences btwn glass and metal? i know they mate really well but i'm going also on this guys 5 yr old truck that i'm sure has a whole gallon of this stuff on there way thicker than 1/4" atta time and it looks as good as new (under the crappy paint job that is). ie could glass bond that much better than this all metal goop? Also, that "kitty hair" stuff. i still have a half a quart. would i be able to coat the all-metal hinge pocket with it?? (pop rivit it first, then glass over it)and what are your thoughts re the bigger panels with using that plasterers mesh with kitty hair. on the 65 i'm definitely not spending any time or money on it. i want to just make it look okay, primer it-use it as a test / training vehicle. i'm telling you that eifs stuff really holds it's shape well, it's figerglass so the kitty hair ought to really stick.

[ October 08, 2002: Message edited by: bullheimer ]

turbo, howd you get the 'glass mat to hold it's shape?

[ October 08, 2002: Message edited by: bullheimer ]</p>
 
#5 ·
Well, I dont really think that is a factor, but that is just me. I think that vibration and wieght are the main problems. I am not familiar with the metal stuff, but i know that the bondo brand fiberglass filler(I think it is called filler, I know it is green) sticks like you would not believe. I am also not sure about "kitty hair", not familiar with that term.......but the fiberglass mat that comes in a sort of roll works very well with the bondo fiberglass filler.

As far as holding the shape...

What I do is spread a coat of the filler/resin on a peice of seran wrap, and then lay a piece of mat precut to the shape i want. Then I coat the other side of the mat. You can put several layers at this point to make it more stiff. Then I lay it over the patch area. If the hole is pretty large, you can have a piece of seran ready to stick on the inside of the repair to keep it from collapsing it. You might have to hold it for a couple minutes untill the filler/resin starts to set.

I dont know what your idea of a big patch area is, but I would not use it on anything over 6 inches.

Also, I only use this in spots that I am not able to fab up a metal panel easily, or if I am in a hurry and it will not be seen, like small holes in a floorpan that will be covered in undercoating on one side and carpet on the other.

Chris
 
#6 ·
thanks, sounds like something i coulda done or what might be a good alternative in some similar cases.

kitty hair comes in a can and is pre mixed glass resin mixed with glass hairs. looks like they put them both in a blender at high speed. so no need to add mat/fiber. just mix with hardener. it's great stuff

since i mentioned "new" ideas i'd like to say that to fix my rusted through, to the tune of a big long crack right above the support bracket of my running board under my door,(as seen on almost every old tri five truck): first i cleaned out that area cutting out the rust and then with a coat hanger reamed out the bracket, and pressure washer from underneath. let dry. covered the bottom of the support bracket where it rusted through with duct tape, as well as the ends, so the whole bracket was semi-"watertight" as possible. then i mixed glass resin with hardener in a zip-lock baggie, cut a tiny corner off, and sqeezed the resin into the support bracket from above filling it all up. takes a couple of applications to get it to the proper level of the running board and it's an easy grind to maintain the stock ridge pattern of the original running board. the reason being that i thought the after market ones i got (and then sent back) were nowhere's near thick enough metal to stand on all the time.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top