Question on repairing small holes in the hood?

[Caveman49]

I’ve searched through the site and found many different techniques to fix/repair small rust holes. I’m looking to repair a couple small rust holes in the hood on our 66 Comet, pics will be posted. I’ve cleaned the pin holes up some and they have expanded just a bit. It now looks pretty solid from what I see. The hoods inner structure sort of prevents me from getting in behind it.

I have a welder, although I’m not that experienced with it, I could give it a try. I’d use .023 if I do use the welder, I do have a bottle on it. I’m concerned it may be a little thin where it needs work, can maybe get some copper behind the larger of the three small holes.

I’ve thought about fiberglass, seen the technique Len posted, and may try it. I really don’t want to cut a patch out, but will if necessary. I’m sorta leaning towards welding it, appreciate any feedback on this, thanks for any and all responses.

[Caveman49]

Well after a few welding and blending tries, it seems I’ll be looking at possibly cutting out a patch, or fiberglass.
The rust is slightly worse then it looked, so I might as well try to get it all, as best I can.

Pic of where I’m at with it now.

[Len]

The longest lasting repair would be to weld in a patch then seal it from behind but if you can't get behind it then I'd probably opt for aluminum tape and fiberglass. If done properly it could last quite a while.

[Caveman49]

Thanks Len, fiberglass is probably my next plan of attack. Gotta go get some more material now….

[bmarler]

when there's rust holes and inner structure preventing you from getting access to the other side, it's almost impossible to just weld up from the outside. the rust behind there will be a lot worse than you think, and you'll just blow holes in it further and further away from the original perforation. maybe if the panel was acid dipped so all the rust was gone you could do it, but the remaining metal will be very thin and you'll chase the damage till you reach sound metal. the right way would be to cut out the damage till you reach good metal and weld in new. kind of like doing a partial door skin. going to be a fair amount of work but certainly doable.
you may also be able to cut away the outer skin to reveal the point where the inner structure and skin come together, but leaving the inside skin that's folded over intact. that would enable you to properly clean and prep the inner structure so any rust won't contaminate the weld. it's hard to say what would work best without seeing it in person.

[Caveman49]

when there's rust holes and inner structure preventing you from getting access to the other side, it's almost impossible to just weld up from the outside. the rust behind there will be a lot worse than you think, and you'll just blow holes in it further and further away from the original perforation. maybe if the panel was acid dipped so all the rust was gone you could do it, but the remaining metal will be very thin and you'll chase the damage till you reach sound metal. the right way would be to cut out the damage till you reach good metal and weld in new. kind of like doing a partial door skin. going to be a fair amount of work but certainly doable.
you may also be able to cut away the outer skin to reveal the point where the inner structure and skin come together, but leaving the inside skin that's folded over intact. that would enable you to properly clean and prep the inner structure so any rust won't contaminate the weld. it's hard to say what would work best without seeing it in person.

Yes I agree, my problem is that I’d probably mess it up more trying to weld it. I’m going to give the fiberglass fix a go, see how that works. Just want it to be a decent looking driver and safe. My daughter will be happy just to drive it.

I’ve new suspension to put on the front, will work on that after I get some of this body work done. Thanks for the input.

[Len]

Yes I agree, my problem is that I’d probably mess it up more trying to weld it. I’m going to give the fiberglass fix a go, see how that works. Just want it to be a decent looking driver and safe. My daughter will be happy just to drive it.

I’ve new suspension to put on the front, will work on that after I get some of this body work done. Thanks for the input.

If possible you'll want to have the area low by tapping it down then install the foil tape then cut the tape so that the edges are within the low area. I normally press the edges of the tape down hard with a hard object like a screw driver handle then scuff the tape with some 80 grit but be careful not to cause any holes or rips in the tape then apply short strand or milled fiberglass filler pressing it into the scratches. After it hardens sand it and if more filler is needed you can use regular bondo-type filler because the fiberglass is only needed as a moisture barrier.

[Caveman49]

If possible you'll want to have the area low by tapping it down then install the foil tape then cut the tape so that the edges are within the low area. I normally press the edges of the tape down hard with a hard object like a screw driver handle then scuff the tape with some 80 grit but be careful not to cause any holes or rips in the tape then apply short strand or milled fiberglass filler pressing it into the scratches. After it hardens sand it and if more filler is needed you can use regular bondo-type filler because the fiberglass is only needed as a moisture barrier.

Tell me, what exactly does the foil tape do, and can any aluminum tape work? I have some that was used on duct repair in the house.

I just purchased one of the spray guns you have on sale, perfect timing, getting ready to shoot the fenders and hood when it’s done 👍

[Len]

Tell me, what exactly does the foil tape do, and can any aluminum tape work? I have some that was used on duct repair in the house.

I just purchased one of the spray guns you have on sale, perfect timing, getting ready to shoot the fenders and hood when it’s done ��

I've never used anything but the 3M aluminum tape so I don't know how other products will work.

If your repair is in a place where moisture can get to the back of the repair (that's usually what caused the problem) it can get under the fiberglass and seep to the edge where it can lift the edge and show the repair. The tape adds another layer of protection to stop that from happening and that's why you use a hard, rounded tool to press the tape down to the metal and have the edges of the tape within the countersunk area.

[bmarler]

i bet the 3m tape has better adhesive than the typical duct sealing foil tape. if i was going that route, i think i'd shoot some (gasp) flex-seal in behind the inner structure to help seal any pin holes and keep water out a little longer.

[Len]

If you can't find it locally you can order it from our store linked on the picture below.

[fj5gtx]

I'd keep cutting a larger patch until you hit good metal, then butt weld in new metal. Match the gauge of the replacement steel to the original (mic what you cut out). Clean the metal well, and practice before working on the hood. Key to welding sheet steel is tacking and letting it cool between tacks. You don't want to try to put a bead, it'll heat the panel up and cause warping.

When done, drill an access hole in the back of the support, and spray it well with fluid film or equivalent when you're done welding. If you can reach it with the spray can included tube - great... If not, buy yourself an extension wand and go to town. Then pop in a sheet metal hole plug where you drilled for access.

I checked out the pics of 1966 comets, I think you're working on the front bent down area where it meets the grille. Likely its a little rusty on the backside in a few areas, so I'd drill some holes in the support and spray the entire area with some fluid film as a preventative measure.

[Caveman49]

Thanks guys, I need a whole lot of practice with my welding to tackle this hood. The backside of it has structural holes designed in it, and from what I’m seeing it looks solid. I like the idea with using the spray film fj5gtx, if just for a protective coating, may look for some here local.

I believe I’ll also practice a bit more with my welding, I have the Migmax 215 from hf, from other things I’ve welded with it so far it’s done good. I know you guys are right about getting to good metal, but I’m leaning towards the fiberglass fix right now, my skills are much better in that direction. Thanks again for the feedback.

[fj5gtx]

Thanks guys, I need a whole lot of practice with my welding to tackle this hood. The backside of it has structural holes designed in it, and from what I’m seeing it looks solid. I like the idea with using the spray film fj5gtx, if just for a protective coating, may look for some here local.

I believe I’ll also practice a bit more with my welding, I have the Migmax 215 from hf, from other things I’ve welded with it so far it’s done good. I know you guys are right about getting to good metal, but I’m leaning towards the fiberglass fix right now, my skills are much better in that direction. Thanks again for the feedback.

HomeDepot carries both Fluid Film and Surface Shield. I prefer Surface Shield, but an adapter is necessary for wand use because Blaster put the wrong type spray button to be directly compatible. AdvanceAuto carries fluid film.

[Caveman49]

Thanks, I’ll check them out 👍