Silly question about applying body filler (Noob)

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PostPosted: Tue Jun 28, 2022 2:59 pm
Hi all,

This is my first time working with body filler. I am using Eastwoods aluminum body filler to fill the welded gaps between the roof steel and the balance of the unibody. I removed the factory leading with a blowtorch as the welding I did nearby caused too much toxicity/mess.

I'm getting the hang of it, with one exception. The filler seems to want to stick to the plastic applicator more than the epoxy substrate. It might be my technique, but then I try to fill in the area, the filler just "sucks" back onto the plastic applicator like glue. It makes it hard to build the right thickness to sand down from. I also have it lifting inconsistently, where little pockets are formed as I pull the applicator away. Best example I can give is trying to put icing on a cake, I get a lot of peaks and valleys which are giving me a ton to sand down from.

Does it have something to do with the applicators themselves? I am using a 20-pack of yellow plastic applicators from harbor Freight.

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PostPosted: Tue Jun 28, 2022 10:05 pm
The glass and metal fillers are usually much more difficult to apply. It's important that the first swipe is put on quite firm, to get the filler well adhered to the substrate. You don't slap it on top, rather wipe it on and in to the surface, a bit like buttering toast.

Filling gaps I'd probably use a metal applicator like a putty knife or small metal blade that can push the filler in hard and against the sides and bottom of the void. In fact I rarely use plastic blades - all metal. Easy to clean for reuse with a tissue and some thinners before it sets hard.
Chris



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PostPosted: Wed Jun 29, 2022 9:55 am
Thanks for the tip Chris! It is reassuring to know its not just me.
I have been squeezing the "tight coat" pretty hard onto the surface, but it does behave a bit like toothpaste. Epoxy is on day 4 and was sanded w/ 80 grit into the depressions, so hopefully we will get a good bite. I sanded it down until I saw bare metal on the surrounding shoulders, then applied more on-top in a larger area. Was waiting overnight for it to harden-up.

I saw the trick Eastwood showed on sanding with a course grit while the filler was curing (smucky), but it doesn't seem to work for AL filler. Was much easier to sand once fully cured.

Im having a weird issue on the roof where my large sanding block keeps gumming up. My first approach was to block sand the epoxy with 400-grit and guide coat to identify the low spots for filler. Now that I am ready to apply, I was scuffing the surface with 80 and having a terrible issue keeping little 1-2mm strips of sanded material from gumming up and glazing the paper. I might have to finish scuffing by hand where I can distribute the pressure a little more and get the filler on. Weird, as I have not had this problem with this epoxy. Maybe its all the wax/oil remover I have used to remove the fine powder. Might have aided the gumming.



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PostPosted: Sat Jul 02, 2022 11:53 am
Ahajmano wrote:Hi all,

This is my first time working with body filler. I am using Eastwoods aluminum body filler to fill the welded gaps between the roof steel and the balance of the unibody.


There is a opinion in the restoration world about using Aluminum/steel fillers:

Aluminum or Steel fillers Do not flex! they become rock hard no matter how thin they are sanded too or filed too, The area between the roof and the quarter panel is a Known flex point in the body meaning it moves quite a bit and is allowed to by design.

Lead flexes and moves with the steel body panels Plastic fillers also flex.
It has been said that Aluminum fillers are too Hard and don't flex and eventually will crack when applied in these areas on some Body designs. Not all cars are the same some are more susceptible than others but its for this reason I have started learning how to apply real lead.
Also there is the point that Alum/steel fillers expansion rates do to heat and cool at the same rate as the body panels causing a visual paint line.

Just food for thought

I am also not sure I would apply Alum or steel fillers over epoxy these I would apply directly to the metal.
Dennis B.
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.



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PostPosted: Sun Jul 03, 2022 8:44 am
Woops… welp, it’s on there now :goodjob:
I’ll have to hope for the best. All four roof seams were welded thoroughly all the way around after the lead was removed so that should help. The cage has also been tied to the unibody stiffener of the roof, Pilars, and windshield sill. It is a race car, so that obviously doesn’t help but the cage should cut back on flex quite a bit.
The epoxy was 3 days old and sanded before applying but I acknowledge applying it to bare metal in the future. I had to remove the lead… It was interfering with my rust repair and metal work, plus it was almost a pound worth (not ideal when shedding weight).

Hey so if the AL filler is poor at replacing leaded seams



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PostPosted: Mon Jul 04, 2022 12:33 pm
Didn't realize you were playing with a Race car build
wont matter then gonna get beat up anyway.

Fully welding area does not help, It was welded before. Running a full bead instead of Spot welds does not make it any stronger or more rigid than the spot welds that were their just makes removing the panel in the future all that more difficult.

The Factory engineers were not stupid if it needed a solid bead in that area it would have received it.
Dennis B.
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.



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PostPosted: Tue Jul 05, 2022 8:27 am
Understood, thanks for the reply. No the OEM engineers were certainly not stupid, no argument. Il refrain from using the product in the future. Thanks you.

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