How to fill indentations in body filler

[Peej]

Hi guys. I'm brand new here and this is my first proper post.
Sorry if it's in the wrong section.

I'm trying to build a helmet from scratch using carboard, fibreglass and car body filler (Currently using P38)
My current problem is, no matter how hard I try, I can't get rid of 'pot holes' in my body filler. (Picture below).
I've tried applying with two different kinds of scraper and bits of card - rather like a playing card. I apply, but it's always rough, so I rub it down. It always ends up where I rub too much off getting rid of the pot hole, and have to start over.
Repeat......

Is P38 a bad filler to use? Is there something thinner that spreads more easily? Am I just useless?
I'm in the UK so US products might not be easy to come by.

Any help would be greatly appreciated.
Cheers.
Peej

 

[Short4ATrooper]

Whenever I use a body filler like P38, once I've sanded it back I like to apply a coat of spray putty which is basically a sprayable filler but it fills a lot smaller holes than P38 or even traditional wood filler. It's available on Amazon, just search for 'Motip Spray Putty.' Sometimes it is seemingly out of stock everywhere online. If that's the case, Halfords do a good spray putty.

Spray a coat on the area with the 'pot holes' and then sand back with something like a 400 grit sandpaper.

I will say though, it currently looks like you need to do a lot more sanding - the above picture looks way too thick.

 

[Peej]

Thanks for your reply.
I agree, the body filler does look thick in places, but in other parts on the dome it's down to the frame.
Its the only way i could get a nice shape that was more like a human head. It's my third attempt at just the dome and all the templates I tried were just half sphere shapes... too pointed on top too.

It's a really difficult shape to get right as I'm sure you know.

 

[BudaFett]

I've always used bondo for filler and I've never had an issue unless the surface wasn't clean and sanded down.

 

[Short4ATrooper]

I've always used bondo for filler and I've never had an issue unless the surface wasn't clean and sanded down.

We're in the UK. No such thing as Bondo over here, P38 - which is what Peej is using is our equivalent.

Whenever I've used it, I've always followed up with a coat of spray putty before sanding that back too. Never had any issues. That's the process I did on my 3D printed Boba helmet:

 

[BudaFett]

Oh man! We got Bondo and you have Dirty Down.

 

[Short4ATrooper]

Oh man! We got Bondo and you have Dirty Down.

Lol Bondo is just a brand name, there’s 10 others here that do exactly the same thing. P38, Big Boy, U-Pol, 2K e.t.c

 

[Peej]

Whenever I use a body filler like P38, once I've sanded it back I like to apply a coat of spray putty which is basically a sprayable filler but it fills a lot smaller holes than P38 or even traditional wood filler. It's available on Amazon, just search for 'Motip Spray Putty.' Sometimes it is seemingly out of stock everywhere online. If that's the case, Halfords do a good spray putty.

Spray a coat on the area with the 'pot holes' and then sand back with something like a 400 grit sandpaper.

I will say though, it currently looks like you need to do a lot more sanding - the above picture looks way too thick.

Hello... sorry to pester with this question.
I can't find halfords spray putty online.
Would you please share a link if you know of one.

Much appreciated.

 

[Short4ATrooper]

Hello... sorry to pester with this question.
I can't find halfords spray putty online.
Would you please share a link if you know of one.

Much appreciated.

My bad, it’s not actually from Halfords it’s this one on Amazon:

 

[Peej]

Ah. Brilliant.
Thanks very much for that.