First Time Doing Bondo

[Carpathia]

It doesn't look terrible. To me, it just looks like you may be applying the layers a bit thick. The first layer can be thick, but any additional layer is meant to smooth out the imperfections of the previous layer, which should be little more than a few pits. What are you using to apply the bondo? Pic?

 

[Monk358]

I'm using a playing card bent in half.

 

[Carpathia]

Ok, that's pretty typical. Try applying thinner layers. With what you've got now, before you apply anything else, go back to sanding. It is coming along and could look a little better with some more sanding. If you get the level down enough and get those pits to a more manageable size, then you may not even have to apply another layer of bondo, just finish it off with some glazing/spot putty.

 

[Monk358]

will Do!!
Thank you very much Carpathia

 

[Spartan1313]

A few odd little smoothing tricks I have noticed while I've been working:

1) mix a little bit of resin in with your bondo for the outer layers. Not much, but like 10%-20% of the total mass. It helps a lot.
2) You can use spot filler to get the little divots.
3)don't use an electric sander for the higher grits

 

[Carpathia]

3)don't use an electric sander for the higher grits

Heck, eliminate the electric sander all together. Instead of a lower grit on a sander, use a rasp to knock down the high stuff, then a file to refine it.

This was the condition of the side of my torso after the first bondo pass using only a rasp and a file...

 

[Monk358]

I do file down before I even start the bondo;
I think I am going to sand down some more, the use a spot filler. Then Sand with a 220 grain

 

[Spartan1313]

Heck, eliminate the electric sander all together. Instead of a lower grit on a sander, use a rasp to knock down the high stuff, then a file to refine it.

This was the condition of the side of my torso after the first bondo pass using only a rasp and a file...

*Starts Rummaging through bins for files and rasps*

 

[Bl00dbasher]

Looks like im going to have to go looking for a couple from some forgetful welders tommorow.

 

[RYNO 666]

Looks like im going to have to go looking for a couple from some forgetful welders tommorow.

Hey, there must be something to that. I'm a welder and I have a lot of files. I also have a lot of grinding wheels, brushes, contour rasps, sanding wheels, emery cloth, etc. . But I can't use them on any of my projects because they usually have layers upon layers of rust and metal all over those tools.

But for this a Mouse a Dremel and good ol fashion elbow grease combined with sandpaper has been invaluable.

Sent from my HTCONE using Tapatalk

 

[vshore100]

Where did you get the small file at the bottom Carpathia?

 

[Carpathia]

Where did you get the small file at the bottom Carpathia?

A number of detail files came with the set pictured. In all, there are about 7 large files/rasps a center punch and 10 or so different-shaped detail files. I got this set years ago when my dad and father-in-law would buy me nothing but tools for birthdays and Christmas.

 

[vshore100]

Nice one Carpathia. I found them at my local Lowe's for $17.58. Thanks for pic.

 

[Monk358]

Hey Carpathia!!
Thank you!! Worked on my helmet again last night....oh so smooth
**I'll post pics tonight after I work on it some more

 

[JayOneSeven]

Where did you get the small file at the bottom Carpathia?

Couple of days ago I found a needle file kit at Walmart for $5. Can't beat that! Comes with like 9 different small ones just like Carpathia's.

 

[Cereal Killl3r]

Ok, I'll chime in here..
I can understand that going through some of the stickies and trying to sort through massive threads can be quite the undertaking. I also understand that all too often people are quick to reply in these threads with things like: "The question you asked is already in this thread, give it a read!" which in itself isn't all that helpful, could have just answered or copy and pasted. But that's neither here nor there... anyways I do understand the needs for answers so lets see if we can do just that!

I may be wrong but I believe rondo is a fiberglass alternative not a bondo one.

My thought was, this was a thread about bondoing and rondo would go along with that. And you posted a link to cereal's videos and cereal seems to like rondo versus bondo. So, I was curious if anyone knew what the advantage was. And I thought the answer would help myself as well as the person asking about first time bondo work. Seemed like something that everyone who was following the thread could benefit from. My apologies. I will stop posting.

Yes.... and No.
I would never consider 'rondo' as an alternative (replacement for) fiberglass & resin. There is just no comparing the two. Fiberglass is a means of adding strength and rigidity to an object while maintaining very light weight and good impact/fall damage resistance. Rondo provides a means to add density/thickness to a piece in very little time. However the trade-off is the lack of strength in comparison to glass as well as it being 'dramatically' heavier! (2.5 ~ 3lb helmet vs 6~ 7lb helmet)

I am not too big of a fan of 'Rondo' despite the fact that in items I've built that is exactly what I've used. Here is my reasoning:
I use rondo because it's fast. That's it. Nothing special. I have No intentions of wearing any of the original pieces that I make. They will all be molded and casted into gel-coated and glassed pieces and some made of polyurethane plastic. If at any point I had the intent on wearing any of these pieces, they would be made of nothing other than fiberglass.

** Please... this is not me pooping on Rondo, only my opinion. What I say is 'not' an absolute! ***

What would you recommend on the outside of a Mark VI helmet? Bondo or Rondo? And inside, fiberglass or rondo?
And yes, I know the second part to that question has nothing to do with bondo, sorry.

Bondo outside, rondo/glass inside. Rondo is a pain to sand. If you add rondo to the outside it will take you 5x longer to sand it than bondo would. Rondo is also runnier than bondo, so when you apply it, it will naturally want to sag and drip making a horrible mess.

So I'm having a ton of issues getting the bondo smooth. I'm on my fourth layer now.
-filled the edges
-first layer was sanded down with 80 grain
-second touch up layer 160 grain
-went to do a couple touch ups and well it looks like the first layer gain.
I know my issue is with applying the bondo, but I just can't get it to go on smooth

Here are some keys to good bondo work:

1. Know where you're going.
- If you're having to do 4 or more layers on the same spot, you don't know where you're going. What I mean by this is, look at the area you plan to work on and figure out where it is you wish/need to be. e.g. if there is a low spot that you're trying to build up; run a ruler or straight edge across it to see the void and how much needs filling. This way you'll never need more then a couple applications and you will cut down on waste in the form of dust on the floor!

2. Put Bondo where bondo is needed, nowhere else!
- Somewhere along the line people seem to have come up with the misconception that bondo needs to be applied to the whole damn surface of what their working on... No! Bondo is used to build up low spots. That's all. If a spot wasn't low, why would you raise it??? If a spot is too high, file it down (lower than it should be) then smooth it over with bondo. If you smear bondo over an entire piece, all you're doing is covering everything up only to remove it all again. If you find this to be fun, I'd suggest working with clay!

3. The 1 wipe rule!
- When you apply bondo to an area; mix it up, put it on you're applicator (bondo scraper, playing card, etc...) and wipe it on in "1" smooth pass... then STOP. If you re-wipe an area you're gonna make a mess. All you will do is lift up what you've already applied. Then you'll try to swipe it again to smooth it back out and all that happens is the mess escalates. All you'll end up doing is pushing everything around making multiple layers to which all will be sanded off and re-applied all the same in a following coat. Trust me, 1 Swipe then leave it alone. If you still have a low spot after you're first pass, it will be there if you mess with it or not. If you mess with it, it will be worse. We have the tenancy to want to fix things until we break them! Less is more in this instance



Cheers,
Dave/Cereal

 

[Monk358]

Thanks Cereal (for the videos too)
One quick follow up to this:
"Bondo outside, rondo/glass inside. Rondo is a pain to sand. If you add rondo to the outside it will take you 5x longer to sand it than bondo would. Rondo is also runnier than bondo, so when you apply it, it will naturally want to sag and drip making a horrible mess."

Do you just Bondo the out side? Or do you Resin the outside too?
The Resin is one reason why I have to bondo "most" of my work, when it dried it left uneven areas.