Bondo Usage Question?

[jareyes]

Hey all, just had a quick question about when you use bondo to smooth/detail the helmet. I've been trying to smooth out my WETA ODST helmet and I think I've used around 7-8 batches of bondo to smooth out the top. In comparison, I've been trying to smooth out my new Rookie ODST helmet and I've used two batches, and I should be able to finish smoothing the top in a third coat.



What I was wondering from you guys is: How many layers of bondo do you use on average to smooth out a piece? I realize it depends on the piece, but ballpark numbers are fine. Do you aim to do it in number of layers? or thickness of the bondo? I'm curious to know if it's normal to expect to use 7-8 batches and still not have it completely smooth.



Thanks in advance for the input!

 

[chipscolaman]

It really always depends on how High def your piece is. The higher the definition is, the less bondo youwill have to use if you did the resin and fibreglass right.



Some people like an extra layer ontop of the actual piece, about a eighth of an inch thick or so...



On my current Flying squirl HD Helmet I already used about 15 batches or more... but I also resined it badly and thats why I have to have more...



It also depends on your experience, a pro knows better how to scoop on the bondo to get less holes to fill up.

 

[harrison]

It also depends on what you are considering a "batch." Personally I like to use smaller amounts and apply more often. It helps to preserve detail and minimize waste. Use as many coats as needed to get the look you want.

 

[S1l3nt V1p3r]

It also depends how much you sand the Fiberglass before you apply the Bondo. Smoothing out the piece before bondo can help cut down the use of bondo by 50%.

 

[phenry]

I usually do 1-2 somewhat thick coats to fill in the large areas, then 5-6 rounds of applying bondo to only the areas that need it. I still wouldn't call my finished product perfectly smooth, but it's nothing that a little weathering can't cover up.

 

[jareyes]

It really always depends on how High def your piece is. The higher the definition is, the less bondo youwill have to use if you did the resin and fibreglass right.



Some people like an extra layer ontop of the actual piece, about a eighth of an inch thick or so...



On my current Flying squirl HD Helmet I already used about 15 batches or more... but I also resined it badly and thats why I have to have more...



It also depends on your experience, a pro knows better how to scoop on the bondo to get less holes to fill up.

That is true. Hopefully they can have a new bondo tut back up. I watched the old one but the audio is removed..ah well, I followed mostly based on what I saw. IS there a particular way to scoop?

It also depends on what you are considering a "batch." Personally I like to use smaller amounts and apply more often. It helps to preserve detail and minimize waste. Use as many coats as needed to get the look you want.

That is also true.. didn't really consider the fact that everyone will use different batch sizes for different applications.

It also depends how much you sand the Fiberglass before you apply the Bondo. Smoothing out the piece before bondo can help cut down the use of bondo by 50%.

Based on today, I couldn't agree more. I used Rundown's rookie helmet and sanded the crap out of it, and I was able to smooth it pretty well with 6 coats of bondo compared to the 9 I used on the WETA ODST and that one still isn't even smooth.

I usually do 1-2 somewhat thick coats to fill in the large areas, then 5-6 rounds of applying bondo to only the areas that need it. I still wouldn't call my finished product perfectly smooth, but it's nothing that a little weathering can't cover up.

What would you consider to be a thick coat? Thick enough that it alters the overall shape of the piece, which I guess would enable you to sand and wittle it down afterwards?



Anyhow, thanks guys for answering my question. There's a part two though that I just thought of now:

When would you consider to be a good time to use the spot putty? With the bondo I've used on my Rookie helm, it's almost as smooth as I want minus some potholes/crater type things. If the crater is a little bit larger than half a centimeter, do you think that the application of body filler is better or spot putty is better?

Lastly, should spot putty be liquid in consistency? The tube I bought is exceptionally liquid-like, even after extensive kneading. When it comes out, it kind of reminds me of when peanut butter has separated, with the oil on top and the thicker portion underneath. Did I buy a bad/possibly expired batch?

 

[S1l3nt V1p3r]

Technically, you never get one even coat of Bondo on your piece. But 1/4 to 1/2 of an inch should be good enough. But you ARE supposed to sand down the bondo until you almost hit the fiberglass.

Also, you'll get an idea of what I mean if you check out my ODST thread. I'll try to get a tutorial up ASAP.

 

[DreadMullet]

id say i never use more than 5 layers... now my first 2 are nice thick layers where it really needs it (i know i break the cardinal rule about bondo....sue me) then its a thinner layer, and one more thin layer, hit that with some spot putty (im counting that as bondo...sue me again) then couple nice coats of sandable primer, and pow.



now i try and stick to this method, mainly because i love to sand. i imagine if i was a little more careful i would only need 3 coats on most pieces.



and the pregame sanding is always the way to go, nothing like a nearly smoothed helmet before you even add a touch of bondo

 

[jareyes]

Technically, you never get one even coat of Bondo on your piece. But 1/4 to 1/2 of an inch should be good enough. But you ARE supposed to sand down the bondo until you almost hit the fiberglass.

Also, you'll get an idea of what I mean if you check out my ODST thread. I'll try to get a tutorial up ASAP.

Wow, I can't even imagine 1/4" of bondo, seems pretty thick to me but maybe the buildup gets a lot thicker than I think. and yeah, sanding almost until you hit the fiberglass.. I'm one of those people that have sanded through the fiberglass .. I've also cut through the fiberglass while detailing as I've seen in your thread...yikes! Anyway thanks for the tips!

id say i never use more than 5 layers... now my first 2 are nice thick layers where it really needs it (i know i break the cardinal rule about bondo....sue me) then its a thinner layer, and one more thin layer, hit that with some spot putty (im counting that as bondo...sue me again) then couple nice coats of sandable primer, and pow.



now i try and stick to this method, mainly because i love to sand. i imagine if i was a little more careful i would only need 3 coats on most pieces.



and the pregame sanding is always the way to go, nothing like a nearly smoothed helmet before you even add a touch of bondo

"...love to sand...." HOW IS THIS POSSIBLE? Do you have a mouse sander? haha. I don't necessarily have a problem with sanding.. but I mean if you're doing it by hand (i.e. folding up a piece of sandpaper and sanding away) like I think most people do, you are either 1)nuts or 2)have super tough hands and inhuman tolerance and endurance. But yeah, thanks for the very specific procedure you provided. I've found that on helmets, I'd have to agree that about 5 is a good amount. Thanks for the play-by-play on bondo-ing .



Also, can anyone give me an answer on the spot putty question? If it's a garbage batch I got in the tube I want to know if I should just go out and buy another one.

 

[S1l3nt V1p3r]

As for the spot putty, go to the place you bought it and demand a refund/Replacement. And yes, you can use Spot Putty on the craters, but only those smaller that your pinky finger nail.

 

[Jjack]

well i used 2 layers of bondo on my chest but just one word of advice if you use pep try to get the pep as smooth as possible for example my MKVI helmet has no bondo its only resin and fiberglass and with filler primer and a coat of hammered paint under i was able to get it pretty smooth wont post pics(dont want to highjack) but you can go to my photobucket account(under sig ) and check it out might give you some ideas but i suked at bondo(too impatient)so i tried to work out an alternative, hope this helps

 

[phenry]

What would you consider to be a thick coat? Thick enough that it alters the overall shape of the piece, which I guess would enable you to sand and wittle it down afterwards?

I guess there really isn't any best answer here, it really just depends on what piece I'm working on and what smoothness I want to attain. For example, on the FS torso I was pretty liberal in my application of bondo to the breast plate to smooth out the spartan boobies (I'd say it's about 1/8" - 3/16" thick now that it's done) but kept with thin coats everywhere else I wanted to smooth.



Also, if an area of my piece warped concavely I hit that place hard with bondo too to raise it up to where it should be. This happened to part of my neck brim, so I had to put about 1/16" of bondo to make it even with the other side.

 

[DreadMullet]

"...love to sand...." HOW IS THIS POSSIBLE? Do you have a mouse sander? haha. I don't necessarily have a problem with sanding.. but I mean if you're doing it by hand (i.e. folding up a piece of sandpaper and sanding away) like I think most people do, you are either 1)nuts or 2)have super tough hands and inhuman tolerance and endurance. But yeah, thanks for the very specific procedure you provided. I've found that on helmets, I'd have to agree that about 5 is a good amount. Thanks for the play-by-play on bondo-ing .

Palm sander for the grunt work, mouse sander for a more finished sand, then hand sand the rest... i do alot of hand sanding, and i love it. and its always a good idea to use a sanding block, if you dont have one just get a small chunk of wood, wrap some sandpaper on it and POW you got a sanding block. I just find the sanding to be the most fun out of the whole pep process.

 

[jareyes]

As for the spot putty, go to the place you bought it and demand a refund/Replacement. And yes, you can use Spot Putty on the craters, but only those smaller that your pinky finger nail.

You know, I think I will. I opened the packaged and applied it, and then said to myself "what is this crap?!?".. Couldn't shake the thought that there was any way this liquid (i.e. VERY DRIPPY) stuff was going to fill in anything. Anyhow, shall do this. Making another batch of bondo (any amount) for filling in small craters always seemed unfeasible to me.

well i used 2 layers of bondo on my chest but just one word of advice if you use pep try to get the pep as smooth as possible for example my MKVI helmet has no bondo its only resin and fiberglass and with filler primer and a coat of hammered paint under i was able to get it pretty smooth wont post pics(dont want to highjack) but you can go to my photobucket account(under sig ) and check it out might give you some ideas but i suked at bondo(too impatient)so i tried to work out an alternative, hope this helps

Can't believe you got it smooth with just resin and fiberglass with the other stuff on top. I applied resin to the outside and it gooped up on the lower parts.. aw well. Also yes, bondo is very frustrating.. worth it, but frustrating.

I guess there really isn't any best answer here, it really just depends on what piece I'm working on and what smoothness I want to attain. For example, on the FS torso I was pretty liberal in my application of bondo to the breast plate to smooth out the spartan boobies (I'd say it's about 1/8" - 3/16" thick now that it's done) but kept with thin coats everywhere else I wanted to smooth.



Also, if an area of my piece warped concavely I hit that place hard with bondo too to raise it up to where it should be. This happened to part of my neck brim, so I had to put about 1/16" of bondo to make it even with the other side.

Sounds good on the Mk. VI chest piece. Was planning on completely finishing that this week so your advice should come very in handy.

About the concave warping, tell me about it! I guess because the resin shrinks a bit when it dries it pulls big, broad areas in? Anyway, I definitely heavily apply the bondo on those areas.

Palm sander for the grunt work, mouse sander for a more finished sand, then hand sand the rest... i do alot of hand sanding, and i love it. and its always a good idea to use a sanding block, if you dont have one just get a small chunk of wood, wrap some sandpaper on it and POW you got a sanding block. I just find the sanding to be the most fun out of the whole pep process.

I can't believe my ears! haha. I think 99% of the human population that's ever sanded finds it irritating.. but I have to admit, after you give a piece a fine sanding it goes from like.. "hey, you can so tell you made that just from paper!" to "damn, that thing looks hella real." and in that sense, I can see what you mean. Also, THANK YOU for the sanding block idea, I had heard of it a long time ago but had totally forgotten about it. I've just been wrapping it around my finger this entire time.. needless to say, my fingers are deadly raw right now.



Anyhow, thanks everyone for your input!! Nice to have some varying opinions.

 

[LastSpartan]

I suggest many thin layers for many reasons.



Depending on your way to mix Bondo, some air bubbles could be trapped. Especially with Bondo brand products.



If you apply 1, 2 or 3 thick layers, some airbubbles could be trapped meaning that if the helmet (or prop) is dropped, a chip could happen more easily. When sanding, you will also find more pinholes.



Thin layers means that your layers have less airbubbles, meaning more strengh.



But it's your choice. Many members like WetOKole prefer thick layers and just sand the hell of it with a power sander.



I use skin-thick coats and I sand it off almost completely before the other layer.



That's just my way of doing it and it's just a matter of preference. Experiment, and find the one that fits you best