"Help!" for: Fiberglassing, Resin, & Bondo

[recon313]

Rondo the outside is a special technique. I highly recommend watching Cereal Killer's videos as they show how to do it.

The basic premise though is this:
Bondo is great over flat areas, but if you want to build it up (adding a comm box or something to a piece) it is actually too brittle to be reliable, so what you do is create a box to contain the rondo, pour it in and then take the cards off when it dries and it will be a very strong thing!

So the basic premise is, rondo on the outside when done carefully can be used to create new built up areas that would not be very high quality if done in bondo, as the resin will make the rondo a lot stronger.

Watch the videos, they're long but good.

Just in case you need a link.

s
i already watch cereal video he's great showing all every steps on making the armor .What i kinda confused only on advatages of rondoing the armor outside instead of inside.

 

[Dorvack]

I think Cereal Killer rondos both the inside for strength and the outside for detail.

 

[RobotChicken]

Key word there is "detail". All strengthening materials should go on the inside, including Rondo if you choose to use that as one of your hardening mediums. The outside gets only what's needed/wanted for paint preparation (smoothing, detailing, endless sanding, more sanding, etc). Like Katsu stated, Bondo (automotive body filler) is used to smooth the outside, but it's too brittle for making raised features. So mixing it with resin (i.e. "Rondo") gives it more strength -- for raised details, not for the whole piece. The Rondo must be poured into a form built around the shape you're wanting to add, as it's runny and will flow all over if not contained. You can use any material you wish for detailing the outside - some people simply prefer to do this with Rondo but that doesn't mean it can't be done with other (less toxic) materials that don't cost as much. As long as it can be sanded, primed, and painted you can use what works best for you.

 

[Katsu]

s
i already watch cereal video he's great showing all every steps on making the armor .What i kinda confused only on advatages of rondoing the armor outside instead of inside.

I explained the advantage in my post, please read it. You don't do one instead of the other. Rondoing outside is for another purpose than rondoing the inside.

 

[recon313]

I explained the advantage in my post, please read it. You don't do one instead of the other. Rondoing outside is for another purpose than rondoing the inside.

Key word there is "detail". All strengthening materials should go on the inside, including Rondo if you choose to use that as one of your hardening mediums. The outside gets only what's needed/wanted for paint preparation (smoothing, detailing, endless sanding, more sanding, etc). Like Katsu stated, Bondo (automotive body filler) is used to smooth the outside, but it's too brittle for making raised features. So mixing it with resin (i.e. "Rondo") gives it more strength -- for raised details, not for the whole piece. The Rondo must be poured into a form built around the shape you're wanting to add, as it's runny and will flow all over if not contained. You can use any material you wish for detailing the outside - some people simply prefer to do this with Rondo but that doesn't mean it can't be done with other (less toxic) materials that don't cost as much. As long as it can be sanded, primed, and painted you can use what works best for you.

by the means rondoing outside i mean like Charlie worsfold had done

but im gonna do it with brush .

I think Cereal Killer rondos both the inside for strength and the outside for detail.

yeah he does make the detail on topside of the armor with rondo and playing card building a dam and inside for strenght

 

[RobotChicken]

What I take away from that video is, if you cut your finger 1 minute into a take and haven't even started pouring anything yet....stop the camera, get a bandage, then start take 2 (which may include a bit about using "the proper tool for opening cans so this doesn't happen" while pointing to bandage). In 3 months of extensive research in hardening pep models this is the first time I've ever heard of anybody using Rondo in this way. Note, that he's using it not to harden his helmet but to fill all the tiny holes left over after sanding the auto filler. I suspect this method works for him because the filler he's using is much thicker. Here, the "conventional" approach I've seen is apply more filler to the deeper pockets and sand again, or apply glazing putty (something Charlie maybe hasn't heard of?) to the smaller ones. Since resin does shrink as it hardens and cures, I'd be curious about how "painting" the outside with Rondo actually turns out. Be sure to come back and post your results of this unusual technique!

 

[Dorvack]

While I am the first to admit that I haven't been in this hobby long enough to speak with any level of authority on the subject of detailing, I can't help thinking that the painting of rondo on the outside of a pepped piece, and over as large an area as is shown in the video you posted, is a good way to lose detail, although I'm sure that it would also hide any pepping irregularities.

It should be interesting to see the results, but I honestly wouldn't follow Charlie's advice on respirators.

 

[Carpathia]

That was just kind of a bad video all around. Obviously the author either unaware of or does not have access to glazing putty, which is a product much better suited to the application he was trying to fill. Even regular body filler can be used for this (slightly thinned in this guy's case since his filler was so thick); no need to make it thin enough to apply with a roller. To top it off, no respirator, no gloves, he does not use any sort of protection (to the point of potentially getting this stuff on his freshly cut finger), and flat out says he doesn't care. You shouldn't be taking lessons from someone like that.

 

[recon313]

What I take away from that video is, if you cut your finger 1 minute into a take and haven't even started pouring anything yet....stop the camera, get a bandage, then start take 2 (which may include a bit about using "the proper tool for opening cans so this doesn't happen" while pointing to bandage). In 3 months of extensive research in hardening pep models this is the first time I've ever heard of anybody using Rondo in this way. Note, that he's using it not to harden his helmet but to fill all the tiny holes left over after sanding the auto filler. I suspect this method works for him because the filler he's using is much thicker. Here, the "conventional" approach I've seen is apply more filler to the deeper pockets and sand again, or apply glazing putty (something Charlie maybe hasn't heard of?) to the smaller ones. Since resin does shrink as it hardens and cures, I'd be curious about how "painting" the outside with Rondo actually turns out. Be sure to come back and post your results of this unusual technique!

While I am the first to admit that I haven't been in this hobby long enough to speak with any level of authority on the subject of detailing, I can't help thinking that the painting of rondo on the outside of a pepped piece, and over as large an area as is shown in the video you posted, is a good way to lose detail, although I'm sure that it would also hide any pepping irregularities.

It should be interesting to see the results, but I honestly wouldn't follow Charlie's advice on respirators.

yeah i will be try posting some dummy test on a part.I'm not gonna really try it on some small detail part actually but on large2 part to remove it paperline as these way's seem to save a lot of time.yeah i agree on that respirator part i will sure still use respirator and glove except for google's as it preety a disturbance as im using spectacle

That was just kind of a bad video all around. Obviously the author either unaware of or does not have access to glazing putty, which is a product much better suited to the application he was trying to fill. Even regular body filler can be used for this (slightly thinned in this guy's case since his filler was so thick); no need to make it thin enough to apply with a roller. To top it off, no respirator, no gloves, he does not use any sort of protection (to the point of potentially getting this stuff on his freshly cut finger), and flat out says he doesn't care. You shouldn't be taking lessons from someone like that.

well im only take the idea of his as it seem preety nice to remove paperline and save time.I do also don't have access to a spot putty so im using alternate tamiya putty which is a bit expensive. i do don't take lesson on that's safety part at least i use glove as resin is very harmfull .

by the way does anyone know that by using thinner you can save brushes from hardening on resin and can be used for longer time?

 

[Dorvack]

What kind of Tamiya putty are you going to use for spot filling?

 

[recon313]

im using tamiya basic putty other tamiya putty can be used too like light curing and such but basic putty give more worktime other tamiya putty this is just an alternate thought as it better to use spot putty i think as it much cheaper.

 

[Chainsaw ninja]

So I'm gonna resin my helmet and I want it really durable, so do I put the mat on with the first layer on the inside then put more layers over that or what? Also I want to put condo in I assume it goes on after the resin. And then how many layers on the outside?

Sorry to post this again but y'all kinda went on to that rondo subject without answering my questions

 

[Silver Gooch]

Hello all, I am currently working on my second attempt at an ironman helmet. My first one I used fiberglass and polyurethane resin to reinforce the helmet. This time I decided to go the Rondo route and see if it is easier. Here is what I have done thus far:

1. Super/Hot Glue pepped my helmet
2. Sealed all seams inside the helmet with hot glue
3. 2 coats of resin on the outside (smooth cast 321)
4. 2 coats of resin on the inside (smooth cast 321)
5. 50/50 mix of Fiberglass Resin and Bondo Automotive Body Filler for 1st coat of Rondo
6. 80/20 mix (more bondo) Rondo mix for 2nd coat
7. 80/20 mix (more bondo) Rondo mix to strengthen the lips of the helmet (on the underside because I noticed that they were still a bit weak)
8. Started 1st thin coat of body filler on the helmet, only did the back of the head and the faceplate

Here is where I need help! After all of the aforementioned steps I realized that something is amiss... There seems to be a gap of air between the hard interior of Rondo and the card stock exterior. It isn't a huge gap of air, just enough to be able to push on the card stock and make it flex. I am worried that as I put body filler onto the helmet that the card stock will flex resulting in cracks in the finished product! Ahhh! Help! It seems to have an air gap in most places around the helmet, not just in one area. Ideas?

 

[Katsu]

Sorry to post this again but y'all kinda went on to that rondo subject without answering my questions

For a really strong helmet, this is what I did:
From the OUTSIDE to the INSIDE!

Bondo -> Pepakura -> Rondo 75/25 -> Fiberglass Cloth x2 -> Rondo 50/50 -> Fiberglass x2 -> Rondo 50/50
It's a little thick and heavy, but darn near rock solid. My helmet at least (I don't pretend to advise you to try this) can support my weight. Fiberglass is used to build boat bodies, if you back it correctly you can make some fairly strong stuff.

If you want something a bit lighter go:

Bondo -> Pepakura -> Rondo 75/25 -> Fiberglass x3 -> Rondo 50/50

These are all just suggestions, and what works for me may not work for you, blah blah, disclaimer, whatever.

Hello all, I am currently working on my second attempt at an ironman helmet. My first one I used fiberglass and polyurethane resin to reinforce the helmet. This time I decided to go the Rondo route and see if it is easier. Here is what I have done thus far:

1. Super/Hot Glue pepped my helmet
2. Sealed all seams inside the helmet with hot glue
3. 2 coats of resin on the outside (smooth cast 321)
4. 2 coats of resin on the inside (smooth cast 321)
5. 50/50 mix of Fiberglass Resin and Bondo Automotive Body Filler for 1st coat of Rondo
6. 80/20 mix (more bondo) Rondo mix for 2nd coat
7. 80/20 mix (more bondo) Rondo mix to strengthen the lips of the helmet (on the underside because I noticed that they were still a bit weak)
8. Started 1st thin coat of body filler on the helmet, only did the back of the head and the faceplate

Here is where I need help! After all of the aforementioned steps I realized that something is amiss... There seems to be a gap of air between the hard interior of Rondo and the card stock exterior. It isn't a huge gap of air, just enough to be able to push on the card stock and make it flex. I am worried that as I put body filler onto the helmet that the card stock will flex resulting in cracks in the finished product! Ahhh! Help! It seems to have an air gap in most places around the helmet, not just in one area. Ideas?

When I get air bubbles, I just drill it out and fill it from the outside. Better to nip it in the bud when you find it, rather than try and ignore it and accidentally pop it later.
PS: You used Smooth cast to resin the helmet? That's a fairly expensive route to go when you can get the same results with a 15 dollar can of resin (Which you'll use like 1/10th of).

 

[Silver Gooch]

Just drill a hole and pour some resin in? Also when you put the process to making a very strong helmet that seems to be very thick, how much larger do you normally make your helmet to compensate for all of the Rondo/Fiberglass? I am still trying to figure out how to properly scale my helmet to my head

 

[Katsu]

If there is an airbubble under the pepakura (between the cardstock and the rondo/fiberglass) it's better to open the hole from the outside, because trying to patch it from the inside can ruin the strength of the armor. You don't drill all the way through, usually a sharp object can poke out the hole, just make sure to expose the entire bubble hole so you can fill it in.

I don't think the thick layering adds too much bulk.. You want to be careful not to make it too much larger because then you'll look like a bobble head. If you are careful about layering the rondo, standard sizing should be fine unless you have a particularly big head, it's kind of your prerogative how much you add (or don't add).

 

[Silver Gooch]

The last pepakura helmet that I attempted fit well in the card stock phase; however, when I proceeded to the fiberglassing stage it became too small in the temple and ear area. On this attempt I sized the file a bit larger to attempt to compensate for the tightness but at the moment it looks as though I will be running into the same issues that I had before.

 

[Silver Gooch]

I have attempted to drill holes and fill the air pockets with resin; however I could not seem to get it to work... I drilled holes with a rather large drill bit and made sure to only drill through the paper and not straight through (I did drill straight through on the first two attempts :-/ ). I also made a little funnel out of card stock to minimize the spillage, but this did not work. As I poured the resin into the newly drilled holes, nothing went in. The resin slowly leaked out of the funnel onto the rest of the helmet instead of going into the drilled hole. Help??
As you can see I had to drill multiple holes because there seemed to be almost an entire layer of air between the rondo and the card stock!

 

[Carpathia]

My concern is that you're getting air bubbles with rondo in the first place. That means your process is flawed somehow.

Now, those holes are not very big at all, you should be able to simply apply a small bit of bondo into each hole, sand it down a bit and bondo your helmet as normal.

 

[Dorvack]

If you only have holes through the front of the piece and are using a funnel, the resin won't be able to go into the hole because you're not giving the air inside a chance to escape.

You could try loading a cheap veterinary syringe with resin and injecting it into the holes, or drill all the way through the mask with a thin (2mm) pilot hole and then expand the outer part of the hole for easier pouring. This will allow some air to escape as you pour.