Muddy Secrets Tutorial

Sigma LS

Sr Member
So I've seen a lot of people attempting to use regular bondo on their stuff and I've been guilty of it too in the past. However by using a mix of bondo and resin, you can save yourself a lot of work and have beautiful results.

This technique was pioneered by Spase who originally used it with metal glaze, but the same principle still applies to using it with the mix.

The mix is referred to by a few different names and has been used by many of experienced molded armorers like Sean and Link. Usually rondo or mud is the commonly used term.


Step 1: What you will need

To use this technique you will need

1. Plastic Spreaders
2. 3M painters tape
3. Polyurethane fiberglassing resin (Resin)
4. Automotive styrene based auto body filler (Bondo)
5. Liquid Catalyst (Hardener)
6. Mixing container
7. Respirator (you know the safety rules, please don't ask if you need one)
8. A fiberglassed piece of pepakura armor
9. Sanding equipment (preferably a dremel and mouse sander)

pic of the essentials to make and apply the mud
HPIM1220.jpg




Step 2: Building the tape wall

The piece of pepakura must be smoothed in sections. First you must determine which areas are similar enough that you want to attempt to include them all in a single smoothed surface.

Next take a strip of painter's tape approximately as long as one of the sides of the section you've chosen.

HPIM1218.jpg



Then fold one edge of the tape approximately 1/2 inch on top of itself. This is critical to reinforce the edge as well as to have the maximum height that the mud can reach before spilling over.

HPIM1219.jpg



Apply the tape to the section you want to smooth while keeping only the doubled up edge above the surface. Repeat until you have completely surrounded the section. Flare the edges slightly and reinforce adjoining edges so they don't interfere or fall apart when you are pouring the mud into it.

* NOTE: If you are working with a highly curved surface, make sure the lower points have slightly higher walls to prevent excess overflow.

Before
HPIM1213.jpg


After
HPIM1215.jpg



Step 3: The recipe for mud

Mud is usually made in a 1:1 ratio of bondo to resin.

However, what you want to do is create a consistency that is like mud (very thick but still pours evenly) adjust your mix accordingly to attain that result. Use more bondo to make it thicker or more resin to make it thinner until you have achieved the desired texture.

To mix it, it is recommended to use a plastic spreader cut to a managable size (about 2 inches across).

After the mud is made, use double the recommended amount of liquid Hardener. This allows you to skip having to deal with using two different catalyst materials.


Step 4: Pour it, leave it, come back later

Make sure the section you want covered is in the most horizontal position it can be before this step.

After the mud is mixed with the catalyst, pour it into the tape walled section. Make sure everything is covered. Don't overfill it as it will just be more sanding work later.

Wait about an hour and a half for it to set then come back and remove the tape and little excess overspill bits while the mud is still a little flexible before it completely cures.

HPIM1216.jpg






Step 5: Sanding

Sand it down to your likeing before beginning the next step.


Step 6: Do it again

Rinse and Repeat until the whole thing is done.
 
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Sigma LS

Sr Member
Xavier said:
actually... SB has been using Mud for his helmets for a long time. He layers Mud and Fiberglass.
I know. Those dudes are smart, my 001 Sean Helm is made of mud, and so was my old Link helm. The difference is that they are using it as a casting material.


Robo- np, not that your models need much of this ;)

Edit: Uh, where did the other replies go?
 
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Xavier

Well-Known Member
Sigma-LS said:
I know. Those dudes are smart, my 001 Sean Helm is made of mud, and so was my old Link helm. The difference is that they are using it as a casting material.
Robo- np, not that your models need much of this ;)

Yea, sorry bout that, i missed that line while reading the tut, so i deleted my post :) good tut.

EDIT: How is this better/easier than just using bondo?
 
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Sigma LS

Sr Member
I know the last pic is a little washed out but you can see how smooth the surface is before sanding. 10 minutes of dremel work and that baby is smooth and ready to go.

Whereas with bondo, you have to worry about thickness, getting it into all the little crevices, air pockets, applying it twice or more to get the surface you want. It starts to set up on you before you can smooth the surface.

Eh, basically it saves a lot of time. That's how I got my CQB done so fast.
 

Leadingspartan

Well-Known Member
Leadingspartan said:
Hey Sigma will this turn out like the CQB Helmet. Oh and you removed me from your Xbox Live Friends List :mad: I sent you a friend request again. Plus like 200 messages. :D I would really like to still be your friend. Im Kevinx001 on XBL.

Is this as good as the elmers glue plus the dentist chemical thing?
 
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Sean Bradley

Sr Member
Xavier said:
EDIT: How is this better/easier than just using bondo?
The mixture is thinner, and can be easily painted or in this case poured over your forms. It's thicker than straight up resin, but not as thick as Bondo... the consistency is just right for many applications.


Personally I just love this stuff. I have found that you can even cut your resin a little... making the mixture 1/3 polyester resin, and 2/3 Bondo, being as resin is more expensive than bondo by about $10/gallon.


Not sure if you mentioned it but be sure to mix the individual materials with their hardeners seperately, then mix the two activated batches together..

EDIT: Just saw what you said about adding 2x the amount of catalyst.. I'll have to give that a try. thanks!
 
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Dark Rogue

Well-Known Member
I've always wondered about proportions and things with mud.

I might just have to try this if I run out of glaze. Nice job, Sigma.

And could you post a pic of the dremel you have so I can buy one like it? My power sander just broke, so I need something else to sand with.
 

jimmyfu

Jr Member
perhaps i'm just an idiot, or the mud just evens itself out in the end, but even if you've got the area where you want to pour mud on as horizontal as possible, wouldn't the mud just drip off the higher points of area and move to the lower points? after all, helmets aren't exactly straight...
 

Vader

Member
I'm assuming the ratio is based on volume, not weight?
And you only use the hardener for the resin, not the hardener for the bondo, correct?
I'll have to try this out in the near future.
 

Sigma LS

Sr Member
Dark Rogue said:
I've always wondered about proportions and things with mud.

I might just have to try this if I run out of glaze. Nice job, Sigma.

And could you post a pic of the dremel you have so I can buy one like it? My power sander just broke, so I need something else to sand with.
Np. My old Multipro broke about a month ago so I got a new 400 XPR with snake attachment as an early Christmas present.

HPIM1221.jpg




jimmyfu said:
perhaps i'm just an idiot, or the mud just evens itself out in the end, but even if you've got the area where you want to pour mud on as horizontal as possible, wouldn't the mud just drip off the higher points of area and move to the lower points? after all, helmets aren't exactly straight...
But enough sticks to the high points to cover them properly so that really winds up helping you out.

Skullcandy Girl said:
Oh thanks for the new Smoothing option :D
Glad you like it. Hope I get to see it used on some of Robo's models


Vader said:
I'm assuming the ratio is based on volume, not weight?
And you only use the hardener for the resin, not the hardener for the bondo, correct?
I'll have to try this out in the near future.
Yes, yes, and looking forward to it!
 
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:not worthy:
Finnally a really good Bondo/Mud Tutorial that has fantastic results...
MODS PLZ STICKY THIS!!! It would help a lot of folks,

And the Hayabusa is looking amazing! Keep it up!


You earned a Dancing Kitty




-Justin
 

Sigma LS

Sr Member
Sean Bradley said:
EDIT: Just saw what you said about adding 2x the amount of catalyst.. I'll have to give that a try. thanks!
np Sean, glad I had something to add that helped a little bit. Thanks for stick too guys!
 
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innerrayg

New Member
jimmyfu said:
perhaps i'm just an idiot, or the mud just evens itself out in the end, but even if you've got the area where you want to pour mud on as horizontal as possible, wouldn't the mud just drip off the higher points of area and move to the lower points? after all, helmets aren't exactly straight...
As a followup; I just want to confirm, you do indeed turn the helmet horizontal when doing this, correct? It's not oriented like in your picture while you pour, I should assume.

PS Can we have more pictures of this method on other, potentially more difficult parts as you keep working on your helmet? I'm thinking like the top spikes. It looks good so far.

Oh, and one more thing...how thick is the layer of Bondo you now have on your helmet? I'm just curious how much you needed and all that. I must thank you for explaining this method....if I can do this, along with the Hotglue support suggested by another member, my suit may become reality. It's been in the planning period for about a year (I originally had dreams of a Haloween suit), but I lacked professional support and every resource I found before here suggested things like Vacuforming and sculpting, all of which are out of my very pitiful income.

So in a word, Hurrah.
 
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Robogenisis

Well-Known Member
Sigma-LS said:
Robo- np, not that your models need much of this ;)

Edit: Uh, where did the other replies go?
Sorry. I started to write a reply, accidently posted it after the first two words, then I had to leave, so I just deleted it.

Nice tutorial though. I'd been wanting to use mud to smooth my pieces. I knew it involved a 1:1 mix, and tape was involved somewhere, but it's nice to have a complete tutorial from someone who's used it. :D
 
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