HELP! Interesting reverse rondo idea, love some help & input.

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New Member
Hey guys, I found thisolder thread about two years ago that would work great for the Mass Effect N7helmet build I've been dreaming of, but in my trying to do the same last year Ifailed miserably. I've got plenty of experience in working with all of therequired materials and techniques involved for the most part, but I'm new toprop making and some of the innovations you guys create with these materialsare new to me.

Basically I'm asking for some input on this interesting technique, as I think it's not only the easier way to do it, but also the much much smarter way. So if you're interested keep reading.

To sum it up. I know all the pictures are dead at this point, but basically what Hass Dardo did was pep the model with the tabs facing out, wax the pep model on the inside, and rondo inside it. Then after fully curing he dunked the whole thing in water and scruffed the waxed paper off the now perfect rondo cast of the pep.
The reason I love this is because it seems like the easiest way to do this sort of work, yet also the smartest. To me layering resin on the pep to strengthen the paper, then to fiberglass the inside to give it the full strength to withstand the work, then bondoing the whole thing to sand and rinse and repeat until the outside looks right, and having to do all of this with a paper model sandwiched between it all that if sanded down through just makes even more work, and the layers upon layers of work you did can throw off the proportions as you’re building on top of as opposed to just working on it. It just doesn’t make sense to me that this is the standard when it comes to the pep castable process. Instead this reverse rondo technique gives you the perfect 1:1 rondo base to work with seems much less work, yet yields a better base to work upon. Sure you’ll have to put in some work to clean it up, but it’s on a rock solid base, and detail isn’t so easily lost when not having to layer and layer all that stuff.

So anyone with any input on this type of process, and or any links to similar builds and or better techniques would be greatly be appreciated. I really think this is the best way that I know of, and I’ll have do a small test and really get the technique down first before throwing away all that paper, rondo, and time again.

Now, as for some pointers that I could use, I’ll explain the issues I had when trying to do this technique previously. Firstly the wax I bought wasn’t a spray wax, and I had already finished the pep so I couldn’t really apply as much as I’d have liked to. I had never played with rondo before. I’ve used Bondo and fiberglass/resin for other applications, but never together, and I apparently messed up by mixing it in solo cups, as that’s how I had seen someone do well with it before, but quickly learned and now know it should be done on a pie tin or flatter surface as the heat from it is compounding when resting upon itself in a half full cup. So the whole thing became a thick mess creating fumes much stronger than anticipated even with a decent ventilation system. So more advice on working with rondo, and anyone with any ideas on this technique would help me greatly.

Thanks in advance to anyone willing to help out.
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Well-Known Member
Not seen that method before, however, it seems to me that without fibreglass matting on the inside, the helmet would be very brittle (with no internal structure). The Rondo technique seems to be very popular over on the 405th.


Sr Member
Yep. I'd like to add my two cents. I've been inspired by Hass Dardo also, and have found that Rondo can be slush-casted into a pep helmet with no trouble.

Main points I have found through trial and error:

1. Assemble your pep with very narrow tabs. I use 3mm (1/8 inch), which means less filling and sanding later on.

2. Use PVA of builder's quality to get a strong bond, but apply it with a toothpick so you don't get too much glue softening the model.

3. Having the tabs on the outside is fine, but for most models it doesn't matter too much.

4. Use car wax or mould release wax, rubbed in with a soft cloth. Use more than you think you will need. Then use some more.

5. Mix 50/50 some polyester resin and Bondo (or whatever body filler) - as long as it is Polyester-resin-based, it will be fine. Pour the mixed resin in to the mould then keep rotating it so the the entire interior of the mould is coated. You might need a couple of cups to get a decent build.Let is cure so that it is stiff, but make sure it is all done in the one day.

6. Lay on some mat or cloth with polyester resin. This is simply to add strength to the rondo. It is important to only apply resin to 'green' or semi-cured rondo so that it bonds well. Otherwise it may de-laminate.

7. Peel off the pepakura card, exposing the rondo. Sand off the various facets, and apply bondo as needed. The conventional method of pepakura is fine, but this way you don't have to sand off the card. Rondo is much easier to deal with, but resin-soaked card is furry and troublesome.

Hope this is of some use. I'd like to add more, but the beer is cutting in...



Active Member
I cannot stress the use of fibreglass in a layer enough, adds strength which you will really need. Also, do some test mixes first as this can be very brittle depending on your filler product. I have also had parts bow and warp in the hot aussie summer here when left in storage too. A few extra's to consider, but it can be a nice quick way to making armour.


New Member
I'd like to thank blue2k and Killtime, and especially thank you Blaxmyth, as I was wondering about that myself. If anyone feels up to talk more about this process or share anything keeping this going by all means do so.

I was going to glass the insides anyways, and mount it to an armature so it could be more easily worked on.

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