A rookie mistake with hollow armour pieces. How to fortify/strengthen it?


VoidRunner

New Member
Hi All, again I turn to you for advice on a little mishap, and maybe the answers will help others.

I've been making good progress on constructing the Mark VI armour by taking pepakura patterns and transfering to 5mm foam. There have been some rough learning moments for cutting and sticking it all together but the base is looking good.

My problem now is I just started working on the shoulder sections and they're in essence just odd shaped boxes, completely enclosed boxes. While I didn't think that was a problem, 5mm is the thickest foam I have and I found that it feels very flimsy and bends inwards when heat sealing the foam.

The pieces aren't entirely closed up at the moment as I'm looking for ways to strengthen the boxes before I fully close them, especially as the shoulders are probably high stress areas, I don't want the piece to collapse, tear, or more likely, I'm expecting the contact adhesive to give way.

What is a good way to fortify these pieces?
My thoughts so far are:
• Expanding foam,
• Stick more foam inside to try and hold the shape

In hindsight I could have used thicker foam, though maybe the problem would remain.
I appreicate any advice and suggestions, or even how you made these pieces and securely attached them.

MarkVIShoulder.jpg
 

RandomRanger

Armory Assistant
Community Staff
Member DIN
S063
I've not heard of Shoe Goo before. What is it? why is it good? how is it used?
Dang, I need to make that shoe goo video.

Basically, it's a super strong shoe repair adhesive. Cobbler craft tools are surprisingly relevant if foam smithing, even barge was originally for shoes.
Basically you cover the back of your seams in shoe goo on the inside of the armor and it becomes nearly indestructible. The downside is coating the inside of a full suit of mjolnir can start getting expensive.

I did that with my Spartan and I've never had to repair it.
 

VoidRunner

New Member
Dang, I need to make that shoe goo video.

Basically, it's a super strong shoe repair adhesive. Cobbler craft tools are surprisingly relevant if foam smithing, even barge was originally for shoes.
Basically you cover the back of your seams in shoe goo on the inside of the armor and it becomes nearly indestructible. The downside is coating the inside of a full suit of mjolnir can start getting expensive.

I did that with my Spartan and I've never had to repair it.
How does it compare to the commonly used contact adhesive (Barge, Evo-Stik, etc)?
Saying it's great for coating seams, I'm guessing it's not suitable, and probably far more expensive, for general construction.
Plus I'll need to find a uk version
 
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VoidRunner

New Member
I thought these pics might help. I've added in yellow lines where I'm considering putting the bracing beams, with obviously much thicker foam sandwiches, plus maybe a cross support from side to side, top to bottom, or that might be overkill and just hitting expanding foam territory.

I was thinking I could contact adhesive the beams in, but the space is too small to coat the areas properly. I hadn't left myself much space to work by the time I realised my error.
Thinking about getting the beams in and orientated properly. Superglue is dangerous in small and likely messy spaces. Hot glue is possible but a limited working time, and hot. Maybe general purpose glue, or shoe glue, but again I need to find a uk equivalent.

It is quite the predicament for any adhesive that requires precision and/or clamping/pressure to efficiently work.

DSC_0801.JPG
DSC_0802.JPG
 

RandomRanger

Armory Assistant
Community Staff
Member DIN
S063
How does it compare to the commonly used contact adhesive (Barge, Evo-Stik, etc)?
Saying it's great for coating seams, I'm guessing it's not suitable, and probably far more expensive, for general construction.
Plus I'll need to find a uk version
It's used in conjunction with your regular adhesive. I still use barge to assemble the part
 

VoidRunner

New Member
I don't think this has been said already, forgive me if it has, but in addition to one of these other strategies I would reinforce the back of all your joints with hot glue. It will take stress off of your contact cement bonds.
That is a reliable one, though with the box constructed it's pretty impossible to get a glue gun inside the one opening to the box anymore without shredding it. In hindsight possibly.

I'm actually going to test the expanding foam and share the results. I've constructed two new boxes out of 5mm foam. Nothing complicated, just thin boxes, one I've only used contact adhesive, the other I used contact adhesive and tried to line some hot glue along the seam before joining the edges. Same methods to slap lids on one end each, leaving one open for the foam to expand out of if I used too much.

Once I pick up some expanding foam the test begins.
 

VoidRunner

New Member
Before I even read your two suggestions, I was thinking expanding foam and internal foam too. I'd go for the internal foam - by that, I mean cutting out and sticking in "beams" of foam that'll brace the part.
I've prepared some beams to stick inside and just pressing them into place by hand it seems to have the right effect.
What kind of adhesive would you use for this?
Bearing in mind the limited space to maneuver through the opening.
 

PlanetAlexander

Active Member
I've prepared some beams to stick inside and just pressing them into place by hand it seems to have the right effect.
What kind of adhesive would you use for this?
Bearing in mind the limited space to maneuver through the opening.
I did something similar for my CE Marine backpack, and honestly I just used hot glue! I just held the part in place and hot glued it in. This is because I didn't have an "exact" spot for the bracing, plus the glue helps reinforce it. If you have limited space and can't get a glue gun in, I'd suggest super glue, that way you can tack the piece down where ever you need it.

Edit: Sorry, didn't see the posts above the one you quoted me in, looks like both my adhesion suggestions aren't applicable
 
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ZiggyGrimm

RMO
405th Regiment Officer
My answer to this is the same answer to everything: more fiberglass and bondo. There is never enough fiberglass and bondo. Put it on the inside put it on the outside, put it EVERYWHERE! When you think you have enough, add more!
 

VoidRunner

New Member
Ok, so progress report.... This was interesting.

I started a test with some simple box shapes. Both used contact adhesive, one had extra hot glue.
I wasn't worried about little nicks and tears as it would show if splits could occur easily.
I filled the bottom of each with some store bought expanding foam, maybe 1"/2cm deep and left overnight to expand and set.

Also, due to the unfortunatly quick expiry of cans of expanding foam if you don't use it all in a few days, I panicked and filled the shoulder boxes too. At this time I had already added some 10mm (5mm foam sandwich) beams inside the shoulder boxes and immediately it felt stronger (I gingerly used hot glue...), though it still warped a bit where it wasn't supported.

So 24hrs later and the foam had set. It's easy to see that it had filled out of the hole like I was hoping for, also it is lightweight and feels really quite solid in the shoulder boxes.
But there are issues:
  1. The foam didn't expand equally in all directions, so squeezing the boxes it's easy to feel the gaps.
  2. For some reason some sections didn't harden as much,
  3. The can is a pain to use
The worst point is that obviously the foam has adhesive properties, and after expanding, the foam shrank slightly. I don't know how clearly it is shown in the images, but as the foam shrank it pulled the boxes inwards.

Should I have decided to continue using the shoulder box it would either need a lot of building out to fill the divets, or shaving it down. In hindsight putting a layer of cling film/saran wrap inside would have helped.

Testing.jpg


I'm not put off of expanding foam, I think it is a good way to give strength to hollow, to be sealed, parts.
However, in the future I definitely think using a liquid 2 part expanding foam would be much better. It would be more cost effective, as it could be stored for longer periods, and it can be poured into parts rather than relying on a straw of silly string.

So the next step I think is to restart the shoulder boxes.
Does anyone have advice on how they tackled this?

I'll probably do the same again, only this time I'll make all pieces 10mm foam sandwiches so it's immediately stronger.
 

ZiggyGrimm

RMO
405th Regiment Officer
one of the best pieces I've made was my purple helmet with like 5 layers of fiberglass cloth where I drenched the cloth in fiberglass before inlaying it. I couldn't agree with this more!

Edit: this was in response to ZiggyGrimm
My best build so far is my Bat Suit. I got in a literal fist fight at the last FanExpo I was at because some dill-weed sucker punched me (still have no idea why). But the suit took an absolute sh*t kicking before I wised up and fought back. It only has one small crack in it. Other than that, it is still minty fresh. Fiberglass and resin are some tough stuff. My goal is to put the bat suit to shame with my upcoming Chief/ Spartan.
 

Angus314

RCO
405th Regiment Officer
Member DIN
S314
My best build so far is my Bat Suit. I got in a literal fist fight at the last FanExpo I was at because some dill-weed sucker punched me (still have no idea why). But the suit took an absolute sh*t kicking before I wised up and fought back. It only has one small crack in it. Other than that, it is still minty fresh. Fiberglass and resin are some tough stuff. My goal is to put the bat suit to shame with my upcoming Chief/ Spartan.
Wow!! I hope you'll never be in a situation like that again!
 
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