Help with filler for cutaways???

[goran_croatia]

I am planning to make a few cutaways of some ex-yugoslavian hand grenades,but I need advice what kind of filler use to represent explosive in cutaways??
Miliput epoxy putty would be ideal but for one cutaway,I need at least 100 grams of that Miliput epoxy two-component putty,and here in Croatia Miliput is very expencive.
What kind of filler do you reccomend which can be easily formed and after drying easily painted in yellow-white colour to represent TNT?

 

[paul the grenade]

what about plaster of paris? its very cheap.
paul.

 

[goran_croatia]

Yes,but plaster of paris is very fragile when it dries

 

[Tmine35]

I have used polyurethane foam ( house building isolation material sold cheap in spray cans ). It'x excellend to fill fragile dug-ups, such as Panzerfaust heads and similar. It binds the weak metal together, is easy to cut and gives a good support base for epoxy filler to make surface on metal and on the cut-away side.
If you have as example a Panzerfaust head with rust removed chemically and lot of small holes existing, first close most of the holes with mask tape and spray the foam inside. Some holes are needed that the extra foam may escape not exploding the head, but it must pe partly closed as some pressure is needed to fill the inside properly.
When the foam has hardened remove tapes, cut extra foam away from outside, and clean outer surface by gentle sandblasting or wire brush. Then apply epoxy filler.
After that you may cut the item if you are doing so.

 

[Fragman]

Hi. Great Topic. I like to experiment with different mediums with my cutaways. The expanding foam is a good idea, as is the rough sand paper suggested in another thread. I look forward to trying them out. Attached is a photo of some of my cutaways using:
Plaster of Paris - Great for when you want to shape the filling to fit the grenade after it hardens,
Nothing - Good for when the inner wall of the grenade is interesting,
Wax - Shrinks as it dries, so it can be easily removed (perfect for filling straight edged cavities),
Clear resin - Will show off those cool frag coils, whilst keeping them together.
I look forward to other people suggestions.
Cheers
Colin

 

[pzgr40]

I use cartboard templates (3.5mm thick) on which I glue sand paper as filler. Plaster of paris has one big disadvantage; it contains water. Water and cutaway models do not go well together. together they form rust:tinysmile_cry_t4: .
I make the templates by placing carbon paper, -carbon side up- over the cut surface, a piece of A4 white paper placed over it, against the centerline of the cutaway. By following the cut surface edge with my nails over the paper I get the negative on a A4. This is glued to the carbon and cut out. Glue sandpaper to the visable side and paint it in the correct colour.

With small cutaway models I glue a 5 mm wide strip in the side of the cutaway model on the depth formed by the thickness of the cartboard and the sandpaper glued together, with big ones I use cartboard discs to support the cartboard templates, often combined with strips in the side.

For small projectile charges I use polyester resign, the same stuff used to repair small dents in cars. with small I mean up to 30 mm M geschoss and 7,5cm KwK Pzgr.
Regards, DJH

 

[pzgr40]

@ kiwicollin, Great stuff!! Nice to see perfect cutaway models from the other side of the earth:tinysmile_fatgrin_t

Ps, about not filling when fragmentation sleeves are visable; I fully agree.

 

[Grenadier]

+++

Hello,
Here an unusual filler - wooden block. But I would prefere plaster of paris, with correspondent protection of metal surface before. Over it one can place sandpaper or other (plastic) sheet to reinforce the surface; it's cheap, effective and rapid.

 

[blu97]

Plaster of paris contains water and is very corosive. I use two compenents polyester car filler, it drys quick and is easy to worh with.

 

[Grenadier]

+++

Hi again,
Here a picture of a cutaway made about 70 years ago; filler plaster of paris. The surface is a bit damaged, but corrosion on the metal is not present after so much time.

 

[Tmine35]

Here pictures of some well corroded and weak items filled with polyurethane foam before further handling.

 

[goran_croatia]

Thank you so much for all advices,I will start my first cutaway project in a mont so I'll put pics in this section when it would be finished:tinysmile_fatgrin_t!!!!

 

[staples57]

A couple of questions about the use of polyurethane foam...

With fragile items, doesn't the expanding nature of polyurethane foam introduce the potential to permanently damage or distort the item being filled?

How do you prevent damaging the item when you remove the excess foam? Specifically, original paint, markings, etc.

Thanks,
Brad

I have used polyurethane foam ( house building isolation material sold cheap in spray cans ). It'x excellend to fill fragile dug-ups, such as Panzerfaust heads and similar. It binds the weak metal together, is easy to cut and gives a good support base for epoxy filler to make surface on metal and on the cut-away side.
If you have as example a Panzerfaust head with rust removed chemically and lot of small holes existing, first close most of the holes with mask tape and spray the foam inside. Some holes are needed that the extra foam may escape not exploding the head, but it must pe partly closed as some pressure is needed to fill the inside properly.
When the foam has hardened remove tapes, cut extra foam away from outside, and clean outer surface by gentle sandblasting or wire brush. Then apply epoxy filler.
After that you may cut the item if you are doing so.

 

[Grenademan2005]

I just buy the item already as a cut away, it is easier.... :tinysmile_fatgrin_t

 

[kz11gr]

what about plaster of paris? its very cheap.
paul.

Hi

material of bad quality that could bring rust and alterate the metal.
Better : polyester or derivared .

--

 

[Tmine35]

A couple of questions about the use of polyurethane foam...

With fragile items, doesn't the expanding nature of polyurethane foam introduce the potential to permanently damage or distort the item being filled?

How do you prevent damaging the item when you remove the excess foam? Specifically, original paint, markings, etc.

Thanks,
Brad

I use polyurethane only on items which do no have original paint, the foam sticks hard on surface and has to be removed mechanically - this will destroy paint and stenciled markings definitely.
You may use it also on items having original paint but then you must carefully cover all outer surface with mask tape, plastic foil or similar. Also be sure first that the tape does not peel the paint off when removing it.

If the item is of very thin and fragile metal it must be covered totally with mask tape on outside, to close all holes and to support the metal.
The expanding foam escapes easily from holes, therefore most of the holes must be closed, but not all to keep the pressure low.

The foam glues the metal from inside to a solid piece which allows quite heavy duty work on outer surface - even sandblasting and wire brushing of paper thin thru rusted metal.