WA stabilization question

[Pnwmedic]

Mostly sandstone from clallam formation WA. The fossils are flaky and the sand stone has many cracks threatening to break into pieces. I know it’s not the prettiest, but I was hoping to stabilize the matrix a bit as well as some of the more preserved shells to expose and highlight them a bit

[Ptychodus04]

You want to use Paraloid B72 or Butvar B76 dissolved in acetone or ethanol. For this application, I would probably go with a 5% solution instead of my typical 2.5% solution for stabilization. 5% works out to 2 parts plastic dissolved in 50 parts solvent. Acetone will evaporate and dissolve the plastic) faster than ethanol. 

[DPS Ammonite]

1 hour ago, Ptychodus04 said:

5% works out to 2 parts plastic dissolved in 50 parts solvent.

By volume or weight?

[Pnwmedic]

Application to entire piece or as I go? I’m afraid the whole thing will crumble if I apply any pressure

[Ptychodus04]

On 4/18/2023 at 9:18 AM, DPS Ammonite said:

By volume or weight?

Either way works. I typically use weight.

 

On 4/18/2023 at 3:03 PM, Pnwmedic said:

Application to entire piece or as I go? I’m afraid the whole thing will crumble if I apply any pressure

I would apply both methods. Consolidate as much as you need right away and add more as needed

[Pnwmedic]

40 minutes ago, Ptychodus04 said:

Either way works. I typically use weight.

 

I would apply both methods. Consolidate as much as you need right away and add more as needed

Great, thanks! I just read a paper on methods and usage for different concentrations, appreciate it

katherine

[caterpillar]

On 4/18/2023 at 2:20 PM, Ptychodus04 said:

5% works out to 2 parts plastic dissolved in 50 parts solvent

 

It's more like 4%, isn't it?

[Tales From the Shale]

I use volume to volune ratio. If you have a balance/scale you could weigh out the proper ratio. For something flaky and concerning matrix, I'd go 8% to ensure proper consolidation.

[Tales From the Shale]

You're gonna want to use a small quantity of paraloid pellets if that is the route you choose to go. For Butvar it may be a little different. I use canning jars as they seal relatively well, but after awhile you will notice evaporation of the solvent. 

[Ptychodus04]

21 hours ago, caterpillar said:

 

It's more like 4%, isn't it?

Yah. Good thing I’m not a mathematician