Paraloid Glue

[Dan 1000]

G'day everyone!

 

My dad and I have tried making some paraloid glue by mixing 25% paraloid with 75% acetone. The paraloid has been dissolving for a few hours and a thick solution with the consistency of wood glue has settled to the bottom. Do we use this thick solution at the bottom to glue and strengthen our fossils?

 

Thanks,

Dan

[TqB]

Let it dissolve altogether - shaking or stirring every now and then, and a warm place, will help.

25 - 30% is good for a glue, 10% or less as an impregnating strengthener. 

[Ptychodus04]

I agree. Let it dissolve completely. For a glue, I like a consistency of cold honey. It doesn't run all over everything as badly. Keep in mind, you need to clamp the pieces together when gluing with Paraloid as it will take several days for all the acetone to evaporate.

[caldigger]

1 hour ago, TqB said:

Let it dissolve altogether - shaking or stirring every now and then, and a warm place, will help.

25 - 30% is good for a glue, 10% or less as an impregnating strengthener. 

So by your statement, you are saying 25-30% Paraloid to 70-75% acetone for glue and 10% Paraloid with 90% acetone for the consolidant. Is this correct?

[TqB]

2 hours ago, caldigger said:

So by your statement, you are saying 25-30% Paraloid to 70-75% acetone for glue and 10% Paraloid with 90% acetone for the consolidant. Is this correct?

That would be right for a weight to weight solution but I make it weight to volume - so 25% would be 25g of paraloid to 100cc acetone.

I know acetone has a different density to water so the numbers aren't really right but it isn't that critical, if it's too thick or thin for your purposes just add a bit more solvent or solid.

[TqB]

2 hours ago, Ptychodus04 said:

Keep in mind, you need to clamp the pieces together when gluing with Paraloid as it will take several days for all the acetone to evaporate.

I don't often use clamps - depends on the pieces but I usually press them well together and then stand it in a sand tray. I did a 4ft ichthyosaur once that was in about 12 bits - glued one piece at a time and propped up vertically overnight before adding the next bit. (I eventually mounted it with a fibreglass backing so I wasn't relying on the paraloid though it seemed pretty stable.)

[Ptychodus04]

1 hour ago, TqB said:

I don't often use clamps - depends on the pieces but I usually press them well together and then stand it in a sand tray. I did a 4ft ichthyosaur once that was in about 12 bits - glued one piece at a time and propped up vertically overnight before adding the next bit. (I eventually mounted it with a fibreglass backing so I wasn't relying on the paraloid though it seemed pretty stable.)

I've done this as well. I prefer to add some additional pressure when possible as a clamped joint adheres more strongly than an un-clamped one. When the pieces don't facilitate clamps, I have employed ratcheting tie down straps to good effect. They can accommodate more oddly shaped specimens than clamps can.

[Dan 1000]

@Ptychodus04 @TqB Thanks for the advice!

 

My first batch turned out quite nicely and had the consistency of honey. I tried gluing a fossil that had split in half  and it stuck together quite nicely. I only put a very thin layer of glue across both sides but still had some glue seep through the cracks which hardened quickly into little bubbles and was hard to remove. Any advice on what I should do next time?

[Ptychodus04]

5 hours ago, DanKurek said:

@Ptychodus04 @TqB Thanks for the advice!

 

My first batch turned out quite nicely and had the consistency of honey. I tried gluing a fossil that had split in half  and it stuck together quite nicely. I only put a very thin layer of glue across both sides but still had some glue seep through the cracks which hardened quickly into little bubbles and was hard to remove. Any advice on what I should do next time?

 

Make your solution a wee bit thicker. The excess can be removed with a local application of acetone. Rub a little on and let it soften the paraloid. Then, you can cut it away with an xacto knife.