Probably a multi-piece mold. There would be other silicone inserts that get pushed into the liquid polyurethane to take up all the negative "hollow" space inside the hold. This is easier said than done, you would have to calculate or estimate the volume of polyurethane required so that it doesn't all overflow once the inserts are added. The only other way would be with injection molding
Can I ask you whether you mix only these 2 polyurethane components or do you need to add sand (and what kind of sand) into the mixture? Are you using organic or inorganic colours? Thank you :).
Generally speaking, sand doesn't need to be added to polyurethane. Poly is very strong and sand would probably only weaken the structure of the plastic. To get the desired texture, the silicone molds are made from foam originals. The texture of the foam is translated onto the silicone, and then into the polyurethane hold. So if you are using a good polyurethane, and the mold comes from a foam original, no sand is needed.
Scott Robinson Thanks! Also, I am going to buy powder colours and wanted to ask, if you have any info how much of powder to add to a certain amount of polyurethane?
@@tinabercic5050 No problem! I have no idea about powdered pigments. I have only used liquid ones before, and they usually tell you right on the label how much to add based on the volume of poly you are casting.
Scott Robinson Thank you! The problem is that in Slovenia I haven’t found any liquid colours specifically for climbing holds. Where are you buying colors / which brand? I guess they have to be made specifically for holds?
@@tinabercic5050 As long as the color is designed to work with the polyurethane, it will be fine for climbing holds. the company that sells the urethane should also sell compatible colors.
At Escape www.escapeclimbing.com we use a Trymers 4000 foam which we sell on our website. Its primarily used for insulation and taxidermy work. We buy it in refrigerator sized blocks. Some of our other brands like www.kingdomclimbing.com use the softer 4lb floral foam from Oasis Floral Products. We also buy this in refrigerator size blocks.
Oh man...it's amazing to see how the whole climbing industry grew and evolved during the past few years.
I love how rock climbing holds look
I've always wondered how do you make a hollow back.
Probably a multi-piece mold. There would be other silicone inserts that get pushed into the liquid polyurethane to take up all the negative "hollow" space inside the hold. This is easier said than done, you would have to calculate or estimate the volume of polyurethane required so that it doesn't all overflow once the inserts are added. The only other way would be with injection molding
Think of a waffle iron
How to make two texture climbing holds?
You can purchase the foam and supplies here: climbingholdsupply.com/
Can I ask you whether you mix only these 2 polyurethane components or do you need to add sand (and what kind of sand) into the mixture? Are you using organic or inorganic colours? Thank you :).
Generally speaking, sand doesn't need to be added to polyurethane. Poly is very strong and sand would probably only weaken the structure of the plastic. To get the desired texture, the silicone molds are made from foam originals. The texture of the foam is translated onto the silicone, and then into the polyurethane hold. So if you are using a good polyurethane, and the mold comes from a foam original, no sand is needed.
Scott Robinson Thanks! Also, I am going to buy powder colours and wanted to ask, if you have any info how much of powder to add to a certain amount of polyurethane?
@@tinabercic5050 No problem! I have no idea about powdered pigments. I have only used liquid ones before, and they usually tell you right on the label how much to add based on the volume of poly you are casting.
Scott Robinson Thank you! The problem is that in Slovenia I haven’t found any liquid colours specifically for climbing holds. Where are you buying colors / which brand? I guess they have to be made specifically for holds?
@@tinabercic5050 As long as the color is designed to work with the polyurethane, it will be fine for climbing holds. the company that sells the urethane should also sell compatible colors.
what type of foam do you guys use
Hay did you ever find out what foam they uaed
Did anybody find out ?
@@adrianboehm floral foam
At Escape www.escapeclimbing.com we use a Trymers 4000 foam which we sell on our website. Its primarily used for insulation and taxidermy work. We buy it in refrigerator sized blocks. Some of our other brands like www.kingdomclimbing.com use the softer 4lb floral foam from Oasis Floral Products. We also buy this in refrigerator size blocks.