Casting a Knight's Sword in Resin

[ramram]

Hi, I am attempting to cast resin copies of a sword which I have made and I am experiencing issues with some of the swords bending after they are taken from the mold.

I am using a polyurethane fast cast resin with metre long metal rods inside the cast for added strength - but the swords are bending about a day after they come out of the mold.

I think it might be because the resin is shrinking and if the metal rods aren't inside straight enough then the sword begins to bow slightly :confused

Anyone got any tips on how to avoid this, or what else I could use to strengthen the swords instead?.. or could it be something else altogether...

Thanks for any help
Jim

 

[Contec]

why don't you leave them in the mold for more than one day. Maybe then they will be straight.

 

[Sidewinder]

You should be able to warm the resin and bend back straight.

SAS

 

[danbakeronline]

The answer to this is actually in the resin itself. Resin is exothermic, meaning the chemical reaction generates heat that the resin uses to cure itself. You said you're using fast-cure resin, which is accomplished by tweaking the catalyst to increase that heat in the reaction. You could either leave the cast in the mold until the curing process is completely finished (sometimes up to 7-10 days) or you could use a slower-curing resin. The cooler exothermic reaction will not have as much of a warping effect on the plastic.

Be sure to read the technical bulletins that come with your resins. They contain a lot of useful information about pot life, de-mold time, and cure cycles.

 

[Contec]

Would love to see pictures of your sword.